Subjects -> CHEMISTRY (Total: 928 journals)
    - ANALYTICAL CHEMISTRY (59 journals)
    - CHEMISTRY (661 journals)
    - CRYSTALLOGRAPHY (23 journals)
    - ELECTROCHEMISTRY (28 journals)
    - INORGANIC CHEMISTRY (45 journals)
    - ORGANIC CHEMISTRY (47 journals)
    - PHYSICAL CHEMISTRY (65 journals)

CHEMISTRY (661 journals)                  1 2 3 4 | Last

Showing 1 - 200 of 735 Journals sorted alphabetically
Accounts of Materials Research     Hybrid Journal  
Accreditation and Quality Assurance: Journal for Quality, Comparability and Reliability in Chemical Measurement     Hybrid Journal   (Followers: 30)
ACS Applied Polymer Materials     Hybrid Journal   (Followers: 8)
ACS Catalysis     Hybrid Journal   (Followers: 52)
ACS Chemical Neuroscience     Hybrid Journal   (Followers: 23)
ACS Combinatorial Science     Hybrid Journal   (Followers: 21)
ACS Environmental Au     Open Access   (Followers: 8)
ACS Macro Letters     Hybrid Journal   (Followers: 25)
ACS Materials Letters     Open Access   (Followers: 2)
ACS Medicinal Chemistry Letters     Hybrid Journal   (Followers: 42)
ACS Nano     Hybrid Journal   (Followers: 181)
ACS Photonics     Hybrid Journal   (Followers: 14)
ACS Symposium Series     Full-text available via subscription   (Followers: 3)
ACS Synthetic Biology     Hybrid Journal   (Followers: 30)
Acta Chemica Malaysia     Open Access  
Acta Chimica Slovaca     Open Access   (Followers: 2)
Acta Chimica Slovenica     Open Access   (Followers: 2)
Acta Chromatographica     Full-text available via subscription   (Followers: 7)
Acta Metallurgica Sinica (English Letters)     Hybrid Journal   (Followers: 8)
Acta Scientifica Naturalis     Open Access   (Followers: 2)
adhäsion KLEBEN & DICHTEN     Hybrid Journal   (Followers: 7)
Adhesion Adhesives & Sealants     Hybrid Journal   (Followers: 9)
Adsorption Science & Technology     Open Access   (Followers: 7)
Advanced Electronic Materials     Hybrid Journal   (Followers: 7)
Advanced Functional Materials     Hybrid Journal   (Followers: 71)
Advanced Journal of Chemistry, Section A     Open Access   (Followers: 3)
Advanced Journal of Chemistry, Section B     Open Access   (Followers: 1)
Advanced Science Focus     Free   (Followers: 6)
Advanced Theory and Simulations     Hybrid Journal   (Followers: 2)
Advanced Therapeutics     Hybrid Journal   (Followers: 1)
Advances in Chemical Engineering and Science     Open Access   (Followers: 109)
Advances in Chemical Science     Open Access   (Followers: 51)
Advances in Chemistry     Open Access   (Followers: 34)
Advances in Colloid and Interface Science     Full-text available via subscription   (Followers: 16)
Advances in Environmental Chemistry     Open Access   (Followers: 10)
Advances in Enzyme Research     Open Access   (Followers: 10)
Advances in Heterocyclic Chemistry     Full-text available via subscription   (Followers: 8)
Advances in Materials Physics and Chemistry     Open Access   (Followers: 33)
Advances in Nanoparticles     Open Access   (Followers: 17)
Advances in Organometallic Chemistry     Full-text available via subscription   (Followers: 18)
Advances in Polymer Science     Hybrid Journal   (Followers: 51)
Advances in Protein Chemistry and Structural Biology     Full-text available via subscription   (Followers: 18)
Advances in Quantum Chemistry     Full-text available via subscription   (Followers: 6)
Advances in Sample Preparation     Open Access   (Followers: 5)
Advances in Science and Technology     Full-text available via subscription   (Followers: 16)
Aerosol Science and Engineering     Hybrid Journal  
African Journal of Chemical Education     Open Access   (Followers: 5)
African Journal of Pure and Applied Chemistry     Open Access   (Followers: 6)
Aggregate     Open Access  
Agrokémia és Talajtan     Full-text available via subscription   (Followers: 2)
Al-Kimia : Jurnal Penelitian Sains Kimia     Open Access  
Alchemy : Journal of Chemistry     Open Access   (Followers: 4)
Alchemy : Jurnal Penelitian Kimia     Open Access  
Alotrop     Open Access  
AMB Express     Open Access   (Followers: 1)
Ambix     Hybrid Journal   (Followers: 3)
American Journal of Biochemistry and Biotechnology     Open Access   (Followers: 43)
American Journal of Biochemistry and Molecular Biology     Open Access   (Followers: 19)
American Journal of Chemistry     Open Access   (Followers: 37)
American Journal of Plant Physiology     Open Access   (Followers: 8)
Analyst     Hybrid Journal   (Followers: 35)
Analytical Science Advances     Open Access   (Followers: 1)
Angewandte Chemie     Hybrid Journal   (Followers: 150)
Angewandte Chemie International Edition     Hybrid Journal   (Followers: 227)
Annales Universitatis Mariae Curie-Sklodowska, sectio AA – Chemia     Open Access   (Followers: 1)
Annals of Clinical Chemistry and Laboratory Medicine     Open Access   (Followers: 6)
Annual Reports in Computational Chemistry     Full-text available via subscription   (Followers: 4)
Annual Reports Section A (Inorganic Chemistry)     Full-text available via subscription   (Followers: 5)
Annual Review of Chemical and Biomolecular Engineering     Full-text available via subscription   (Followers: 12)
Annual Review of Food Science and Technology     Full-text available via subscription   (Followers: 13)
Antiviral Chemistry and Chemotherapy     Open Access   (Followers: 1)
Applied Organometallic Chemistry     Hybrid Journal   (Followers: 7)
Applied Spectroscopy     Full-text available via subscription   (Followers: 24)
Applied Surface Science     Hybrid Journal   (Followers: 31)
Arabian Journal of Chemistry     Open Access   (Followers: 4)
ARKIVOC     Open Access   (Followers: 1)
Asian Journal of Applied Chemistry Research     Open Access   (Followers: 1)
Asian Journal of Biochemistry     Open Access   (Followers: 2)
Asian Journal of Chemical Sciences     Open Access  
Asian Journal of Chemistry and Pharmaceutical Sciences     Open Access  
Asian Journal of Physical and Chemical Sciences     Open Access   (Followers: 2)
Australian Journal of Chemistry     Hybrid Journal   (Followers: 7)
Autophagy     Hybrid Journal   (Followers: 7)
Biochemical Pharmacology     Hybrid Journal   (Followers: 11)
Biochemistry     Hybrid Journal   (Followers: 200)
Biochemistry Insights     Open Access   (Followers: 6)
Biochemistry Research International     Open Access   (Followers: 5)
BioChip Journal     Hybrid Journal  
Bioinorganic Chemistry and Applications     Open Access   (Followers: 5)
Biointerface Research in Applied Chemistry     Open Access  
Biointerphases     Open Access   (Followers: 1)
Biology, Medicine, & Natural Product Chemistry     Open Access   (Followers: 2)
Biomacromolecules     Hybrid Journal   (Followers: 23)
Biomass Conversion and Biorefinery     Partially Free   (Followers: 10)
Biomedical Chromatography     Hybrid Journal   (Followers: 6)
Biomolecular NMR Assignments     Hybrid Journal   (Followers: 3)
BioNanoScience     Partially Free   (Followers: 3)
Bioorganic & Medicinal Chemistry     Hybrid Journal   (Followers: 90)
Bioorganic & Medicinal Chemistry Letters     Hybrid Journal   (Followers: 66)
Bioorganic Chemistry     Hybrid Journal   (Followers: 9)
Biopolymers     Hybrid Journal   (Followers: 15)
Biosensors     Open Access   (Followers: 3)
Biotechnic and Histochemistry     Hybrid Journal   (Followers: 3)
Bitácora Digital     Open Access  
Boletin de la Sociedad Chilena de Quimica     Open Access  
Bulletin of Institute of Chemistry and Chemical Technology, Mongolian Academy of Sciences     Open Access  
Bulletin of the Chemical Society of Ethiopia     Open Access   (Followers: 1)
Bulletin of the Chemical Society of Japan     Full-text available via subscription   (Followers: 24)
Bulletin of the Korean Chemical Society     Hybrid Journal   (Followers: 1)
C - Journal of Carbon Research     Open Access   (Followers: 5)
Cakra Kimia (Indonesian E-Journal of Applied Chemistry)     Open Access  
Canadian Association of Radiologists Journal     Full-text available via subscription   (Followers: 1)
Canadian Journal of Chemistry     Hybrid Journal   (Followers: 12)
Canadian Mineralogist     Full-text available via subscription   (Followers: 5)
Carbohydrate Polymer Technologies and Applications     Open Access  
Carbohydrate Polymers     Hybrid Journal   (Followers: 9)
Carbohydrate Research     Hybrid Journal   (Followers: 24)
Carbon     Hybrid Journal   (Followers: 65)
Carbon Capture Science & Technology     Open Access  
Carbon Trends     Open Access   (Followers: 3)
Catalysis Reviews: Science and Engineering     Hybrid Journal   (Followers: 9)
Catalysis Science and Technology     Hybrid Journal   (Followers: 9)
Catalysis Surveys from Asia     Hybrid Journal   (Followers: 4)
Catalysts     Open Access   (Followers: 11)
Cell Reports Physical Science     Open Access  
Cellulose     Hybrid Journal   (Followers: 7)
Cereal Chemistry     Full-text available via subscription   (Followers: 4)
Chem     Hybrid Journal  
Chem Catalysis     Hybrid Journal  
ChemBioEng Reviews     Full-text available via subscription   (Followers: 3)
ChemCatChem     Hybrid Journal   (Followers: 8)
Chemical and Engineering News     Free   (Followers: 22)
Chemical Bulletin of Kazakh National University     Open Access  
Chemical Communications     Hybrid Journal   (Followers: 81)
Chemical Engineering Research and Design     Hybrid Journal   (Followers: 26)
Chemical Physics Impact     Full-text available via subscription  
Chemical Research in Chinese Universities     Hybrid Journal   (Followers: 4)
Chemical Research in Toxicology     Hybrid Journal   (Followers: 22)
Chemical Reviews     Hybrid Journal   (Followers: 168)
Chemical Science     Open Access   (Followers: 39)
Chemical Science International Journal     Open Access  
Chemical Technology     Open Access   (Followers: 75)
Chemical Thermodynamics and Thermal Analysis     Open Access   (Followers: 2)
Chemical Vapor Deposition     Hybrid Journal   (Followers: 4)
Chemie in Unserer Zeit     Hybrid Journal   (Followers: 54)
Chemie-Ingenieur-Technik (Cit)     Hybrid Journal   (Followers: 22)
ChemInform     Hybrid Journal   (Followers: 5)
Chemistry     Open Access  
Chemistry & Biodiversity     Hybrid Journal   (Followers: 7)
Chemistry & Industry     Full-text available via subscription   (Followers: 6)
Chemistry - A European Journal     Hybrid Journal   (Followers: 121)
Chemistry - An Asian Journal     Hybrid Journal   (Followers: 19)
Chemistry Africa : A Journal of the Tunisian Chemical Society     Hybrid Journal  
Chemistry and Materials Research     Open Access   (Followers: 18)
Chemistry Central Journal     Open Access   (Followers: 4)
Chemistry Education Research and Practice     Free   (Followers: 6)
Chemistry Education Review     Open Access   (Followers: 1)
Chemistry in Education     Open Access   (Followers: 3)
Chemistry Letters     Full-text available via subscription   (Followers: 44)
Chemistry of Heterocyclic Compounds     Hybrid Journal   (Followers: 4)
Chemistry of Materials     Hybrid Journal   (Followers: 161)
Chemistry of Natural Compounds     Hybrid Journal   (Followers: 10)
Chemistry World     Hybrid Journal   (Followers: 20)
Chemistry-Didactics-Ecology-Metrology     Open Access  
ChemistryOpen     Open Access   (Followers: 1)
ChemistrySelect     Hybrid Journal  
Chemistry–Methods     Open Access   (Followers: 1)
Chemkon - Chemie Konkret, Forum Fuer Unterricht Und Didaktik     Hybrid Journal  
ChemNanoMat     Hybrid Journal   (Followers: 1)
Chemoecology     Hybrid Journal   (Followers: 2)
Chemometrics and Intelligent Laboratory Systems     Hybrid Journal   (Followers: 13)
Chemosensors     Open Access   (Followers: 1)
ChemPhotoChem     Hybrid Journal  
ChemPhysChem     Hybrid Journal   (Followers: 12)
ChemPhysMater     Full-text available via subscription  
ChemPlusChem     Hybrid Journal   (Followers: 2)
Chempublish Journal     Open Access  
ChemSystemsChem     Hybrid Journal   (Followers: 1)
ChemTexts     Hybrid Journal   (Followers: 1)
CHIMIA International Journal for Chemistry     Open Access   (Followers: 2)
Chinese Journal of Chemistry     Hybrid Journal   (Followers: 6)
Chinese Journal of Polymer Science     Hybrid Journal   (Followers: 9)
Chromatographia     Hybrid Journal   (Followers: 22)
Chromatography     Open Access   (Followers: 2)
Chromatography Research International     Open Access   (Followers: 4)
Ciencia     Open Access  
Clay Minerals     Hybrid Journal   (Followers: 8)
Cogent Chemistry     Open Access   (Followers: 3)
Colloid and Interface Science Communications     Open Access  
Colloid and Polymer Science     Hybrid Journal   (Followers: 6)
Colloids and Interfaces     Open Access  
Colloids and Surfaces B: Biointerfaces     Hybrid Journal   (Followers: 8)
Combinatorial Chemistry & High Throughput Screening     Hybrid Journal   (Followers: 2)
Combustion Science and Technology     Hybrid Journal   (Followers: 26)
Comments on Inorganic Chemistry: A Journal of Critical Discussion of the Current Literature     Hybrid Journal   (Followers: 1)
Communications Chemistry     Open Access   (Followers: 2)
Communications Materials     Open Access  
Composite Interfaces     Hybrid Journal   (Followers: 6)
Comptes Rendus : Chimie     Open Access  
Comptes Rendus : Physique     Open Access   (Followers: 2)

        1 2 3 4 | Last

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Journal Cover
Number of Followers: 11  

  This is an Open Access Journal Open Access journal
ISSN (Online) 2073-4344
Published by MDPI Homepage  [84 journals]
  • Catalysts, Vol. 12, Pages 450: CO2 Electroreduction over Metallic Oxide,
           Carbon-Based, and Molecular Catalysts: A Mini-Review of the Current

    • Authors: Hassan Ait Ahsaine, Mohamed Zbair, Amal BaQais, Madjid Arab
      First page: 450
      Abstract: Electrochemical CO2 reduction reaction (CO2RR) is one of the most challenging targets of current energy research. Multi-electron reduction with proton-coupled reactions is more thermodynamically favorable, leading to diverse product distribution. This requires the design of stable electroactive materials having selective product generation and low overpotentials. In this review, we have explored different CO2RR electrocatalysts in the gas phase and H-cell configurations. Five groups of electrocatalysts ranging from metals and metal oxide, single atom, carbon-based, porphyrins, covalent, metal–organic frameworks, and phthalocyanines-based electrocatalysts have been reviewed. Finally, conclusions and prospects have been elaborated.
      Citation: Catalysts
      PubDate: 2022-04-19
      DOI: 10.3390/catal12050450
      Issue No: Vol. 12, No. 5 (2022)
  • Catalysts, Vol. 12, Pages 451: A Study on the Effects of Gallium Droplet
           Consumption and Post Growth Annealing on Te-Doped GaAs Nanowire Properties
           Grown by Self-Catalyzed Molecular Beam Epitaxy

    • Authors: Shisir Devkota, Mehul Parakh, Priyanka Ramaswamy, Hirandeep Kuchoor, Aubrey Penn, Lewis Reynolds, Shanthi Iyer
      First page: 451
      Abstract: In this work, the effects of arsenic (As) flux used during gallium (Ga) seed droplet consumption and the post-growth annealing on the optical, electrical, and microstructural properties of self-catalyzed molecular beam epitaxially grown tellurium (Te)-doped GaAs nanowires (NWs) have been investigated using a variety of characterization techniques. NWs using the same amount of As flux for growth of the seed droplet consumption demonstrated reduced density of stacking faults at the NW tip, with four-fold enhancement in the 4K photoluminescence (PL) intensity and increased single nanowire photocurrent over their higher As flux droplet consumption counterparts. Post-growth annealed NWs exhibited an additional low-energy PL peak at 1.31 eV that significantly reduced the overall PL intensity. The origin of this lower energy peak is assigned to a photocarrier transition from the conduction band to the annealing assisted Te-induced complex acceptor state (TeAsVGa−). In addition, post-growth annealing demonstrated a detrimental impact on the electrical properties of the Te-doped GaAs NWs, as revealed by suppressed single nanowire (SNW) and ensemble NW photocurrent, with a consequent enhanced low-frequency noise level compared to as-grown doped NWs. This work demonstrates that each parameter in the growth space must be carefully examined to successfully grow self-catalyzed Te-doped NWs of high quality and is not a simple extension of the growth of corresponding intrinsic NWs.
      Citation: Catalysts
      PubDate: 2022-04-19
      DOI: 10.3390/catal12050451
      Issue No: Vol. 12, No. 5 (2022)
  • Catalysts, Vol. 12, Pages 452: CeO2-Based Heterogeneous Catalysts in Dry
           Reforming Methane and Steam Reforming Methane: A Short Review

    • Authors: Wan Nabilah Manan, Wan Nor Roslam Wan Isahak, Zahira Yaakob
      First page: 452
      Abstract: Transitioning to lower carbon energy and environment sustainability requires a reduction in greenhouse gases such as carbon dioxide (CO2) and methane (CH4) that contribute to global warming. One of the most actively studied rare earth metal catalysts is cerium oxide (CeO2) which produces remarkable improvements in catalysts in dry reforming methane. This paper reviews the management of CO2 emissions and the recent advent and trends in bimetallic catalyst development utilizing CeO2 in dry reforming methane (DRM) and steam reforming methane (SRM) from 2015 to 2021 as a way to reduce greenhouse gas emissions. This paper focus on the identification of key trends in catalyst preparation using CeO2 and the effectiveness of the catalysts formulated.
      Citation: Catalysts
      PubDate: 2022-04-19
      DOI: 10.3390/catal12050452
      Issue No: Vol. 12, No. 5 (2022)
  • Catalysts, Vol. 12, Pages 453: Efficient CO2 Electroreduction over Silver
           Hollow Fiber Electrode

    • Authors: Shoujie Li, Xiao Dong, Wei Chen, Yanfang Song, Guihua Li, Wei Wei, Yuhan Sun
      First page: 453
      Abstract: Electrocatalytic reduction of CO2 to fuels and chemicals is one of the most attractive routes for CO2 utilization. However, low efficiency and poor stability restrict the practical application of most conventional electrocatalysts. Here, a silver hollow fiber electrode is presented as a novel self-supported gas diffusion electrode for efficient and stable CO2 electroreduction to CO. A CO faradaic efficiency of over 92% at current densities of above 150 mA∙cm−2 is achieved in 0.5 M KHCO3 for over 100 h, which is comparable to the most outstanding Ag-based electrocatalysts. The electrochemical results suggest the excellent electrocatalytic performance of silver hollow fiber electrode is attributed to the unique pore structures providing abundant active sites and favorable mass transport, which not only suppresses the competitive hydrogen evolution reaction (HER) but also facilitates the CO2 reduction kinetics.
      Citation: Catalysts
      PubDate: 2022-04-19
      DOI: 10.3390/catal12050453
      Issue No: Vol. 12, No. 5 (2022)
  • Catalysts, Vol. 12, Pages 454: High-Performance of Electrocatalytic CO2
           Reduction on Defective Graphene-Supported Cu4S2 Cluster

    • Authors: Qiyan Zhang, Yawei Li, Haiyan Zhu, Bingbing Suo
      First page: 454
      Abstract: Electrochemical CO2 reduction reaction (CO2RR) to high-value chemicals is one of the most splendid approaches to mitigating environmental threats and energy shortage. In this study, the catalytic performance of CO2RR on defective graphene-supported Cu4S2 clusters as well as isolated Cu4Xn (X = O, S, Se; n = 2, 4) was systematically investigated based on density functional theory (DFT) computations. Calculation results revealed that the most thermodynamically feasible product is CH3OH among the C1 products on Cu4X2 clusters, in which the Cu4S2 cluster has the best activity concerning CH3OH synthesis with a limiting potential of −0.48 V. When the Cu4S2 cluster was further supported on defective graphene, the strong interaction between cluster and substrate could greatly improve the performance via tuning the electronic structure and improving the stability of the Cu4S2 cluster. The calculated free energy diagram indicated that it is also more energetically preferable for CH3OH production with a low limiting potential of −0.35 V. Besides, the defective graphene support has a significant ability to suppress the competing reactions, such as the hydrogen evolution reaction (HER) and CO and HCOOH production. Geometric structures, limiting potentials, and reduction pathways were also discussed to gain insight into the reaction mechanism and to find the minimum-energy pathway for C1 products. We hope this work will provide theoretical reference for designing and developing advanced supported Cu-based electrocatalysts for CO2 reduction.
      Citation: Catalysts
      PubDate: 2022-04-19
      DOI: 10.3390/catal12050454
      Issue No: Vol. 12, No. 5 (2022)
  • Catalysts, Vol. 12, Pages 455: Advances in the Catalytic Conversion of
           Biomass Components to Ester Derivatives: Challenges and Opportunities

