A  B  C  D  E  F  G  H  I  J  K  L  M  N  O  P  Q  R  S  T  U  V  W  X  Y  Z  

  First | 1 2        [Sort alphabetically]   [Restore default list]

  Subjects -> SCIENCES: COMPREHENSIVE WORKS (Total: 374 journals)
Showing 201 - 265 of 265 Journals sorted by number of followers
Revista Científica de la Universidad Nacional del Este     Open Access   (Followers: 12)
Orbis Cógnita : Revista Científica     Open Access   (Followers: 5)
Research Policy : X     Open Access   (Followers: 4)
Data     Open Access   (Followers: 4)
Advanced Theory and Simulations     Hybrid Journal   (Followers: 4)
Frontiers in Climate     Open Access   (Followers: 4)
MUST : Journal of Mathematics Education, Science and Technology     Open Access   (Followers: 4)
History of Science and Technology     Open Access   (Followers: 4)
Journal of the Indian Institute of Science     Hybrid Journal   (Followers: 4)
Discover Sustainability     Open Access   (Followers: 3)
Journal of Composites Science     Open Access   (Followers: 3)
Journal of Big History     Open Access   (Followers: 3)
People and Nature     Open Access   (Followers: 3)
Science & Technology Studies     Open Access   (Followers: 3)
Indonesian Journal of Science and Mathematics Education     Open Access   (Followers: 2)
Citizen Science : Theory and Practice     Open Access   (Followers: 2)
Patterns     Open Access   (Followers: 2)
Research     Open Access   (Followers: 2)
Scientonomy : Journal for the Science of Science     Open Access   (Followers: 1)
ARPHA Conference Abstracts     Open Access   (Followers: 1)
AAS Open Research     Open Access   (Followers: 1)
Journal of Science and Technology     Open Access   (Followers: 1)
Uluslararası Bilimsel Araştırmalar Dergisi (IBAD)     Open Access   (Followers: 1)
Bilge International Journal of Science and Technology Research     Open Access   (Followers: 1)
Journal of Science and Engineering     Open Access   (Followers: 1)
Applied Mathematics and Nonlinear Sciences     Open Access   (Followers: 1)
Acta Scientifica Malaysia     Open Access   (Followers: 1)
International Journal of Innovative Research and Scientific Studies     Open Access   (Followers: 1)
Futures & Foresight Science     Hybrid Journal   (Followers: 1)
Revista Vivências em Ensino de Ciências     Open Access   (Followers: 1)
iScience     Open Access   (Followers: 1)
Global Journal of Science Frontier Research     Open Access   (Followers: 1)
International Journal of Research in Science     Open Access   (Followers: 1)
Impact     Open Access   (Followers: 1)
Jaunujų mokslininkų darbai     Open Access   (Followers: 1)
Experimental Results     Open Access   (Followers: 1)
Revista Saber Digital     Open Access   (Followers: 1)
Fundamental Research     Open Access  
BJHS Themes     Open Access  
South American Sciences     Open Access  
Middle European Scientific Bulletin     Open Access  
Journal of Alasmarya University     Open Access  
Research Integrity and Peer Review     Open Access  
Natural Sciences Education     Hybrid Journal  
International Journal of Culture and Modernity     Open Access  
Proceedings of the Indian National Science Academy     Full-text available via subscription  
Indian Journal of History of Science     Hybrid Journal  
RAC: Revista Angolana de Ciências     Open Access  
The Innovation     Open Access  
Journal of Responsible Technology     Open Access  
Natural Sciences     Open Access  
Revista de la Sociedad Científica del Paraguay     Open Access  
Rekayasa     Open Access  
Rihan Journal for Scientific Publishing     Open Access  
Türk Bilim ve Mühendislik Dergisi     Open Access  
ArtefaCToS : Revista de estudios sobre la ciencia y la tecnología     Open Access  
Ethiopian Journal of Sciences and Sustainable Development     Open Access  
Vilnius University Proceedings     Open Access  
Sciential     Open Access  
ARPHA Proceedings     Open Access  
Gaudium Sciendi     Open Access  
Crea Ciencia Revista Científica     Open Access  
Rafidain Journal of Science     Open Access  
Journal of Al-Qadisiyah for Pure Science     Open Access  
Revista Tecnológica     Open Access  
Himalayan Journal of Science and Technology     Open Access  
International Journal of Academic Research in Business, Arts & Science     Open Access  
Universidad, Ciencia y Tecnología     Open Access  
Fides et Ratio : Revista de Difusión Cultural y Científica     Open Access  
Acta Nova     Open Access  
Revista de la Academia Colombiana de Ciencias Exactas, Físicas y Naturales     Open Access  
Entre Ciencia e Ingeniería     Open Access  
Revista Politécnica     Open Access  
