Subjects -> CHEMISTRY (Total: 975 journals)
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CHEMISTRY (703 journals)                  1 2 3 4 | Last

Showing 1 - 200 of 735 Journals sorted alphabetically
2D Materials     Hybrid Journal   (Followers: 19)
Accreditation and Quality Assurance: Journal for Quality, Comparability and Reliability in Chemical Measurement     Hybrid Journal   (Followers: 33)
ACS Applied Polymer Materials     Hybrid Journal   (Followers: 1)
ACS Catalysis     Hybrid Journal   (Followers: 58)
ACS Chemical Neuroscience     Hybrid Journal   (Followers: 23)
ACS Combinatorial Science     Hybrid Journal   (Followers: 23)
ACS Macro Letters     Hybrid Journal   (Followers: 29)
ACS Medicinal Chemistry Letters     Hybrid Journal   (Followers: 48)
ACS Nano     Hybrid Journal   (Followers: 400)
ACS Photonics     Hybrid Journal   (Followers: 17)
ACS Symposium Series     Full-text available via subscription   (Followers: 3)
ACS Synthetic Biology     Hybrid Journal   (Followers: 31)
Acta Chemica Iasi     Open Access   (Followers: 8)
Acta Chimica Slovaca     Open Access   (Followers: 4)
Acta Chimica Slovenica     Open Access   (Followers: 2)
Acta Chromatographica     Full-text available via subscription   (Followers: 9)
Acta Facultatis Medicae Naissensis     Open Access   (Followers: 1)
Acta Metallurgica Sinica (English Letters)     Hybrid Journal   (Followers: 8)
Acta Scientifica Naturalis     Open Access   (Followers: 3)
adhäsion KLEBEN & DICHTEN     Hybrid Journal   (Followers: 9)
Adhesion Adhesives & Sealants     Hybrid Journal   (Followers: 10)
Adsorption Science & Technology     Open Access   (Followers: 8)
Advanced Electronic Materials     Hybrid Journal   (Followers: 1)
Advanced Functional Materials     Hybrid Journal   (Followers: 68)
Advanced Science Focus     Free   (Followers: 6)
Advanced Theory and Simulations     Hybrid Journal   (Followers: 1)
Advanced Therapeutics     Hybrid Journal   (Followers: 1)
Advances in Chemical Engineering and Science     Open Access   (Followers: 94)
Advances in Chemistry     Open Access   (Followers: 30)
Advances in Colloid and Interface Science     Full-text available via subscription   (Followers: 21)
Advances in Drug Research     Full-text available via subscription   (Followers: 26)
Advances in Environmental Chemistry     Open Access   (Followers: 9)
Advances in Enzyme Research     Open Access   (Followers: 11)
Advances in Fluorine Science     Full-text available via subscription   (Followers: 9)
Advances in Fuel Cells     Full-text available via subscription   (Followers: 17)
Advances in Heterocyclic Chemistry     Full-text available via subscription   (Followers: 11)
Advances in Materials Physics and Chemistry     Open Access   (Followers: 31)
Advances in Nanoparticles     Open Access   (Followers: 19)
Advances in Organometallic Chemistry     Full-text available via subscription   (Followers: 18)
Advances in Polymer Science     Hybrid Journal   (Followers: 49)
Advances in Protein Chemistry     Full-text available via subscription   (Followers: 19)
Advances in Protein Chemistry and Structural Biology     Full-text available via subscription   (Followers: 20)
Advances in Quantum Chemistry     Full-text available via subscription   (Followers: 7)
Advances in Science and Technology     Full-text available via subscription   (Followers: 14)
Aerosol Science and Engineering     Hybrid Journal  
African Journal of Bacteriology Research     Open Access  
African Journal of Chemical Education     Open Access   (Followers: 5)
African Journal of Pure and Applied Chemistry     Open Access   (Followers: 7)
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)
Alkaloids: Chemical and Biological Perspectives     Full-text available via subscription   (Followers: 2)
Alotrop     Open Access  
AMB Express     Open Access   (Followers: 1)
Ambix     Hybrid Journal   (Followers: 3)
American Journal of Biochemistry and Biotechnology     Open Access   (Followers: 71)
American Journal of Biochemistry and Molecular Biology     Open Access   (Followers: 22)
American Journal of Chemistry     Open Access   (Followers: 36)
American Journal of Plant Physiology     Open Access   (Followers: 13)
American Mineralogist     Hybrid Journal   (Followers: 14)
Anadolu University Journal of Science and Technology A : Applied Sciences and Engineering     Open Access  
Analyst     Full-text available via subscription   (Followers: 37)
Angewandte Chemie     Hybrid Journal   (Followers: 196)
Angewandte Chemie International Edition     Hybrid Journal   (Followers: 306)
Annales Universitatis Mariae Curie-Sklodowska, sectio AA – Chemia     Open Access   (Followers: 1)
Annals of Clinical Chemistry and Laboratory Medicine     Open Access   (Followers: 5)
Annual Reports in Computational Chemistry     Full-text available via subscription   (Followers: 3)
Annual Reports Section A (Inorganic Chemistry)     Full-text available via subscription   (Followers: 4)
Annual Reports Section B (Organic Chemistry)     Full-text available via subscription   (Followers: 8)
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: 15)
Antiviral Chemistry and Chemotherapy     Open Access   (Followers: 2)
Applied Organometallic Chemistry     Hybrid Journal   (Followers: 9)
Applied Spectroscopy     Full-text available via subscription   (Followers: 26)
Applied Surface Science     Hybrid Journal   (Followers: 33)
Arabian Journal of Chemistry     Open Access   (Followers: 6)
ARKIVOC     Open Access   (Followers: 1)
Asian Journal of Applied Chemistry Research     Open Access   (Followers: 1)
Asian Journal of Biochemistry     Open Access   (Followers: 3)
Asian Journal of Chemical Sciences     Open Access   (Followers: 1)
Asian Journal of Chemistry and Pharmaceutical Sciences     Open Access   (Followers: 2)
Asian Journal of Physical and Chemical Sciences     Open Access   (Followers: 1)
Atomization and Sprays     Full-text available via subscription   (Followers: 6)
Australian Journal of Chemistry     Hybrid Journal   (Followers: 7)
Autophagy     Hybrid Journal   (Followers: 4)
Avances en Quimica     Open Access  
Biochemical Pharmacology     Hybrid Journal   (Followers: 11)
Biochemistry     Hybrid Journal   (Followers: 423)
Biochemistry Insights     Open Access   (Followers: 7)
Biochemistry Research International     Open Access   (Followers: 7)
BioChip Journal     Hybrid Journal  
Bioinorganic Chemistry and Applications     Open Access   (Followers: 11)
Bioinspired Materials     Open Access   (Followers: 5)
Biointerface Research in Applied Chemistry     Open Access   (Followers: 2)
Biointerphases     Open Access   (Followers: 1)
Biology, Medicine, & Natural Product Chemistry     Open Access   (Followers: 3)
Biomacromolecules     Hybrid Journal   (Followers: 25)
Biomass Conversion and Biorefinery     Partially Free   (Followers: 11)
Biomedical Chromatography     Hybrid Journal   (Followers: 6)
Biomolecular NMR Assignments     Hybrid Journal   (Followers: 3)
BioNanoScience     Partially Free   (Followers: 6)
Bioorganic & Medicinal Chemistry     Hybrid Journal   (Followers: 191)
Bioorganic & Medicinal Chemistry Letters     Hybrid Journal   (Followers: 89)
Bioorganic Chemistry     Hybrid Journal   (Followers: 10)
Biopolymers     Hybrid Journal   (Followers: 17)
Biosensors     Open Access   (Followers: 3)
Biotechnic and Histochemistry     Hybrid Journal   (Followers: 1)
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: 26)
Bulletin of the Korean Chemical Society     Hybrid Journal   (Followers: 1)
C - Journal of Carbon Research     Open Access   (Followers: 4)
Cakra Kimia (Indonesian E-Journal of Applied Chemistry)     Open Access  
Canadian Association of Radiologists Journal     Full-text available via subscription   (Followers: 2)
Canadian Journal of Chemistry     Hybrid Journal   (Followers: 12)
Canadian Mineralogist     Full-text available via subscription   (Followers: 7)
Carbohydrate Research     Hybrid Journal   (Followers: 24)
Carbon     Hybrid Journal   (Followers: 73)
Catalysis for Sustainable Energy     Open Access   (Followers: 10)
Catalysis Reviews: Science and Engineering     Hybrid Journal   (Followers: 9)
Catalysis Science and Technology     Hybrid Journal   (Followers: 10)
Catalysis Surveys from Asia     Hybrid Journal   (Followers: 3)
Catalysts     Open Access   (Followers: 13)
Cellulose     Hybrid Journal   (Followers: 14)
Cereal Chemistry     Full-text available via subscription   (Followers: 5)
ChemBioEng Reviews     Full-text available via subscription   (Followers: 2)
ChemCatChem     Hybrid Journal   (Followers: 8)
Chemical and Engineering News     Free   (Followers: 22)
Chemical Bulletin of Kazakh National University     Open Access  
Chemical Communications     Full-text available via subscription   (Followers: 80)
Chemical Engineering Research and Design     Hybrid Journal   (Followers: 27)
Chemical Physics Letters : X     Open Access   (Followers: 2)
Chemical Research in Chinese Universities     Hybrid Journal   (Followers: 3)
Chemical Research in Toxicology     Hybrid Journal   (Followers: 24)
Chemical Reviews     Hybrid Journal   (Followers: 237)
Chemical Science     Open Access   (Followers: 35)
Chemical Science International Journal     Open Access   (Followers: 1)
Chemical Technology     Open Access   (Followers: 54)
Chemical Vapor Deposition     Hybrid Journal   (Followers: 5)
Chemie in Unserer Zeit     Hybrid Journal   (Followers: 56)
Chemie-Ingenieur-Technik (Cit)     Hybrid Journal   (Followers: 21)
ChemInform     Hybrid Journal   (Followers: 9)
Chemistry     Open Access  
Chemistry & Biodiversity     Hybrid Journal   (Followers: 7)
Chemistry & Biology     Full-text available via subscription   (Followers: 32)
Chemistry & Industry     Full-text available via subscription   (Followers: 8)