    • Authors: Domenico Licursi
      First page: 455
      Abstract: Sustainable conversion of biomass feedstocks into valuable bio-fuels and bio-products plays a strategic role within modern industrial catalysis [...]
      Citation: Catalysts
      PubDate: 2022-04-20
      DOI: 10.3390/catal12050455
      Issue No: Vol. 12, No. 5 (2022)
  • Catalysts, Vol. 12, Pages 456: Investigations on Structural, Electronic
           and Optical Properties of MoS2/CDs Heterostructure via First-Principles

    • Authors: Xianglu Yin, Aijun Teng, Zhi Chang, Peng Yuan, Dongbin Zhang, Jiyang Yu
      First page: 456
      Abstract: Much effort has been made for MoS2/CDs heterostructure application in the field of photocatalysts. However, the impacts of functional groups of CDs on the properties of the heterostructure are ambiguous. Here, the impacts of hydroxyl, carbonyl, and carboxyl groups of CDs on the structural, electronic, and optical properties of MoS2/CDs’ heterostructure were investigated by conducting a first-principles study. The calculated energy band structure and band gap of monolayer MoS2 were consistent with the experimental values. The band gap of MoS2 was obviously decreased after the construction of MoS2/CDs and MoS2/CDs–hydroxyl/carboxyl, thus helping to improve the light adsorption range. However, the band gap of MoS2/CDs–carbonyl was slightly increased compared with that of monolayer MoS2. The CDs with functional groups can spontaneously bind on 2D-MoS2 and form a stable MoS2/CDs heterostructure. It was confirmed that the MoS2/CDs’ heterostructure belongs to the typical type-II band alignment, which contributes to the separation of photogenerated charge and hole. Notably, the carbonyl and carboxyl groups on the CDs obviously reduced the optical absorption intensity of the MoS2/CDs in the ultraviolet region. The hydroxyl groups have little effect on optical absorption intensity. Thus, the CDs with more hydroxyl groups are beneficial to produce a higher photocatalytic performance. This paper reveals the impacts of surface functional groups and provides a promising approach for designing the MoS2/CDs’ heterostructure to enhance the photocatalytic properties.
      Citation: Catalysts
      PubDate: 2022-04-20
      DOI: 10.3390/catal12050456
      Issue No: Vol. 12, No. 5 (2022)
  • Catalysts, Vol. 12, Pages 457: Synthesis and Evaluation of FeSX/TiO2 for
           the Photocatalytic Degradation of Phenol under Visible-Light Region

    • Authors: Diego Alvarez-Bustos, Felipe Sanchez-Minero, Victor Santes, Issis Claudette Romero-Ibarra, José Antonio de los Reyes Heredia, Reyna Rios-Escobedo, Francisco Tzompantzi-Morales, Carlos Eduardo Santolalla-Vargas
      First page: 457
      Abstract: In the present work, phenol was used as a model molecule to the photocatalytic evaluation of TiO2 impregnated with iron sulphide and chlorine on a visible-light reactor. The iron–chlorine catalyst was prepared by incipient impregnation with the metal precursors, Fe (NO3)3 and NaCl on previously calcined TiO2. The catalyst was sulphurized with H2S at 300 °C for 1 h. The catalysts were prepared at different chlorine concentrations using HYDRA chemical equilibrium diagrams to obtain different fractions of FeCl+. The oxide catalysts were characterized with diffuse reflectance (DRS UV–Vis) and temperature programmed reduction analysis (TPR). Sulphurized catalysts were characterized with Raman spectrometry and X-ray photoelectron spectrometry (XPS). The FeS–2Cl/TiO2 catalyst presented 8.35 times higher photodegradation than TiO2 and 6.4 times higher compared to the FeS–0.25Cl/TiO2 catalyst. DRS and XPS showed similar results of band gap, proving that the catalyst remain stable after sulphurisation. The TPR results of FeS–2Cl/TiO2 showed an increment of 86.29% in Fe2+/Fe3+ compared to FeS–0.25Cl/TiO2. XPS and Raman results for oxide and sulphated iron species relation suggested that FeS–2Cl/TiO2 decreased 4.45% compared to FeS–0.25Cl/TiO2 catalyst. XPS semiquantitative for S/Fe results showed that the FeS–2Cl/TiO2 catalyst increased 73.17% in comparison to FeS–0.25Cl/TiO2. These results suggested the increment of sulphurisation degree for FeS–2Cl/TiO2. In this regard, the catalyst characterization results showed that the presence of FeCl+ (0.85 fractions) in solution before impregnation promoted the active sulphide species maintaining the band gap and improved the degradation of phenol on visible light.
      Citation: Catalysts
      PubDate: 2022-04-20
      DOI: 10.3390/catal12050457
      Issue No: Vol. 12, No. 5 (2022)
  • Catalysts, Vol. 12, Pages 458: Novel Photocatalysts for Environmental and
           Energy Applications

    • Authors: Dionysios D. Dionysiou, Sami Rtimi, Ewa Kowalska, Changseok Han, Marcin Janczarek
      First page: 458
      Abstract: Due to exponential industrialization and rapid population growth, the global energy crisis and environmental pollution have become two of the greatest humanitarian challenges of the 21st century [...]
      Citation: Catalysts
      PubDate: 2022-04-20
      DOI: 10.3390/catal12050458
      Issue No: Vol. 12, No. 5 (2022)
  • Catalysts, Vol. 12, Pages 459: A Review on Green Synthesis of

    • Authors: Melvin S. Samuel, Madhumita Ravikumar, Ashwini John, Ethiraj Selvarajan, Himanshu Patel, P. Sharath Chander, J. Soundarya, Srikanth Vuppala, Ramachandran Balaji, Narendhar Chandrasekar
      First page: 459
      Abstract: In recent times, metal oxide nanoparticles (NPs) have been regarded as having important commercial utility. However, the potential toxicity of these nanomaterials has also been a crucial research concern. In this regard, an important solution for ensuring lower toxicity levels and thereby facilitating an unhindered application in human consumer products is the green synthesis of these particles. Although a naïve approach, the biological synthesis of metal oxide NPs using microorganisms and plant extracts opens up immense prospects for the production of biocompatible and cost-effective particles with potential applications in the healthcare sector. An important area that calls for attention is cancer therapy and the intervention of nanotechnology to improve existing therapeutic practices. Metal oxide NPs have been identified as therapeutic agents with an extended half-life and therapeutic index and have also been reported to have lesser immunogenic properties. Currently, biosynthesized metal oxide NPs are the subject of considerable research and analysis for the early detection and treatment of tumors, but their performance in clinical experiments is yet to be determined. The present review provides a comprehensive account of recent research on the biosynthesis of metal oxide NPs, including mechanistic insights into biological production machinery, the latest reports on biogenesis, the properties of biosynthesized NPs, and directions for further improvement. In particular, scientific reports on the properties and applications of nanoparticles of the oxides of titanium, cerium, selenium, zinc, iron, and copper have been highlighted. This review discusses the significance of the green synthesis of metal oxide nanoparticles, with respect to therapeutically based pharmaceutical applications as well as energy and environmental applications, using various novel approaches including one-minute sonochemical synthesis that are capable of responding to various stimuli such as radiation, heat, and pH. This study will provide new insight into novel methods that are cost-effective and pollution free, assisted by the biodegradation of biomass.
      Citation: Catalysts
      PubDate: 2022-04-20
      DOI: 10.3390/catal12050459
      Issue No: Vol. 12, No. 5 (2022)
  • Catalysts, Vol. 12, Pages 460: Towards the Efficient Catalytic
           Valorization of Chitin to N-Acylethanolamine over Ni/CeO2 Catalyst:
           Exploring the Shape-Selective Reactivity

    • Authors: Yifan Zheng, Lijun Lu, Wei Chen, Anmin Zheng, Aiwen Lei, Abhishek Dutta Chowdhury
      First page: 460
      Abstract: Global warming and rising waste content collectively accelerate the development of renewable-derived ‘low-carbon’ chemical technologies. Among all abundant renewables, marine-/food-waste-derived chitin, the only nitrogen-containing sustainable biomass, contains the unique N-acetylglucosamine units, which could be synthetically manipulated to a plethora of organonitrogen chemicals. Herein, we report the efficient one-step catalytic valorization of chitin to N-acylethanolamine over cost-effective Ni/CeO2-based materials, which interestingly demonstrate shape-based reactivity based on CeO2 supports. In general, all three catalysts (Ni on cubic-, rod-, and polyhedral-shaped CeO2 supports) were active for this reaction, but they differed in their catalytic efficiency and time-monitored reaction profiles. Herein, Ni on cubic-shaped CeO2 delivered relatively better and stable catalytic performance, along with its rod-shaped counterpart, while the polyhedral CeO2-based material also delivered decent performance. Such interesting catalytic behavior has been corroborated by their physicochemical properties, as revealed by their characterization studies. Herein, to establish an appropriate structure-property-reactivity relationship, multimodal characterization techniques and control mechanistic experiments have been performed. This work demonstrates a concept to reduce the consumption of primary carbon resources and increase the utilization of secondary waste materials to facilitate a smooth transition from a linear economy (cf. cradle-to-grave model) to a circular economy (cf. cradle-to-cradle model).
      Citation: Catalysts
      PubDate: 2022-04-20
      DOI: 10.3390/catal12050460
      Issue No: Vol. 12, No. 5 (2022)
  • Catalysts, Vol. 12, Pages 461: Enzymatic Pretreatment Improved the In
           Vitro Ruminal Degradability of Oil Palm Fronds

    • Authors: Mohammad Azri Azmi, Ahmad Fariz Nicholas, Amirul Faiz Mohd Azmi, Mohd Huzairi Mohd Zainudin, Mohd Termizi Yusof, Zunita Zakaria, Noordin Mohamed Mustapha, Mohd Zamri Saad, Nor Dini Rusli, Hasliza Abu Hassim
      First page: 461
      Abstract: This study aims to increase the in vitro ruminal degradability of oil palm fronds (OPFs) through enzymatic pretreatment. The isolated fungi were selected based on their lignocellulosic degrading enzyme activities. Eleven fungi were successfully isolated, and their enzyme activities were evaluated. Three fungi, F1, F2 and F4 were selected, and they were identified as Trichoderma harzianum MK027305, Trichoderma harzianum MK027306 and Fusarium solani MK027309, respectively. The highest total gas and methane production was produced when OPFs were pretreated with an enzyme extract from 15 and 30 days of solid-state fermentation of T. harzianum MK027305 and T. harzianum MK027306, respectively. Meanwhile, OPFs pretreated with an enzyme extract from F. solani MK027309 after 45 days of solid-state fermentation produced the highest amount of volatile fatty acids. The pretreatment using the enzymes extracted from 45 days of solid-state fermentation of F. solani MK027309 increases the apparent rumen degradable carbohydrate (ARDC) by 35.29% compared to unpretreated OPF. This study showed that pretreatment of the OPFs using selected fungi’s enzymes increases the volatile fatty acid production and in vitro ruminal degradability of OPF, hence improving livestock production via increased utilization of agricultural by-products with minimal impact on the production cost.
      Citation: Catalysts
      PubDate: 2022-04-21
      DOI: 10.3390/catal12050461
      Issue No: Vol. 12, No. 5 (2022)
  • Catalysts, Vol. 12, Pages 462: Aspergillus flavus-Mediated Green Synthesis
           of Silver Nanoparticles and Evaluation of Their Antibacterial,
           Anti-Candida, Acaricides, and Photocatalytic Activities

    • Authors: Amr Fouda, Mohamed A. Awad, Zarraq E. AL-Faifi, Mohammed E. Gad, Areej A. Al-Khalaf, Reham Yahya, Mohammed F. Hamza
      First page: 462
      Abstract: Aspergillus flavus F5 was used to reduce AgNO3 to form silver nanoparticles (Ag-NPs) that were monitored by a color change from colorless to yellowish-brown. The characterizations were achieved by UV-Vis spectroscopy, FT-IR, TEM, SEM-EDX, and XRD. Data showed that there was a successful formation of crystalline, spherical shape Ag-NPs with a particle average size of 12.5 ± 5.1 nm. The FT-IR clarified the role of various functional groups in the reducing/capping process. EDX-SEM revealed that the main component of the as-formed sample was set to be mainly Ag with a weight percentage of 46.1%. The synthesized Ag-NPs exhibit antibacterial and anti-Candida activity against Staphylococcus aureus, Bacillus subtilis, Pseudomonas aeruginosa, Escherichia coli, Candida albicans, C. glabrata, C. tropicalis, and C. parapsilosis, with inhibition zones ranging between 9.3 ± 0.5 to 20.8 ± 0.3 nm based on concentrations used and MIC values between 6.25 to 25 ppm. The mortality percentages of Tyrophagus putrescentiae mite species due to the mixing of their diet with different Ag-NPs concentrations of 0.5, 1.0, and 1.5 mg were 55.7 ± 2.1, 73.3 ± 1.5, and 87.4 ± 1.6% respectively after 20 days post-treatment. The catalytic activity of Ag-NPs to degrade methylene blue (MB) was investigated in the presence and absence of light irradiation. Data showed that a high photocatalytic degradation of MB compared with dark conditions at various times and concentrations. At a concentration of 70 mg/30 mL after 200 min., the dye removal percentages were 86.4 ± 0.4% in the presence of light irradiation versus 66.5 ± 1.1% in dark conditions.
      Citation: Catalysts
      PubDate: 2022-04-21
      DOI: 10.3390/catal12050462
      Issue No: Vol. 12, No. 5 (2022)
  • Catalysts, Vol. 12, Pages 463: Optimization of Liquid Hot Water
           Pretreatment and Fermentation for Ethanol Production from Sugarcane
           Bagasse Using Saccharomyces cerevisiae

    • Authors: Punjarat Khongchamnan, Nopparat Suriyachai, Torpong Kreetachat, Navadol Laosiripojana, Khatiya Weerasai, Verawat Champreda, Kowit Suwannahong, Chainarong Sakulthaew, Chanat Chokejaroenrat, Saksit Imman
      First page: 463
      Abstract: Sugarcane bagasse can be considered a potential raw material in terms of quantity and quality for the production of alternative biofuels. In this research, liquid hot water (LHW) was studied as a pretreatment process to enhance the digestibility of pretreated material for further conversion into bioethanol. Different variables (temperature, residual time, and acid concentration) were determined to predict the optimized condition. LHW pretreatment showed an impact on the hemicellulose structure. The optimized condition at 160 °C for 60 min with 0.050 M acid concentration reached the highest glucose yield of 96.86%. Scanning electron microscopy (SEM) showed conspicuous modification of the sugarcane bagasse structure. The effect of LHW pretreatment was also demonstrated by the changes in crystallinity and surface area analysis. FTIR techniques revealed the chemical structure changes of pretreated sugarcane bagasse. The prepared material was further converted into ethanol production with the maximized ethanol concentration of 19.9 g/L.
      Citation: Catalysts
      PubDate: 2022-04-21
      DOI: 10.3390/catal12050463
      Issue No: Vol. 12, No. 5 (2022)
  • Catalysts, Vol. 12, Pages 464: Mechanochemical Synthesis Method for Drugs
           Used in the Treatment of CNS Diseases under PTC Conditions

    • Authors: Jolanta Jaśkowska, Anna Karolina Drabczyk, Piotr Michorczyk, Damian Kułaga, Przemysław Zaręba, Przemysław Jodłowski, Zbigniew Majka, Jarosław Jakubski, Edyta Pindelska
      First page: 464
      Abstract: Phase transfer catalysis (PTC) is an excellent possibility in the synthesis of organic compounds as it allows the reactions to be carried out under the conditions of green chemistry, while maintaining high yields and selectivity. The great advantage of these reactions is also the possibility of carrying out the reactions not only under conventional conditions, but also mechanochemically in solvent-free processes. Bearing this in mind, we decided to develop a new method for the synthesis of known biologically active compounds from the group of long-chain arylpiperazines (LCAPs). The first mortar trials were very promising and prompted us to carry out a series of ball mill reactions. One of the technological problems that we encountered while conducting reactions in the ball mill was the difficulty in extracting the post-reaction mixture. We tested the effects of additives improving the insulation of the product, such as, e.g., starch, zeolites, and silica. Research has proven that with appropriate process conditions using TBAB as a catalyst and in the presence of potassium carbonate and a small amount of Zeolite ZSM5 or silica, aripiprazole can be obtained with a yield of 90% in just five minutes. The obtained results are very promising and it is worth considering them as an alternative to the synthesis of other compounds from the LCAPS group.
      Citation: Catalysts
      PubDate: 2022-04-21
      DOI: 10.3390/catal12050464
      Issue No: Vol. 12, No. 5 (2022)
  • Catalysts, Vol. 12, Pages 465: Quo Vadis Dry Reforming of
           Methane'—A Review on Its Chemical, Environmental, and Industrial

    • Authors: Luis E. Sandoval-Diaz, Robert Schlögl, Thomas Lunkenbein
      First page: 465
      Abstract: In recent years, the catalytic dry reforming of methane (DRM) has increasingly come into academic focus. The interesting aspect of this reaction is seemingly the conversion of CO2 and methane, two greenhouse gases, into a valuable synthesis gas (syngas) mixture with an otherwise unachievable but industrially relevant H2/CO ratio of one. In a possible scenario, the chemical conversion of CO2 and CH4 to syngas could be used in consecutive reactions to produce synthetic fuels, with combustion to harness the stored energy. Although the educts of DRM suggest a superior impact of this reaction to mitigate global warming, its potential as a chemical energy converter and greenhouse gas absorber has still to be elucidated. In this review article, we will provide insights into the industrial maturity of this reaction and critically discuss its applicability as a cornerstone in the energy transition. We derive these insights from assessing the current state of research and knowledge on DRM. We conclude that the entire industrial process of syngas production from two greenhouse gases, including heating with current technologies, releases at least 1.23 moles of CO2 per mol of CO2 converted in the catalytic reaction. Furthermore, we show that synthetic fuels derived from this reaction exhibit a negative carbon dioxide capturing efficiency which is similar to burning methane directly in the air. We also outline potential applications and introduce prospective technologies toward a net-zero CO2 strategy based on DRM.
      Citation: Catalysts
      PubDate: 2022-04-22
      DOI: 10.3390/catal12050465
      Issue No: Vol. 12, No. 5 (2022)
  • Catalysts, Vol. 12, Pages 466: Cathodic Activation of Titania-Fly Ash
           Cenospheres for Efficient Electrochemical Hydrogen Production: A Proposed
           Solution to Treat Fly Ash Waste

    • Authors: Tariq Altalhi, Amine Mezni, Mohamed M. Ibrahim, Moamen S. Refat, Adil A. Gobouri, Ayham M. Safklou, Adel M. Mousli, Mohamed S. Attia, Purna K. Boruah, Manash R. Das, Jacek Ryl, Rabah Boukherroub, Mohammed A. Amin
      First page: 466
      Abstract: Fly ash (FA) is a waste product generated in huge amounts by coal-fired electric and steam-generating plants. As a result, the use of FA alone or in conjunction with other materials is an intriguing study topic worth exploring. Herein, we used FA waste in conjunction with titanium oxide (TiO2) to create (FA-TiO2) nanocomposites. For the first time, a cathodic polarization pre-treatment regime was applied to such nanocomposites to efficiently produce hydrogen from an alkaline solution. The FA-TiO2 hybrid nanocomposites were prepared by a straightforward solvothermal approach in which the FA raw material was mixed with titanium precursor in dimethyl sulfoxide (DMSO) and refluxed during a given time. The obtained FA-TiO2 hybrid nanocomposites were fully characterized using various tools and displayed a cenosphere-like shape. The synthesized materials were tested as electrocatalysts for the hydrogen evolution reaction (HER) in 0.1 M KOH solution in the dark, employing various electrochemical techniques. The as-prepared (unactivated) FA-TiO2 exhibited a considerable HER electrocatalytic activity, with an onset potential (EHER) value of −144 mV vs. RHE, a Tafel slope (−bc) value of 124 mV dec−1 and an exchange current density (jo) of ~0.07 mA cm−2. The FA-TiO2′s HER catalytic performance was significantly enhanced upon cathodic activation (24 h of chronoamperometry measurements performed at a high cathodic potential of −1.0 V vs. RHE). The cathodically activated FA-TiO2 recorded HER electrochemical kinetic parameters of EHER = −28 mV, −bc = 115 mV dec−1, jo = 0.65 mA cm−2, and an overpotential η10 = 125 mV to yield a current density of 10 mA cm−2. Such parameters were comparable to those measured here for the commercial Pt/C under the same experimental conditions (EHER = −10 mV, −bc = 113 mV dec−1, jo = 0.88 mA cm−2, η10 = 110 mV), as well as to the most active electrocatalysts for H2 generation from aqueous alkaline electrolytes.
      Citation: Catalysts
      PubDate: 2022-04-22
      DOI: 10.3390/catal12050466
      Issue No: Vol. 12, No. 5 (2022)
  • Catalysts, Vol. 12, Pages 467: Comparison of Catalysts with MIRA21 Model
           in Heterogeneous Catalytic Hydrogenation of Aromatic Nitro Compounds