Reportes Científicos de la FaCEN     Open Access  
Jurnal Ilmiah Ilmu Terapan Universitas Jambi : JIITUJ     Open Access  
Revista Eletrônica Ludus Scientiae     Open Access  
Emergent Scientist     Open Access  
Journal of Scientific Research and Reports     Open Access  
Asian Journal of Advanced Research and Reports     Open Access  
Archives of Current Research International     Open Access  
Advances in Research     Open Access  
International Journal of Applied Science     Open Access  
Iranian Journal of Science and Technology, Transactions A : Science     Hybrid Journal  
J : Multidisciplinary Scientific Journal     Open Access  
Revista Binacional Brasil - Argentina: Diálogo entre as ciências     Open Access  
Revista Ciencia y Tecnología     Open Access  
Journal of Institute of Science and Technology     Open Access  
Journal of Science (JSc)     Open Access  
WikiJournal of Science     Open Access  
Acta Materialia Transilvanica     Open Access  
Integrated Research Advances     Open Access  
PENDIPA : Journal of Science Education     Open Access  
Open Conference Proceedings Journal     Open Access  
Naturen     Full-text available via subscription  
Ekaia : EHUko Zientzia eta Teknologia aldizkaria     Open Access  
Sci     Open Access  
Maskana     Open Access  
Hoosier Science Teacher     Open Access  
Reports in Advances of Physical Sciences     Open Access  
Facets     Open Access  
Adıyaman University Journal of Science     Open Access  
Revista Brasileira de Iniciação Científica     Open Access  
Communications Faculty of Sciences University of Ankara Series A2-A3 Physical Sciences and Engineering     Open Access  
Scientific African     Open Access  
Scientific Journal of Mehmet Akif Ersoy University     Open Access  
Black Sea Journal of Engineering and Science     Open Access  
Fırat University Turkish Journal of Science & Technology     Open Access  
Gazi University Journal of Science     Open Access  
Middle East Journal of Science     Open Access  
International Journal of Computational and Experimental Science and Engineering (IJCESEN)     Open Access  
International Journal of Engineering, Technology and Natural Sciences     Open Access  
Bulletin of the National Research Centre     Open Access  
Uni-pluriversidad     Open Access  
ConCiencia     Open Access  
Ciencia y Tecnología     Open Access  
Revista Bases de la Ciencia     Open Access  
Elkawnie : Journal of Islamic Science and Technology     Open Access  
Ciência ET Praxis     Open Access  
Arab Journal of Basic and Applied Sciences     Open Access  
International Annals of Science     Open Access  
Science Heritage Journal     Open Access  
Avrasya Terim Dergisi     Open Access  
International Scientific and Vocational Studies Journal     Open Access  
TÜBAV Bilim Dergisi     Open Access  
LOGIKA Jurnal Ilmiah Lemlit Unswagati Cirebon     Open Access  
Dalat University Journal of Science     Open Access  
Investiga : TEC     Open Access  
Investigación Joven     Open Access  
Respuestas     Open Access  
Science Diliman     Open Access  
Instruments     Open Access  
Revista Científica y Tecnológica UPSE     Open Access  
HardwareX     Open Access  
Sultan Qaboos University Journal for Science     Open Access  
Borneo Journal of Resource Science and Technology     Open Access  
Sainstek : Jurnal Sains dan Teknologi     Open Access  
Revista de Información Científica     Open Access  
Indonesian Journal of Fundamental Sciences     Open Access  
Sainteknol : Jurnal Sains dan Teknologi     Open Access  
Jurnal Natural     Open Access  
Frontiers for Young Minds     Open Access  
Revista Ciência, Tecnologia & Ambiente     Open Access  
Journal of Indian Council of Philosophical Research     Hybrid Journal  
Journal of Negative and No Positive Results     Open Access  
Revista Conhecimento Online     Open Access  
Nova     Open Access  
CienciaUAT     Open Access  
Enseñanza de las Ciencias : Revista de Investigación y Experiencias Didácticas     Open Access  
Makara Journal of Science     Open Access  
Jurnal Sains Dasar     Open Access  
Indonesian Journal of Science and Technology     Open Access  
Ethiopian Journal of Science and Technology     Open Access  
Jurnal Matematika, Sains, Dan Teknologi     Open Access  
Heidelberger Jahrbücher Online     Open Access  
ARO. The Scientific Journal of Koya University     Open Access  
International Journal of Recent Contributions from Engineering, Science & IT     Open Access  
Estação Científica (UNIFAP)     Open Access  
The Winnower     Open Access  