Chemistry - A European Journal     Hybrid Journal   (Followers: 203)
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: 24)
Chemistry Central Journal     Open Access   (Followers: 5)
Chemistry Education Research and Practice     Free   (Followers: 5)
Chemistry in Education     Open Access   (Followers: 9)
Chemistry International     Open Access   (Followers: 3)
Chemistry Letters     Full-text available via subscription   (Followers: 47)
Chemistry of Heterocyclic Compounds     Hybrid Journal   (Followers: 4)
Chemistry of Materials     Hybrid Journal   (Followers: 300)
Chemistry of Natural Compounds     Hybrid Journal   (Followers: 10)
Chemistry World     Full-text available via subscription   (Followers: 21)
Chemistry-Didactics-Ecology-Metrology     Open Access   (Followers: 1)
ChemistryOpen     Open Access   (Followers: 1)
ChemistrySelect     Hybrid Journal  
Chemkon - Chemie Konkret, Forum Fuer Unterricht Und Didaktik     Hybrid Journal  
ChemNanoMat     Hybrid Journal   (Followers: 1)
Chemoecology     Hybrid Journal   (Followers: 3)
Chemometrics and Intelligent Laboratory Systems     Hybrid Journal   (Followers: 15)
Chemosensors     Open Access   (Followers: 1)
ChemPhotoChem     Hybrid Journal  
ChemPhysChem     Hybrid Journal   (Followers: 12)
ChemPlusChem     Hybrid Journal   (Followers: 2)
Chempublish Journal     Open Access   (Followers: 1)
ChemSystemsChem     Hybrid Journal   (Followers: 1)
ChemTexts     Hybrid Journal   (Followers: 1)
CHIMIA International Journal for Chemistry     Full-text available via subscription   (Followers: 2)
Chinese Journal of Chemistry     Hybrid Journal   (Followers: 6)
Chinese Journal of Polymer Science     Hybrid Journal   (Followers: 12)
Chromatographia     Hybrid Journal   (Followers: 22)
Chromatography     Open Access   (Followers: 3)
Chromatography Research International     Open Access   (Followers: 5)
Ciencia     Open Access   (Followers: 1)
Clay Minerals     Hybrid Journal   (Followers: 9)
Cogent Chemistry     Open Access   (Followers: 3)
Colloid and Interface Science Communications     Open Access  
Colloid and Polymer Science     Hybrid Journal   (Followers: 12)
Colloids and Interfaces     Open Access  
Colloids and Surfaces B: Biointerfaces     Hybrid Journal   (Followers: 8)
Combinatorial Chemistry & High Throughput Screening     Hybrid Journal   (Followers: 4)
Combustion Science and Technology     Hybrid Journal   (Followers: 23)
Comments on Inorganic Chemistry: A Journal of Critical Discussion of the Current Literature     Hybrid Journal   (Followers: 2)
Communications Chemistry     Open Access   (Followers: 2)
Communications Materials     Open Access  
Composite Interfaces     Hybrid Journal   (Followers: 9)
Comprehensive Chemical Kinetics     Full-text available via subscription   (Followers: 2)
Comptes Rendus Chimie     Full-text available via subscription  
Comptes Rendus Physique     Full-text available via subscription   (Followers: 2)
Computational and Theoretical Chemistry     Hybrid Journal   (Followers: 10)
Computational Biology and Chemistry     Hybrid Journal   (Followers: 13)
Computational Chemistry     Open Access   (Followers: 3)

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Journal Cover
Applied Surface Science
Journal Prestige (SJR): 1.093
Citation Impact (citeScore): 4
Number of Followers: 33  
  Hybrid Journal Hybrid journal (It can contain Open Access articles)
ISSN (Print) 0169-4332 - ISSN (Online) 0169-4332
Published by Elsevier Homepage  [3206 journals]
  • Computational exploration of the anion exchange on the basal surface of
           layered double hydroxides by molecular dynamics
    • Abstract: Publication date: 30 May 2020Source: Applied Surface Science, Volume 513Author(s): Sergio R. Tavares, Juliana F.S. Haddad, Pedro Ivo R. Moraes, Alexandre A. LeitãoThe anion exchange between the adsorbed anions on the basal surface of Mg2Al-layered double hydroxide and a guest anion (OH–) was monitored by means of molecular dynamics. A bottom-up strategy was adopted in order to investigate this phenomenon. First, the structural features of the exfoliated forms in vacuum were analyzed. The distribution of the water molecules and anions (NO3–, Br−, Cl−, F− and CO32–) on the Mg2Al layer could be elucidated. Afterwards, the size of the simulation systems was increased by bringing the exfoliated structures into contact with liquid water and by stacking adjacent Mg2Al layers. The comparison between the dispersion of adsorbed anions throughout the liquid water indicated a strong affinity between CO32-/Mg2Al layer. Furthermore, no anion exchange between CO32- and the guest OH− was detected, suggesting that the hydroxyl anions only approach the available adsorption sites on the surface.Graphical abstractGraphical abstract for this article
  • Thermal stability of CH3NH3PbIxCl3-x versus
           [HC(NH2)2]0.83Cs0.17PbI2.7Br0.3 perovskite films by X-ray photoelectron
    • Abstract: Publication date: 30 May 2020Source: Applied Surface Science, Volume 513Author(s): Małgorzata Kot, Mykhailo Vorokhta, Zhiping Wang, Henry J. Snaith, Dieter Schmeißer, Jan Ingo FlegeAbstractThe thermal stability of CH3NH3PbIxCl3-x and [HC(NH2)2]0.83Cs0.17PbI2.7Br0.3 perovskite films was studied in-situ by X-ray photoelectron spectroscopy. It was found that below 85 °C both of them are relatively stable. After annealing above 85 °C, we observe a clear perovskite surface decomposition, i.e., a release of organic cations and creation of “metallic lead”. The mixed cation lead mixed halide perovskite, however, decomposes at a much lower rate. For both perovskite films, the metallic to the total lead ratio changes with the same rate for the same annealing temperatures. The release of A-site cations from the ABX3 crystal structure of perovskite and/or creation of “metallic lead” causes also a small shift of the valence band maximum towards the Fermi level. The release of [HC(NH2)2]± or Cs± is not as significant as the release of CH3NH3±; therefore, it may explain why [HC(NH2)2]0.83Cs0.17PbI2.7Br0.3 solar cells are thermally more stable. Therefore, as the stability of CH3NH3PbIxCl3-x is same as the stability of [HC(NH2)2]0.83Cs0.17PbI2.7Br0.3 below 85 °C, there must be more severe degradation pathways that are currently underappreciated on the solar cell level.
  • Investigation of the dimensionality using temperature-dependent decay
           times in InGaAs-coupled quantum well-quantum dots structures
    • Abstract: Publication date: 30 May 2020Source: Applied Surface Science, Volume 513Author(s): Heedae Kim, Akihiro MurayamaAbstractThe radiative temperature-dependent decay times were exploited to understand the confinement size analyzing the relaxation from thermally-excited states in InGaAs coupled quantum well (QW)–quantum dots (QDs) structures. We investigated the confinement size from coupled QW-QDs structures by measuring the decay time of radiative process from exciton states when the temperature is gradually increased. The photoluminescence (PL) decay time from the exciton states is amended with the PL intensity at low temperature (~5 K) to distinguish the radiative decay time. The zero-dimensional and the two-dimensional confinement size are obtained from the isolated QDs and QW. However, this assumption is no longer correct for optical coupling because of the direct tunneling when the distance between the QW and the QDs becomes less than 10 nm in the coupled QW-QDs structures. Below 6 nm between the QW and the QDs in the coupled QW-QDs structures, the power factor from the temperature variations increases from 0 to 0.3 (for QDs) and from 1 to 1.37 (for QW), which accords with a quasi-zero-dimensional density of states (~Tα=0.3) and a quasi-two-dimensional density of states (~Tα=1.37), respectively, because of the extended wave functions in the optical couplings and the existence of dark states in the coupled QW-QDs structures.
  • Recent progress in laser materials processing and synthesis
    • Abstract: Publication date: 30 May 2020Source: Applied Surface Science, Volume 513Author(s): Bilal Gökce, Mihaela Filipescu, Stephan Barcikowski
  • In-situ growth of silica nano-protrusions on halloysite nanotubes for
           interfacial reinforcement in polymer/halloysite scaffolds
    • Abstract: Publication date: 30 May 2020Source: Applied Surface Science, Volume 513Author(s): Wang Guo, Li Xu, Pei Feng, Yifan Gu, Cijun ShuaiAbstractThe mechanical reinforcing effects of halloysite nanotubes (HNT) on polymer scaffolds were restricted due to poor interfacial adhesion and dispersion. In this study, silica (SiO2) nano-protrusions were in-situ grown on HNT via the hydrolysis of tetraethoxysilane (TEOS) and the polycondensation of its intermediates with the surface O–H groups of HNT. Then, HNT@SiO2 was introduced to poly (L-lactide) (PLLA) scaffolds for better mechanical reinforcing, which were prepared by laser additive manufacturing. The results indicated many irregularly shaped SiO2 nano-protrusions were in-situ grown on HNT with Si-O bonding under a low (L) and medium (M) concentration of TEOS, while there formed many free SiO2 particles under a high (H) concentration. The in-situ grown organosilane-derived SiO2 nano-protrusions effectively strengthened the interaction of HNT@SiO2 with PLLA, contributing to strong interfacial adhesion between HNT@SiO2 and the PLLA matrix as well as good dispersion of HNT@SiO2. As a result, PLLA/HNT@SiO2-L and M scaffolds showed much higher tensile strength and modulus than those of PLLA and PLLA/HNT. Besides, PLLA/HNT@SiO2 scaffolds supported the responses of stem cells, and showed improved apatite-forming ability and hydrophilicity. This study suggested the potential application of HNT@SiO2 in reinforcing polymer-based bone tissue engineering scaffolds.