    • Authors: Alexandra Jakab-Nácsa, Emőke Sikora, Ádám Prekob, László Vanyorek, Milán Szőri, Renáta Zsanett Boros, Károly Nehéz, Martin Szabó, László Farkas, Béla Viskolcz
      First page: 467
      Abstract: The vast majority of research and development activities begins with a detailed literature search to explore the current state-of-the-art. However, this search becomes increasingly difficult as we go into the information revolution of 21st century. The aim of the work is to establish a functional and practical mathematical model of catalyst characterization and exact comparison of catalysts. This work outlines the operation of the MIskolc RAnking 21 (MIRA21) model through the reaction of nitrobenzene catalytic hydrogenation to aniline. A total of 154 catalysts from 45 research articles were selected, studied, characterized, ranked, and classified based on four classes of descriptors: catalyst performance, reaction conditions, catalyst conditions, and sustainability parameters. MIRA21 is able to increase the comparability of different types of catalysts and support catalyst development. According to the model, 8% of catalysts received D1 (top 10%) classification. This ranking model is able to show the most effective catalyst systems that are suitable for the production of aniline.
      Citation: Catalysts
      PubDate: 2022-04-22
      DOI: 10.3390/catal12050467
      Issue No: Vol. 12, No. 5 (2022)
  • Catalysts, Vol. 12, Pages 468: Transition Metal Dichalcogenides [MX2] in
           Photocatalytic Water Splitting

    • Authors: Paul O. Fadojutimi, Siziwe S. Gqoba, Zikhona N. Tetana, John Moma
      First page: 468
      Abstract: The quest for a clean, renewable and sustainable energy future has been highly sought for by the scientific community over the last four decades. Photocatalytic water splitting is a very promising technology to proffer a solution to present day environmental pollution and energy crises by generating hydrogen fuel through a “green route” without environmental pollution. Transition metal dichalcogenides (TMDCs) have outstanding properties which make them show great potential as effective co-catalysts with photocatalytic materials such as TiO2, ZnO and CdS for photocatalytic water splitting. Integration of TMDCs with a photocatalyst such as TiO2 provides novel nanohybrid composite materials with outstanding characteristics. In this review, we present the current state of research in the application of TMDCs in photocatalytic water splitting. Three main aspects which consider their properties, advances in the synthesis routes of layered TMDCs and their composites as well as their photocatalytic performances in the water splitting reaction are discussed. Finally, we raise some challenges and perspectives in their future application as materials for water-splitting photocatalysts.
      Citation: Catalysts
      PubDate: 2022-04-22
      DOI: 10.3390/catal12050468
      Issue No: Vol. 12, No. 5 (2022)
  • Catalysts, Vol. 12, Pages 469: Ni-Based Catalyst for Carbon Dioxide
           Methanation: A Review on Performance and Progress

    • Authors: Nur Diyan Mohd Ridzuan, Maizatul Shima Shaharun, Mohd Azrizan Anawar, Israf Ud-Din
      First page: 469
      Abstract: Catalytic conversion of CO2 into methane is an attractive method because it can alleviate global warming and provide a solution for the energy depletion crisis. Nickel-based catalysts were commonly employed in such conversions due to their high performance over cost ratio. However, the major challenges are that Ni tends to agglomerate and cause carbon deposition during the high-temperature reaction. In the past decades, extensive works have been carried out to design and synthesize more active nickel-based catalysts to achieve high CO2 conversion and CH4 selectivity. This review critically discusses the recent application of Ni-based catalyst for CO2 methanation, including the progress on the effect of supporting material, promoters, and catalyst composition. The thermodynamics, kinetics, and mechanism of CO2 methanation are also briefly addressed.
      Citation: Catalysts
      PubDate: 2022-04-22
      DOI: 10.3390/catal12050469
      Issue No: Vol. 12, No. 5 (2022)
  • Catalysts, Vol. 12, Pages 470: Impact of Black Body Material Enhanced Gas
           Movement on CO2 Photocatalytic Reduction Performance

    • Authors: Akira Nishimura, Takaharu Kato, Homare Mae, Eric Hu
      First page: 470
      Abstract: Gas movement around and/or through the photocatalyst is thought to be an inhibition factor to promote photocatalytic CO2 reduction performance. In this study, a hypothesis is put forward that the natural thermosiphon movement of gases around the photocatalyst can be improved by using black body material/surface. The black body material/surface that is placed underneath the photocatalyst in the reactor would be heated by absorbing light and then this heats up the gases to promote their movement around/through the photocatalyst. The aim of this study is to prove or disprove this hypothesis by conducting CO2 reduction performance of a TiO2 photocatalyst with NH3 under the conditions without black body material (W/O B.B.), with one black body material (W B.B.-1), and with three black body materials (W B.B.-3). The impact of molar ratio of CO2/NH3 on CO2 reduction performance is also investigated. This study revealed/proved that the hypothesis worked and that the CO2 reduction performance is promoted more with W B.B.-3 compared to that with W B.B.-1. The maximum concentration of formed CO with W B.B.-3 is two to five times as large as that under the condition W/O B.B.
      Citation: Catalysts
      PubDate: 2022-04-22
      DOI: 10.3390/catal12050470
      Issue No: Vol. 12, No. 5 (2022)
  • Catalysts, Vol. 12, Pages 471: Low-Temperature NH3-SCR on Cex-Mn-Tiy Mixed
           Oxide Catalysts: Improved Performance by the Mutual Effect between Ce and

    • Authors: Qianwen Zhu, Aiyong Wang, Jinshui Zhang, Yanglong Guo, Yun Guo, Li Wang, Wangcheng Zhan
      First page: 471
      Abstract: A series of Cex-Mn-Tiy catalysts were synthesized using the coprecipitation method, and sodium carbonate solution was used as a precipitant. The various catalysts were assessed by selective catalytic reduction of NOx with NH3, and characterized by X-ray diffraction, Raman spectroscopy, H2 temperature-programmed reduction, NH3 temperature-programmed desorption, and X-ray photoelectron spectroscopy to investigate the physicochemical properties, surface acidity, and redox abilities of the Cex-Mn-Tiy catalysts. The Ce0.1-Mn-Ti0.1 catalyst exhibited the best catalytic performance (more than 90% NOx conversion in the range of 75 to 225 °C), as a result of proper redox ability, abundant acid sites, high content of Mn4+ and Ce3+, and surface-adsorbed oxygen (OS). The results of in situ DRIFT spectroscopy showed that the NH3-SCR reaction followed both the E-R and L-H paths over the Ce0.1-Mn-Ti0.1 catalyst, and it occurred faster and more sharply when it mainly abided by the E-R mechanism.
      Citation: Catalysts
      PubDate: 2022-04-22
      DOI: 10.3390/catal12050471
      Issue No: Vol. 12, No. 5 (2022)
  • Catalysts, Vol. 12, Pages 472: Immobilization of Polyoxometalates on
           Carbon Nanotubes: Tuning Catalyst Activity, Selectivity and Stability in
           H2O2-Based Oxidations

    • Authors: Vasilii Yu. Evtushok, Vladimir A. Lopatkin, Olga Yu. Podyacheva, Oxana A. Kholdeeva
      First page: 472
      Abstract: In recent years, carbon nanotubes (CNTs), including N-doped ones (N-CNTs), have received significant attention as supports for the construction of heterogeneous catalysts. In this work, we summarize our progress in the application of (N)-CNTs for immobilization of anionic metal-oxygen clusters or polyoxometalates (POMs) and use of (N)-CNTs-supported POM as catalysts for liquid-phase selective oxidation of organic compounds with the green oxidant–aqueous hydrogen peroxide. We discuss here the main factors, which favor adsorption of POMs on (N)-CNTs and ensure a quasi-molecular dispersion of POM on the surface and their strong attachment to the support. The effects of the POM nature, N-doping of CNTs, acid additives, and other factors on the POM immobilization process and catalytic activity/selectivity of the (N)-CNTs-immobilized POMs are analyzed. Particular attention is drawn to the critical issue of the catalyst stability and reusability. The scope and limitations of the POM/(N)-CNTs catalysts in H2O2-based selective oxidations are discussed.
      Citation: Catalysts
      PubDate: 2022-04-22
      DOI: 10.3390/catal12050472
      Issue No: Vol. 12, No. 5 (2022)
  • Catalysts, Vol. 12, Pages 473: PTCL1-EstA from Paenarthrobacter aurescens
           TC1, a Candidate for Industrial Application Belonging to the VIII Esterase

    • Authors: Qinyu Li, Xiaojia Chen, Xiangcen Liu, Zheng Chen, Yang Han, Peng Zhou, Jiping Shi, Zhijun Zhao
      First page: 473
      Abstract: The esterase PTCL1-EstA from Paenarthrobacter aurescens TC1 was expressed in Escherichia coli and characterized. An 1152 bp open reading frame encoding a 383 amino acid polypeptide was successfully expressed, the C-terminally His6-tagged PTCL1-EstA enzyme was purified, and the predicted molecular mass of the purified PTCL1-EstA was 40.6 kDa. The EstA family serine hydrolase PTCL1-EstA belongs to the esterase family VIII, contains esterase-labeled S-C-S-K sequences, and homologous class C beta-lactamase sequences. PTCL1-EstA favored p-nitrophenyl esters with C2-C6 chain lengths, but it was also able to hydrolyze long-chain p-nitrophenyl esters. Homology modelling and substrate docking predicted that Ser59 was an active site residue in PTCL1-EstA, as well as Tyr148, Ala325, and Asp323, which are critical in catalyzing the enzymatic reaction of p-nitrophenyl esters. PTCL1-EstA reached the highest specific activity against p-nitrophenyl butyrate (C4) at pH 7.0 and 45 °C but revealed better thermal stability at 40 °C and maintained high relative enzymatic activity and stability at pH 5.0–9.0. Fermentation medium optimization for PTCL1-EstA increased the enzyme activity to 510.76 U/mL, tapping the potential of PTCL1-EstA for industrial production.
      Citation: Catalysts
      PubDate: 2022-04-23
      DOI: 10.3390/catal12050473
      Issue No: Vol. 12, No. 5 (2022)
  • Catalysts, Vol. 12, Pages 474: Chemo-Enzymatic Production of
           4-Nitrophenyl-2-acetamido-2-deoxy-α-D-galactopyranoside Using
           Immobilized β-N-Acetylhexosaminidase

    • Authors: Helena Hronská, Vladimír Štefuca, Ema Ondrejková, Mária Bláhová, Jozef Višňovský, Michal Rosenberg
      First page: 474
      Abstract: α-Nitrophenyl derivatives of glycosides are convenient substrates used to detect and characterize α-N-acetylgalactosaminidase. A new procedure combining chemical and biocatalytic steps was developed to prepare 4-nitrophenyl-2-acetamido-2-deoxy-α-D-galactopyranoside (4NP-α-GalNAc). The α-anomer was prepared through chemical synthesis of an anomeric mixture followed by selective removal of the β-anomer using specific enzymatic hydrolysis. Fungal β-N-acetylhexosaminidase (Hex) from Penicillium oxalicum CCF 1959 served this purpose owing to its high chemo-and regioselectivity towards the β-anomeric N-acetylgalactosamine (GalNAc) derivative. The kinetic measurements of the hydrolytic reaction showed that the enzyme was not inhibited by the substrate or reaction products. The immobilization of Hex in lens-shaped polyvinyl alcohol hydrogel capsules provided a biocatalyst with very good storage and operational stability. The immobilized Hex retained 97% of the initial activity after ten repeated uses and 90% of the initial activity after 18 months of storage at 4 °C. Immobilization inactivated 65% of the enzyme activity. However, the effectiveness factor and kinetic and mass transfer phenomena approached unity indicating negligible mass transfer limitations.
      Citation: Catalysts
      PubDate: 2022-04-23
      DOI: 10.3390/catal12050474
      Issue No: Vol. 12, No. 5 (2022)
  • Catalysts, Vol. 12, Pages 475: Solar Light-Assisted Oxidative Degradation
           of Ciprofloxacin in Aqueous Solution by Iron(III) Chelated Cross-Linked
           Chitosan Immobilized on a Glass Plate

    • Authors: Soma Saha, Tapan Kumar Saha, Subarna Karmaker, Zinia Islam, Serhiy Demeshko, Holm Frauendorf, Franc Meyer
      First page: 475
      Abstract: The massive worldwide use of antibiotics leads to water pollution and increasing microbial resistance. Hence, the removal of antibiotic residues is a key issue in water remediation. Here, we report the solar light-assisted oxidative degradation of ciprofloxacin (CPF), using H2O2 in aqueous solution, catalyzed by iron(III) chelated cross-linked chitosan (FeIII-CS-GLA) immobilized on a glass plate. The FeIII-CS-GLA catalyst was characterized by FTIR and 57Fe-Mössbauer spectroscopies as well as X-ray diffraction, revealing key structural motifs and a high-spin ferric character of the metal. Catalytic degradation of CPF was investigated as a function of solar light irradiation time, solution pH, concentration of H2O2 and CPF, as well as cross-linker dosage and iron(III) content in FeIII-CS-GLA. The system was found to serve as an efficient catalyst with maximum CPF degradation at pH 3. The specific ·OH scavenger mannitol significantly reduces the degradation rate, indicating that hydroxyl radicals play a key role. The mechanism of catalytic CPF degradation was evaluated in terms of pseudo-first-order and Langmuir-Hinshelwood kinetic models; adsorption of CPF onto the FeIII-CS-GLA surface was evidenced by field emission scanning electron microscopy coupled with energy dispersive X-ray spectroscopy. FeIII-CS-GLA can be reused multiple times with only minor loss of catalytic efficiency. Antimicrobial activity tests performed against both Gram-negative (Escherichia coli DH5α, Salmonella typhi AF4500) and Gram-positive bacteria (Bacillus subtilis RBW) before and after treatment confirmed complete degradation of CPF. These results establish the immobilized FeIII-CS-GLA as a rugged catalyst system for efficient photo-Fenton type degradation of antibiotics in aqueous solutions.
      Citation: Catalysts
      PubDate: 2022-04-23
      DOI: 10.3390/catal12050475
      Issue No: Vol. 12, No. 5 (2022)
  • Catalysts, Vol. 12, Pages 476: Highly Active Ni–Fe Based Oxide
           Oxygen Evolution Reaction Electrocatalysts for Alkaline Anion Exchange
           Membrane Electrolyser

    • Authors: Immanuel Vincent, Eun-Chong Lee, Hyung-Man Kim
      First page: 476
      Abstract: Oxygen evolution reaction (OER) electrocatalysts are pivotal for sustainable hydrogen production through anion exchange membrane electrolysis. Cost-effective transition metals such as nickel and iron-based oxides (Ni–Fe–Ox) have been recognized as viable catalysts for the oxygen evolution process in alkaline media. In this work, we study the electrochemical characterization and stability of the Ni–Fe–Ox to find the suitability for AEM electrolysis. The results indicate that Ni–Fe–Ox has 5 times higher activity than pure Ni. The Ni–Fe–Ox electrodes exhibit an exceptionally high catalytic activity of 22 mA cm−2 at 1.55 V vs. RHE, and a Tafel value as low as 97 dec−1, for OER to occur. These findings imply that OER occurs at similar places along the Ni–Fe–Ox interface and that the Ni—Fe2O3 contact plays a significant role as the OER active site. Furthermore, it is also worth noting that the presence of metallic Ni allows for fast electron transit within the interface, which is necessary for successful electrocatalysis. Aside from the excellent OER performance, the exfoliated Ni–Fe–Ox demonstrated great stability with almost constant potential after 10 h of electrolysis at a current density of 10 mA cm−2. This work confirms Ni–Fe–Ox is a promising, highly efficient and cost-effective OER catalyst for AEM electrolysis.
      Citation: Catalysts
      PubDate: 2022-04-23
      DOI: 10.3390/catal12050476
      Issue No: Vol. 12, No. 5 (2022)
  • Catalysts, Vol. 12, Pages 477: Effect of Different Carbon Supports on the
           Activity of PtNi Bimetallic Catalysts toward the Oxygen Reduction

    • Authors: Juan C. Ortíz-Herrera, Miriam M. Tellez-Cruz, Omar Solorza-Feria, Dora I. Medina
      First page: 477
      Abstract: To evaluate supports’ effects on catalytic activity toward the oxygen reduction reaction (ORR), a simple and controlled chemical synthesis, involving the hot injection of metal precursors, was developed to produce bimetallic PtNi nanoparticles (75 wt.% Pt and 25 wt.% Ni), supported on carbon nanotubes (CNTs) and carbon nanofibers (CNFs). The synthesized electrocatalyst was characterized using X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDS), and scanning transmission electron microscopy (STEM). To determine the catalytic activity, an electrochemical evaluation of the synthesized catalysts in an acidic medium was performed using cyclic voltammetry (CV), CO stripping, and rotating disk electrode (RDE) tests. The presence of Pt and Ni in the nanoparticles was confirmed by EDS and XRD. Based on the STEM micrographs, the average particle size was 30 nm. Compared to the commercial Pt/C catalyst, the PtNi/CNT catalyst exhibited higher specific activity and slightly lower mass activity toward ORR in a 0.1 M HClO4 electrolyte solution.
      Citation: Catalysts
      PubDate: 2022-04-23
      DOI: 10.3390/catal12050477
      Issue No: Vol. 12, No. 5 (2022)
  • Catalysts, Vol. 12, Pages 478: Cu Modified TiO2 Catalyst for
           Electrochemical Reduction of Carbon Dioxide to Methane

    • Authors: Akihiko Anzai, Ming-Han Liu, Kenjiro Ura, Tomohiro G. Noguchi, Akina Yoshizawa, Kenichi Kato, Takeharu Sugiyama, Miho Yamauchi
      First page: 478
      Abstract: Electrochemical reduction of CO2 (ECO2R) is gaining attention as a promising approach to store excess or intermittent electricity generated from renewable energies in the form of valuable chemicals such as CO, HCOOH, CH4, and so on. Selective ECO2R to CH4 is a challenging target because the rate-determining step of CH4 formation, namely CO* protonation, competes with hydrogen evolution reaction and the C–C coupling toward the production of longer-chain chemicals. Herein, a Cu-TiO2 composite catalyst consisting of CuOx clusters or Cu nanoparticles (CuNPs), which are isolated on the TiO2 grain surface, was synthesized using a one-pot solvothermal method and subsequent thermal treatment. The Cu-TiO2 catalyst exhibited high selectivity for CH4, and the ratio of FE for CH4 to total FE for all products in ECO2R reached 70%.
      Citation: Catalysts
      PubDate: 2022-04-23
      DOI: 10.3390/catal12050478
      Issue No: Vol. 12, No. 5 (2022)
  • Catalysts, Vol. 12, Pages 479: Silver-Carbonaceous Microsphere
           Precursor-Derived Nano-Coral Ag Catalyst for Electrochemical Carbon
           Dioxide Reduction

    • Authors: Xiangxiang Li, Shuling Chang, Yanting Wang, Lihong Zhang
      First page: 479
      Abstract: The selective and effective conversion of CO2 into available chemicals by electrochemical methods was applied as a promising way to mitigate the environment and energy crisis. Metal silver is regarded as an efficient electrocatalyst that can selectively convert CO2 into CO at room temperature. In this paper, a series of coral-like porous Ag (CD-Ag) catalysts were fabricated by calcining silver-carbonaceous microsphere (Ag/CM) precursors with different Ag content and the formation mechanism of CD-Ag catalysts was proposed involving the Ag precursor reduction and CM oxidation. In the selective electrocatalytic reduction of CO2 to CO, the catalyst 15 CD-Ag showed a stable current density at −6.3 mA/cm2 with a Faraday efficiency (FE) of ca. 90% for CO production over 5 h in −0.95 V vs. RHE. The excellent performance of the 15 CD-Ag catalysts is ascribed to the special surface chemical state and the particular nano-coral porous structure with uniformly distributed Ag particles and pore structure, which can enhance the electrochemical active surface areas (ECSA) and provide more active sites and porosity compared with other CD-Ag catalysts and even Ag foil.
      Citation: Catalysts
      PubDate: 2022-04-23
      DOI: 10.3390/catal12050479
      Issue No: Vol. 12, No. 5 (2022)
  • Catalysts, Vol. 12, Pages 480: Study of the Relationship between
           Metal–Support Interactions and the Electrocatalytic Performance of
           Pt/Ti4O7 with Different Loadings

    • Authors: Xiuyu Sun, Zhenwei Wang, Wei Yan, Chuangan Zhou
      First page: 480
      Abstract: The application potential of Pt/Ti4O7 has been reported, but the lack of research on the relationship between Pt loading, MSI, and catalytic activity hinders further development. Micron-sized Ti4O7 powders synthesized by a thermal reduction method under an H2 atmosphere were used as a support material for Pt-based catalysts. Using a modified polyol method, Pt/Ti4O7-5, Pt/Ti4O7-10, and Pt/Ti4O7-20 with different mass ratios (Pt to Pt/Ti4O7 is 0.05, 0.1, 0.2) were successfully synthesized. Uniformly dispersed platinum nanoparticles exhibit disparate morphologies, rod-like for Pt/Ti4O7-5 and approximately spherical for Pt/Ti4O7-10 and Pt/Ti4O7-20. Small-angle deflections and lattice reconstruction induced by strong metal–support interactions were observed in Pt/Ti4O7-5, which indicated the formation of a new phase at the interface. However, lattice distortions and dislocations for higher loading samples imply the existence of weak metal–support interactions. A possible mechanism is proposed to explain the different morphologies and varying metal–support interactions (MSI). With X-ray photoelectron spectroscopy, spectrums of Pt and Ti display apparent shifts in binding energy compared with commercial Pt-C and non-platinized Ti4O7, which can properly explain the changes in absorption ability and oxygen reduction reaction activity, as described in the electrochemical results. The synthetic method, Pt loading, and surface coverage of the support play an important role in the adjustment of MSI, which gives significant guidance for better utilizing MSI to prepare the target catalyst.
      Citation: Catalysts
      PubDate: 2022-04-25
      DOI: 10.3390/catal12050480
      Issue No: Vol. 12, No. 5 (2022)
  • Catalysts, Vol. 12, Pages 481: Cu-Y2O3 Catalyst Derived from Cu2Y2O5
           Perovskite for Water Gas Shift Reaction: The Effect of Reduction