  First | 1 2        [Sort alphabetically]   [Restore default list]

Similar Journals
Journal Cover
Transactions of Tianjin University
Journal Prestige (SJR): 0.166
Number of Followers: 0  
 
  Full-text available via subscription Subscription journal
ISSN (Print) 1006-4982 - ISSN (Online) 1995-8196
Published by Tianjin University Homepage  [1 journal]
  • Electrochemically Generated Iodine Cations from a Glassy Carbon Electrode
           for Highly Selective Iodination of Anisole

    • Free pre-print version: Loading...

      Abstract: Abstract The synthesis of aryl iodides from commercially available raw chemicals by simple, cheap and green strategies is of fundamental significance. Aryl iodides can undergo a series of homo-/cross-coupling reactions for the synthesis of important industrial chemicals and materials. Traditional methods require the electrophilic substitution on aromatic compounds by iodine or hypervalent iodine compounds, which suffers from the use of erosive halogens or hazardous oxidants. With the development of green chemistry in the field of electrochemical synthesis, anodic oxidation-derived I+ cations have been used for substitution reactions. However, the selectivity of the iodination by these electrochemical methods remains unsatisfactory. We believed that the anolyte is contaminated by trace platinum species from the working electrode. Herein, we report the generation of active I+ species from the anodic oxidation of I2 in acetonitrile using a glassy carbon electrode. With the presence of H+, electrolyte prepared with a glassy carbon anode can react with anisole to selectively form 4-iodoanisole with a yield as high as 97%. On contrast, the electrolytes prepared from Pt and graphite anodes finished the reaction with yields of 16% and 60% for 4-iodoanisole, respectively. This electrochemical method also applies to the iodination of toluene, benzonitrile and bromobenzene, delivering the target para-iodination products with 92%, 84%, and 73% yields, respectively. Thus, an atom-efficient and highly selective aryl iodination method was developed without the use of excessive oxidants.
      PubDate: 2022-09-07
       
  • Applications of Transition Metal (Fe, Co, Ni)-Based Metal–Organic
           Frameworks and their Derivatives in Batteries and Supercapacitors

    • Free pre-print version: Loading...

      Abstract: Abstract Metal–organic frameworks (MOFs), which are generally considered to be crystalline materials comprising metal centers and organic ligands, have attracted growing attention because of their controllable structures and high porosity. MOFs based on transition metals (Fe, Co, Ni) are highly efficient electrode materials for electrochemical energy storage. In this review, the characteristics of Fe-MOFs, Co-MOFs, Ni-MOFs, and their derivatives are summarized, and the relationships between the structures and performance are unveiled in depth. Additionally, their applications in lithium–ion batteries, lithium–sulfur batteries, and supercapacitors are discussed. This review sheds light on the development of MOFs and their derivatives to realize excellent electrochemical performance.
      PubDate: 2022-09-04
       
  • Review on Metallization Approaches for High-Efficiency Silicon
           Heterojunction Solar Cells

    • Free pre-print version: Loading...

      Abstract: Abstract Crystalline silicon (c-Si) heterojunction (HJT) solar cells are one of the promising technologies for next-generation industrial high-efficiency silicon solar cells, and many efforts in transferring this technology to high-volume manufacturing in the photovoltaic (PV) industry are currently ongoing. Metallization is of vital importance to the PV performance and long-term reliability of HJT solar cells. In this review, we summarize the development status of metallization approaches for high-efficiency HJT solar cells. For conventional screen printing technology, to avoid the degradation of the passivation properties of the amorphous silicon layer, a low-temperature-cured (< 250 ℃) paste and process are needed. This process, in turn, leads to high line/contact resistances and high paste costs. To improve the conductivity of electrodes and reduce the metallization cost, multi-busbar, fine-line printing, and low-temperature-cured silver-coated copper pastes have been developed. In addition, several potential metallization technologies for HJT solar cells, such as the Smart Wire Contacting Technology, pattern transfer printing, inkjet/FlexTrailprinting, and copper electroplating, are discussed in detail. Based on the summary, the potential and challenges of these metallization technologies for HJT solar cells are analyzed.
      PubDate: 2022-08-30
       
  • Li2TiO3 Dopant and Phosphate Coating Improve the Electrochemical
           Performance of LiCoO2 at 3.0–4.6 V

    • Free pre-print version: Loading...