  • Single-femtosecond-laser-pulse interaction with mica
    • Abstract: Publication date: 30 May 2020Source: Applied Surface Science, Volume 513Author(s): Saurabh Awasthi, Douglas J. Little, A. Fuerbach, D.M. KaneUltrafast, femtosecond laser pulse interaction with dielectric materials has shown them to have significantly higher laser fluence threshold requirements, as compared to metals and semiconductors, for laser material modification such as laser ablation. The interaction between femtosecond laser pulses and a dielectric, at a wavelength with negligible linear absorption, has usually been found to be weak, and multiple pulse irradiation is therefore typically used to observe quantifiable effects. In this study, the dielectric is the crystalline layered natural mineral muscovite, a mica with formula KAl2(Si3Al) O10(OH)2. A single ~150 fs laser pulse, ~800 nm wavelength, ~6 µm spotsize, is found to lead to a systematic range of laser modification topologies, as a function of fluence of the single laser pulse, including bulk removal. The fs laser pulse/material interaction is greater than expected for a standard dielectric at a given fluence. Optical surface profiling and FESEM are used to characterise the topologies. Contrasting the results of the two techniques supports the use of optical surface profiling to characterise the material modification despite its limitations in lateral resolution as compared to FESEM. The interlayer mineral water content of natural muscovite is proposed as the primary reason that mica behaves differently to a standard dielectric.Graphical abstractGraphical abstract for this article
  • Evaluation of antimicrobial activity of ZnO based nanocomposites for the
           coating of non-critical equipment in medical-care facilities
    • Abstract: Publication date: 30 May 2020Source: Applied Surface Science, Volume 513Author(s): A.P. Piedade, A.C. Pinho, R. Branco, P.V. MoraisNosocomial infections are quite common in medical facilities environment and the highest percentage is caused by bacteria. The transmission of such infections is often made by direct contact with non-critical surfaces. Therefore, it is important to develop surfaces able to inhibit microbial adhesion and proliferation. In this work monolithic ZnO and copper and carbon nanocomposite ZnO thin films were studied to evaluate their antimicrobial activity for the coating of non-critical surfaces at medical care facilities. ZnO-Cu functioned as reference for the comparison of the ZnO-C thin films performance. The coatings were deposited by r.f. magnetron sputtering technique and were thoroughly characterized, before the antimicrobial tests against two distinct bacteria: Pseudomonas aeruginosa and Staphylococcus aureus. The tests were conducted in liquid and solid culture media under three different light incubation conditions. The results indicate that the antimicrobial properties of ZnO thin films were enhanced by the incorporation of C and Cu. The integration of carbon in ZnO produced similar results to copper doped thin films, allowing to produce metal-free surfaces that do not induce metal bacteria resistance.Graphical abstractGraphical abstract for this article
  • Infiltration mechanism of Ca-Mg-Al-silicate (CMAS) melt on Yttria
           stabilized zirconia (YSZ) columnar crystal at high temperature:
           First-principles research
    • Abstract: Publication date: 30 May 2020Source: Applied Surface Science, Volume 513Author(s): Peifeng Zhou, Guifa Li, Yongqing Zhang, Yuncheng Wang, Haizhong Zheng, Bintian Li, Ping PengThrough Yttria stabilized zirconia (YSZ) microfacet models, the infiltration mechanism of Ca-Mg-Al-silicate (CMAS) melt on the corner of YSZ columnar crystal at high temperature was studied by first-principles calculation. The results show that the contact angles of CMAS melt on YSZ[(0 1 0 × 0 1 0)], YSZ[(0 1 0 × 1 0 1)] and YSZ[(1 0 1 × 1 0 1)] are equal to 40°, 48° and 38° respectively, which exhibit hydrophilicity. Their adhesion energies Wad are also larger than that of CMAS/YSZ bulk surface. Elements diffusion points out that the large wettability of CMAS melt on the corner of YSZ columnar crystal comes from the powerful converging ability of Y and Ca elements, which have the similar energy levels of electrons at d orbital. And their large and positive charged of electrostatic potentials provide further chemical corrosion reaction of CMAS melt.Graphical abstractGraphical abstract for this article
  • Performance and damage mechanism of TiN/ZrN nano-multilayer coatings based
           on different erosion angles
    • Abstract: Publication date: 30 May 2020Source: Applied Surface Science, Volume 513Author(s): Jiao Chen, Zhaolu Zhang, Guanjun Yang, Zhihao Fang, Zhufang Yang, Zhe Li, Guangyu HeNano-multilayer coating is an effective method for improving the sand erosion resistance of a material employed in any industrial field. However, very few studies have addressed this subject of research, especially in the aspects of the multi-angles erosion performance and the corresponding mechanism. In this study, a TiN/ZrN nano-multilayer coating was prepared on the Ti6Al4V substrate by employing physical vapor deposition; the nano-layer thickness of the alternating structure of this coating was less than 200 nm. The mechanical and erosion properties of TiN/ZrN were examined, accompanied by varying the erosion angles from 15° to 90°. The 3D surface topographies of the eroded surface were characterized by using a white-light interfering profilometer. The coating damage was examined by cross-sectioning the samples using the focused ion beam (FIB) method. The experiment shows that the maximum erosion rate occurs at 90°, which is approximately 3.1, 2.8 and 1.2 times larger than 15°, 45°, and 75° erosion angles, respectively. The diameter, depth and density of the erosion pit increases with a rise in the erosion angle. The erosion mechanism of the TiN/ZrN nano-multilayer coatings is governed by lateral cracks and the tensile stress of the coating itself at 15° and 45°; further, it is influenced by the longitudinal cracks at 75° and 90°. Lateral cracks in the erosion damage of coating are primarily Mode Ⅱ cracks. The average crack density in the effective FIB trenches reveals that the cracks are more probable to occur at high angles (75° and 90°); this further explains the results of a higher erosion rate at a high erosion angle.Graphical abstractGraphical abstract for this article
  • Enhanced performance and stability of ambient-processed CH3NH3PbI3-x(SCN)x
           planar perovskite solar cells by introducing ammonium salts
    • Abstract: Publication date: 30 May 2020Source: Applied Surface Science, Volume 513Author(s): Yuzhu Li, Zongbao Zhang, Yang Zhou, Lai Xie, Naitao Gao, Xubing Lu, Xingsen Gao, Jinwei Gao, Lingling Shui, Sujuan Wu, Junming LiuAbstractMetal halide perovskite solar cells have drawn a lot of attention due to their excellent photovoltaic properties. However, a simple method to prepare perovskite films with high quality in ambient air remains a big challenge, which has become an obstacle for the commercialization of PSCs. Here we propose a facile method to prepare efficient CH3NH3PbI3-x(SCN)x-based planar PSCs in ambient conditions and ammonium salts (NH4Cl, NH4SCN) are used to regulate the microstructure of CH3NH3PbI3-x(SCN)x perovskite film prepared in ambient air. At the optimal concentration, the devices with NH4Cl or NH4SCN additives achieve the champion efficiency of 14.71% and 16.61% respectively, which are much higher than the 12.97% of the reference device. The stability of the unsealed devices with additives in ambient air has also been significantly improved. The modified devices without any encapsulation still retain about 80% of initial efficiency after 30 days in ambient air. The conductive atomic force microscopy and photoluminescence measurement are used to characterize photoelectric properties of perovskite film. The trap-state density and charge recombination of the devices have been investigated. The results suggest that the improved photovoltaic characteristics and stability may be attributed to the improved quality of perovskite films, the reduced trap states and the suppressed charge recombination.
  • Engineering compositions and hierarchical yolk-shell structures of
           NiCo/GC/NPC nanocomposites with excellent electromagnetic wave absorption
    • Abstract: Publication date: 30 May 2020Source: Applied Surface Science, Volume 513Author(s): Juan Xiong, Zhen Xiang, Baiwen Deng, Mengchen Wu, Lunzhou Yu, Zhicheng Liu, Erbiao Cui, Fei Pan, Rui Liu, Wei LuDesignable microstructure was crucial for fabricating electromagnetic wave (EMW) absorbing materials. Herein, NiCo nanoparticles/graphitic carbon/nanoporous carbon (NiCo/GC/NPC) core–shell nanocomposites with novel hierarchical double yolk-shell structure were synthesized from metal-organic frameworks by a facile process. The yolk-shell nanoporous core–shell structure of the NiCo/GC/NPC nanocomposites was expertly tuned by regulating the composition of the Ni and Co elements, leading to the engineering relaxation polarization, conductive loss, magnetic resonance and multiple scatterings and reflections. The Ni1Co2/GC/NPC nanocomposite exhibited a minimum reflection loss (RLmin) value of −52.2 dB and a broad effective absorbing bandwidth (EAB) of 7.2 GHz (from 10.8 to 18 GHz) for RL 
  • Three-dimensional honeycomb-like MoSe2/rGO as high performance sodium ions
           storage materials with long cycle stability and high rate capability
    • Abstract: Publication date: 30 May 2020Source: Applied Surface Science, Volume 513Author(s): Bin-Mei Zhang, Chong-Bo Zhang, Hui Zhang, Yu-Xia Hu, Yu-Shan Zhang, Chun Lu, Jun Li, Ling-Bin Kong, Mao-Cheng LiuAbstractTransition metal dichalcogenides (TMDs) caused widespread concern because of their possess graphite-like two-dimensional structure, which allows Na+ reversible de-intercalation between the interlayers and contributes high theoretical capacity. However, the poor conductivity and structural instability greatly limited their application to sodium ion batteries (SIBs). Herein, three-dimensional (3D) honeycomb MoSe2/rGO nanocomposites with outstanding sodium ion storage performance were prepared. The MoSe2/rGO combined the advantages of MoSe2 and rGO. The typical layered structure of MoSe2 provide Na+ diffusion pathways and sufficient active sites, while the rGO increase conductivity and alleviate structural change during Na+ insertion/extraction process. The stable discharge capacity of MoSe2/rGO reaches 300 mAh g−1 at 0.1 A g−1 and retains 247 mAh g−1 after 100 times. It retains a high capacity of 214.7 mAh g−1 at 1 A g−1 and shows outstanding rate capability. The MoSe2/rGO//AC hybrid sodium-ion capacitors (HSIC) achieves a high capacitance of 56.7 F g−1 at 0.1 A g−1, it exhibits an energy density of 87.7 W kg−1 at a power density of 208.8 W h kg−1 and retains 50.5 W h kg−1 when it increases to 1051.4 W kg−1. The article brings up a novel opinion for designing porous TMDs based composites as ideal energy storage materials.