    • Authors: Zeyu Wang, Fengying Luo, Nan Wang, Xinjun Li
      First page: 481
      Abstract: Cu2Y2O5 perovskite was reduced at different temperatures under H2 atmosphere to prepare two Cu-Y2O3 catalysts. The results of the activity test indicated that the Cu-Y2O3 catalyst after H2-reduction at 500 °C (RCYO-500) exhibited the best performance in the temperature range from 100 to 180 °C for water gas shift (WGS) reaction, with a CO conversion of 57.30% and H2 production of 30.67 μmol·gcat−1·min−1 at 160 °C and a gas hourly space velocity (GHSV) of 6000 mL·gcat−1·h−1. The catalyst reduced at 320 °C (RCYO-320) performed best at the temperature range from 180 to 250 °C, which achieved 86.44% CO conversion and 54.73 μmol·gcat−1·min−1 H2 production at 250 °C. Both of the Cu-Y2O3 catalysts had similar structures including Cu°, Cu+, oxygen vacancies (Vo) on the Cu°-Cu+ interface and Y2O3 support. RCYO-500, with a mainly exposed Cu° (100) facet, was active in the low-temperature WGS reaction, while the WGS activity of RCYO-320, which mainly exposed the Cu° (111) facet, was greatly enhanced above 180 °C. Different Cu° facets have different abilities to absorb H2O and then dissociate it to form hydroxyl groups, which is the main step affecting the catalytic rate of the WGS reaction.
      Citation: Catalysts
      PubDate: 2022-04-25
      DOI: 10.3390/catal12050481
      Issue No: Vol. 12, No. 5 (2022)
  • Catalysts, Vol. 12, Pages 482: Pt/Pd Decorate MOFs Derived Co-N-C
           Materials as High-Performance Catalysts for Oxygen Reduction Reaction

    • Authors: Yuhang Jiang, Dejing Zhu, Xiangchuan Zhao, Zhaoyun Chu, Liping Zhang, Yue Cao, Weimeng Si
      First page: 482
      Abstract: We report here, a strategy to prepare Pt/Pd nanoparticles decorated with Co-N-C materials, where Co-N-C was obtained via pyrolysis of ZIF-67 directly. As-prepared Pt/Pd/Co-N-C catalysts showed excellent ORR performance, offered with a higher limit current density (6.6 mA cm−2) and similar half-wave potential positive (E1/2 = 0.84 V) compared with commercial Pt/C. In addition to an ORR activity, it also exhibits robust durability. The current density of Pt/Pd/Co-N-C decreased by only 9% after adding methanol, and a 10% current density loss was obtained after continuous testing at 36,000 s.
      Citation: Catalysts
      PubDate: 2022-04-25
      DOI: 10.3390/catal12050482
      Issue No: Vol. 12, No. 5 (2022)
  • Catalysts, Vol. 12, Pages 483: Synthesis, Characterization, and Catalytic
           Activity of Nickel Sulfided Catalysts for the Dehydrogenation of Propane:
           Effect of Sulfiding Agent and Sulfidation Temperature

    • Authors: Tayyibah Tahier, Ebrahim Mohiuddin, Alicia Botes, Madelaine Frazenburg, Subelia Botha, Masikana M. Mdleleni
      First page: 483
      Abstract: The effect of sulfiding agent and sulfidation temperature on nickel catalysts supported on MgAl2O4 were investigated for propane dehydrogenation. The catalysts were prepared by reduction of NiO/MgAl2O4, followed by sulfidation using (NH4)2SO4 (S1), (NH4)2S (S2), and DMSO (S3) as sulfiding agents. The catalysts were sulfided at 200 °C, 400 °C, and 550 °C to form Ni/MgAl2O4-Sx-y, where x and y represent the sulfiding agent and sulfidation temperature, respectively. Physiochemical properties of the catalysts were characterized by XRD, BET, SEM, TEM, and TGA to investigate the type of nickel-sulfur species, surface area, morphology, particle size, and stability of the catalysts. Structural and textural properties revealed that the anion present on the sulfiding agent as well as the sulfidation temperature affect both the type and the strength of the Ni-S species. For the S1 catalysts, the SO42− ion interacted with the support to form MgSO4, while the S2− ion on the S2 and S3 catalysts was responsible for the formation of the Ni3S2 phase. The sulfidation temperature contributed to the %S present on each catalyst. Although the catalysts sulfided by S3 contained the least %S, Ni/MgAl2O4-S3-550 displayed the best catalytic performance as a result of the higher particle dispersion and stronger Ni-S interaction compared to S1 and S2 catalysts.
      Citation: Catalysts
      PubDate: 2022-04-25
      DOI: 10.3390/catal12050483
      Issue No: Vol. 12, No. 5 (2022)
  • Catalysts, Vol. 12, Pages 484: Effect of the Heterovalent Doping of TiO2

    • Authors: Petr D. Murzin, Aida V. Rudakova, Alexei V. Emeline, Detlef W. Bahnemann
      First page: 484
      Abstract: Two series of Sc3+- and Nb5+-doped TiO2 (rutile) samples were synthesized and characterized by SEM, ICPE spectroscopy, XPS, and BET methods. Photocatalytic activity of the doped TiO2 samples was tested in photocatalytic degradation of phenol. Dependences of the photocatalytic activities of the doped TiO2 samples demonstrate a volcano-like behavior, indicating the existence of the optimal dopant concentrations to achieve the highest activity of photocatalysts. Remarkably, the optimal dopant concentrations correspond to the extrema observed in work function dependences on the dopant concentrations, that indicates a significant energy redistribution of the defect states within the bandgap of TiO2. Such a redistribution of the defect states is also proven by the alterations of the optical and EPR spectra of the intrinsic Ti3+ defect states in TiO2. Based on the analysis of the experimental results, we conclude that both Sc3+ and Nb5+ doping of TiO2 results in redistribution of the defect states and the optimal dopant concentrations correspond to the defect structures, which are ineffective in charge carrier recombination, that ultimately leads to the higher photocatalytic activity of doped TiO2.
      Citation: Catalysts
      PubDate: 2022-04-25
      DOI: 10.3390/catal12050484
      Issue No: Vol. 12, No. 5 (2022)
  • Catalysts, Vol. 12, Pages 485: Methane Hydrate Formation in Hollow ZIF-8
           Nanoparticles for Improved Methane Storage Capacity

    • Authors: Chong Chen, Yun Li, Jilin Cao
      First page: 485
      Abstract: Methane hydrate has been extensively studied as a potential medium for natural gas storage and transportation. Due to their high specific surface area, tunable porous structure, and surface chemistry, metal–organic frameworks are ideal materials to exhibit the catalytic effect for the formation process of gas hydrate. In this paper, hollow ZIF-8 nanoparticles are synthesized using the hard template method. The synthesized hollow ZIF-8 nanoparticles are used in the adsorption and methane hydrate formation process. The effect of pre-adsorbed water mass in hollow ZIF-8 nanoparticles on methane storage capacity and the hydrate formation rate is investigated. The storage capacity of methane on wet, hollow ZIF-8 is augmented with an increase in the mass ratio of pre-adsorbed water and dry, hollow ZIF-8 (RW), and the maximum adsorption capacity of methane on hollow ZIF-8 with a RW of 1.2 can reach 20.72 mmol/g at 275 K and 8.57 MPa. With the decrease in RW, the wet, hollow ZIF-8 exhibits a shortened induction time and an accelerated growth rate. The formation of methane hydrate on hollow ZIF-8 is further demonstrated with the enthalpy of the generation reaction. This work provides a promising alternative material for methane storage.
      Citation: Catalysts
      PubDate: 2022-04-26
      DOI: 10.3390/catal12050485
      Issue No: Vol. 12, No. 5 (2022)
  • Catalysts, Vol. 12, Pages 486: Synthesis, Structure, and Photocatalytic
           Activity of TiO2-Montmorillonite Composites

    • Authors: Yonghui Zhang, Baoji Miao, Qiuling Chen, Zhiming Bai, Yange Cao, Basandorj Davaa
      First page: 486
      Abstract: In the present study, TiO2-montmorillonite (MMT) composites were synthesized hydrothermally under variable conditions, including the TiO2/MMT mass ratio, reaction pH, reaction temperature, and dwelling time. These samples were determined by X-ray photoelectron spectrometry (XPS), ultraviolet–visible spectroscopy% (UV-Vis DRS), electrochemical impedance spectroscopy (EIS), transient photocurrent responses, photoluminescence (PL) spectra, electron paramagnetic resonance (EPR), and N2 adsorption–desorption isotherms. The photocatalytic activity was evaluated as the ability to promote the visible-light-driven degradation of 30 mg/L of aqueous methylene blue, which was maximized for the composite with a TiO2 mass ratio of 30 wt% prepared at a pH of 6, a reaction temperature of 160 °C, and a dwelling time of 24 h (denoted as 30%-TM), which achieved a methylene blue removal efficiency of 95.6%, which was 4.9 times higher than that of pure TiO2. The unit cell volume and crystallite size of 30%-TM were 92.43 Å3 and 9.28 nm, respectively, with a relatively uniform distribution of TiO2 particles on the MMT’s surface. In addition, 30%-TM had a large specific surface area, a strong light absorption capacity, and a high Ti3+ content among the studied catalysts. Thus, the present study provides a basis for the synthesis of composites with controlled structures.
      Citation: Catalysts
      PubDate: 2022-04-26
      DOI: 10.3390/catal12050486
      Issue No: Vol. 12, No. 5 (2022)
  • Catalysts, Vol. 12, Pages 487: Metal-Organic Frameworks Decorated Cu2O
           Heterogeneous Catalysts for Selective Oxidation of Styrene

    • Authors: Mengyi Han, Xue Tang, Peng Wang, Zhiyong Zhao, Xiaohua Ba, Yu Jiang, Xiaowei Zhang
      First page: 487
      Abstract: The selective oxidation of styrene with highly efficient, environmentally benign, and cost-effective catalysts are of great importance for sustainable chemical processes. Here, we develop an in situ self-assembly strategy to decorate Cu-based metal-organic framework (MOF) Cu-BDC-NH2 nanocrystals on Cu2O octahedra to construct a series of Cu2O@Cu-BDC-NH2 catalysts for selective oxidation of styrene. Using H2O2 as green oxidants, the optimized sample of Cu2O@Cu-BDC-NH2-8h could achieve 85% styrene conversion with 76% selectivity of benzaldehyde under a mild condition of 40 °C. The high performance of the as-prepared heterogeneous catalysts was attributed to the well-designed Cu+/Cu2+ interface between Cu2O and Cu-BDC-NH2 as well as the porous MOF shells composed of the uniformly dispersed Cu-BDC-NH2 nanocrystals. The alkaline properties of Cu2O and the –NH2 modification of MOFs enable the reaction to be carried out in a base-free condition, which simplifies the separation process and makes the catalytic system more environmentally friendly. Besides the Cu2O octahedra (od-Cu2O), the Cu2O cuboctahedrons (cod-Cu2O) were synthesized by adjusting the added polyvinyl pyrrolidone, and the obtained cod-Cu2O@Cu-BDC-NH2 composite also showed good catalytic performance. This work provides a useful strategy for developing highly efficient and environmentally benign heterogeneous catalysts for the selective oxidation of styrene.
      Citation: Catalysts
      PubDate: 2022-04-26
      DOI: 10.3390/catal12050487
      Issue No: Vol. 12, No. 5 (2022)
  • Catalysts, Vol. 12, Pages 488: Promoted Performance of Layered Perovskite
           PrBaFe2O5+δ Cathode for Protonic Ceramic Fuel Cells by Zn Doping

    • Authors: Birkneh Sirak Teketel, Bayu Admasu Beshiwork, Dong Tian, Shiyue Zhu, Halefom G. Desta, Khan Kashif, Yonghong Chen, Bin Lin
      First page: 488
      Abstract: Proton-conducting solid–oxide fuel cell (H-SOFC) is an alternative promising low-temperature electrochemical cell for renewable energy, but the performance is insufficient because of the low activity of cathode materials at low temperatures. A layered perovskite oxide PrBaFe1.9Zn0.1O5+δ (PBFZ) was synthesized and investigated as a promising cathode material for low-temperature H-SOFC. Here, the partial substitution of Fe by Zn further enhances the electrical conductivity and thermal compatibility of PrBaFe2O5+δ (PBF). The PBFZ exhibits improved conductivity in the air at intermediate temperatures and good chemical compatibility with electrolytes. The oxygen vacancy formed at the PBFZ lattice due to Zn doping enhances proton defects, resulting in an improved performance by extending the catalytic sites to the whole cathode area. A single cell with a Ni-BZCY anode, PBFZ cathode, and BaZr0.7Ce0.2Y0.1O3-δ (BZCY) electrolyte membrane was successfully fabricated and tested at 550–700 °C. The maximum power density and Rp were enhanced to 513 mW·cm−2 and 0.3 Ω·cm2 at 700 °C, respectively, due to Zn doping.
      Citation: Catalysts
      PubDate: 2022-04-27
      DOI: 10.3390/catal12050488
      Issue No: Vol. 12, No. 5 (2022)
  • Catalysts, Vol. 12, Pages 489: A Promising Catalyst for the
           Dehydrogenation of Perhydro-Dibenzyltoluene: Pt/Al2O3 Prepared by
           Supercritical CO2 Deposition

    • Authors: Phillimon Modisha, Rudaviro Garidzirai, Hande Güneş, Selmi Erim Bozbag, Sarshad Rommel, Erdal Uzunlar, Mark Aindow, Can Erkey, Dmitri Bessarabov
      First page: 489
      Abstract: Pt/Al2O3 catalysts prepared via supercritical deposition (SCD), with supercritical CO2, wet impregnation (WI) methods and a selected benchmark catalyst, were evaluated for the dehydrogenation of perhydro-dibenzyltoluene (H18-DBT) at 300 °C in a batch reactor. After ten dehydrogenation runs, the average performance of the catalyst prepared using SCD was the highest compared to the benchmark and WI-prepared catalysts. The pre-treatment of the catalysts with the product (dibenzyltoluene) indicated that the deactivation observed is mainly due to the adsorbed H0-DBT blocking the active sites for the reactant (H18-DBT). Furthermore, the SCD method afforded a catalyst with a higher dispersion of smaller sized Pt particles, thus improving catalytic performance towards the dehydrogenation of H18-DBT. The particle diameters of the SCD- and WI-prepared catalysts varied in the ranges of 0.6–2.2 nm and 0.8–3.4 nm and had average particle sizes of 1.1 nm and 1.7 nm, respectively. Energy dispersive X-ray spectroscopy analysis of the catalysts after ten dehydrogenation runs revealed the presence of carbon. In this study, improved catalyst performance led to the production of more liquid-based by-products and carbon material compared to catalysts with low catalytic performance.
      Citation: Catalysts
      PubDate: 2022-04-28
      DOI: 10.3390/catal12050489
      Issue No: Vol. 12, No. 5 (2022)
  • Catalysts, Vol. 12, Pages 490: Water-Based Electrophoretic Deposition of
           Ternary Cobalt-Nickel-Iron Oxides on AISI304 Stainless Steel for Oxygen

    • Authors: Ieva Barauskienė, Eugenijus Valatka
      First page: 490
      Abstract: Coatings consisting of cobalt, nickel and iron (Co-Ni-Fe) oxides were electrophoretically deposited on AISI 304-type stainless steel using aqueous suspensions without any binder. The synthesis of Co-Ni-Fe oxides was carried out by the thermal decomposition of metal nitrates with various molar ratios at 673 K. Structural and morphological analysis confirmed that the deposited coatings were mainly composed of spinel-type oxides with predominantly round-shaped particles. The prepared electrodes were examined for their electrocatalytic performance in oxygen generation under alkaline conditions. Various electrochemical techniques indicated the influence of iron content on the electrochemical activity of Co-Ni-Fe oxides, with the calculated values of the Tafel constant being in the range of 52–59 mV dec−1. Long-term oxygen generation for 24 h at 1.0 V revealed very good mechanical and electrocatalytic stability of the prepared electrodes, since they were able to maintain up to 98% of their initial activity.
      Citation: Catalysts
      PubDate: 2022-04-28
      DOI: 10.3390/catal12050490
      Issue No: Vol. 12, No. 5 (2022)
  • Catalysts, Vol. 12, Pages 491: Efficient Synthesis of
           3-Sulfonyl-2-sulfonylmethyl-2H-chromenes via Tandem Knoevenagel
           Condensation/Oxa-Michael Addition Protocol

    • Authors: Lin Jiang, Peiying Peng, Min Li, Lu Li, Menglin Zhao, Minglong Yuan, Mingwei Yuan
      First page: 491
      Abstract: An organocatalytic [4 + 2] cascade annulation of salicylaldehydes and 1,3-bisarylsulfonylpropenes has been developed. This protocol enables the efficient and straightforward synthesis of a new series of 3-sulfonyl-2-sulfonylmethyl-2H-chromenes that are useful for exploring pharmacologically valued compounds. Further reductive modifications result in 3-desulfonylated chromene or chromane derivatives. This protocol can be expanded to the synthesis of 3-sulfonyl-2-sulfonylmethyl 1,2-dihydroquinoline.
      Citation: Catalysts
      PubDate: 2022-04-28
      DOI: 10.3390/catal12050491
      Issue No: Vol. 12, No. 5 (2022)
  • Catalysts, Vol. 12, Pages 492: Inorganic Salt Catalysed Hydrothermal
           Carbonisation (HTC) of Cellulose

    • Authors: James M. Hammerton, Andrew B. Ross
      First page: 492
      Abstract: The presence of inorganic salts either as part of the substrate or added to the reaction medium are known to significantly affect the reaction pathways during hydrothermal carbonisation (HTC) of biomass. This work aims to understand the influence of salts on hydrothermal carbonisation by processing cellulose in the presence of one or more inorganic salts with different valency. Batch experiments and Differential Scanning Calorimetry were used to investigate the change in reaction pathways during hydrothermal conversion. The effect of salts on the rate of HTC of cellulose can be correlated with the Lewis acidity of the cation and the basicity of the anion. The effect of the anion was more pH-dependent than the cation because it can protonate during the HTC process as organic acids are produced. The introduction of salts with Lewis acidity increases the concentration of low molecular weight compounds in the process water. The addition of a second salt can influence the catalytic effect of the first salt resulting in greater levulinic acid yields at the expense of hydrochar formation. Salts also play an important role in cellulose dissolution and can be used to modify the yield and composition of the hydrochars.
      Citation: Catalysts
      PubDate: 2022-04-28
      DOI: 10.3390/catal12050492
      Issue No: Vol. 12, No. 5 (2022)
  • Catalysts, Vol. 12, Pages 493: Oxidative Dehydrogenation of Ethane with
           CO2 over Mo/LDO Catalyst: The Active Species of Mo Controlled by LDO

    • Authors: Gengzhe Song, Qi Wang, Liang Yang, Duohua Liao, Shuang Li
      First page: 493
      Abstract: A series of the layered double oxides supported molybdenum oxide catalysts were synthesized and evaluated in the oxidative dehydrogenation of ethane with CO2 (CO2-ODHE). The 22.3 wt% Mo/LDO catalyst delivered a 92.3%selectivity to ethylene and a 7.9% ethane conversion at relatively low temperatures. The molybdenum oxide catalysts were fully characterized by XRD, BET, SEM, TEM, UV–vis, Raman TG, and XPS. Isolated [MoO4]2− dominated on the surface of the fresh 12.5 wt% Mo/LDO catalyst. With the increase of the Mo content, the Mo species transformed from [MoO4]2− to [Mo7O24]6− and [Mo8O26]4− on the 22.3 wt% and 30.1 wt% Mo/LDO catalysts, respectively. The redox mechanism was proposed and three Mo species including [MoO4]2−, [Mo7O24]6−, and [Mo8O26]4− showed quite different functions in the CO2-ODHE reaction: [MoO4]2−, with tetrahedral structure, preferred the non-selective pathway; [Mo7O24]6−, with an octahedral construction, promoted the selective pathway; and the existence of [Mo8O26]4− reduced the ability to activate ethane. This work provides detailed insights to further understand the relationship between structure–activity and the role of surface Mo species as well as their aggregation state in CO2-ODHE.
      Citation: Catalysts
      PubDate: 2022-04-28
      DOI: 10.3390/catal12050493
      Issue No: Vol. 12, No. 5 (2022)
  • Catalysts, Vol. 12, Pages 494: Role of Lewis Acid Metal Centers in
           Metal–Organic Frameworks for Ultrafast Reduction of 4-Nitrophenol

    • Authors: Jagannath Panda, Soumya Prakash Biswal, Himanshu Sekhar Jena, Arijit Mitra, Raghabendra Samantray, Rojalin Sahu
      First page: 494
      Abstract: Metal–Organic Frameworks (MOFs) can be a good alternative to conventional catalysts because they are non-toxic and can be selective without compromising efficiency. Nano MOFs such as UiO-66 have proven themselves to be competitive in the catalytic family. In this study, we report the excellent catalytic behavior of UiO-66 MOF in the reduction of a model reaction: 4-Nitrophenol (4-NP) to 4-Aminophenol (4-AP) over MOF-5 (Zn-BDC) and MIL-101 (Fe-BDC). Nano UiO-66 crystals were synthesized by a hydrothermal process and characterized by Powder X-ray Diffraction, Diffused Reflectance UV-Vis spectroscopy, Scanning Electron Microscopy, and Transmission Electron Microscopy. The catalysts’ performance during the hydrogenation reduction reaction from 4-NP to 4-AP was investigated in the presence of a reducer, NaBH4. The UiO-66 nano crystals exhibited excellent catalytic behavior owing to its large surface area and Lewis acidic nature at the metal nodes. Furthermore, UiO-66 showed excellent recyclability behavior, verified during repeated consecutive use in a sequence. The catalyst yielded similar catalytic behavior during the reduction of nitrophenols at each cycle, which is a novel finding.
      Citation: Catalysts
      PubDate: 2022-04-29
      DOI: 10.3390/catal12050494
      Issue No: Vol. 12, No. 5 (2022)
  • Catalysts, Vol. 12, Pages 495: Kinetics of Catalytic Decarboxylation of
           Naphthenic Acids over HZSM-5 Zeolite Catalyst