      Abstract: Abstract A sol–gel tandem with a solid-phase modification procedure was developed to synthesize Li2TiO3-doped LiCoO2 together with phosphate coatings (denoted as LCO-Ti/P), which possesses excellent high-voltage performance in the range of 3.0–4.6 V. The characterizations of X-ray diffraction, high-resolution transmission electron microscopy, and X-ray photoelectron spectroscopy illustrated that the modified sample LCO-Ti/P had the dopant of monoclinic Li2TiO3 and amorphous Li3PO4 coating layers. LCO-Ti/P has an initial discharge capacity of 211.6 mAh/g at 0.1 C and a retention of 85.7% after 100 cycles at 1 C and 25 ± 1 °C between 3.0 and 4.6 V. Nyquist plots reflect that the charge transfer resistance of LCO-Ti/P after 100 cycles at 1 C is much lower than that of the spent LCO, which benefits Li-ion diffusion. Density functional theory calculations disclose the superior lattice-matching property of major crystal planes for Li2TiO3 and LiCoO2, the lower energy barriers for Li-ion diffusion in Li2TiO3, and the suppressed oxygen release performance resulting from phosphate adsorption. This work provides useful guidance on the rational design of the high-voltage performance of modified LiCoO2 materials in terms of lattice-matching properties aside from the phosphate coating to reduce the energy barriers of Li-ion diffusion and enhance cycling stability.
      PubDate: 2022-08-29
       
  • Ultrasmall NiS2 Nanocrystals Embedded in Ordered Macroporous Graphenic
           Carbon Matrix for Efficiently Pseudocapacitive Sodium Storage

    • Free pre-print version: Loading...

      Abstract: Abstract Sodium-ion hybrid capacitor (SIHC) is one of the most promising alternatives for large-scale energy storage due to its high energy and power densities, natural abundance, and low cost. However, overcoming the imbalance between slow Na+ reaction kinetics of battery-type anodes and rapid ion adsorption/desorption of capacitive cathodes is a significant challenge. Here, we propose the high-rate-performance NiS2@OMGC anode material composed of monodispersed NiS2 nanocrystals (8.8 ± 1.7 nm in size) and N, S-co-doped graphenic carbon (GC). The NiS2@OMGC material has a three-dimensionally ordered macroporous (3DOM) morphology, and numerous NiS2 nanocrystals are uniformly embedded in GC, forming a core–shell structure in the local area. Ultrafine NiS2 nanocrystals and their nano–microstructure demonstrate high pseudocapacitive Na-storage capability and thus excellent rate performance (355.7 mAh/g at 20.0 A/g). A SIHC device fabricated using NiS2@OMGC and commercial activated carbon (AC) cathode exhibits ultrahigh energy densities (197.4 Wh/kg at 398.8 W/kg) and power densities (43.9 kW/kg at 41.3 Wh/kg), together with a long life span. This outcome exemplifies the rational architecture and composition design of this type of anode material. This strategy can be extended to the design and synthesis of a wide range of high-performance electrode materials for energy storage applications.
      PubDate: 2022-08-24
       
  • Modulating the Selectivity of Photocatalytic CO2 Reduction in Barium
           Titanate by Introducing Oxygen Vacancies

    • Free pre-print version: Loading...

      Abstract: Abstract Artificial photosynthetic reduction of CO2 into valuable chemicals is one of the most promising approaches to solve the energy crisis and decreasing atmospheric CO2 emissions. However, the poor selectivity accompanied by the low activity of photocatalysts limits the development of photocatalytic CO2 reduction. Herein, inspired by the use of oxygen vacancy engineering to promote the adsorption and activation of CO2 molecules, we introduced oxygen vacancies in the representative barium titanate (BaTiO3) photocatalyst for photocatalytic CO2 reduction. We found that oxygen vacancies brought significant differences in the CO2 photoreduction activity and selectivity of BaTiO3. The intrinsic BaTiO3 showed a low photocatalytic activity with the dominant product of CO, whereas BaTiO3 with oxygen vacancies exhibited a tenfold improvement in photocatalytic activity, with a high selectivity of ~ 90% to CH4. We propose that the presence of oxygen vacancies promotes CO2 and H2O adsorption onto the BaTiO3 surface and also improves the separation and transfer of photogenerated carriers, thereby boosting the photocatalytic CO2 reduction to CH4. This work highlights the essential role of oxygen vacancies in tuning the selectivity of photocatalytic reduction of CO2 into valuable chemicals.
      PubDate: 2022-08-23
       
  • Review on Heteroatom Doping Carbonaceous Materials Toward Electrocatalytic
           Carbon Dioxide Reduction

    • Free pre-print version: Loading...