  • Enriched active surface structure in nanosized tungsten-cobalt oxides
           electrocatalysts for efficient oxygen redox reactions
    • Abstract: Publication date: 30 May 2020Source: Applied Surface Science, Volume 513Author(s): Mabrook S. Amer, Prabhakarn Arunachalam, Mohamed A. Ghanem, Abdullah M. Al-Mayouf, Muhammad Ali SharNanosized tungsten-cobalt oxide (WCoO-NP) electrodes were prepared using self-assembly template approach and their bifunctional electrocatalytic behaviour for the oxygen redox reactions was investigated. The texture, morphology, specific surface area, crystallinity, and electrocatalytic activity of the WCoO-NP were strongly associated with the W and Co content. The WCoO-NP materials contains 15 mol% of tungsten showed enhanced electrocatalytic behaviour, substantial shift in the OER onset potential of 190 mV, Tafel slope (92 mV/dec), ultra-low charge-transfer resistance, and current density of 30 mA cm−2 at 1.55 VRHE, which is more efficient catalyst than bare cobalt oxide nanoparticles (Co3O4-NP) counterpart and comparable to benchmark transition metal oxide electrocatalysts. The WCoO-NP materials exhibits long-term durability and good bifunctional electrocatalytic behaviour for both the OER and ORR, having ΔE (=EOER − EORR) of only 0.92 V which could be credited to the synergistic effect, enriched specific surface area, and improved electrical conductivity upon tungsten-doping. The WCoO-NP electrocatalysts prepared from earth-abundant materials are a promising candidate for high-efficiency OER and ORR applications.Graphical abstractGraphical abstract for this article
  • Whisker inhibited Sn–Bi alloy coating on copper surface to increase
           copper bonding strength for signal loss reduction of PCB in high-frequency
    • Abstract: Publication date: 30 May 2020Source: Applied Surface Science, Volume 513Author(s): Guoyun Zhou, Yepei Tao, Wei He, Shouxu Wang, Yan Hong, Chia-Yun Chen, Yuanming Chen, Chong Wang, Chaoying Ma, Shan Guo, Hua Miao, Jinqun ZhouIntroducing Bi in the coating of Sn on copper surfaces for chemical bonding with prepreg was proposed to inhibit the serious whisker growth of Sn in the post–application process. The desired bonding strength and low roughness of copper surfaces (Ra = 0.5 μm) coated with this Sn–Bi alloy were both obtained under characterizations of peeling strength test and roughness measurement. Scanning electron microscopy (SEM) and X–ray photoelectron spectroscopy (XPS) confirmed that the high bonding strength is related to the high content of SnO2 in as–coated Sn–Bi alloy and the plating time with 180 s gives rise to the optimized bonding strength. Agilent Vector Network Analyzer (VNA) affirmed the lower signal loss (7 dB/m@10 GHz) in comparison with that treated with conventional brown–oxidation. Accordingly, the Sn–Bi coating on copper surface is suggested to be a candidate for layer bonding in high frequency PCB.Graphical abstractGraphical abstract for this article
  • Enhanced solar- photocatalytic activity for the simultaneous degradation
           and detoxification of multiple chlorophenols by embedding plasmonic Pt
           into TiO2/H3PW12O40 nanopore
    • Abstract: Publication date: 30 May 2020Source: Applied Surface Science, Volume 513Author(s): Jiunian Guan, Lu Li, Chaohuang Chen, Ping Lu, Yu Yan, Zirui Wang, Nan Lu, Mingxin HuoA novel Pt-TiO2/H3PW12O40 film was fabricated, which showed a considerable nonselective degradation and detoxification efficiency towards multiple chlorophenols (CPs), owing to the enhanced yield and separation efficiency of photogenerated electrons and holes. Based on the Mott-Schottky analysis, the carrier density of as-prepared Pt-TiO2/H3PW12O40 film reached 9.72 × 1022 cm−1, which was higher than that of Pt-TiO2, TiO2/H3PW12O40, and TiO2. The outstanding properties were attributed to the SPR effect and the formation of electrons traps from Pt0 (which was well protected by the nanopores that were formed by Ti-O-W and Ti-O-P); and H3PW12O40 that can efficiently transport electrons via its self-generated redox cycle. Meanwhile, the Pt-TiO2/H3PW12O40 film considerably lowers ecological risks of multiple CPs because O2−, as the primary radicals, can largely avoid the generation of products with a quinoid structure. The degradation pathways of multiple CPs were similar to those of single CP because the same hydroxyl substitution intermediate products were detected during the degradation, all of which followed the first-order reaction kinetics. Moreover, the excellent recycling performance of the Pt-TiO2/H3PW12O40 film guaranteed the reduction in economic cost and risks of secondary pollution. Therefore, the Pt-TiO2/H3PW12O40 film showed a considerable application potential in the removal of organic contaminants in aqueous environments.Graphical abstractGraphical abstract for this article
  • Amorphous intermixing of noble and magnetic metals in thin film-based
    • Abstract: Publication date: 30 May 2020Source: Applied Surface Science, Volume 513Author(s): C. Maurizio, N. Michieli, B. Kalinic, V. Mattarello, C. Scian, G. Ciatto, G. MatteiIn nanostructures made of a mixture of bulk-immiscible metallic species, the alloy formation down to the atomic scale is a crucial and debated point. We report on the first experimental evidence of an amorphous metallic phase in Au-Co thin films and 2D array of nanostructures, that is constituted by a fine mixing of single-metal (sub)-nm domains, as shown by experiments coupling short- and long range- order characterization techniques, as X-ray Absorption Spectroscopy-XAS, X-ray Diffraction-XRD, Diffraction Anomalous Fine Structure-DAFS. Despite the mixing does not reach the atomic scale, the extended Au-Co interface can entail about half of atoms, and is responsible for the previously measured magnetic moment of Au in these systems. This amorphous nanomixed phase coexists with a minor fraction of fcc AuxCo1-x nanocrystals, preferentially oriented with the 111 crystallographic planes parallel to the film surface. 2D patterned Au-Co films with very similar structure can be easily obtained, but with smaller and randomly oriented nanocrystals. The thermal stability of the system (amorphous and crystalline) is limited to below 250 °C. At higher temperatures an extended decomposition occurs and Au and fcc Co nanocrystals coexist.Graphical abstractGraphical abstract for this article
  • Co-doped 1T′/T phase dominated MoS1+XSe1+Y alloy nanosheets as
           bifunctional electrocatalyst for overall water splitting
    • Abstract: Publication date: 30 May 2020Source: Applied Surface Science, Volume 513Author(s): Qiulan Zhou, Xiaohu Luo, Zhen Liu, Shuyi Li, Yanxia Nan, Haoyun Deng, Yaping Ma, Weijian XuAbstractThe electrocatalytic overall water splitting is currently regarded as an efficient method for reservation and conversion of sustainable energy sources. The earth-abundant transition-metal chalcogenides (TMCs) possess unique properties to realize hydrogen evolution reaction (HER), but the semiconductor 2H phase behaves a medial activity for HER and even worse performance for oxygen evolution reaction (OER). To date, developing the efficient and bifunctional TMCs electrocatalyst is an attractive but difficult task. Herein, Co-doped 1T′/T phase dominated MoS1+XSe1+Y alloy (Co-MoS1+XSe1+Y) nanosheets electrocatalysts were synthesized by a one-step facial hydrothermal method. Meanwhile, the crystal structures and element composition of the Co-MoS1+XSe1+Y were determined by transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and Raman spectroscopy. Importantly, the as-prepared catalysts Co-MoS1+XSe1+Y with the atomic ratio of Co: Mo = 1: 5 (Co-MoS1+XSe1+Y1-5) shows superior electrochemical activity, achieving current density (j) of 10 mA cm−2 at small overpotentials of 119 mV and 280 mV for HER and OER in 1.0 M KOH, respectively. Moreover, applying the bifunctional electrode in an alkaline water electrolytic cell allows a high-efficiency electrocatalyst with only 1.60 V at j = 10 mA cm−2, which could be practical in electrocatalytic overall water splitting reaction devices.
  • Two-dimensional tetragonal Ti2BN: A novel potential anode
           material for Li-ion batteries
    • Abstract: Publication date: 30 May 2020Source: Applied Surface Science, Volume 513Author(s): Yi-Yuan Wu, Tao Bo, Xueliang Zhu, Zhiguang Wang, Junwei Wu, Yuhong Li, Bao-Tian WangIn this work, we theoretically design a new class of two-dimensional (2D) ternary transition-metal compound, namely, tetragonal Ti2BN monolayer sheet. The first-principles calculations proved that this system exhibits good dynamic and thermal stability, inherent metal properties and good mechanical properties. Additionally, we investigate the suitability of 2D Ti2BN as host materials in Li-ion batteries (LIBs). Our results show that the diffusion barrier of Li on surface (24 meV) and interlayer (165 meV) of Ti2BN monolayer are extremely low. At 300 K, their corresponding diffusion coefficient of Li are 6.08 × 10−3 and 0.028 × 10−3 cm s−1, respectively. Besides, it also exhibits extremely high theoretical capacity (889 mA h g−1) and low average open circuit voltage (0.24 V). All these advanced properties indicate that Ti2BN monolayer is a promising negative electrode material for LIBs. In order to facilitate the experimental synthesis of this material, we theoretically predicted that Ag (1 0 0), Au (1 0 0) and Sn (1 0 0) may be good growth substrates for Ti2BN sheet.Graphical abstractGraphical abstract for this article
  • Magnetic yolk-shell structure of ZnFe2O4 nanoparticles for enhanced
           visible light photo-Fenton degradation towards antibiotics and mechanism
    • Abstract: Publication date: 30 May 2020Source: Applied Surface Science, Volume 513Author(s): Yanbin Xiang, Yanhong Huang, Bing Xiao, Xiaoyong Wu, Gaoke ZhangConstructing yolk-shell structure is a promising strategy for creating much more active sites and enhancing relative light absorption. Yolk-shell ZnFe2O4 has been well used in the areas of electrocatalysis, sensor, etc., but no corresponding application in photo-Fenton reaction. In this work, yolk-shell ZnFe2O4 was firstly employed as photo-Fenton catalyst to investigate its advantage for antibiotics degradation. Interestingly, the yolk-shell ZnFe2O4 showed much improved photo-Fenton catalytic performance with magnetic recycling property, which is 5 times and 23 times higher than the ZnFe2O4 normal particles and α-Fe2O3, respectively, for degradation of contaminants under visible light irradiation. The superiority was mainly attributed to its relatively large surface area and much enhanced light absorption as well as effective charge separation, induced by unique yolk-shell structure. Besides, from the practical application view, the effect of reaction conditions, co-existing cations and anions were systematically investigated for the tetracycline (TC) photo-Fenton degradation. The TC degradation intermediate products were analyzed by HPLC-MS and a possible degradation pathway was proposed to illustrate the mechanism of TC degradation. The as-employed yolk-shell structure of ZnFe2O4 in this work probably provides a new method for designing high efficiency of photo-Fenton catalyst towards the decontamination of refractory pollutants in aqueous solution.Graphical abstractGraphical abstract for this article
  • Stabilization of the perovskite phase in PMN-PT epitaxial thin films via
           increased interface roughness
    • Abstract: Publication date: 30 May 2020Source: Applied Surface Science, Volume 513Author(s): Urška Gabor, Damjan Vengust, Zoran Samardžija, Aleksander Matavž, Vid Bobnar, Danilo Suvorov, Matjaž SpreitzerPulsed-laser deposition was used to prepare Pb(Mg1/3Nb2/3)O3-PbTiO3 (PMN-PT) thin films on (LaNiO3)/SrTiO3 substrates. We found that the bottom electrode has an immense influence on the properties of the overgrown active layer. Specifically, we found that the use of LaNiO3 (LNO) as the electrode material strongly stabilizes the perovskite phase and significantly expands the process window for the preparation of phase-pure PMN-PT as compared to a direct deposition on SrTiO3 (STO) substrates. Based on our experiments, the stabilization is achieved primarily due to the increased interface roughness, which enhances the sticking of Pb-based species, thereby suppressing the formation of undesired Pb-deficient pyrochlore inclusions. The roughness of the interface does not have adverse effects on the quality of the films. In fact, the film prepared on the LNO/STO template from the Pb-rich target exhibited superior electrical properties as compared to the film prepared directly on STO. By understanding the mechanism, we were able to exploit it and prepare an STO/Nb:STO template with a rough surface, which strongly enhanced the stability of the perovskite phase. This approach can be used to design templates for different device configurations.Graphical abstractGraphical abstract for this article
  • Towards understanding the role of carbon atoms on transition metal
           surfaces: Implications for catalysis