    • Authors: Nihad Omer Hassan, Mohamed Challiwala, Dhallia Mamoun Beshir, Nimir O. Elbashir
      First page: 495
      Abstract: Naphthenic acids are naturally occurring carboxylic acids in crude oil with cyclic or aromatic rings in their structure. These carboxylic acids are responsible for the acidity of crude oil, leading to corrosion problems in refinery equipment and the deactivation of catalysts while creating a continuous need for maintenance. Therefore, removing naphthenic acids has become an important requirement in refining acidic crude oil. In this paper, experiments are conducted to investigate the use of HZSM-5 zeolite catalyst to reduce the total acid number (TAN) of a typical acidic crude oil obtained from Al-Fula blocks in Western Sudan. TAN is an important metric signifying the acidity of crude oil. A full factorial design of the experiment (DOE) framework enabled a better understanding of the efficacy of the catalyst at three parametric levels (reaction temperature: 250-270-300 °C, reaction time: 2-3-4 h, and oil:catalyst weight ratio: 20-22-25 g/g). The results demonstrate that the HZSM-5 zeolite catalyst provides up to 99% removal of naphthenic acids via the decarboxylation route. Additionally, the removal efficiency increases with increasing temperature and residence time. The acidity of the crude oil was shown to decrease after treatment with the catalyst for four hrs.; from 6.5 mg KOH/g crude to 1.24; 0.39 and 0.17 mg KOH/g at 250; 270 and 300 °C, respectively. A sharp decrease of TAN was observed at the oil catalyst mass ratio of 20 g/g at 250 °C, and almost complete conversion of acids was achieved after 4 hrs. Another experiment at 270 °C showed a converse relationship between the oil:catalyst ratio and acid removal; suggesting the activation of side reactions at higher temperature conditions catalyzed by excess acid. Finally; a Langmuir–Hinshelwood (LH) kinetic model has been developed to enable rapid prediction of the performance of the HZSM-5 zeolite catalyst for decarboxylation reaction. The model has also been validated and tested in ASPEN® software for future simulation and scalability studies.
      Citation: Catalysts
      PubDate: 2022-04-28
      DOI: 10.3390/catal12050495
      Issue No: Vol. 12, No. 5 (2022)
  • Catalysts, Vol. 12, Pages 496: Hydrogen-Rich Gas Production with the
           Ni-La/Al2O3-CaO-C Catalyst from Co-Pyrolysis of Straw and Polyethylene

    • Authors: Jianfen Li, Rongyi Gao, Longkai Zhu, Yiran Zhang, Zeshan Li, Bolin Li, Jiaxiang Wang, Ji He, Yun He, Zhenhua Qin, Mahmood Laghari, Dabin Guo
      First page: 496
      Abstract: Ni-based catalysts have been extensively investigated because of their superior catalytic performance. In this study, the Ni-La/Al2O3-CaO-C catalyst was prepared by homogeneous precipitation, employed in the co-pyrolysis of soybean straw with polyethylene to produce hydrogen. The optimal experimental conditions were identified by discussing the carrier synthesis ratio, feedstock ratio, and addition of La. Additionally, the stability of the catalyst was evaluated. It was established that the carrier was produced using a molar ratio, the raw ingredients ratio of 5:5, and that the optimum catalytic action was obtained when La was added. Co-pyrolysis of soybean straw with polyethylene (PE) that was catalyzed by Ni-La/Al2O3-CaO-C generated 55.45 vol% of H2 under ideal experimental circumstances. After six applications, the H2 yield was 33.89 vol%, compared to 27.5 vol% for the Ni/Al2O3-CaO-C catalyst. The experimental results indicate that Ni-La/Al2O3-CaO-C exhibits superior catalytic activity and stability than Ni/Al2O3-CaO-C.
      Citation: Catalysts
      PubDate: 2022-04-28
      DOI: 10.3390/catal12050496
      Issue No: Vol. 12, No. 5 (2022)
  • Catalysts, Vol. 12, Pages 497: Silica-Supported Copper (II) Oxide Cluster
           via Ball Milling Method for Catalytic Combustion of Ethyl Acetate

    • Authors: Yuhang Ye, Han Chen, Yuchuan Ye, Huiqiu Zhang, Jing Xu, Luhui Wang, Liuye Mo
      First page: 497
      Abstract: Highly dispersed CuO/SiO2 catalysts were successfully synthesized by a green process of ball milling (BM) under solvent-free and room temperature conditions. The structural evolution of CuO/SiO2 catalysts prepared by BM was elucidated by TG-DSC, XRD, FT-IR, and XPS characterizations. We found that the copper acetate precursor was dispersed over the layer of copper phyllosilicate which was formed by reacting between the copper acetate precursor and the silica support during the BM process. The copper phyllosilicate layer over the support might play an important role in the stabilization of the CuO cluster (<2 nm) during thermal pretreatment. The 15% CuO/SiO2 catalyst exhibited the best catalytic activity for the catalytic combustion of ethyl acetate as it owned a highest active surface area of CuO among the CuO/SiO2 catalysts with different copper loadings.
      Citation: Catalysts
      PubDate: 2022-04-29
      DOI: 10.3390/catal12050497
      Issue No: Vol. 12, No. 5 (2022)
  • Catalysts, Vol. 12, Pages 498: Novel Heterogeneous Catalysts for Advanced
           Oxidation Processes (AOPs)

    • Authors: Olívia Salomé G. P. Soares, Carla A. Orge, Raquel Pinto Rocha
      First page: 498
      Abstract: With the increasing global usage of water and the continuous addition of contaminants to water sources, new challenges associated with the abatement of organic pollutants, particularly those that are refractory to conventional water and wastewater treatment technologies, have arisen [...]
      Citation: Catalysts
      PubDate: 2022-04-29
      DOI: 10.3390/catal12050498
      Issue No: Vol. 12, No. 5 (2022)
  • Catalysts, Vol. 12, Pages 499: Establishment of Integrated Analysis Method
           for Probing and Reconstructing Hydrogenation Mechanism of a Model Reaction

    • Authors: Mailidan Wumaer, Rahima Abdulla, Yuli Kou, Ziran Liu, Naeem Akram, Haji Akber Aisa, Jide Wang
      First page: 499
      Abstract: The hydrogenation of 4-nitrophenol (4-NP) has attracted much attention, since it is typically used as a model reaction for evaluating newly developed catalysts, but its mechanism is still debated. Herein, Co(OH)2-modified CuO catalyst (Co(OH)2/CuO) was used for the reduction of 4-NP to 4-aminophenol (4-AP) in an aqueous sodium borohydride (NaBH4) solution. The reaction mechanism was investigated by UV-Vis spectroscopy (UV-Vis), high-performance liquid chromatography (HPLC), HPLC-Q-orbitrap high-resolution mass spectrometry (LC-MS/MS), and 1HNMR spectroscopy (1HNMR) as an integrated technology at different concentrations of NaBH4. Samples were taken at specified time intervals and monitored using UV-Vis, HPLC, LC-MS/MS, and 1HNMR. With the help of comprehensive analysis, eight intermediates, including azo and azoxy compounds, were effectively captured, and the variation tendency of each intermediate was determined, revealing that the hydrogenation of 4-NP proceeds via a coexistence of the direct and condensation routes. The integrated analysis methods were powerful technical supports for the study of the catalysis mechanism.
      Citation: Catalysts
      PubDate: 2022-04-29
      DOI: 10.3390/catal12050499
      Issue No: Vol. 12, No. 5 (2022)
  • Catalysts, Vol. 12, Pages 500: Bismuth Sillenite Crystals as Recent
           Photocatalysts for Water Treatment and Energy Generation: A Critical

    • Authors: Oussama Baaloudj, Hamza Kenfoud, Ahmad K. Badawi, Achraf Amir Assadi, Atef El Jery, Aymen Amine Assadi, Abdeltif Amrane
      First page: 500
      Abstract: Photocatalysis has been widely studied for environmental applications and water treatment as one of the advanced oxidation processes (AOPs). Among semiconductors that have been employed as catalysts in photocatalytic applications, bismuth sillenite crystals have gained a great deal of interest in recent years due to their exceptional characteristics, and to date, several sillenite material systems have been developed and their applications in photoactivity are under study. In this review paper, recent studies on the use of Bi-based sillenites for water treatment have been compiled and discussed. This review also describes the properties of Bi-based sillenite crystals and their advantages in the photocatalytic process. Various strategies used to improve photocatalytic performance are also reviewed and discussed, focusing on the specific advantages and challenges presented by sillenite-based photocatalysts. Furthermore, a critical point of certain bismuth catalysts in the literature that were found to be different from that reported and correspond to the sillenite form has also been reviewed. The effectiveness of some sillenites for environmental applications has been compared, and it has demonstrated that the activity of sillenites varies depending on the metal from which they were produced. Based on the reviewed literature, this review summarizes the current status of work with binary sillenite and provides useful insights for its future development, and it can be suggested that Bismuth sillenite crystals can be promising photocatalysts for water treatment, especially for degrading and reducing organic and inorganic contaminants. Our final review focus will emphasize the prospects and challenges of using those photocatalysts for environmental remediation and renewable energy applications.
      Citation: Catalysts
      PubDate: 2022-04-29
      DOI: 10.3390/catal12050500
      Issue No: Vol. 12, No. 5 (2022)
  • Catalysts, Vol. 12, Pages 501: Efficient Utilization of Hydrocarbon
           Mixture to Produce Aromatics over Zn/ZSM-5 and Physically Mixed with ZSM-5

    • Authors: Hyunjin Shim, Jinju Hong, Kyoung-Su Ha
      First page: 501
      Abstract: A mixture of saturated and unsaturated light hydrocarbon was used as feed gas for the production of aromatics. Natural gas liquids (NGL) from gas fields and hydrocarbon molecules obtained in the middle of conversion processes could be considered a kind of light hydrocarbon mixture. Therefore, for the conversion of the mixture into aromatics compounds, Zn-impregnated ZSM-5 catalysts were prepared and evaluated by employing different loading of Zn. In addition, the catalytic performance was tested and compared by charging physically mixed two different kinds of catalysts in the bed. The NH3-TPD result showed that the impregnation of Zn led to an increase in the number of medium-strength acid sites, whereas those of weak and strong acid sites were decreased. From the results of the catalytic activity tests, 0.5Zn/ZSM-5 showed the highest aromatics yield. As the amount of Zn loading was further increased to 1 wt.%, the yield of aromatics decreased. The test result in the case of the physically mixed catalysts showed a slightly lower yield in terms of total aromatics, but showed the highest BTX yield. To reveal the relative contribution of each hydrocarbon conversion to aromatics yield, each C2 compound was separately tested for aromatization over Zn/ZSM-5.
      Citation: Catalysts
      PubDate: 2022-04-29
      DOI: 10.3390/catal12050501
      Issue No: Vol. 12, No. 5 (2022)
  • Catalysts, Vol. 12, Pages 502: Catalysis in Advanced Oxidation
           Technologies (AOTs) for Water, Air and Soil Treatment

    • Authors: Guillard, Robert
      First page: 502
      Abstract: The environment is what supports life on Earth. However, it is dangerously affected by human activities that lead to significant pollution of the water, air, soil, etc. [...]
      Citation: Catalysts
      PubDate: 2022-04-29
      DOI: 10.3390/catal12050502
      Issue No: Vol. 12, No. 5 (2022)
  • Catalysts, Vol. 12, Pages 503: Identification of Novel Potential
           Heparanase Inhibitors Using Virtual Screening

    • Authors: Alfredo Rus, Victor M. Bolanos-Garcia, Agatha Bastida, Paula Morales
      First page: 503
      Abstract: Heparanase (HPSE) is a mammalian endo-β-D-glucuronidase that cleaves heparan sulphate (HS) side chains of heparin sulphate proteoglycans (HSPG), a class of molecules composed of repeating polysulfated disaccharide units of glucosamine and hexuronic acid residues. HPSE controls the availability of growth factors, chemokines, lipoproteins and other bioactive molecules by degrading HS into smaller fractions, allowing the release of saccharide fragments that activate a plethora of signaling processes. HPSE overexpression has been correlated with tumor survival and metastasis as well as several diseases associated with chronic inflammation, including the ongoing COVID-19 pandemic caused by SARS-CoV-2. Thus, the search for molecules that could potentially inhibit HPSE has become increasingly relevant in the clinic. In this study, we have integrated a strategy that combines virtual screening and molecular docking of publicly available chemical databases to identify small compounds that can be developed into novel HPSE inhibitors. Structural rationalization of the interactions previously reported compounds led us to identify promising unexplored chemotypes. Here we show that these novel potential HPSE inhibitors present optimized in silico druggability and docking properties and may serve as pharmacological tools for the treatment of chronic and infectious diseases associated with chronic inflammation.
      Citation: Catalysts
      PubDate: 2022-04-30
      DOI: 10.3390/catal12050503
      Issue No: Vol. 12, No. 5 (2022)
  • Catalysts, Vol. 12, Pages 504: Combined Biological and Photocatalytic
           Degradation of Dibutyl Phthalate in a Simulated Wastewater Treatment Plant

    • Authors: Ipoteng Justice Mphahlele, Soraya Phumzile Malinga, Langelihle Nsikayezwe Dlamini
      First page: 504
      Abstract: The removal of organic pollutant in wastewater has become a major priority in water treatment. In this study, organic pollutant dibutyl phthalate (DBP) has been biologically and photocatalytically degraded in wastewater using modified transition metal dichalcogenides. The as-synthesized nanoparticles were characterized using various characterization techniques, which includes XRD, Raman, FT-IR, SEM, TEM, UV-Vis, XPS, PL, EIS, and photocurrent responses. The nanoparticles synthesized by slightly modified hydrothermal method depicted a hexagonal phase, as evidenced by XRD and Raman analyses. The biological degradation of 69% dibutyl phthalate was achieved. Moreover, the total organic carbon removal efficiency of 70% was further achieved. Incorporating biological and photocatalytic systems significantly improved dibutyl phthalate removal in secondary effluent by three folds when compared to the unilateral operating setup. The optimized parameters such as pH = 7, 5 ppm and DBP concentration with the addition of 10 mg catalysts loading were employed for the photocatalytic degradation of dibutyl phthalate in water. Pristine WS2 exhibited photocatalytic efficiencies of 46% after 60 min illumination. The use of dual system 3% Ce/Gd-WS2 exhibited the highest photodegradation of 85%, with a chemical oxygen demand of 80% and total organic carbon of 77%. The enhanced activity by the composite is attested to the formation of heterojunction exhibiting excellent charge separation and low rate of recombination. The 3% Ce/Gd-WS2 can be used up to seven times and still achieve a degradation of 56%.
      Citation: Catalysts
      PubDate: 2022-04-30
      DOI: 10.3390/catal12050504
      Issue No: Vol. 12, No. 5 (2022)
  • Catalysts, Vol. 12, Pages 505: High-Performance Ligand-Protected Metal
           Nanocluster Catalysts for CO2 Conversion through the Exposure of
           Undercoordinated Sites

    • Authors: Dominic Alfonso
      First page: 505
      Abstract: Previous experimental breakthroughs reveal the potential to create novel heterogeneous catalysts for the electroreduction of CO2 to a high-value product CO using ligand-protected Au-based nanoclusters. Since the chemical composition and geometric structures have been precisely defined, it is possible to adopt robust design guidelines for the development of practical catalysts and to fundamentally elucidate the underlying reaction mechanism. In this short review, the computational progress made to understand the experimentally observed reduction process on the following subset of materials—Au25(SR)18−, Au24Pd(SR)18, Au23(SR)16− and Au21Cd2(SR)16−—is described. A significant finding from our first-principles mechanistic studies is that CO2 conversion on the fully ligand protected nanoclusters is thermodynamically unfavorable due to the very weak binding of intermediates on the surface region. However, the reaction becomes feasible when either Au or S sites are exposed through the removal of a ligand. The results particularly point to the role of undercoordinated S sites in the creation of highly functional heterogeneous catalysts that are both active and selective for the CO2 conversion process. The incorporation of dopants could significantly influence the catalytic reactivity of the nanoclusters. As demonstrated in the case of the monopalladium substitution in Au25(SR)18−, the presence of the foreign atom leads to an enhancement of CO production selectivity due to the greater stabilization of the intermediates. With the Cd substitution doping of Au23(SR)16−, the improvement in performance is also attributed to the enhanced binding strength of the intermediates on the geometrically modified surface of the nanocluster.
      Citation: Catalysts
      PubDate: 2022-04-30
      DOI: 10.3390/catal12050505
      Issue No: Vol. 12, No. 5 (2022)
  • Catalysts, Vol. 12, Pages 506: Partial Hydrogenation of Soybean and Waste
           Cooking Oil Biodiesel over Recyclable-Polymer-Supported Pd and Ni

    • Authors: Ambra Maria Fiore, Giuseppe Romanazzi, Cristina Leonelli, Piero Mastrorilli, Maria Michela Dell’Anna
      First page: 506
      Abstract: Biodiesel obtained through the transesterification in methanol of vegetable oils, such as soybean oil (SO) and waste cooking oil (WCO), cannot be used as a biofuel for automotive applications due to the presence of polyunsaturated fatty esters, which have a detrimental effect on oxidation stability (OS). A method of upgrading this material is the catalytic partial hydrogenation of the fatty acid methyl ester (FAME) mixture. The target molecule of the partial hydrogenation reaction is monounsaturated methyl oleate (C18:1), which represents a good compromise between OS and the cold filter plugging point (CFPP) value, which becomes too high if the biodiesel consists of unsaturated fatty esters only. In the present work, polymer-supported palladium (Pd-pol) and nickel (Ni-pol) nanoparticles were separately tested as catalysts for upgrading SO and WCO biodiesels under mild conditions (room temperature for Pd-pol and T = 100 °C for Ni-pol) using dihydrogen (p = 10 bar) as the reductant. Both catalysts were obtained through co-polymerization of the metal containing monomer M(AAEMA)2 (M = Pd, Ni; AEEMA− = deprotonated form of 2-(acetoacetoxy)ethyl methacrylate)) with co-monomers (ethyl methacrylate for Pd and N,N-dimethylacrilamide for Ni) and cross-linkers (ethylene glycol dimethacrylate for Pd and N,N’-methylene bis-acrylamide for Ni), followed by reduction. The Pd-pol system became very active in the hydrogenation of C=C double bonds, but poorly selective towards the desirable C18:1 product. The Ni-pol catalyst was less active than Pd-pol, but very selective towards the mono-unsaturated product. Recyclability tests demonstrated that the Ni-based system retained its activity and selectivity with both the SO and WCO substrates for at least five subsequent runs, thus representing an opportunity for waste biomass valorization.
      Citation: Catalysts
      PubDate: 2022-04-30
      DOI: 10.3390/catal12050506
      Issue No: Vol. 12, No. 5 (2022)
  • Catalysts, Vol. 12, Pages 507: Tetrabutyl Ammonium Salts of Keggin-Type
           Vanadium-Substituted Phosphomolybdates and Phosphotungstates for Selective
           Aerobic Catalytic Oxidation of Benzyl Alcohol

    • Authors: Juan Díaz, Luis R. Pizzio, Gina Pecchi, Cristian H. Campos, Laura Azócar, Rodrigo Briones, Romina Romero, Adolfo Henríquez, Eric M. Gaigneaux, David Contreras
      First page: 507
      Abstract: A series of tetrabutyl ammonium (TBA) salts of V-included Keggin-type polyoxoanions with W (TBA4PW11V1O40 and TBA5PW10V2O40) and Mo (TBA4PMo11V1O40 and TBA5PMo10V2O40) as addenda atoms were prepared using a hydrothermal method. These synthesized materials were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), UV-Vis diffuse reflectance (DRS UV-Vis), thermogravimetric analysis (TGA), CHN elemental analysis (EA), inductively coupled plasma spectrometry (ICP-MS), and N2 physisorption techniques to assess their physicochemical/textural properties and correlate them with their catalytic performances. According to FT-IR and DRS UV-Vis, (PVXW(Mo)12−XO40)(3+X)− anions are the main species present in the TBA salts. Additionally, CHN-EA and ICP-MS revealed that the desired stoichiometry was obtained. Their catalytic activities in the liquid-phase aerobic oxidation of benzyl alcohol to benzaldehyde were studied at 5 bar of O2 at 170 °C. Independently of the addenda atom nature, the catalytic activity increased with the number of V in the Keggin anion structure. For both series of catalysts, TBA salts of polyoxometalates with the highest V-substitution degree (TBA5PMo10V2O40 and TBA5PW10V2O40) showed higher activity. The maximum benzyl alcohol conversions obtained were 93% and 97% using (TBA)5PMo10V2O40 and (TBA)5PW10V2O40 as catalysts, respectively. In all the cases, the selectivity toward benzaldehyde was higher than 99%.
      Citation: Catalysts
      PubDate: 2022-04-30
      DOI: 10.3390/catal12050507
      Issue No: Vol. 12, No. 5 (2022)
  • Catalysts, Vol. 12, Pages 508: Preparation of TiO2-CNT-Ag Ternary
           Composite Film with Enhanced Photocatalytic Activity via Plasma-Enhanced
           Chemical Vapor Deposition