      Abstract: Abstract Carbon dioxide (CO2) reduction into chemicals or fuels by electrocatalysis can effectively reduce greenhouse gas emissions and alleviate the energy crisis. Currently, CO2 electrocatalytic reduction (CO2RR) has been considered as an ideal way to achieve “carbon neutrality.” In CO2RR, the characteristics and properties of catalysts directly determine the reaction activity and selectivity of the catalytic process. Much attention has been paid to carbon-based catalysts because of their diversity, low cost, high availability, and high throughput. However, electrically neutral carbon atoms have no catalytic activity. Incorporating heteroatoms has become an effective strategy to control the catalytic activity of carbon-based materials. The doped carbon-based catalysts reported at present show excellent catalytic performance and application potential in CO2RR. Based on the type and quantity of heteroatoms doped into carbon-based catalysts, this review summarizes the performances and catalytic mechanisms of carbon-based materials doped with a single atom (including metal and without metal) and multi atoms (including metal and without metal) in CO2RR and reveals prospects for developing CO2 electroreduction in the future.
      PubDate: 2022-08-16
       
  • Integrated Photothermal Nanoreactors for Efficient Hydrogenation of CO2

    • Free pre-print version: Loading...

      Abstract: Abstract To alleviate the energy crisis and global warming, photothermal catalysis is an attractive way to efficiently convert CO2 and renewable H2 into value-added fuels and chemicals. However, the catalytic performance is usually restricted by the trade-off between the dispersity and light absorption property of metal catalysts. Here we demonstrate a simple SiO2-protected metal–organic framework pyrolysis strategy to fabricate a new type of integrated photothermal nanoreactor with a comparatively high metal loading, dispersity, and stability. The core-satellite structured Co@SiO2 exhibits strong sunlight-absorptive ability and excellent catalytic activity in CO2 hydrogenation, which is ascribed to the functional separation of different sizes of Co nanoparticles. Large-sized plasmonic Co nanoparticles are mainly responsible for the light absorption and conversion to heat (nanoheaters), whereas small-sized Co nanoparticles with high intrinsic activities are responsible for the catalysis (nanoreactors). This study provides a new concept for designing efficient photothermal catalytic materials.
      PubDate: 2022-08-16
       
  • Temperature Gradient Analyses of a Tubular Solid Oxide Fuel Cell Fueled by
           Methanol

    • Free pre-print version: Loading...

      Abstract: Abstract Thermal management in solid oxide fuel cells (SOFC) is a critical issue due to non-uniform electrochemical reactions and convective flows within the cells. Therefore, a 2D mathematical model is established herein to investigate the thermal responses of a tubular methanol-fueled SOFC. Results show that unlike the low-temperature condition of 873 K, where the peak temperature gradient occurs at the cell center, it appears near the fuel inlet at 1073 K because of the rapid temperature rise induced by the elevated current density. Despite the large heat convection capacity, excessive air could not effectively eliminate the harmful temperature gradient caused by the large current density. Thus, optimal control of the current density by properly selecting the operating potential could generate a local thermal neutral state. Interestingly, the maximum axial temperature gradient could be reduced by about 18% at 973 K and 20% at 1073 K when the air with a 5 K higher temperature is supplied. Additionally, despite the higher electrochemical performance observed, the cell with a counter-flow arrangement featured by a larger hot area and higher maximum temperature gradients is not preferable for a ceramic SOFC system considering thermal durability. Overall, this study could provide insightful thermal information for the operating condition selection, structure design, and stability assessment of realistic SOFCs combined with their internal reforming process.
      PubDate: 2022-08-10
       
  • MXene-Based Photocatalysts and Electrocatalysts for CO2 Conversion to
           Chemicals

    • Free pre-print version: Loading...