    • Abstract: Publication date: 30 May 2020Source: Applied Surface Science, Volume 513Author(s): Biel Martínez, Oriol Piqué, Hèctor Prats, Francesc Viñes, Francesc IllasCarbon moieties, in a low coverage regime being reduced to C adatoms, are a rock-in-the-shoe for heterogeneously catalyzed processes involving carbon-containing species. Their presence affects the performance of Transition Metal (TM) based industrial catalysts, often resulting in poisoning. Recent studies on the C adatom thermodynamic stability revealed that both surface and subsurface C atoms may coexist, indicating additional poisoning mechanisms, yet also new catalytic promoting mechanisms. The present work provides a systematic study of the potential dynamic relevance of such subsurface C atoms in the most stable (111) surface of all fcc TMs at low C coverages. This relies on evaluating the composition at thermodynamic equilibrium and the time scale of the different involved processes by means of Density Functional Theory (DFT) and kinetic Monte Carlo (kMC) simulations, respectively. These DFT and kMC simulations highlight the relevant role of subsurface C atoms for Ag and Pd, and a fast C mobility for Au and Pt, which might be important factors contributing to poisoning or opening new reactive path mechanisms, especially relevant at high temperature working conditions.Graphical abstractGraphical abstract for this article
  • Porous CoP@N/P co-doped carbon/CNTs nanocubes: In-situ autocatalytic
           synthesis and excellent performance as the anode for lithium-ion batteries
    • Abstract: Publication date: 30 May 2020Source: Applied Surface Science, Volume 513Author(s): Chengli Yao, Jianglin Xu, Yaping Zhu, Ruili Zhang, Yuhua Shen, Anjian XieA rational and convenient method was selected to prepare CoP@N/P-co-doped-(C/CNTs) (CoP@N/P-(C/CNTs)) composites with porous nanocubic structure through a pyrolysis-phosphorization strategy derived from ZIF-67. The production of N, P-doped carbon and CNTs formed by in-situ autocatalysis improved the electrical conductivity of the nanocomposite greatly and made the combination of N, P-(C/CNTs) with CoP nanoparticles (NPs) very tightly. The CoP NPs were well encapsulated into the N/P-(C/CNTs) polyhedron. The prepared CoP@N/P-(C/CNTs) had a large specific surface area with 114 m2 g−1 and an average pore diameter of about 10 nm, which were helpful for the efficient diffusion of electrolyte and transfer of ions/electrons. Benefiting from the synergistic effects between highly active CoP NPs and wonderfully conductive N/P-C/CNTs, the CoP@N/P-(C/CNTs) composites exhibited outstanding electrochemical performance. As anodes for lithium-ion batteries (LIBs), the CoP@N/P-(C/CNTs) composites exhibited an excellent initial discharge capacity of 1215 mA h g−1 and reversible capacity of 600 mA h g−1 after 200 cycles at 0.5 A g−1. Even at the high current density of 2 A g−1, it still retained a capacity of 385 mA h g−1. It proved that the autocatalytic formation of CoP@N/P-(C/CNTs) resulted from Co-MOFs is an economical and convenient approach to synthesize electrode materials with high performance for LIBs.Graphical abstractCoP@N/P-(C/CNTs) with porous nanocubic structure exhibited outstanding electrochemical property with high specific capacity, high-rate performance and cycle stability which benefiting from the synergistic effects between highly active CoP nanoparticles and N/P-C/CNTs.Graphical abstract for this article
  • Synthesis and characterization of Bi-BiPO4 nanocomposites as plasmonic
           photocatalysts for oxidative NO removal
    • Abstract: Publication date: 30 May 2020Source: Applied Surface Science, Volume 513Author(s): Meijuan Chen, Xinwei Li, Yu Huang, Jie Yao, Yan Li, Shun-cheng Lee, Wingkei Ho, Tingting Huang, Kehao ChenBi metal–BiPO4 (Bi-BPO) nanocomposites formed by in situ solvothermal reduction were employed as plasmonic photocatalysts for oxidative NO removal, achieving a removal efficiency of 32.8% in a continuous NO flow (400 ppb) under illumination with visible light. This high performance was ascribed to the generation of energetic hot electrons (and their subsequent surface chemical reactions) due to the surface plasmon resonance (SPR) of Bi metal, as validated by numerical simulations. The combined results of density functional theory (DFT) calculations and electrochemical analysis revealed that hot electrons are transferred from Bi metal to BPO via the Bi-BPO interface. DFT calculations further showed that enhanced O2 activation on the Bi-BPO interface facilitates the generation of both superoxide (O2−) and hydroxyl (OH) radicals, as confirmed by electron spin resonance, while in situ DRIFTS analysis demonstrated that NO is activated on the Bi-BPO interface and then oxidized to nitrates. Thus, this work highlights the SPR effects of Bi metal and promoted O2 and NO activation in plasmonic photocatalysis, showing that the adopted approach can be generalized to design efficient and cost-effective photocatalytic systems for the removal of other gaseous pollutants.Graphical abstractGraphical abstract for this article
  • Effect of Ag-CeO2 interface formation during one-spot synthesis of Ag-CeO2
           composites to improve their catalytic performance for CO oxidation
    • Abstract: Publication date: 30 May 2020Source: Applied Surface Science, Volume 513Author(s): Richuan Rao, Fuliang Shao, Xiongzi Dong, Huaze Dong, Song Fang, Hai Sun, Qiang LingAg-CeO2 composites are synthesized by controlling Ag-CeO2 interfacial formation during a wet chemical impregnation or a one-spot thermal decomposition. For Ag-CeO2 composites via a wet chemical impregnation, the introduction of Ag species can change the reductivity of CeO2 nanoparticles and increases oxygen vacancies associated with Ce3+ ions due to the production of Ag-CeO2 interface. Simultaneously, CeO2 nanoparticles grow into larger particles, lowering their specific surface area. Interestingly, the direct introduction of Ag species via a one-spot thermal decomposition induces the simultaneous formation of Ag-CeO2 interface during the formation of CeO2 nanoparticles and greatly improves physicochemical properties of CeO2 nanoparticles. CO oxidation is used to reveal the effect of surface microstructure on catalytic performance of Ag-CeO2 composites. Although CeO2 nanoparticles show higher catalytic activity than CeO2 samples with main [1 1 1] crystal planes due to the exposure of multiple crystal planes with higher reactivity, Ag-CeO2 composites conversely exhibit lower catalytic activity than Ag/CeO2 samples due to the sintering of CeO2 nanoparticles during the wet chemical impregnation. However, Ag-CeO2 composites via one-spot thermal decomposition show higher catalytic activity, indicating that it is feasible to enhance the catalytic performance of Ag-CeO2 composites by tuning the production of Ag-CeO2 interface during their synthesis.Graphical abstractGraphical abstract for this article
  • Functionalizing organic powder coatings with nanoparticles through ball
           milling for wear applications
    • Abstract: Publication date: 30 May 2020Source: Applied Surface Science, Volume 513Author(s): María Fernández-Álvarez, Francisco Velasco, Asunción Bautista, Beatriz GalianaEpoxy powder coatings were functionalized with nanosilica to improve wear resistance. Ten different organic coatings were studied: 0.25–1% (by wt.) of SiO2 nanoparticles (both hydrophilic -HL- and hydrophilic -HB-) were added to epoxy powders. The homogeneity of the distribution of the silica nanoparticles in the epoxy powder matrix was achieved with an innovative ball-milling mixing method. This homogeneity was confirmed through transmission electron microscopy (TEM) observations. Powder coatings were sprayed and cured on steel sheets. The wear resistance of the coatings was evaluated in reciprocating wear equipment, measuring the depth and the width of the wear tracks obtained by an optoelectronic microscopy. Results reveal very significant improvement in wear resistance, with the best wear performance being observed for the epoxy reinforced with 0.75%HB SiO2 nanoparticles. This is related to the enhanced crosslinking of the matrix in the coatings due to SiO2, as shown by the mechanical properties. The curing kinetics of the functionalized epoxy powders was studied by non-isothermal differential scanning calorimetry (DSC). Activation energies (Ea) calculated from DSC are related to in the diffusion-controlled reactions.Graphical abstractGraphical abstract for this article
  • Periodic pattern of iron oxide using 2D microgel colloidal crystal as
    • Abstract: Publication date: 30 May 2020Source: Applied Surface Science, Volume 513Author(s): Mengxin Zhang, Ruiqin Wang, Zuwei Wang, Ying Guan, Yongjun ZhangHigh-throughput and low-cost methods for the fabrication of 2D patterned structures are highly desirable. Herein we proposed a new colloidal lithography method using 2D microgel colloidal crystal (CC) as template. Unlike the previously developed methods in which the microgel spheres act as lithography mask, herein they act as nanoreactors to convert a precursor into the target product. As an example, highly ordered 2D CC of poly(N-isopropylacrylamide-co-acrylic acid) (P(NIPAM-AA)) microgel was prepared on charge-reversible silicon wafer. The template was first treated with trimethylchlorosilane (TMCS) and then loaded with Fe(NO3)3. Finally the polymer was removed and Fe(NO3)3 was converted in situ to Fe2O3 by calcination, and an ordered Fe2O3 array was obtained. The composition left after calcination was confirmed to be Fe2O3 by XPS. TMCS treatment was demonstrated to be necessary to obtain arrays of discrete patches, instead of continuous film. 0.2 mM Fe(NO3)3 solution was found to be optimal for Fe(NO3)3 loading. A calcination temperature of 600 °C was high enough to remove the polymeric materials and convert Fe(NO3)3 to Fe2O3. The method not only allows constructing ordered structures in a simple and cost-efficient way, but also adjusting the parameters of the pattern by adjusting the parameters of the template.Graphical abstractGraphical abstract for this article
  • Evolution mechanism of surface hydroxyl groups of silica during heat
    • Abstract: Publication date: 30 May 2020Source: Applied Surface Science, Volume 513Author(s): Zhimin Cheng, Hongwei Shan, Ying Sun, Ling Zhang, Haibo Jiang, Chunzhong LiThe surface hydroxyl groups of nano-silica have a great influence on its application properties. In this paper, the changes of the number of various hydroxyl groups after dehydroxylation and rehydration progress of silica were quantitatively analyzed by thermogravimetric (TG) analysis and 29Si Magic Angle Spinning (MAS) Nuclear Magnetic Resonance (NMR) measurements. According to the different stability of Si-O-Si bond formed after dehydroxylation, we propose two types of hydroxyl groups depending on the relative positions of them: chain adjacent hydroxyl groups (C-OHs) and spatially adjacent hydroxyl groups (S-OHs). DFT calculations indicate that two C-OHs dehydroxylation form a four-atoms ring structure, and the resulting OSiO bond angle deviation from optimal value is up to 19.56°, and the average bond length of the SiO bond increase more than 4.66%. Further more, its rehydration reaction activation energy (Ear) is very low, even only 0.21 kJ/mol, so it is easy to re-open and return to hydroxyl groups under environmental conditions. Conversely, the S-OHs dehydroxylation form a stable multi-atoms ring. The DFT calculations are a good illustration of the phenomenon in which some unstable siloxane bonds in a dehydroxylated sample are restored to hydroxyl groups in TG analysis and 29Si MAS NMR measurements.Graphical abstractGraphical abstract for this article
  • The importance of residual water for the reactivity of MPTMS with silica
           on the example of SBA-15
    • Abstract: Publication date: 30 May 2020Source: Applied Surface Science, Volume 513Author(s): Katarzyna Stawicka, Maciej Gierada, Julia Gajewska, Frederik Tielens, Maria ZiolekAbstractThe role of water present in the mesopores of SBA-15 on the level of (3-mercaptopropyl)trimethoxysilane (MPTMS) and ((3-aminopropyl)trimethoxysilane (APTMS) for comparison) loading and their stability were studied by experimental and theoretical approaches. N2 ads./des., XRD, XPS, FTIR, thermogravimetry and elemental analyses were used for materials characterization. The results obtained from the periodic DFT calculations and the ab initio molecular dynamics (AIMD) simulations were analyzed to study various possible structures of anchored MPTMS on the surface of SBA-15. Experimental results were very well consistent with theoretical calculations and indicated that the higher the amount of water in SBA-15 the higher the level of modifier loading was obtained. Theoretical calculations allowed the explanation of such feature. The effect of water and modifier concentration in SBA-15 on the oligomerization of MPTMS was considered. The catalytic activity was analyzed in the context of the anchored modifier amount and forms. The H2S release and CC bond formation in the modifier moiety after thermal treatment of the sample in vacuum was analyzed. The effect of water on the efficiency of MPTMS loading on differently hydrated SBA-15 as well as on its forms and properties is presented for the first time, according to our knowledge.