    • Authors: Jianghua Lang, Kazuma Takahashi, Masaru Kubo, Manabu Shimada
      First page: 508
      Abstract: In this study, a TiO2-CNT-Ag ternary composite film was successfully synthesized using the plasma-enhanced chemical vapor deposition method by simultaneously feeding a carbon nanotube (CNT)/Ag suspension and titanium tetraisopropoxide gas. The prepared TiO2-CNT-Ag film was characterized by scanning electron microscopy, transmission electron microscopy, energy-dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy, X-ray diffraction, and ultraviolet-visible spectroscopy. Moreover, the Ag/Ti ratio of the film was confirmed using an inductivity-coupled plasma optical emission spectrometer. The performance of the TiO2-composite film for the degradation of rhodamine 6G under simulated solar light irradiation was evaluated. The rate constant of the prepared TiO2-CNT-Ag for rhodamine 6G degradation was approximately 1.8 times greater than that of prepared TiO2. This result indicates that the addition of CNT and Ag significantly improved the photocatalytic activity of the prepared films.
      Citation: Catalysts
      PubDate: 2022-04-30
      DOI: 10.3390/catal12050508
      Issue No: Vol. 12, No. 5 (2022)
  • Catalysts, Vol. 12, Pages 509: Synergistic Effect between Ni and Ce Dual
           Active Centers Initiated by Activated Fullerene Soot for
           Electro−Fenton Degradation of Tetracycline

    • Authors: Chi Li, Yongfu Lian, Qin Zhou
      First page: 509
      Abstract: The degradation of a high concentration of organic pollutants has long been a challenge to water restoration, and the development of electro−Fenton catalysis offers a practical approach to solving this problem. In this study, a novel electro−Fenton catalyst, activated fullerene soot−loaded NiO−doped CeO2 (0.4(0.4NiO−CeO2)−AFS) nanoparticles, was prepared through the impregnation of 0.4NiO−CeO2 particles and activated fullerene soot (AFS). When applied for the degradation of 200 mg/L of tetracycline, this catalyst demonstrated a degradation rate as high as 99%. Even after 20 cycles, the degradation rate was more than 80%. Moreover, it was concluded that AFS could initiate the synergistic effect between Ni and Ce dual active centers in the degradation of tetracycline; this can be ascribed to the extremely large specific surface area of AFS.
      Citation: Catalysts
      PubDate: 2022-05-02
      DOI: 10.3390/catal12050509
      Issue No: Vol. 12, No. 5 (2022)
  • Catalysts, Vol. 12, Pages 510: C−H Methylation Using Sustainable

    • Authors: Ishika Agrawal, Gaurav Prakash, Shaeel Ahmed Al-Thabaiti, Mohamed Mokhtar, Debabrata Maiti
      First page: 510
      Abstract: C−H methylation of sp2 and sp3 carbon centers is significant in many biological processes. Methylated drug candidates show unique properties due to the change in solubility, conformation and metabolic activities. Several photo-catalyzed, electrochemical, mechanochemical and metal-free techniques that are widely utilized strategies in medicinal chemistry for methylation of arenes and heteroarenes have been covered in this review.
      Citation: Catalysts
      PubDate: 2022-05-02
      DOI: 10.3390/catal12050510
      Issue No: Vol. 12, No. 5 (2022)
  • Catalysts, Vol. 12, Pages 511: Novel Enzymatic Method for Imine Synthesis
           via the Oxidation of Primary Amines Using D-Amino Acid Oxidase from
           Porcine Kidney

    • Authors: Nobuhiro Kawahara, Kunwadee Palasin, Yasuhisa Asano
      First page: 511
      Abstract: During studies on the oxidative cyanation reaction catalyzed by a variant of D-amino acid oxidase from porcine kidney (pkDAO) (Y228L/R283G), an unexpected formation of 1-phenyl-N-(1-phenylethylidene)ethanamine (PPEA) was detected. The optimal reaction conditions for the synthesis of PPEA and the reaction mechanism were investigated using the pkDAO variant. The highest PPEA synthesis was obtained in the reaction with 150 mM (R)-MBA at pH 9.0 and at 20 °C. Since PPEA synthesis proceeded by trapping the intermediate 1-phenylethanimine (1-PEI) by 15N-labeled n-hexylamine, which is not a substrate for the pKDAO variant, it was deduced that PPEA would be synthesized by a nucleophilic substitution of 1-PEI by another molecule of (R)-MBA. PPEA was further identified by its conversion to bis(1-phenylethyl)amine (BPEA) through reduction with NaBH4. Thus, a new enzymatic method of imine synthesis by oxidation of primary amine by the variant pkDAO was achieved for the first time.
      Citation: Catalysts
      PubDate: 2022-05-04
      DOI: 10.3390/catal12050511
      Issue No: Vol. 12, No. 5 (2022)
  • Catalysts, Vol. 12, Pages 512: Fabrication of a Heterobinuclear Redox
           Cycle to Enhance the Photocatalytic Activity of BiOCl

    • Authors: Dongmei Li, Guisheng Liu, Xiaojie Li, Zhuo Gao, Hangqi Shao, Zhongzhen Tian
      First page: 512
      Abstract: La3+ and Ni2+-doped BiOCl were prepared by sol–gel method and characterized by physicochemical and spectroscopic techniques. Their photocatalytic performances were investigated by the degradation of gentian violet under visible light. The results indicated that the co-doping of Ni and La significantly enhanced the photocatalytic performance of BiOCl. The photodegradation efficiency of LaNiBiOCl reached 95.5% in 105 min, which was 1.5 times that of BiOCl. This significant enhancement in photocatalytic activity was mainly attributed to the effective capture and transfer of photogenerated electrons between heterobinuclear La and Ni redox cycle, which benefited the photodegradation of active h+ and the formation of active •O2−. Furthermore, the photodegradation activity did not show an obvious drop after five recycles, indicating that LaNiBiOCl was a promising semiconductor photocatalyst for the degradation of gentian violet.
      Citation: Catalysts
      PubDate: 2022-05-04
      DOI: 10.3390/catal12050512
      Issue No: Vol. 12, No. 5 (2022)
  • Catalysts, Vol. 12, Pages 513: Formation Mechanism of Carbon-Supported
           Hollow PtNi Nanoparticles via One-Step Preparations for Use in the Oxygen
           Reduction Reaction

    • Authors: Dong-gun Kim, Yeonsun Sohn, Injoon Jang, Sung Jong Yoo, Pil Kim
      First page: 513
      Abstract: Hollow Pt-based nanoparticles are known to possess the properties of high electrocatalytic activity and durability. Nonetheless, their practical applications as catalytic materials are limited because of the requirement for exhaustive preparation. In this study, we prepared carbon-supported hollow PtNix (x = the moles of the Ni precursor to the Pt precursor in the catalyst preparation step) catalysts using a one-step preparation method, which substantially reduced the complexity of the conventional method for preparing hollow Pt-based catalysts. In particular, this hollow structure formation mechanism was proposed based on extensive characterizations. The prepared catalysts were examined to determine if they could be used as electrocatalysts for the oxygen reduction reaction (ORR). Among the investigated catalysts, the acid-treated hollow PtNi3/C catalyst demonstrated the best ORR activity, which was 3 times higher and 2.3 times higher than those of the commercial Pt/C and acid-treated particulate PtNi3/C catalysts, respectively.
      Citation: Catalysts
      PubDate: 2022-05-04
      DOI: 10.3390/catal12050513
      Issue No: Vol. 12, No. 5 (2022)
  • Catalysts, Vol. 12, Pages 514: Changes in Heavy Oil Saturates and
           Aromatics in the Presence of Microwave Radiation and Iron-Based

    • Authors: Alexey V. Vakhin, Mohammed A. Khelkhal, Irek I. Mukhamatdinov, Rezeda E. Mukhamatdinova, Arash Tajik, Olga V. Slavkina, Sergey Y. Malaniy, Marat R. Gafurov, Aydar R. Nasybullin, Oleg G. Morozov
      First page: 514
      Abstract: Our knowledge of electromagnetic heating’s effect on heavy oil upgrading is largely based on very limited data. The aim of the present research was thus to study in detail the effect of microwave exposure in the absence and presence of nanosized magnetite on the composition of heavy oil. The obtained data reveal that the use of nanosized magnetite improves not only microwave radiation application as a result of its absorption and release of thermal energy but also that these nanoparticles have a catalytic ability to break carbon–heteroatom bonds in the composition of resins and asphaltene molecules. In fact, the overall reduction in asphaltenes or resins does not always adequately describe very important changes in asphaltene composition. Even a small fraction of broken carbon–heteroatom bonds can lead to an increase in the mobility of asphaltenes. Moreover, this study has shed light on the important evidence for asphaltenes’ transformation, which was found to be the formation of light aromatic compounds, such as alkylbenzenes, naphthalenes and phenanthrenes. These compounds were fixed in the composition of the aromatic fraction. We believe that these compounds could be the fragments obtained from asphaltenes’ degradation. The evidence from this study points toward the idea that asphaltenes’ destruction is crucial for increasing oil mobility in the reservoir rock during its thermal stimulation.
      Citation: Catalysts
      PubDate: 2022-05-04
      DOI: 10.3390/catal12050514
      Issue No: Vol. 12, No. 5 (2022)
  • Catalysts, Vol. 12, Pages 515: Facile Synthesis of Fe(0)@Activated Carbon
           Material as An Active Adsorbent towards the Removal of Cr (VI) from
           Aqueous Media

    • Authors: Mohammed J. Almujaybil, Dania Fathi Mohammed Abunaser, Mohamed Gouda, Mai M. Khalaf, Ibrahim M. A. Mohamed, Hany M. Abd El-Lateef
      First page: 515
      Abstract: A novel adsorbent substrate based on zero-valent iron in activated carbon (Fe(0)@AC) was introduced in this work, and was evaluated as a cheap adsorbent for the removal of Cr(VI) from aqueous solutions. The as-prepared Fe(0)@AC material was chemically prepared via NaBH4 reduction in the presence of ferric chloride as an iron source, followed by the addition of powdered activated carbon. The different physicochemical tools confirm the successful preparation of Fe(0) composite with activated carbon as a heterogeneous composite with heterogeneous morphology of the rock-shape structure, which could play a role in the metal adsorption application. Interestingly, the removal efficiency (RE) of Cr(VI) was increased from 52% to 84% due to the Fe(0)@AC adsorbent being changed from 0.2 to 0.4 g/100 mL. Following this, the increase rate was stabilized, and the RE reached 95% in the case of 0.8 g/100 mL from Fe(0)@AC adsorbent. This result could be due to the increase in the sorbent active sites with more contents from Fe(0)@AC. The adsorption model based on the Langmuir approach could successfully describe the experimental outcomes for Cr(VI) removal by Fe(0)@AC with the correlation coefficient of 0.977. To conclude, Fe(0)@AC heterogeneous material is an active adsorbent for Cr(VI) removal from aqueous solutions.
      Citation: Catalysts
      PubDate: 2022-05-04
      DOI: 10.3390/catal12050515
      Issue No: Vol. 12, No. 5 (2022)
  • Catalysts, Vol. 12, Pages 516: Hydrogenation of CO2 on Nanostructured
           Cu/FeOx Catalysts: The Effect of Morphology and Cu Load on Selectivity

    • Authors: Karolína Simkovičová, Muhammad I. Qadir, Naděžda Žilková, Joanna E. Olszówka, Pavel Sialini, Libor Kvítek, Štefan Vajda
      First page: 516
      Abstract: The aim of this work was to study the influence of copper content and particle morphology on the performance of Cu/FeOx catalysts in the gas-phase conversion of CO2 with hydrogen. All four investigated catalysts with a copper content between 0 and 5 wt% were found highly efficient, with CO2 conversion reaching 36.8%, and their selectivity towards C1 versus C2-C4, C2-C4=, and C5+ products was dependent on catalyst composition, morphology, and temperature. The observed range of products is different from those observed for catalysts with similar composition but synthesized using other precursors and chemistries, which yield different morphologies. The findings presented in this paper indicate potential new ways of tuning the morphology and composition of iron-oxide-based particles, ultimately yielding catalyst compositions and morphologies with variable catalytic performances.
      Citation: Catalysts
      PubDate: 2022-05-04
      DOI: 10.3390/catal12050516
      Issue No: Vol. 12, No. 5 (2022)
  • Catalysts, Vol. 12, Pages 517: Modified MgH2 Hydrogen Storage Properties
           Based on Grapefruit Peel-Derived Biochar

    • Authors: Jiaqi Zhang, Quanhui Hou, Xintao Guo, Xinglin Yang
      First page: 517
      Abstract: Carbon materials play an important role in the development of solid hydrogen storage materials. The main purpose of this work is to study the low-cost synthesis of biomass carbon (BC) and its positive effect on the hydrogen storage behavior of magnesium hydride (MgH2). Herein, it is proven that when biomass carbon (BC) is used together with magnesium hydride (MgH2), biomass carbon can be used as an adsorption and desorption channel for hydrogen. The initial dehydrogenation temperature of MgH2 + 10 wt% BC composite is 250 °C, which is 110 °C lower than that of pure MgH2. In addition, the MgH2 + 10 wt% BC composite system can complete all dehydrogenation processes within 10 min at 350 °C. Meanwhile, 5.1 wt% H2 can also be dehydrogenated within 1 h at 300 °C. Under the same conditions, MgH2 hardly starts to release hydrogen. After complete dehydrogenation, the composite can start to absorb hydrogen at 110 °C. Under the conditions of 225 °C and 3 MPa, 6.13 wt% H2 can be absorbed within 1 h, basically reaching the theoretical dehydrogenation limit. Cycling experiments show that the MgH2 + 10 wt% BC composite has a good stability. After 10 cycles, the hydrogen storage capacity shows almost no obvious decline. It is believed that this study can help in the research and development of efficient carbon-based multifunctional catalysts.
      Citation: Catalysts
      PubDate: 2022-05-05
      DOI: 10.3390/catal12050517
      Issue No: Vol. 12, No. 5 (2022)
  • Catalysts, Vol. 12, Pages 518: Effect of Iodide on the pH-Controlled
           Hydrogenations of Diphenylacetylene and Cinnamaldehyde Catalyzed by
           Ru(II)-Sulfonated Triphenylphosphine Complexes in Aqueous–Organic
           Biphasic Systems

    • Authors: Ágnes Kathó, Henrietta H. Horváth, Gábor Papp, Ferenc Joó
      First page: 518
      Abstract: The effect of NaI on hydrogenation of diphenylacetylene catalyzed by the water-soluble [{RuCl(mtppms-Na)2}2(µ-Cl)2] (1) (mtppms-Na = meta-monosulfonated triphenylphosphine sodium salt) is reported. Hydrogenations were performed under mild conditions (P(H2) = 1 bar, T = 50–80 ℃) in aqueous–organic biphasic reaction mixtures wherein the catalyst was dissolved in aqueous phase of various pHs. In acidic solutions, addition of NaI to 1 + mtppms-Na increased the selective conversion of diphenylacetylene to stilbenes from 10% to 90% but did not effect the high Z-selectivity (up to 98%). In contrast, in basic solutions the major product was diphenylethane (up to 70%), and the yield of E-stilbene exceeded that of the Z-isomer. 1H and 31P NMR measurements revealed that depending on the absence or presence of NaI, the catalytically active Ru(II)-hydride species in acidic solutions was [RuHCl(mtppms-Na)3], 2, or [RuHI(mtppms-Na)3], 5, respectively, while in basic solutions, both 2 and 5 were hydrogenated further to yield the same hydride species, cis,fac-[RuH2(H2O)(mtppms-Na)3]. [RuHI(mtppms-Na)3] proved superior to [RuHCl(mtppms-Na)3] as a catalyst for the selective hydrogenation of cinnamaldehyde to dihydrocinamaldehyde. This finding was explained by a facile formation of a (putative) dihydrogen complex [Ru(H2)I2(H2O)(mtppms-Na)2] intermediate, resulting in fast heterolytic activation of H2.
      Citation: Catalysts
      PubDate: 2022-05-05
      DOI: 10.3390/catal12050518
      Issue No: Vol. 12, No. 5 (2022)
  • Catalysts, Vol. 12, Pages 519: How to Obtain Maximum Environmental
           Applicability from Natural Silicates

    • Authors: Daliborka Popadić, Nemanja Gavrilov, Ljubiša Ignjatović, Danina Krajišnik, Slavko Mentus, Maja Milojević-Rakić, Danica Bajuk-Bogdanović
      First page: 519
      Abstract: Unmodified natural silicates (bentonite, kaolin, clinoptilolite and diatomites) were tested as adsorbents for the organic pollutants in water tables using Methylene Blue (MB) as the model adsorbate. Among the selected materials, bentonite adsorbed as much as 237 mg/g, confirming its excellent suitability for pollutant removal. Spectral evidence confirmed successful MB immobilization at the bentonite surface. Furthermore, the thermal treatment of MB-saturated adsorbent in an inert atmosphere at 700 °C produced a carbon/silicate composite. EDX confirmed the formation of the nitrogen-doped carbon overlay on the silica scaffold and the obtained composite material was probed as an electrode material for oxygen reduction in an alkaline solution. Reduction proceeded via a two-electron mechanism with the main product being HO2−, a known nucleophile, which was subsequently used to degrade/demethylate MB. The composite showed a considerable 70% MB removal rate after an hour of electrochemical treatment. The synergy between the processes of adsorption of MB and the surface-generated HO2− dictates the efficiency of the method and points to a possible route for spent adsorbent reuse in the form of a durable product for environmental protection.
      Citation: Catalysts
      PubDate: 2022-05-05
      DOI: 10.3390/catal12050519
      Issue No: Vol. 12, No. 5 (2022)
  • Catalysts, Vol. 12, Pages 520: Electrodeposition of a Li-Al Layered Double
           Hydroxide (LDH) on a Ball-like Aluminum Lathe Waste Strips in Structured
           Catalytic Applications: Preparation and Characterization of Ni-Based LDH
           Catalysts for Hydrogen Evolution

    • Authors: Song-Hui Huang, Yu-Jia Chen, Wen-Fu Huang, Jun-Yen Uan
      First page: 520
      Abstract: A functionally structured catalyst was explored for ethanol steam reforming (ESR) to generate H2. Aluminum lathe waste strips were employed as the structured catalytic framework. The mixed metal oxide (Li-Al-O) was formed on the surface of Al lathe waste strips through calcination of the Li-Al-CO3 layered double hydroxide (LDH), working as the support for the formation of Ni catalyst nanoparticles. NaOH and NaHCO3 titration solutions were, respectively, used for adjusting the pH of the NiCl2 aqueous solutions at 50 °C when developing the precursors of the Ni-based catalysts forming in-situ on the Li-Al-O oxide support. The Ni precursor on the Al structured framework was reduced in a H2 atmosphere at 500 °C for 3 h, changing the hydroxide precursor into Ni nanoparticles. The titration agent (NaOH or NaHCO3) effectively affected the physical and chemical characterizations of the catalyst obtained by the different titrations. The ESR reaction catalyzed by the structured catalysts at a relatively low temperature of 500 °C was studied. The catalyst using NaHCO3 titration presented good stability for generating H2 during ESR, achieving a high rate of H2 volume of about 122.9 L/(gcat·h). It also had a relatively low acidity on the surface of the Li-Al-O oxide support, leading to low activity for the dehydration of ethanol and high activity to H2 yield. The interactions of catalysts between the Ni precursors and the Li-Al-O oxide supports were discussed in the processes of the H2 reduction and the ESR reaction. Mechanisms of carbon formation during the ESR were proposed by the catalysts using NaOH and NaHCO3 titration agents.
      Citation: Catalysts
      PubDate: 2022-05-05
      DOI: 10.3390/catal12050520
      Issue No: Vol. 12, No. 5 (2022)
  • Catalysts, Vol. 12, Pages 521: Two-Dimensional Zeolitic Imidazolate
           Framework ZIF-L: A Promising Catalyst for Polymerization

    • Authors: M. Abdur Rahaman, Bibimaryam Mousavi, Farah Naz, Francis Verpoort
      First page: 521
      Abstract: Here, for the first time, a 2D and leaf-like zeolitic imidazolate framework (ZIF-L) is reported for the synthesis of ultrahigh molecular weight (UHMW) poly(methyl methacrylate) (PMMA) with Mn up to 1390 kg mol−1. This synthesis method is a one-step process without any co-catalyst in a solvent-free medium. SEM, PXRD, FT-IR, TGA, and nitrogen sorption measurements confirmed the 2D and leaf-like structure of ZIF-L. The results of PXRD, SEM, TGA demonstrate that the catalyst ZIF-L is remarkably stable even after a long-time polymerization reaction. Zwitterionic Lewis pair polymerization (LPP) has been proposed for the catalytic performance of ZIF-L on methyl methacrylate (MMA) polymerization. This MMA polymerization is consistent with a living system, where ZIF-L could reinitiate the polymerization and propagates the process by gradually growing the polymer chains.
      Citation: Catalysts
      PubDate: 2022-05-06
      DOI: 10.3390/catal12050521
      Issue No: Vol. 12, No. 5 (2022)
  • Catalysts, Vol. 12, Pages 522: Exploration of the Interactions between
           Maltase–Glucoamylase and Its Potential Peptide Inhibitors by
           Molecular Dynamics Simulation