      Abstract: Abstract The interest in CO2 conversion to value-added chemicals and fuels has increased in recent years as part of strategic efforts to mitigate and use the excessive CO2 concentration in the atmosphere. Much attention has been given to developing two-dimensional catalytic materials with high-efficiency CO2 adsorption capability and conversion yield. While several candidates are being investigated, MXenes stand out as one of the most promising catalysts and co-catalysts for CO2 reduction, given their excellent surface functionalities, unique layered structures, high surface areas, rich active sites, and high chemical stability. This review aims to highlight research progress and recent developments in the application of MXene-based catalysts for CO2 conversion to value-added chemicals, paying special attention to photoreduction and electroreduction. Furthermore, the underlying photocatalytic and electrocatalytic CO2 conversion mechanisms are discussed. Finally, we provide an outlook for future research in this field, including photoelectrocatalysis and photothermal CO2 reduction.
      PubDate: 2022-08-09
       
  • Heterogeneous Catalysis for CO2 Conversion into Chemicals and Fuels

    • Free pre-print version: Loading...

      Abstract: Catalytic conversion of CO2 into chemicals and fuels is a viable method to reduce carbon emissions and achieve carbon neutrality. Through thermal catalysis, electrocatalysis, and photo(electro)catalysis, CO2 can be converted into a wide range of valuable products, including CO, formic acid, methanol, methane, ethanol, acetic acid, propanol, light olefins, aromatics, and gasoline, as well as fine chemicals. In this mini-review, we summarize the recent progress in heterogeneous catalysis for CO2 conversion into chemicals and fuels and highlight some representative studies of different conversion routes. The structure–performance correlations of typical catalytic materials used for the CO2 conversion reactions have been revealed by combining advanced in situ/operando spectroscopy and microscopy characterizations and density functional theory calculations. Catalytic selectivity toward a single CO2 reduction product/fraction should be further improved at an industrially relevant CO2 conversion rate with considerable stability in the future. Graphical
      PubDate: 2022-08-09
       
  • Rational Manipulation of Intermediates on Copper for CO2 Electroreduction
           Toward Multicarbon Products

    • Free pre-print version: Loading...

      Abstract: Abstract Excess greenhouse gas emissions, primarily carbon dioxide (CO2), have caused major environmental concerns worldwide. The electroreduction of CO2 into valuable chemicals using renewable energy is an ecofriendly approach to achieve carbon neutrality. In this regard, copper (Cu) has attracted considerable attention as the only known metallic catalyst available for converting CO2 to high-value multicarbon (C2+) products. The production of C2+ involves complicated C–C coupling steps and thus imposes high demands on intermediate regulation. In this review, we discuss multiple strategies for modulating intermediates to facilitate C2+ formation on Cu-based catalysts. Furthermore, several sophisticated in situ characterization techniques are outlined for elucidating the mechanism of C–C coupling. Lastly, the challenges and future directions of CO2 electroreduction to C2+ are envisioned.
      PubDate: 2022-08-03
       
  • Recent Development of Quantum Dot Deposition in Quantum Dot-Sensitized
           Solar Cells

    • Free pre-print version: Loading...

      Abstract: Abstract As new-generation solar cells, quantum dot-sensitized solar cells (QDSCs) have the outstanding advantages of low cost and high theoretical efficiency; thus, such cells receive extensive research attention. Their power conversion efficiency (PCE) has increased from 5% to over 15% in the past decade. However, compared with the theoretical efficiency (44%), the PCE of QDSCs still needs further improvement. The low loading amount of quantum dots (QDs) is a key factor limiting the improvement of cell efficiency. The loading amount of QDs on the surface of the substrate film is important for the performance of QDSCs, which directly affects the light-harvesting ability of the device and interfacial charge recombination. The optimization of QD deposition and the improvement of the loading amount are important driving forces for the rapid development of QDSCs in recent years and a key breakthrough in future development. In this paper, the research progress of QD deposition on the surface of substrate films in QDSCs was reviewed. In addition, the main deposition methods and their advantages and disadvantages were discussed, and future research on the further increase in loading amount was proposed.
      PubDate: 2022-07-27
       
  • Metal-Oxo Cluster Catalysts for Photocatalytic Water Splitting and Carbon
           Dioxide Reduction

    • Free pre-print version: Loading...