  • V2O3/MoS2 microspheres as a
           high-performance anode for Li-storage
    • Abstract: Publication date: 30 May 2020Source: Applied Surface Science, Volume 513Author(s): Jinlei Sun, Cai Lu, Qiong Tian, Yufan Mei, Jinfeng Peng, Yanhuai DingV2O3/MoS2 composites were synthesized by a simple and efficient microwave-assistant hydrothermal method. V2O3 particles are uniformly coated with flexible MoS2 nanosheets. The optimized composites exhibit large reversible capacity, good cycling performance and high rate capability as anode materials for Li-storage. An initial discharge capacity of 1420 mAhg−1 can be obtained with capacity retention around 730 mAhg−1 after 500 cycles at a current density of 0.1 Ag−1.Graphical abstractGraphical abstract for this article
  • Effect of the oxide layer on the interfacial Dyzaloshinskii-Moriya
           interaction in perpendicularly magnetized Pt/Co/SmOx and Pt/Co/AlOx
    • Abstract: Publication date: 30 May 2020Source: Applied Surface Science, Volume 513Author(s): Dong Li, Rui Ma, Baoshan Cui, Jijun Yun, Zhiyong Quan, Yalu Zuo, Li Xi, Xiaohong XuAbstractThe interfacial Dyzaloshinskii-Moriya interaction (DMI) plays a crucial role in stabilizing a chiral Néel-type magnetic domain wall in perpendicularly magnetized multilayers. In this work, we investigate the effect of oxide layers on interfacial DMI in ultrathin Pt/Co/SmOx and Pt/Co/AlOx stacks with the perpendicular magnetic anisotropy. The DMI effective field was characterized using the field driven domain wall creep and current-induced hysteresis loop shift methods. The experimental results show that an enhanced interfacial DMI is obtained in Pt/Co/SmOx stacks, which may be related to the oxidation degrees of the Co layer in view of the difference of Co/metallic oxide interfaces. Moreover, the X-ray photoelectron spectroscopy with the argon ion etching technique was used to further verify the weaker oxidation of the Co layer existed in Pt/Co/SmOx than that in Pt/Co/AlOx in the same annealing process due to the smaller electronegativity of the Sm compared to the Al element. Our results provide a promising route to effectively manipulate the interfacial DMI in spin-orbit-torque-based spintronic devices through the element electronegativity.
  • Wrinkled smart surfaces: Enhanced switchable wettability and directional
           liquid transportation
    • Abstract: Publication date: 30 May 2020Source: Applied Surface Science, Volume 513Author(s): Haoran Zhang, He Zhu, Xin Liang, Pingwei Liu, Qi Zhang, Shiping ZhuSmart surfaces that can convert external stimuli to changes of surface properties are playing a significant role in both fundamental research and practical applications. However, it is still a challenge to create smart surfaces with good switchability in a facile and controllable way. Herein, a wrinkled smart surface is prepared by a strategy which combines stimuli-responsive polymers and surface wrinkles, where polymers provide surface responsiveness and wrinkles result in enhancement and a regulation effect. A model system composed of the pH-responsive polymer PDEAEMA grafted on the surface of a wrinkled Au/PS bilayer via Au-SH bonding is presented. The contact angle (CA) difference between acidic/basic droplets is found to be much larger for wrinkled surfaces (~117°) than that of flat surfaces (~30°), suggesting that wrinkles can significantly reinforce the switchability of wetting. Moreover, by taking advantage of wrinkles in sample processing and high controllability, we further optimize the wrinkle structure and incorporate asymmetric patterns into the wrinkled smart surface, thereby achieving directional manipulation of acidic and basic droplets/liquids. Due to the excellent capability found in this study, wrinkled smart surfaces may find potential applications in sensors, microfluidics, separation, and smart interfacial design.Graphical abstractGraphical abstract for this article
  • Synthesis of porphyrin nanodisks from COFs through mechanical stirring and
           their photocatalytic activity
    • Abstract: Publication date: 30 May 2020Source: Applied Surface Science, Volume 513Author(s): Xinxi Li, Tomoyo Goto, Kota Nomura, Mingshan Zhu, Tohru Sekino, Yasuko OsakadaThe synthesis of thin-layered two dimensional (2D) organic nanomaterials has recently attracted considerable attention because of their potential for use in photo-electrochemistry and photocatalysis. To synthesize thin-layered organic polymers such as polymer nanosheets and nanodisks, covalent organic frameworks (COFs) with benzene or triphenylbenzene core units, are immersed or mechanically sonicated in common solvent. However, it is still challenging to exfoliate the π-conjugated COFs containing such porphyrin units. In this study, we investigated the liquid-phase exfoliation of COFs comprising porphyrin using common solvents, and found that tuning the solvent surface energy as well as mechanical stirring is crucial for effective exfoliation. We synthesized thin-layered, covalent organic porphyrin nanodisks in a common solvent by mechanical stirring and observed their enhanced photocatalytic activity.Graphical abstractGraphical abstract for this article
  • Strong pyro-catalysis of shape-controllable bismuth oxychloride
           nanomaterial for wastewater remediation
    • Abstract: Publication date: 30 May 2020Source: Applied Surface Science, Volume 513Author(s): Zheng Wu, Wenshu Luo, Hongfang Zhang, Yanmin JiaIn this work, the shape-controllable bismuth oxychloride nanomaterials were hydrothermally synthesized for pyro-catalysis treatment of dye wastewater. Under the 25–65 °C cold-hot excitation, the bismuth oxychloride nanoplates, nanoflowers and nanospheres with different specific surface areas of 5.9813, 6.2281 and 12.9614 m2/g, can respectively decompose 12.20%, 58.80% and 85.31% dye solution. The radicals’ trapping experiment confirms that superoxide radicals, hydroxyl radicals and holes are the major active species in this pyro-catalysis process. The bismuth oxychloride nanosphere material with the excellent pyro-catalysis performance is potential for dye decomposition and wastewater remediation through utilizing thermal energy from temperature fluctuation.Graphical abstractGraphical abstract for this article
  • Process-dependent effects of water on the chemistry of aluminum oxide and
           aromatic polyimide interface in composite materials
    • Abstract: Publication date: 30 May 2020Source: Applied Surface Science, Volume 513Author(s): Yugo Kubo, Hirokazu Tanaka, Yoshihiro Saito, Akira MizoguchiReplacement of Cu wires with Al wires has a significant impact on the overall cable and wire fields. This replacement is particularly important for reducing the weight of hybrid vehicles, significantly improving fuel efficiency, and reducing CO2 emissions. A promising analytical protocol is proposed for investigating the Al and polymer coating interface in samples fabricated by semiconductor-device-manufacturing techniques. The samples were analyzed by time-of-flight secondary ion spectrometry (TOF-SIMS), synchrotron hard-X-ray photoelectron spectroscopy (HAXPES), and electron energy loss spectroscopy with scanning transmission electron microscopy (STEM-EELS). The protocol provides information about the chemistry of interfaces fabricated by (1) Al deposition on a polymer substrate and (2) coating of a polymer precursor on Al. Observation of the Al and pyromellitic-dianhydride-oxydianiline-type polyimide (PMDA-ODA PI) interfaces revealed: For (1), the water adsorbed on the pristine PI surface contributed mainly to formation of the Al hydrate. For (2), at the Al/PI interface, the two events occur in a chain: first, hydrolysis of PAA occurred to form the carboxyl group, followed by acid-base reactions between the carboxyl group and hydroxide/oxide to generate water. Thus, AlOCO bonds form at the interface. The proposed protocol is applicable to the investigation of a wide-ranging combination of metals and polymers.Graphical abstractGraphical abstract for this article
  • Different sources of silicon precursors influencing on surface
           characteristics and pore morphologies of mesoporous silica nanoparticles
    • Abstract: Publication date: 30 May 2020Source: Applied Surface Science, Volume 513Author(s): Chutima Vanichvattanadecha, Wadwan Singhapong, Angkhana JaroenworaluckMesoporous silica nanoparticles (MSNs) were synthesized via a sol–gel method simplified by using pluronic F127 surfactant as a pore template without following the two steps of butanol co-surfactant mixing and hydrothermal processing. Tetraethyl orthosilicate (TEOS) and rice husk (RH) were used as chemical and natural sources of silicon (Si) precursors, respectively. As-received RH was pre-treated with naturally enzyme solutions to extract its impurities. As-synthesized powders were calcined at 500 and 600 °C to optimize heating conditions for removing organic matters. Surface characteristics, chemical functionalities and ordered-disordered mesopores of the calcined powders were characterized using various techniques. Experimental results revealed that highly ordered (SBA-16) and disordered MSNs were obtained from the synthesized routes using TEOS and pre-treated RH, respectively. Disordered mesopores formed have been explored and discussed in terms of metal oxides, trace elements and surface characteristics analyzed by X-ray fluorescent analysis (XRF), X-ray photoelectron spectroscopy (XPS) and Atomic force microscopy (AFM), respectively. In summary, SBA-16 and the disordered MSNs obtained from the synthesized method have potential as drug deliveries or catalyst supports due to their high purities and typical characteristics of the mesopores with possessing large surface areas and pore sizes.Graphical abstractGraphical abstract for this article