    • Authors: Shanshan Guan, Xu Han, Zhan Li, Xifei Xu, Yongran Cui, Zhiwen Chen, Shuming Zhang, Shi Chen, Yaming Shan, Song Wang, Hao Li
      First page: 522
      Abstract: Diabetes mellitus, a chronic metabolic disorder, represents a serious threat to human health. The gut enzyme maltase–glucoamylase (MGAM) has attracted considerable attention as a potential therapeutic target for the treatment of type 2 diabetes. Thus, developing novel inhibitors of MGAM holds the promise of improving clinical management. The dipeptides, Thr-Trp (TW) and Trp-Ala (WA), are known inhibitors of MGAM; however, studies on how they interact with MGAM are lacking. The work presented here explored these interactions by utilizing molecular docking and molecular dynamics simulations. Results indicate that the active center of the MGAM could easily accommodate the flexible peptides. Interactions involving hydrogen bonds, cation-π, and hydrophobic interactions are predicted between TW/WA and residues including Tyr1251, Trp1355, Asp1420, Met1421, Glu1423, and Arg1510 within MGAM. The electrostatic energy was recognized as playing a dominant role in both TW-MGAM and WA-MGAM systems. The binding locations of TW/WA are close to the possible acid-base catalytic residue Asp1526 and might be the reason for MGAM inhibition. These findings provide a theoretical structural model for the development of future inhibitors.
      Citation: Catalysts
      PubDate: 2022-05-07
      DOI: 10.3390/catal12050522
      Issue No: Vol. 12, No. 5 (2022)
  • Catalysts, Vol. 12, Pages 523: Dependence of Photocatalytic Activity on
           the Morphology of Strontium Titanates

    • Authors: Tamás Gyulavári, Daniella Dusnoki, Viktória Márta, Mohit Yadav, Mahsa Abedi, András Sápi, Ákos Kukovecz, Zoltán Kónya, Zsolt Pap
      First page: 523
      Abstract: Strontium titanates were prepared with different morphologies by varying the ratio of solvents used during the synthesis. The effects of morphology and solvent (ethylene glycol to water) ratio were investigated both on the structure and photocatalytic activity of the samples. Structural properties were determined by X-ray diffraction, scanning electron microscopy, diffuse reflectance spectroscopy, and nitrogen adsorption measurements. The photocatalytic activity of the samples was evaluated by the photocatalytic oxidation of phenol and by the photocatalytic reduction of carbon dioxide. The ratio of solvents notably influenced the morphology, strontium carbonate content, primary crystallite size, and specific surface area of the samples. Samples prepared at low ethylene glycol to water ratios were spherical, while the ones prepared at high ethylene glycol to water ratios could be characterized predominantly by lamellar morphology. The former samples were found to have the highest efficiency for phenol degradation, while the sample with the most well-defined lamellar morphology proved to be the best for CO2 reduction.
      Citation: Catalysts
      PubDate: 2022-05-07
      DOI: 10.3390/catal12050523
      Issue No: Vol. 12, No. 5 (2022)
  • Catalysts, Vol. 12, Pages 524: Reducibility Studies of Ceria,
           Ce0.85Zr0.15O2 (CZ) and Au/CZ Catalysts after Alkali Ion Doping: Impact on
           Activity in Oxidation of NO and CO

    • Authors: Ewa Maria Iwanek (nee Wilczkowska), Leonarda Francesca Liotta, Shazam Williams, Linjie Hu, Huitian Ju, Giuseppe Pantaleo, Zbigniew Kaszkur, Donald W. Kirk, Wojciech Patkowski, Marek Gliński
      First page: 524
      Abstract: The aim of these studies was to perform thorough research on the influence of alkali metal ions (Li, Na, K and Cs) on the properties of nanogold catalysts supported on ceria–zirconia. The addition of alkali metal ions onto CeO2 further affected the reducibility, which was not noted for the Zr-doped support (Ce0.85Zr0.15O2). Despite the substantial impact of alkali metal ions on the reducibility of ceria, the activity in CO oxidation did not change much. In contrast, they do not have a large effect on the reducibility of Au/CZ but suppressed the activity of this system in CO oxidation. The results show that for CO oxidation, the negative effect of potassium ions is greater than that of sodium, which corresponds to the shift in the Tmax of the reduction peak towards higher temperatures. The negative effect of Li+ and Cs+ spans 50% CO conversion. The negative effect was visible for CO oxidation in both the model stream and the complex stream, which also contained hydrocarbons and NO. In the case of NO oxidation to NO2, two temperature regimes were observed for Au + 0.3 at% K/CZ, namely in the temperature range below 350 °C; the effect of potassium ions was beneficial for NO oxidation, whereas at higher temperatures, the undoped gold catalyst produced more NO2.
      Citation: Catalysts
      PubDate: 2022-05-07
      DOI: 10.3390/catal12050524
      Issue No: Vol. 12, No. 5 (2022)
  • Catalysts, Vol. 12, Pages 525: Research Progress in ZIF-8 Derived Single
           Atomic Catalysts for Oxygen Reduction Reaction

    • Authors: Siqi Shen, Yuanyuan Sun, Hao Sun, Yuepeng Pang, Shuixin Xia, Taiqiang Chen, Shiyou Zheng, Tao Yuan
      First page: 525
      Abstract: Transition metal (TM) single atomic catalysts (MSAC-N-C) derived from doped zeolite imidazolate frameworks (ZIF-8) are considered attractive oxygen reduction reaction (ORR) catalysts for fuel cells and metal-air batteries due to their advantages of high specific surface area, more active catalytic sites, adjustable pore size, and coordination topology features. This review provides an updated overview of the latest advances of MSAC-N-C catalysts derived from ZIF-8 precursors in ORR electrocatalysis. Particularly, some key challenges, including coordination environments regulation of catalysis center in MSAC-N-C, the active sites loading optimization and synergistic effects between TM nanoclusters/nanoparticles and the single atoms on MSAC-N-C catalysis activity, as well as their adaptability in various devices, are summarized for improving future development and application of MSAC-N-C catalysts. In addition, this review puts forward future research directions, making it play a better role in ORR catalysis for fuel cells and metal air batteries.
      Citation: Catalysts
      PubDate: 2022-05-07
      DOI: 10.3390/catal12050525
      Issue No: Vol. 12, No. 5 (2022)
  • Catalysts, Vol. 12, Pages 526: Copper Catalyzed Inverse Electron Demand
           [4+2] Cycloaddition for the Synthesis of Oxazines

    • Authors: Weiguang Yang, Zitong Zhou, Yu Zhao, Danyang Luo, Xiai Luo, Hui Luo, Liao Cui, Li Li
      First page: 526
      Abstract: A copper catalyzed tandem CuAAC/ring cleavage/[4+2] annulation reaction of terminal ynones, sulfonyl azides, and imines has been developed to synthesize the functionalized oxazines under mild conditions. Particularly, the intermediate N-sulfonyl acylketenimines undergo cycloaddition of an inverse electron demand Diels–Alder reaction with imines and a series of 1,3-oxazine derivatives were obtained successfully in good yields.
      Citation: Catalysts
      PubDate: 2022-05-07
      DOI: 10.3390/catal12050526
      Issue No: Vol. 12, No. 5 (2022)
  • Catalysts, Vol. 12, Pages 527: Flower-like Co3O4 Catalysts for Efficient
           Catalytic Oxidation of Multi-Pollutants from Diesel Exhaust

    • Authors: Zihao Li, Xianhuai Chen, Jinghuan Chen, Huazhen Chang, Lei Ma, Naiqiang Yan
      First page: 527
      Abstract: Nowadays, the oxidation activity at the low-temperature regime for Co3O4 catalysts needs to be improved to meet the stringent regulation of multi-pollutant diesel exhaust. Herein, nanoflower-like Co3O4 diesel oxide catalysts (DOCs) were fabricated with the addition of a low-content Pt to trigger better catalytic activities for oxidizing multi-pollutants (CO, C3H6, and NO) emissions by taking advantage of the strong-metal supporting interaction. Compared to the conventional DOCs based on Pt/Al2O3, the as-synthesized Pt/Co3O4 catalysts not only exhibited better multi-pollutants oxidation activities at the low temperature but also obtained better resistance toward NO inhibition. Moreover, Pt/Co3O4 catalysts showed exceptional hydrothermal durability throughout long-term tests in the presence of water vapor. According to the XPS and H2-TPR results, Pt promoted low-temperature catalytic activity by increasing the active surface oxygen species and reducibility due to the robust synergistic interaction between metallic Pt and supporting Co3O4. Meanwhile, TGA curves confirmed the Pt atoms that facilitated the desorption of surface-active oxygen and hydroxyl radicals in a low-temperature regime. Furthermore, instead of probing the intermediates during CO and C3H6 oxidation for Pt/Co3O4 catalysts, which included carbonates, formate, and acetate species, in situ DRIFTs experiments also revealed C3H6 oxidation mainly took place over metallic Pt sites.
      Citation: Catalysts
      PubDate: 2022-05-07
      DOI: 10.3390/catal12050527
      Issue No: Vol. 12, No. 5 (2022)
  • Catalysts, Vol. 12, Pages 528: Pt–Pd Bimetallic Aerogel as
           High-Performance Electrocatalyst for Nonenzymatic Detection of Hydrogen

    • Authors: Chuxuan Pan, Yuanyuan Zheng, Jing Yang, Dongyang Lou, Jian Li, Yujing Sun, Wei Liu
      First page: 528
      Abstract: Hydrogen peroxide (H2O2) plays an indispensable role in the biological, medical, and chemical fields. The development of an effective H2O2 detecting method is of great importance. In the present work, a series of PtxPdy bimetallic aerogels and Pt, Pd monometallic aerogels were controllably synthesized by one-step gelation method. Their morphologies and compositions were characterized by transmission electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy, and so forth. These aerogels were used as nonenzyme electrocatalysts for the detection of H2O2. The cyclic voltammetric and amperometric results demonstrated that the performance of the metal aerogels showed volcano-type behavior, with the Pt50Pd50 aerogel sitting on top. The Pt50Pd50 aerogel-based electrochemical sensor exhibited excellent comprehensive performance, with a low overpotential of −0.023 V vs. Ag/AgCl, a broad linear range from 5.1 to 3190 μM (R2 = 0.9980), and a high sensitivity of 0.19 mA mM−1 cm−2, in combination with good anti-interference ability and stability. A comprehensive study indicated that the superior sensing performance of the Pt50Pd50 aerogel is closely related to its optimized d-band center and larger cumulative pore volume. This work first applied Pt–Pd bimetallic aerogels into the detection of H2O2 and shows the promising application of noble metal aerogels in the electrochemical sensing area.
      Citation: Catalysts
      PubDate: 2022-05-08
      DOI: 10.3390/catal12050528
      Issue No: Vol. 12, No. 5 (2022)
  • Catalysts, Vol. 12, Pages 529: Promotional Effect of Pt-Doping on the
           Catalytic Performance of Pt−CeO2 Catalyst for CO Oxidation

    • Authors: Angran Jiang, Zhibo Ren, Yaqi Qu, Yanjun Zhang, Jianwei Li
      First page: 529
      Abstract: Growing interest in the development of a hydrogen economy means that CO oxidation is increasingly important for upgrading H2-rich fuel gas streams for fuel cells. CeO2-supported catalysts are the most promising candidates for the catalytic oxidation of CO because of their high activity. In the present work, DFT+U calculations were performed to investigate the stability and CO oxidation reactivity of Ptn (n = 1−4) clusters supported on CeO2(111) (Pt/CeO2) and Pt-doped CeO2(111) (Pt/(Pt−Ce)O2) surfaces. The Pt clusters showed similar nucleation behavior on both CeO2 and (Pt−Ce)O2 surfaces. Further, the formation of oxygen vacancies (Ov) was facilitated because of surface charge depletion caused by the dopant Pt. Our DFT results suggest that the interfacial OV plays an important role in the CO oxidation reaction cycle, and the calculated energy barrier for the CO oxidation reaction on the Pt/(Pt−Ce)O2 surface is approximately 0.43 eV lower than that on the surface of the undoped catalyst, suggesting enhanced CO oxidation reactivity. Therefore, the chemical modification of the CeO2 support via doping is an effective strategy for improving the catalytic performance of Pt/CeO2.
      Citation: Catalysts
      PubDate: 2022-05-09
      DOI: 10.3390/catal12050529
      Issue No: Vol. 12, No. 5 (2022)
  • Catalysts, Vol. 12, Pages 530: Reduced Graphene Oxide Supported Zinc
           Tungstate Nanoparticles as Proficient Electro-Catalysts for Hydrogen
           Evolution Reactions

    • Authors: Norah Alhokbany, Tansir Ahamad, Saad M. Alshehri, Jahangeer Ahmed
      First page: 530
      Abstract: The nanocomposites of reduced graphene oxide (rGO) supported zinc tungstate nanoparticles (ZnWO4-NPs) receive considerable attention in electro-catalytic hydrogen evolution reactions (HER) and reveal significantly higher electro-catalytic performances than pure ZnWO4-NPs in alkaline media (i.e., 0.5 M KOH electrolyte). The polarization studies show that the ZnWO4-NPs@rGO nanocomposites exhibit low energy loss and good electrode stability during electrochemical reactions for HER. Furthermore, the Tafel slope of ZnWO4-NPs@rGO nanocomposites is found to be approximately 149 mV/dec, which closely agrees with the reported Tafel values of the noble metal electrocatalyst. In contrast, the performance of the ZnWO4-NPs@rGO nanocomposite is found to be approximately 1.5 times higher than that of ZnWO4-NPs in hydrogen production efficiency. Our results emphasize the significance of the nanocomposites with enhanced electro-catalytic activities by lowering the energy loss during electro-catalysis in an alkaline medium.
      Citation: Catalysts
      PubDate: 2022-05-09
      DOI: 10.3390/catal12050530
      Issue No: Vol. 12, No. 5 (2022)
  • Catalysts, Vol. 12, Pages 531: One-Pot Synthesis of Benzopyrano-Pyrimidine
           Derivatives Catalyzed by P-Toluene Sulphonic Acid and Their Nematicidal
           and Molecular Docking Study

    • Authors: Mehtab Parveen, Mohammad Azeem, Azmat Ali Khan, Afroz Aslam, Saba Fatima, Mansoor A. Siddiqui, Yasser Azim, Kim Min, Mahboob Alam
      First page: 531
      Abstract: A cost-effective and environmentally benign benzopyrano-pyrimidine derivative synthesis has been established with the condensation of different salicylaldehyde derivatives, piperidine/morpholine with malononitrile, in the presence of a catalyst containing p-toluene sulphonic acid (PTSA) at 80 °C temperature. This procedure offers a new and enriched approach for synthesizing benzopyrano-pyrimidine derivatives with high yields, a straightforward experimental method, and short reaction times. The synthesized compounds were investigated for their nematocidal activity, and the result shows that among the four compounds, compounds 4 and 5 showed strong nematocidal activity against egg hatching and J2s mortality. The nematocidal efficacy of the compounds might be due to the toxicity of chemicals which are soluble in ethanol. The nematocidal effectiveness was directly related to the concentration of ethanolic dilutions of the compounds, i.e., the maximum treatment concentration, the higher the nematocidal action, or the higher the mortality and egg hatching inhibition. In the present study, with support from docking analysis, the relation between chemical reactivity and nematocidal activity of compound 4 was inferred.
      Citation: Catalysts
      PubDate: 2022-05-09
      DOI: 10.3390/catal12050531
      Issue No: Vol. 12, No. 5 (2022)
  • Catalysts, Vol. 12, Pages 532: Stability of Pt-Adsorbed CO on Catalysts
           for Room Temperature-Oxidation of CO

    • Authors: Frédéric C. Meunier, Taha Elgayyar, Kassiogé Dembélé, Helena Kaper
      First page: 532
      Abstract: A large signal of gas-phase CO overlapping with those of adsorbates is often present when investigating catalysts by operando diffuse reflectance FT-IR spectroscopy. Physically removing CO(g) from the IR cell may lead to a fast decay of adsorbate signals. Our work shows that carbonyls adsorbed on metallic Pt sites fully vanished in less than 10 min at 30 °C upon removing CO(g) when redox supports were used. In contrast, a broad band assigned to CO adsorbed on oxidized Pt sites was stable. It was concluded that physically removing CO(g) at room temperature during IR analyses will most likely lead to changes in the distribution of CO(ads) and a misrepresentation of the Pt site speciation, misguiding the development of efficient low-temperature CO oxidation catalysts. A tentative representation of the nature of the Pt phases present depending on the feed composition is also proposed.
      Citation: Catalysts
      PubDate: 2022-05-11
      DOI: 10.3390/catal12050532
      Issue No: Vol. 12, No. 5 (2022)
  • Catalysts, Vol. 12, Pages 533: Photo-Induced Preparation of Ag@MOF-801
           Composite Based Heterogeneous Nanocatalyst for the Production of Biodiesel

    • Authors: Osamah M. Alduhaish, Mohammed Rafi Shaik, Syed Farooq Adil
      First page: 533
      Abstract: Hybrid materials based on metal-organic frameworks (MOFs) and nanoparticles (NPs) have gained considerable popularity in a variety of applications. Particularly, these types of materials have demonstrated excellent efficiency in heterogeneous catalysis due to the synergistic effect between the components. Herein, we report a simple, eco-friendly, photocatalytic method for the fabrication of Zr containing MOF-801 and a silver (Ag) NPs-based hybrid (Ag@MOF-801). In this method, the photocatalytic property of the central metal ion (Zr) of MOF was exploited to promote the formation and deposition of Ag NPs on the surface of the MOF-801 under the irradiation of visible light. The successful incorporation of Ag NPs was ascertained by powder X-ray diffraction (XRD) and UV-Vis analysis, while the morphology and surface area of the sample was determined by N2 adsorption–desorption and scanning electron microscopy (SEM), respectively. The resulting Ag@MOF-801 hybrid served as a highly efficient catalyst for the transesterification of used vegetable oil (UVO) for the production of biodiesel. The Ag@MOF-801 catalyst exhibited superior catalytic activity compared to its pristine MOF-801 counterpart due to the enhanced surface area of the material.
      Citation: Catalysts
      PubDate: 2022-05-11
      DOI: 10.3390/catal12050533
      Issue No: Vol. 12, No. 5 (2022)
  • Catalysts, Vol. 12, Pages 534: SO2 Tolerance of Rice Hull Ash Based Fe-Cu
           Catalysts for Low-Temperature CO-SCR of NO

    • Authors: Zhaohui Teng, Shan Huang, Na Li, Qulan Zhou
      First page: 534
      Abstract: Rice husk ash (RHA) has potential as a supporter of catalysts. In this research, we studied the activity and SO2 tolerance of RHA-based Fe-Cu oxide in the reduction of NO by CO. Characterization methods were employed to study the properties of the catalysts and their SO2 tolerance. Activity and SO2 resistance were also tested at different temperatures. We recommend two catalysts with SO2 resistance ability: Fe0.67Cu0.33/RHA (the highest catalytic activity) and Fe0.8Cu0.2/RHA. The NO removal rate hardly changed with the addition of SO2 and was kept at about 100%. However, the CO conversion rate decreased with increasing SO2 at the lower reaction temperatures, which may be due to the formation of sulfites. Fortunately, the deactivation was reversible and can be reduced with an increase in the reaction temperature. The results of our research may help promote the application of CO-SCR.
      Citation: Catalysts
      PubDate: 2022-05-12
      DOI: 10.3390/catal12050534
      Issue No: Vol. 12, No. 5 (2022)
  • Catalysts, Vol. 12, Pages 535: Catalytic Oxidation of Chlorobenzene over
           Ce-Mn-Ox/TiO2: Performance Study of the Porous Structure

    • Authors: Bo Yang, Maosen Ni, Qiuxiang Gu, Qiong Huang, Leilei Xu, Mindong Chen, Qijie Jin, Zhenhui Wang
      First page: 535
      Abstract: Chlorobenzene (CB) is a volatile and harmful organic molecule that may result in deformities, cancer, etc. Catalytic oxidization of CB may be a way to manage it. The development of nonprecious catalysts with high catalytic activity is the key but is still a challenge. In this work, a series of Ce-Mn-Ox/TiO2 modified by citric acid monohydrate were developed and exhibited a composite pore structure. This pore structure leads to a large specific surface area, highly exposed activity sites, and excellent catalytic activity. The as-prepared 10C-CM/T exhibited nearly 100% efficiency for CB oxidization in the temperature range of 300–350 °C. The in situ DRIFT measurements demonstrated that the main intermediates at 250 °C are maleate and phenolic acid, whereas when the temperature is 350 °C, the main intermediates are carbonate, bidentate carbonate, and maleate.
      Citation: Catalysts
      PubDate: 2022-05-13
      DOI: 10.3390/catal12050535
      Issue No: Vol. 12, No. 5 (2022)
  • Catalysts, Vol. 12, Pages 536: Strengthen Air Oxidation of Refractory
           Humic Acid Using Reductively Etched Nickel-Cobalt Spinel Catalyst

    • Authors: Qi Jing, Jiabai Cai, Huan Li
      First page: 536
      Abstract: Nickel-cobalt spinel catalyst (NCO) is a promising catalyst for air oxidation of humic acid, which is a typical natural refractory organic matter and a precursor of toxic disinfection by-products. In this study, reductive etchers, NaBH4 or Na2SO3, were used to adjust the NCO surface structure to increase the performance. The modified catalyst (NCO-R) was characterized, and the relationship between its intrinsic properties and catalytic paths was discovered. The results of O2-temperature programmed desorption, NH3-temperature programmed desorption, and X-ray photoelectron spectroscopy (XPS) demonstrated that reductant etching introduced oxygen vacancies to the surface of NCO and increased active surface oxygen species and surface acidity. In addition, the modification did not change the raw hollow sphere structure of NCO. The crystallinity and specific surface area of NCO-R increased, and average pore size of NCO-R decreased. XPS results showed that the ratio of Co3+/Co2+ in NCO-R decreased compared with NCO, while the ratio of Ni3+/Ni2+ increased. The results of H2-temperature programmed reduction showed that the H2 reduction ability of NCO-R was stronger. Due to these changes in chemical and physical properties, NCO-R exhibited much better catalytic performance than NCO. In the catalytic air oxidation of humic acid at 25 °C, the total organic carbon (TOC) removal rate increased significantly from 44.4% using NCO to 77.0% using NCO-R. TOC concentration of humic acid decreased by 90.0% after 12 h in the catalytic air oxidation using NCO-R at 90 °C.
      Citation: Catalysts
      PubDate: 2022-05-13
      DOI: 10.3390/catal12050536
      Issue No: Vol. 12, No. 5 (2022)
  • Catalysts, Vol. 12, Pages 537: Different Chiral Ligands Assisted
           Enantioselective C-H Functionalization with Transition-Metal Catalysts