      Abstract: Abstract Photocatalytic water splitting and carbon dioxide photoreduction are considered effective strategies for alleviating the energy crisis and environmental pollution. Polynuclear metal-oxo clusters possess excellent electron storage/release ability and unique catalytic properties via intermetallic synergy, which enables them with great potential in environmentally friendly photosynthesis. Importantly, metal-oxo clusters with precise structure can not only act as high-efficiency catalysts but also provide well-defined structural models for exploring structure–activity relationships. In this review, we systematically summarize recent progress in the catalytic application of polynuclear metal-oxo clusters, including polyoxometalate clusters, low-cost transition metal clusters, and metal-oxo-cluster-based metal–organic frameworks for water splitting and CO2 reduction. Furthermore, we discuss the challenges and solutions to the problems of polynuclear metal-oxo clusters in photocatalysis.
      PubDate: 2022-07-22
       
  • Metal–Support Interactions on Ag/Co3O4 Nanowire Monolithic Catalysts
           Promoting Catalytic Soot Combustion

    • Free pre-print version: Loading...

      Abstract: Abstract Tuning metal–support interactions (MSIs) is an important strategy in heterogeneous catalysis to realize the desirable metal dispersion and redox ability of metal catalysts. Herein, we use pre-reduced Co3O4 nanowires (Co-NWs) in situ grown on monolithic Ni foam substrates to support Ag catalysts (Ag/Co-NW-R) for soot combustion. The macroporous structure of Ni foam with crossed Co3O4 nanowires remarkably increases the soot–catalyst contact efficiency. Our characterization results demonstrate that Ag species exist as Ag0 because of the equation Ag+  + Co2+  = Ag0 + Co3+, and the pre-reduction treatment enhances interactions between Ag and Co3O4. The number of active oxygen species on the Ag-loaded catalysts is approximately twice that on the supports, demonstrating the significant role of Ag sites in generating active oxygen species. Additionally, the strengthened MSI on Ag/Co-NW-R further improves this number by increasing metal dispersion and the intrinsic activity determined by the turnover frequency of these oxygen species for soot oxidation compared with the catalyst without pre-reduction of Co-NW (Ag/Co-NW). In addition to high activity, Ag/Co-NW-R exhibits high catalytic stability and water resistance. The strategy used in this work might be applicable in related catalytic systems.
      PubDate: 2022-07-20
       
  • Regioisomeric Polymer Semiconductors Based on Cyano-Functionalized
           Dialkoxybithiophenes: Structure–Property Relationship and Photovoltaic
           Performance

    • Free pre-print version: Loading...

      Abstract: Cyano substitution is vital to the molecular design of polymer semiconductors toward highly efficient organic solar cells. However, how regioselectivity impacts relevant optoelectronic properties in cyano-substituted bithiophene systems remain poorly understood. Three regioisomeric cyano-functionalized dialkoxybithiophenes BTHH, BTHT, and BTTT with head-to-head, head-to-tail, and tail-to-tail linkage, respectively, were synthesized and characterized in this work. The resulting polymer semiconductors (PBDTBTs) based on these building blocks were prepared accordingly. The regiochemistry and property relationships of PBDTBTs were investigated in detail. The BTHH moiety has a higher torsional barrier than the analogs BTHT and BTTT, and the regiochemistry of dialkoxybithiophenes leads to fine modulation in the optoelectronic properties of these polymers, such as optical absorption, band gap, and energy levels of frontier molecular orbitals. Organic field-effect transistors based on PBDTBTHH had higher hole mobility (4.4 × 10−3 cm2/(V·s)) than those (ca. 10−4 cm2/(V·s)) of the other two polymer analogs. Significantly different short-circuit current densities and fill factors were obtained in polymer solar cells using PBDTBTs as the electron donors. Such difference was probed in greater detail by performing space-charge-limited current mobility, thin-film morphology, and transient photocurrent/photovoltage characterizations. The findings highlight that the BTHH unit is a promising building block for the construction of polymer donors for high-performance organic photovoltaic cells. Graphical abstract
      PubDate: 2022-07-11
       
  • Evaluating the Stability of Active Manganese Sites During Electrochemical
           Reactions by Cyclic Voltammetry

    • Free pre-print version: Loading...

      Abstract: Abstract Manganese oxides are a promising class of electrocatalysts for renewable energy devices, such as fuel cells. Mn(III) ions with eg electron filling of − 1 are the active sites for manganese-based electrocatalysts. However, Mn(III) sites may be disproportionated during electrochemical reactions, thus reducing the number of Mn(III) active sites and decreasing the catalytic activity of manganese oxides. In this work, we developed a facile cyclic voltammetry method to monitor the evolution of Mn(III) sites on a series of manganese oxides under “working” conditions. We proposed a descriptor SMn(III) to describe the stability of Mn(III). Our simulated and experimental results show that the higher is SMn(III), the higher the active Mn(III) density, and the higher the electrocatalytic activity of the manganese oxide electrocatalyst.
      PubDate: 2022-07-07
       
  • Manipulating Spin Polarization of Defected Co3O4 for Highly Efficient
           Electrocatalysis

    • Free pre-print version: Loading...