  • CdS core-Au/MXene-based photodetectors: Positive deep-UV photoresponse and
           negative UV–Vis-NIR photoresponse
    • Abstract: Publication date: 30 May 2020Source: Applied Surface Science, Volume 513Author(s): Tiancai Jiang, Yanshan Huang, Xianquan MengExploring photodetectors with higher responsitivity and broader spectral response is crucial for optoelectronic applications. Inverse photoresponse is discovered from photodetectors based on cadmium sulfide modified by Au (CdS core-Au). The devices are capable of detecting photons with a broader spectrum from deep-ultraviolet to near-infrared. Under the illumination of visible light at 405 nm, negative photoresponse with higher responsivity (86 mA/W) and larger specific detectivity (1.34 × 1011 Jones) are observed owing to the thermal mechanism. Upon deep-ultraviolet light illumination, the photodetectors exhibit positive photoresponse. These findings provide a new approach to broad spectral photodetectors and other inventive optoelectronic devices.Graphical abstractWe designed CdS core-Au/MXene-based photodetector with inverse photoresponse and detection of broad spectrum from deep-UV to near infrared.Graphical abstract for this article
  • Facile synthesis of CuxS coated electrodes for the efficient
           hydrogen evolution reaction
    • Abstract: Publication date: 30 May 2020Source: Applied Surface Science, Volume 513Author(s): Xin Zeng, Qingjie Jiao, Nan Li, Jichang WangA facile transformation of copper substrates into CuxS coated electrodes for the improved electrochemical production of hydrogen was reported. The utilization of sulfide-mediated underpotential oxidations of copper led to the simultaneous formation of CuxO nanoparticles at the deployed copper counter electrode, doubling the efficiency of this modification method. Equally significant, our experiments show that sizes of the thus-synthesized nanoparticles could be conveniently controlled by adjusting the relative surface area of the working and counter electrodes. Characterizations with scanning electron microscopy show that the CuxS deposits have a distinct pine leaf shape or a spherical morphology, depending on the electrochemical parameters used in the synthesis. The as-prepared electrodes exhibit promising catalytic performance in the electrochemical production of hydrogen, where the onset potential of CuxS coated electrode was found to be around – 90 mV (vs RHE) and the slope of Tafel plot was about 100 mV/Dec. The improved performance is attributed to the in-situ modification that ensured better and more intimate interconnection between the CuxS/CuxO coating and copper substrate, facilitating charge transfer.Graphical abstractCuxS and CuxO coated electrodes, synthesized simultaneously through in-situ electrochemical oxidations, exhibit promising catalytic activity towards hydrogen evolution reaction.Graphical abstract for this article
  • Hetero-structure La2O3-modified SnO2-Sn3O4 from tin anode slime for highly
           sensitive and ppb-Level formaldehyde detection
    • Abstract: Publication date: 30 May 2020Source: Applied Surface Science, Volume 513Author(s): Huimin Yu, Jianzhong Li, Wenbin Luo, Zaiyuan Li, Yanwen Tian, Zhongdong Yang, Xuanwen Gao, Hang LiuTin oxides SnO2-Sn3O4 was recovered from tin anode slime via pretreatment process, and creatively applied in ultrasensitive formaldehyde detection by doping La2O3 using high energy ball milling method. Composition, morphology, structure and chemical state of the samples were characterized in detail by XRF, FT-IR, XRD, SEM, HRTEM, XPS techniques. Gas sensing results showed that 1.0 ωt. % La2O3-modified SnO2-Sn3O4 revealed a prominently ultrahigh sensitivity of 117.27 towards 100 ppm formaldehyde, which was 4.9 times higher than pristine SnO2-Sn3O4, as well as rapid response/recovery speed (3 s/3 s) at 220 °C. Furthermore, the sensor was also found to exhibit an ultra-low detection limit of 80 ppb HCHO (S = 1.44). Outstanding selectivity, great repeatability to ppb-level HCHO and remarkable long-term stability were also displayed. The effect of doping appropriate amount of La2O3 and the possible sensing mechanism were investigated particularly. Complex hetero-structures, mixed-valence and catalytic activity of La2O3 made pivotal contributions to the improvement of HCHO sensing properties. The ultimate concept is to realize cycling economy, not only to develop a promising excellent performance formaldehyde sensor from industrial waste to increase the economic efficiency, but also to make a great contribution to environment protection and increase the value of tin slime.Graphical abstractSnO2-Sn3O4 recycled from tin anode slime could be creatively applied in ultrasensitive ppb-level formaldehyde detection by adding La2O3. The complex hetero-structures, mixed-valence and the catalytic activity of La2O3 make pivotal contributions to the enhancement of formaldehyde sensing properties. Recycling and reusing of tin secondary resources belong to resource-saving and environment-friendly research.Graphical abstract for this article
  • An efficient g-C3N4-decorated CdS-nanoparticle-doped Fe3O4 hybrid catalyst
    • Abstract: Publication date: 30 May 2020Source: Applied Surface Science, Volume 513Author(s): Ankireddy Seshadri Reddy, Jongsung KimWe developed a highly efficient and stable g-C3N4-decorated CdS-nanoparticle-doped Fe3O4 nanocube catalyst, g-C3N4@CdS–Fe3O4 (gCNCSF), with a two-step solvo-thermal process in an aqueous phase. It enhanced H2 evolution via photoelectrochemical (PEC) water splitting. Melamine and isolated onion leaf extract were used to prepare g-C3N4 by calcination under an N2 atmosphere at 450 °C. Subsequently, a CdS@Fe3O4 catalyst was fabricated by doping CdS nanoparticles into the interfacial layers of Fe3O4, via a hydrothermal method, following calcination at 450 °C under N2. According to the PEC analysis, the gCNCSF catalyst exhibited a photo-current density of 0.023 mA/cm2, approximately 2.5 and 6.25 times higher than those of binary hybrids g-C3N4@CdS and CdS@Fe3O4, respectively. In addition, approximately 4.1 and 27.7 times higher performance has been recorded than those of neat CdS and g-C3N4, respectively. This was at an applied bias potential of 0.2 V vs. Ag/AgCl. The high rate of H2 evolution could be attributed to the interfacial coordination between g-C3N4 and CdS nanoparticles doped in the Fe3O4 nanocubes, which eventually promoted the bandgap-dependent interfacial charge transfer.Graphical abstractGraphical abstract for this article
  • Durable ice-lubricating surfaces based on polydimethylsiloxane embedded
           silicone oil infused silica aerogel
    • Abstract: Publication date: 15 May 2020Source: Applied Surface Science, Volume 512Author(s): Jin Hwan Kim, Mi Jin Kim, Byungsu Lee, Ji Min Chun, Virendra Patil, Young-Seok KimThe anti-ice coatings play a key role to save huge social and economic costs required for ice removal from variety of ice accreted structures. Typically, icephobic surfaces are defined by a low ice adhesion strength (τice) of less than 100 kPa, and current developments aim at much lower values (τice 
  • Spatial elemental investigations in nanostructured alloyed Ag/Au SERS
           substrates by magnetron sputtering oblique-angle co-deposition towards
           increased performance and shelf life
    • Abstract: Publication date: 30 May 2020Source: Applied Surface Science, Volume 513Author(s): Pitak Eiamchai, Chanunthorn Chananonnawathorn, Mati Horprathum, Viyapol Patthanasettakul, Saksorn Limwichean, Noppadon NuntawongAbstractThis work proposed thorough investigations of Ag/Au alloy SERS substrates at different element compositions that allowed the highest SERS performance. Film-based slanted alloy nanorod arrays were prepared by a magnetron sputtering oblique-angle co-deposition. With silicon substrates mounted at 86° oblique angle, the SERS samples were prepared towards varying alloyed compositions, to be individually separated into 6 × 6 sample grid. Each of which was physically observed by field-emission scanning electron microscopy (FE-SEM), and elementally analyzed by energy-dispersive X-ray spectroscopy (EDS) and X-ray photoelectron spectroscopy. The SERS performance was finally investigated with a confocal Raman spectroscopy. The results showed that the Ag/Au slanted nanorods were partially isolated. The smallest Au sputtering power mostly introduced irregularly shaped nanostructures. The higher the power, the more well-observed the nanorods became. In addition, the increased power source also affected the average dimensions of the nanorods. The EDS contour-plotted results showed the Au percentage gradually decreased from the position closest to farthest from the source, with the atomic Au percentage ranged from 0 up to 40%. Finally, the Raman performance was investigated across all gridded SERS samples and the highest SERS activities were obtained from the sample with the 23% Au content.