    • Authors: Jian-Zhen Lv, Yue-Ting Wei, Li-Yan Yang, Deng-Feng Yang, Hong-Liang Li
      First page: 537
      Abstract: C–H bonds are common in organic molecules, and the functionalization of these inactive C–H bonds has become one of the most powerful methods used to assemble complicated bioactive molecules from readily available starting materials. However, a central challenge in these reactions is controlling their stereoselectivity. Recently, significant progress has been made in the development of enantioselective C–H activation enabled by different chiral ligands for the formation of C–C and C–X bonds bearing a chiral center. In this paper, we focus on some archetypal chiral ligands for enantioselective C–H functionalization developed in recent years and analyze the mechanism of these methods, aiming to accelerate related research and to search for more efficient strategies.
      Citation: Catalysts
      PubDate: 2022-05-13
      DOI: 10.3390/catal12050537
      Issue No: Vol. 12, No. 5 (2022)
  • Catalysts, Vol. 12, Pages 438: DFT Study on the Combined Catalytic Removal
           of N2O, NO, and NO2 over Binuclear Cu-ZSM-5

    • Authors: Congru Gao, Jianwei Li, Jie Zhang, Xiuliang Sun
      First page: 438
      Abstract: The large amount of nitrogen oxides (N2O, NO, NO2, etc.) contained in the flue gas of industrial adipic acid production will seriously damage the environment. A designed binuclear Cu-ZSM-5 catalyst can be applied to decompose N2O and reduce NO and NO2, purifying the air environment. Using the density functional theory method, the catalytic decomposition mechanisms of N2O, NOX-NH3-SCR, and NOX-assisted N2O decomposition is simulated over the Cu-ZSM-5 model. The results indicate that N2O can be catalytically decomposed over the binuclear Cu active site in the sinusoidal channel. The speed-limiting step is the second N2O molecule activation process. After the decomposition of the first N2O molecule, a stable extra-frame [Cu-O-Cu]2+ structure will generate. The subsequent discussion proved that the NOX-NH3-SCR reaction can be realized over the [Cu-O-Cu]2+ active site. In addition, it proved that the decomposition reaction of NO and NO2 can be carried out over the [Cu-O-Cu]2+ active site, and NO can greatly reduce the energy barrier for the conversion of the active site from [Cu-O-Cu]2+ to the binuclear Cu form, while NO2 can be slightly reduced. Through discussion, it is found that the binuclear Cu-ZSM-5 can realize the combined removal of N2O and NOX from adipic acid flue gas, hoping to provide a theoretical basis for the development of a dual-functional catalyst.
      Citation: Catalysts
      PubDate: 2022-04-13
      DOI: 10.3390/catal12040438
      Issue No: Vol. 12, No. 4 (2022)
  • Catalysts, Vol. 12, Pages 439: Isospecific Polymerization of Halide- and
           Amino-Substituted Styrenes Using a Bis(phenolate) Titanium Catalyst

    • Authors: Qiyuan Wang, Zhen Zhang, Yang Jiang, Yanfeng Zhang, Shihui Li, Dongmei Cui
      First page: 439
      Abstract: Isospecific polymerization of polar styrenes is a challenge of polymer science. Particularly challenging are monomers bearing electron-withdrawing substituents or bulky substituents. Here, we report the coordination polymerization of halide- and amino-functionalized styrenes including para-fluorostyrene (pFS), para-chlorostyrene (pClS), para-bromostyrene (pBrS), and para-(N,N-diethylamino)styrene (DMAS) using 2,2′-sulfur-bridged bis(phenolate) titanium precursor (1). The combination of 1 and [Ph3C][B(C6F5)4] and AliBu3 provides crystalline poly(pFS)s with perfect isotacticity (mmmm > 95%) and high molecular weights (≤16.0 × 104 g mol−1). Upon activation with a large excess of DMAO, 1 reaches polymerization activity of 5.58 × 105 g molTi−1 h−1 producing isotactic poly(pFS)s featuring higher molecular weights (≤39.6 × 104 g mol−1). The distinguished performance of the 1/DMAO system has been extended to the polymerization of pClS and pBrS, both usually involve halogen abstraction during the polymerization, to produce isotactic and high molecular weight (Mn = 32.2 × 104 vs. 13.7 × 104 g mol−1) polymers in good activities (2.18 × 105 vs. 1.31 × 105 g molTi−1 h−1). Surprisingly, 1/DMAO is nearly inactive for DMAS polymerization, on contrary, the system 1/[Ph3C][B(C6F5)4]/AliBu3 displays isoselectivity (mmmm > 95%) albeit in a moderate activity.
      Citation: Catalysts
      PubDate: 2022-04-13
      DOI: 10.3390/catal12040439
      Issue No: Vol. 12, No. 4 (2022)
  • Catalysts, Vol. 12, Pages 440: Synergetic Effects of Mixed-Metal
           Polyoxometalates@Carbon-Based Composites as Electrocatalysts for the
           Oxygen Reduction and the Oxygen Evolution Reactions

    • Authors: Inês S. Marques, Bruno Jarrais, Israël-Martyr Mbomekallé, Anne-Lucie Teillout, Pedro de Oliveira, Cristina Freire, Diana M. Fernandes
      First page: 440
      Abstract: The smart choice of polyoxometalates (POMs) and the design of POM@carbon-based composites are promising tools for producing active electrocatalysts for both the oxygen reduction (ORR) and the oxygen evolution reactions (OER). Hence, herein, we report the preparation, characterization and application of three composites based on doped, multi-walled carbon nanotubes (MWCNT_N6) and three different POMs (Na12[(FeOH2)2Fe2(As2W15O56)2]·54H2O, Na12[(NiOH2)2Ni2(As2W15O56)2]·54H2O and Na14[(FeOH2)2Ni2(As2W15O56)2]·55H2O) as ORR and OER electrocatalysts in alkaline medium (pH = 13). Overall, the three POM@MWCNT_N6 composites showed good ORR performance with onset potentials between 0.80 and 0.81 V vs. RHE and diffusion-limiting current densities ranging from −3.19 to −3.66 mA cm−2. Fe4@MWCNT_N6 and Fe2Ni2@MWCNT_N6 also showed good stability after 12 h (84% and 80% of initial current). The number of electrons transferred per O2 molecule was close to three, suggesting a mixed regime. Moreover, the Fe2Ni2@MWCNT_N6 presented remarkable OER performance with an overpotential of 0.36 V vs. RHE (for j = 10 mA cm−2), a jmax close to 135 mA cm−2 and fast kinetics with a Tafel slope of 45 mV dec−1. More importantly, this electrocatalyst outperformed not only most POM@carbon-based composites reported so far but also the state-of-the-art RuO2 electrocatalyst. Thus, this work represents a step forward towards bifunctional electrocatalysts using less expensive materials.
      Citation: Catalysts
      PubDate: 2022-04-14
      DOI: 10.3390/catal12040440
      Issue No: Vol. 12, No. 4 (2022)
  • Catalysts, Vol. 12, Pages 441: Expanding the Range: AuCu Metal Aerogels
           from H2O and EtOH

    • Authors: Maximilian Georgi, Johannes Kresse, Karl Hiekel, René Hübner, Alexander Eychmüller
      First page: 441
      Abstract: Due to their self-supporting and nanoparticulate structure, metal aerogels have emerged as excellent electrocatalysts, especially in the light of the shift to renewable energy cycles. While a large number of synthesis parameters have already been studied in depth, only superficial attention has been paid to the solvent. In order to investigate the influence of this parameter with respect to the gelation time, crystallinity, morphology, or porosity of metal gels, AuxCuy aerogels were prepared in water and ethanol. It was shown that although gelation in water leads to highly porous gels (60 m2g−1), a CuO phase forms during this process. The undesired oxide could be selectively removed using a post-washing step with formic acid. In contrast, the solvent change to EtOH led to a halving of the gelation time and the suppression of Cu oxidation. Thus, pure Cu aerogels were synthesized in addition to various bimetallic Au3X (X = Ni, Fe, Co) gels. The faster gelation, caused by the lower permittivity of EtOH, led to the formation of thicker gel strands, which resulted in a lower porosity of the AuxCuy aerogels. The advantage given by the solvent choice simplifies the preparation of metal aerogels and provides deeper knowledge about their gelation.
      Citation: Catalysts
      PubDate: 2022-04-14
      DOI: 10.3390/catal12040441
      Issue No: Vol. 12, No. 4 (2022)
  • Catalysts, Vol. 12, Pages 442: Catalytic Conversion of High Fructose Corn
           Syrup to Methyl Lactate with CoO@silicalite-1

    • Authors: Yuxi Jiang, Xilei Lyu, Hao Chen, Xiwen Wei, Zihao Zhang, Xiuyang Lu
      First page: 442
      Abstract: Methyl lactate (MLA), a versatile biomass platform, was typically produced from the catalytic conversion of high-priced fructose. High fructose corn syrup (HFCS) is a mixture of glucose, fructose, water, etc., which is viewed as an economical substitute for fructose to produce MLA due to the much lower cost of separation and drying processes. However, the transformation of HFCS to MLA is still a challenge due to its complex components and the presence of water. In this work, the catalytic conversion of HFCS to MLA over CoO@silicalite-1 catalyst synthesized via a straightforward post citric acid treatment approach was reported. The maximum MLA yield reached 43.8% at 180 °C for 18 h after optimizing the reaction conditions and Co loading. Interestingly, adding extra 3% water could further increase the MLA yield, implying that our CoO@silicalite-1 catalyst is also capable for upgrading wet HFCS. As a result, the costly drying process of wet HFCS can be avoided. Moreover, the activity of CoO@silicalite-1 catalyst can be regenerated for at least four cycles via facile calcination in air. This study, therefore, will provide a new opportunity to not only solve the HFCS-overproduction issues but also produce value-added MLA.
      Citation: Catalysts
      PubDate: 2022-04-14
      DOI: 10.3390/catal12040442
      Issue No: Vol. 12, No. 4 (2022)
  • Catalysts, Vol. 12, Pages 443: The Preparation of g-C3N4/CoAl-LDH
           Nanocomposites and Their Depollution Performances in Cement Mortars under
           UV-Visible Light

    • Authors: Mengya Huang, Zhengxian Yang, Lin Lu, Jiankun Xu, Wencheng Wang, Can Yang
      First page: 443
      Abstract: In this study, new organic-inorganic g-C3N4/CoAl-LDH nanocomposites were prepared and introduced to fabricate photocatalytic cement mortars by internal mixing, coating, and spraying. The photocatalytic depollution of both g-C3N4/CoAl-LDH and cement mortars was assessed by NOx degradation reaction under UV-visible light irradiation. The study results suggested that the degradation efficiency of g-C3N4/CoAl-LDH nanocomposites improved with an increase in g-C3N4 content. The g-C3N4/CoAl-LDH1.5 nanocomposite displayed the highest NOx degradation capacity, which was about 1.23 and 3.21 times that of pure g-C3N4 and CoAl-LDH, respectively. The photocatalytic cement mortars which were all fabricated using different approaches could effectively degrade the target pollutants and exhibited significant compatibility between g-C3N4/CoAl-LDH and cementitious substrate. Among them, the coated mortars showed strong resistance to laboratory-simulated wearing and abrasion with a small decrease in degradation rate.
      Citation: Catalysts
      PubDate: 2022-04-15
      DOI: 10.3390/catal12040443
      Issue No: Vol. 12, No. 4 (2022)
  • Catalysts, Vol. 12, Pages 444: Spherical ZVI/Mn-C Bimetallic Catalysts for
           Efficient Fenton-Like Reaction under Mild Conditions

    • Authors: Lu Qin, Xin Yu, Kang Wang, Xitao Wang
      First page: 444
      Abstract: The heterogeneous Fenton-like reaction has been receiving increasing attention for its inexpensiveness and high efficiency in water treatment. In this study, a novel strategy was proposed for preparing spherical ZVI/Mn-C bimetallic catalysts with a high activity for a Fenton-like reaction by using the ammonium alginate assisted sol–gel method coupled with a carbothermic reduction. The results showed that the obtained ZVI/Mn-C spheres had a uniform size, smooth surface and good sphericity, and the particle size of ZVI was limited to about 30 nm by the carbon layer. Among all catalysts, the ZVI/Mn-C-31 catalyst exhibited the highest phenol degradation efficiency in the Fenton-like process, and almost 100% phenol degradation efficiency was achieved under neutral pH at room temperature within 5 min. Moreover, the ZVI/Mn-C-31/H2O2 system showed a 100% degradation efficiency for removing a wide range of aromatic pollutants, including catechol, resorcinol and o-nitrophenol. Moreover, the radicals-scavenging experiment illustrated that the ·OH played a key factor in mineralizing the organic matters, and the ·O2− generated from the MnO-H2O2 system accelerated the conversion rate of ferric iron to ferrous iron. Due to the synergistic effects between ZVI and MnO, the ZVI/Mn-C-31 catalyst performed excellently in the Fenton-like reaction at an extended pH range.
      Citation: Catalysts
      PubDate: 2022-04-15
      DOI: 10.3390/catal12040444
      Issue No: Vol. 12, No. 4 (2022)
  • Catalysts, Vol. 12, Pages 445: A Critical Study of Cu2O: Synthesis and Its
           Application in CO2 Reduction by Photochemical and Electrochemical

    • Authors: Sathya Mohan, Brahmari Honnappa, Ashil Augustin, Mariyappan Shanmugam, Chitiphon Chuaicham, Keiko Sasaki, Boopathy Ramasamy, Karthikeyan Sekar
      First page: 445
      Abstract: Copper oxide (Cu2O) is a potential material as a catalyst for CO2 reduction. Cu2O nanostructures have many advantages, including interfacial charge separation and transportation, enhanced surface area, quantum efficiency, and feasibility of modification via composite development or integration of the favorable surface functional groups. We cover the current advancements in the synthesis of Cu2O nanomaterials in various morphological dimensions and their photochemical and electrochemical applications, which complies with the physical enrichment of their enhanced activity in every application they are employed in. The scope of fresh designs, namely composites or the hierarchy of copper oxide nanostructures, and various ways to improve CO2 reduction performance are also discussed in this review. Photochemical and electrochemical CO2 transformations have received tremendous attention in the last few years, thanks to the growing interest in renewable sources of energy and green facile chemistry. The current review provides an idea of current photochemical and electrochemical carbon dioxide fixing techniques by using Cu2O-based materials. Carboxylation and carboxylative cyclization, yield valuable chemicals such as carboxylic acids and heterocyclic compounds. Radical ions, which are induced by photo- and electrochemical reactions, as well as other high-energy organic molecules, are regarded as essential mid-products in photochemical and electrochemical reactions with CO2. It has also been claimed that CO2 can be activated to form radical anions.
      Citation: Catalysts
      PubDate: 2022-04-17
      DOI: 10.3390/catal12040445
      Issue No: Vol. 12, No. 4 (2022)
  • Catalysts, Vol. 12, Pages 446: Sugarcane Bagasse Ash as a Catalyst Support
           for Facile and Highly Scalable Preparation of Magnetic Fenton Catalysts
           for Ultra-Highly Efficient Removal of Tetracycline

    • Authors: Natthanan Rattanachueskul, Oraya Dokkathin, Decha Dechtrirat, Joongjai Panpranot, Waralee Watcharin, Sulawan Kaowphong, Laemthong Chuenchom
      First page: 446
      Abstract: Sugarcane bagasse ash, which is waste from the combustion process of bagasse for electricity generation, was utilized as received as a catalyst support to prepare the magnetic sugarcane bagasse ash (MBGA) with different iron-to-ash ratios using a simple co-precipitation method, and the effects of NaOH and iron loadings on the physicochemical properties of the catalyst were investigated using various intensive characterization techniques. In addition, the catalyst was used with a low amount of H2O2 for the catalytic degradation of a high concentration of tetracycline (800 mg/L) via a Fenton system. The catalyst exhibited excellent degradation activity of 90.43% removal with good magnetic properties and high stabilities and retained good efficiency after four cycles with NaOH as the eluent. Moreover, the hydroxyl radical on the surface of catalyst played a major role in the degradation of TC, and carbon-silica surface of bagasse ash significantly improved the efficiencies. The results indicated that the MBGA catalyst shows the potential to be highly scalable for a practical application, with high performance in the heterogeneous Fenton system.
      Citation: Catalysts
      PubDate: 2022-04-18
      DOI: 10.3390/catal12040446
      Issue No: Vol. 12, No. 4 (2022)
  • Catalysts, Vol. 12, Pages 447: Catalytic Routes to Produce Polyphenolic
           Esters (PEs) from Biomass Feedstocks

    • Authors: Antonio Faggiano, Maria Ricciardi, Antonio Proto
      First page: 447
      Abstract: Polyphenolic esters (PEs) are valuable chemical compounds that display a wide spectrum of activities (e.g., anti-oxidative effects). As a result, their production through catalytic routes is an attractive field of research. The present review aims to discuss recent studies from the literature regarding the catalytic production of PEs from biomass feedstocks, namely, naturally occurred polyphenolic compounds. Several synthetic approaches are reported in the literature, mainly bio-catalysis and to a lesser extent acid catalysis. Immobilized lipases (e.g., Novozym 435) are the preferred enzymes thanks to their high reactivity, selectivity and reusability. Acid catalysis is principally investigated for the esterification of polyphenolic acids with fatty alcohols and/or glycerol, using both homogeneous (p-toluensulfonic acid, sulfonic acid and ionic liquids) and heterogeneous (strongly acidic cation exchange resins) catalysts. Based on the reviewed publications, we propose some suggestions to improve the synthesis of PEs with the aim of increasing the greenness of the overall production process. In fact, much more attention should be paid to the use of new and efficient acid catalysts and their reuse for multiple reaction cycles.
      Citation: Catalysts
      PubDate: 2022-04-18
      DOI: 10.3390/catal12040447
      Issue No: Vol. 12, No. 4 (2022)
  • Catalysts, Vol. 12, Pages 448: Low-Temperature O3 Decomposition over
           Pd-TiO2 Hybrid Catalysts

    • Authors: Houcine Touati, Afef Mehri, Fathi Karouia, Frédéric Richard, Catherine Batiot-Dupeyrat, Stéphane Daniele, Jean-Marc Clacens
      First page: 448
      Abstract: In aircraft and spacecraft, outside air is not directly fed to the passenger because it contains ozone at elevated altitudes. The decomposition of low concentration ozone in the air was carried out at 25 °C by catalytic oxidation on Pd-based catalysts supported on a high surface area hybrid TiO2. The use of these hybrid catalysts has shown a beneficial effect, both on the catalytic activity and on the catalyst stability. Kinetic studies showed that the most promising catalytic phase (Pd/TiO2_100) was the one obtained from the TiO2 support containing the lowest content of citrate ligands and leading to small Pd particles (around 4 nm). The effect of catalyst synthesis on the decomposition of O3 gas (15 ppm) in a dry and humid (HR = 10%) stream in a closed environment such as aircraft or spacecraft was also investigated in this study and further elucidated by detailed characterizations. It was shown that the system could be used as an effective treatment for air coming from outside.
      Citation: Catalysts
      PubDate: 2022-04-18
      DOI: 10.3390/catal12040448
      Issue No: Vol. 12, No. 4 (2022)
  • Catalysts, Vol. 12, Pages 449: Thermal Behavior of Heavy Oil Catalytic
           Pyrolysis and Aquathermolysis

    • Authors: Mohammed A. Khelkhal, Semen E. Lapuk, Aleksey V. Buzyurov, Nikita E. Ignashev, Elvira I. Shmeleva, Irek I. Mukhamatdinov, Alexey V. Vakhin
      First page: 449
      Abstract: There is still considerable controversy surrounding the mechanisms, thermodynamics, and kinetics of heavy oil aquathermolysis and pyrolysis processes. The present paper aims to widen our knowledge about the effect of iron tallates on pyrolysis and aquathermolysis of Cuban heavy oil. The obtained SARA (S: saturates, A: aromatics, R: resins, A: asphaltenes) analysis has shown a significant increase in light hydrocarbon content during aquathermolysis. Moreover, the elemental analysis has indicated an increase in C and H content by almost 4% and 6%, respectively, with a significant decrease in S and O content by up to 23% in the presence of iron tallates. These results have been further confirmed by infrared spectrometry. The obtained IR data indicated that asphaltene and resin compounds transform into light hydrocarbons after aquathermolysis. On another hand, the activation energy of heavy oil pyrolysis decreased in the presence of the utilized catalyst; meanwhile, the reaction rate increased, especially in the temperature range of 200–480 °C, which may validate a significant effect of the used catalyst in real conditions. Moreover, the obtained thermodynamic data showed a decrease in the enthalpy and entropy of activation of oil pyrolysis in the presence of iron tallates. Our results are encouraging in terms of energy consumption, optimization, and process control and should be validated by a larger sample size.
      Citation: Catalysts
      PubDate: 2022-04-18
      DOI: 10.3390/catal12040449
      Issue No: Vol. 12, No. 4 (2022)
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