      Abstract: Abstract Electrocatalytic water splitting is limited by kinetics-sluggish oxygen evolution, in which the activity of catalysts depends on their electronic structure. However, the influence of electron spin polarization on catalytic activity is ambiguous. Herein, we successfully regulate the spin polarization of Co3O4 catalysts by tuning the concentration of cobalt defects from 0.8 to 14.5%. X-ray absorption spectroscopy spectra and density functional theory calculations confirm that the spin polarization of Co3O4 is positively correlated with the concentration of cobalt defects. Importantly, the enhanced spin polarization can increase hydroxyl group absorption to significantly decrease the Gibbs free energy change value of the OER rate-determining step and regulate the spin polarization of oxygen species through a spin electron-exchange process to easily produce triplet-state O2, which can obviously increase electrocatalytic OER activity. In specific, Co3O4-50 with 14.5% cobalt defects exhibits the highest spin polarization and shows the best normalized OER activity. This work provides an important strategy to increase the water splitting activity of electrocatalysts via the rational regulation of electron spin polarization.
      PubDate: 2022-06-15
       
  • A Thiazole-Based Polymer Donor for Efficient Organic Solar Cells

    • Free pre-print version: Loading...

      Abstract: Abstract The development of new materials plays a critical role in improving the efficiency of organic solar cells (OSCs). At present, the relatively high-lying highest occupied molecular orbital (HOMO) level of the high-efficiency polymer donor is regarded as one of the main reasons for the low open-circuit voltage (Voc). In this work, we introduced the strong electron-withdrawing thiazole unit into the construction of a polymer donor. We designed and prepared an alternating donor–acceptor material, namely PSZ, by copolymerizing 4-methyl thiazole with an electron-donating benzodithiophene unit and studied its application in high-efficiency OSCs. The optical and electrical properties of the new material were characterized by UV–Vis absorption spectroscopy and electrochemical cyclic voltammetry. Results show that PSZ is a typical wide-bandgap material with a high optical bandgap of 2.0 eV and a deep HOMO level of − 5.70 eV. When a non-fullerene BTP-eC9 was selected as the acceptor material, Voc reached 0.88 V in the resulting device, and the corresponding power conversion efficiency (PCE) was 8.15%. In addition, when PSZ was added as the third component to the binary photoactive combination with PBDB-TF as the donor and BTP-eC9 as the acceptor, Voc of the cell device could be increased, thereby obtaining a high PCE of 17.4%. These results indicated that introducing thiazole units into polymer donors can remarkably reduce the HOMO levels and improve Voc and PCE in OSCs.
      PubDate: 2022-06-09
       
  • Research Progress of Catalysts and Initiators for Promoting the Cracking
           of Endothermic Hydrocarbon Fuels

    • Free pre-print version: Loading...

      Abstract: Abstract Catalytic/initiated cracking of endothermic hydrocarbon fuels is an effective technology for cooling a hypersonic aircraft with a high Mach number (over 5). Catalysts and initiators can promote fuel cracking at low temperatures, increase fuel conversion and the heat sink capacity, and suppress coke deposition, thereby reducing waste heat. Catalysts mainly include metal oxide catalysts, noble metal catalysts and metal nanoparticles, zeolite catalysts, nanozeolite catalysts, and coating catalysts. Moreover, initiators roughly include nitrogenous compounds, oxygenated compounds, and hyperbranched polymer initiators. In this review, we aim to summarize the catalysts and initiators for cracking endothermic hydrocarbon fuels and their mechanisms for promoting cracking. This review will facilitate the development of the synthesis and exploration of catalysts and initiators.
      PubDate: 2022-05-03
       
 
JournalTOCs
School of Mathematical and Computer Sciences
Heriot-Watt University
Edinburgh, EH14 4AS, UK
Email: journaltocs@hw.ac.uk
Tel: +00 44 (0)131 4513762
 


Your IP address: 44.201.95.84
 
Home (Search)
API
About JournalTOCs
News (blog, publications)
JournalTOCs on Twitter   JournalTOCs on Facebook

JournalTOCs © 2009-