  • A facile and large-scale synthesis of Co3O4/N-doped graphene for CO
           oxidation: Low-temperature catalytic activity and the role of nitrogen
    • Abstract: Publication date: 30 May 2020Source: Applied Surface Science, Volume 513Author(s): Richuan Rao, Hai Sun, Xiongzi Dong, Huaze Dong, Weiguang Fang, Yongqiang Tang, Song Fang, Chunming HuCo3O4/N-doped graphene is synthesized with a one-pot and low-cost thermal decomposition in air. N-doped graphene improves their reductivity and their low-temperature catalytic performance of CO oxidation. After the treatment with dry reaction gases, the treated composites show the changed chemical structure of nitrogen species from N(C)3 structure to CNC structure. After the treatment with wet reaction gases, nitrogen species on N-doped graphene are decomposed and the anchored sites of Co3O4 nanoparticles are converted into oxygenated groups. The nitrogen sites of N(C)3 structure are beneficial to promote the reversible conversion between the reduced Co2+ ions and active Co3+ ions on Co3O4 nanoparticles at low temperature, but Co3+ ions can irreversibly be converted into the reduced Co2+ ions on Co3O4 nanoparticles anchored at the nitrogen sites of CNC structure and it is more difficult to reduce Co3O4 nanoparticles anchored at oxygenated groups from the converted nitrogen species. Since CO oxidation is promoted by the reversible conversion between Co2+ ions and Co3+ ions on Co3O4 nanoparticles, Co3O4/N-doped graphene has low-temperature catalytic activity, but the composites treated with dry reaction gases require higher temperature to show catalytic activity and the composites treated with wet reaction gases show lower catalytic performance.Graphical abstractGraphical abstract for this article
  • Photocatalytic CO2 reduction catalyzed by metalloporphyrin: Understanding
           of cobalt and nickel sites in activity and adsorption
    • Abstract: Publication date: 30 May 2020Source: Applied Surface Science, Volume 513Author(s): Jie Xu, Xiaowei Liu, Zijian Zhou, Minghou XuPorphyrin based MOFs have exhibited excellent photocatalytic properties in photocatalytic CO2 reduction and metal sites in porphyrin units play an important role in the reactions. For investigating the mechanism of different photocatalytic performance of metals sites in porphyrin units, metalloporphyrin complexes with Co and Ni metal sites (Co-POR, Ni-POR) were prepared by a short term method and used for visible-light drived CO2 photoreduction conversion with water vapor as sacrificial agent. PL spectra indicates that the fluorescence intensity of Co-POR was obviously lower than that of Ni-POR and DFT calculation indicates that CO2 adsorption energy on Co-POR (17.92 kJmol−1) is higher than that on Ni-POR (16.37 kJmol−1). The efficient separation of charge carries and the strong CO2 adsorption ability are main advantages of Co-POR compared with Ni-POR. As a direct result, the experimental results showed that 0.40 μmolg-1h-1 CO was produced over Co-POR after 4 h reaction, which is about equivalent to a 1.7-fold enhancement compared to Ni-POR under the same reaction condition.Graphical abstractGraphical abstract for this article
  • Adsorption of Pd on the Cu(1 1 1) surface and its catalysis of methane
           partial oxidation: A density functional theory study
    • Abstract: Publication date: 30 May 2020Source: Applied Surface Science, Volume 513Author(s): Yuanyuan Meng, Chuanmin Ding, Xiaofeng Gao, lichao Ma, Kan Zhang, Junwen Wang, Zhe LiAbstractThe single atom alloy catalysts that Pd atoms alloy on Cu(1 1 1) surface has been extensively researched for catalytic partial oxidation of methane (CH4), however the current model mainly focuses on atomic substitution. Here, a new single atom alloy configuration of a Pd atom adsorbed on Cu (1 1 1) surface is proposed (A-Pd/Cu(1 1 1)). We systematically studied the partial oxidation of methane over a doped Pd/Cu(1 1 1) (D-Pd/Cu(1 1 1)) catalyst and over a adsorbed Pd/Cu(1 1 1) (A-Pd/Cu(1 1 1)) catalyst with the help of density functional theory (DFT) simulation. The results indicate that using oxygen as oxidant can reduce the activation energy barrier of CHx oxidation than hydroxy. The partial oxidation of methane process on the D-Pd/Cu(1 1 1) catalyst (CH4 → CH3 → CH3O → CH2O → CHO → CO) was different to that on the A-Pd/Cu(1 1 1) catalyst (CH4 → CH3 → CH2 → CH → CHO → CO). By comparison, we believe that CO is more likely generated on the catalyst of D-Pd/Cu(1 1 1) and it shows better performance in thermodynamics and has a higher capacity for sintering resistance.
  • Fabrication of durable superhydrophobic surfaces using PDMS and beeswax
           for drag reduction of internal turbulent flow
    • Abstract: Publication date: 30 May 2020Source: Applied Surface Science, Volume 513Author(s): Hossein Pakzad, Mohammad Liravi, Ali Moosavi, Ali Nouri-Borujerdi, Hossein NajafkhaniNowadays, one of the biggest concerns in the world is increasing the CO2 emissions and global warming due to the over-consumption of fossil fuels. In addition, under the intense market competition, the demand for more efficient systems with higher performance and lower energy consumption has escalated. Since the drag force contributes to a considerable percentage of the energy loss and reducing the performance, a large number of studies have been conducted to improve the surface characteristics and, subsequently, declining the drag force. Making the surface superhydrophobic is one of the most effective ways for this purpose. In this work, two different superhydrophobic surfaces using SiO2 nanoparticles modified by PDMS and beeswax were prepared, which were named PS and BWS, respectively. The results indicate that the coated substrates display excellent water repellency with contact angles of 154.6° and 153.3° for PS and BWS coatings, respectively. Also, the drag reduction tests reveal that the obtained surfaces can result in up to 24% reduction in drag force for internal turbulent flow at Re = 20,000. Furthermore, it is shown that the resultant surfaces possess high durability against various destructive conditions such as immersing in distilled water, seawater, acidic and alkaline solutions.Graphical abstractGraphical abstract for this article
  • Atomic defects in ultra-thin mesoporous TiO2 enhance photocatalytic
           hydrogen evolution from water splitting
    • Abstract: Publication date: 30 May 2020Source: Applied Surface Science, Volume 513Author(s): Hongjin Li, Sujuan Wu, Zachary D. Hood, Jianguo Sun, Biao Hu, Chuanhui Liang, Shize Yang, Yunfan Xu, Bin JiangDefects engineering is a promising and versatile method to improve solar-light-driven photocatalytic activity of photocatalysts. Mesoporous materials possess a versatile defective structure as well as a large exposed surface, which are particularly important in photocatalysis. Still, the underlying impact of defects in mesoporous photocatalysts remains elusive, as limited studies detail the exact atomistic surface structure and how the concentration of defects is directly related to the photocatalytic activity. Here, we successfully synthesized ultra-thin mesoporous-structured anatase TiO2 and changed the overall concentration of defects by improving the crystallinity. Without Pt deposition, the highest H2 production of ~3.507 mmol h−1g−1 was obtained under simulated solar light. We interrogated the atomic structure using scanning transmission electron microscopy, which directly revealed the coexistence of the lattice distortions and point defects in the mesoporous TiO2. Improving the crystallinity in TiO2 reduced these defects and slightly enhanced the H2 yield from water splitting, while the charge-transfer resistance increased. Further introduction of Ti3+ atomic defects decreased the charge-transfer resistance and facilitated the separation of electron-hole pairs in the photocatalysis. This study offers inspiration for designing efficient photocatalysts and provides valuable insights towards defect engineering in photocatalysts.Graphical abstractGraphical abstract for this article
  • Isomeric effect of solvents on a sugar-based supergelator with
           self-healing ability
    • Abstract: Publication date: 30 May 2020Source: Applied Surface Science, Volume 513Author(s): Tao Wang, Yajuan Li, Fengjuan Shen, Jujie Ren, Xudong YuA novel gelator PNDS contains pyridine and naphthalimide groups is designed and characterized. PNDS forms green emissive, self-healing and transparent super gel (0.1 wt%) in isopropanol with monomolecular aggregations. While, it forms yellow emissive and opaque gels in other short alcohols with bimolecular aggregations. The gelation arrays endow selective discrimination of isopropanol with n-propanol and other short alcohols. It is presented that PNDS adopts different assembly modes in these alcohols, leading to different optical, chiral, morphological and rheological properties. Also, we also demonstrate that the gels could selectively respond to HSO4− among test anions in proton solvents.Graphic abstractGraphical abstract for this article
  • Bandstructure engineering in 2D materials using Ferroelectric materials
    • Abstract: Publication date: 30 May 2020Source: Applied Surface Science, Volume 513Author(s): Dimuthu Wijethunge, Cheng Tang, Chunmei Zhang, Lei Zhang, Xin Mao, Aijun DuAbstractEngineering Bandstructure of two-dimensional (2D) materials is one of the strong requirements to increase their effectiveness in various applications. Among many methods, constructing van der Waals heterostructures (vdW_HTS) is one of the proven method to tune the bandstructure of the 2D materials. In this work, HTS has been constructed using ferroelectric (FE) materials to get advantages of its unique properties such as built-in polarization and reversibility of polarization under moderate external field. Among FE materials, In2Se3 is chosen due to its good optical and electrical properties. Heterostructure was constructed by encapsulating bilayer graphene (BLG) and MoS2 with In2Se3 layers to impose an electric field on them. There is strong possibility to alter the contact surface of In2Se3 which forms the heterostructure interface, by applying moderate electric field owing to its reversible polarization. Therefore, several heterostructure types based on In2Se3 orientation have been studied and each resulted unique and distinctive band structures for both MoS2 and BLG vdW_HTS. Based on polarization direction heterostructures are categorized as AB, AA and BB. And among them AB and BB vdW_HTS configurations, resulted considerable band gap on BLG. In addition, behaviour of vdW_HTS are thoroughly observed by charge transfer and electrostatic potential analysis to provide an accurate insight.
  • Different behaviors between interband and intraband transitions generated
           hot carriers on g-C3N4/Au for photocatalytic H2 production
    • Abstract: Publication date: 30 May 2020Source: Applied Surface Science, Volume 513Author(s): Wei Wang, Jiaojiao Fang, Xu HuangPlasmon hot carriers with different kinetic energies, excited-state lifetimes, and interfacial transfer dynamics have been widely studied in metal-semiconductor composites for photocatalytic applications. Here we make a systematic study on the g-C3N4/Au hybrid photocatalyst to understand the different roles of the hot carriers generated by the localized surface plasmon resonance (LSPR) intraband transitions and d → sp interband transitions, respectively, on the contributions to photocatalytic H2 production by employing different monochromatic lights as the excitation sources. Results show that the hot carriers generated by the d → sp interband transitions are much more superior than those generated by the LSPR intraband transitions in improving the H2 production activity and the apparent quantum efficiency (AQE). The significance of the on resonance excitation of the LSPR and the synergistic effect between the Au nanoparticles (NPs) and Pt NPs in producing the H2 are also discussed. This work may help to guide the designing, preparation, and mechanism study of plasma material assisted photocatalysis.Graphical abstractGraphical abstract for this article
  • Development of nanohybrids based on porous spinel MCo2O4 (M = Zn, Cu, Ni
           and Mn)/reduced graphene oxide/carbon nanotube as promising electrodes for
           high performance energy storage devices
    • Abstract: Publication date: 30 May 2020Source: Applied Surface Science, Volume 513Author(s): T. Kavinkumar, K. Vinodgopal, B. NeppolianDesigning advanced hybrid supercapacitors (SCs) with high energy density and long-term cycling stability remains a significant hurdle. Herein, we developed a hierarchal porous spinel MCo2O4 (M = Zn, Cu, Ni and Mn)/reduced graphene oxide (RGO)/carbon nanotube (CNT) nanocomposite as a binder-free SC electrode. The effects of cation substitution and carbon nanomaterials in the content of Co3O4 electrodes and its electrochemical performances are thoroughly studied. The highest activity observed for a SC constructed with NiCo2O4/RGO/CNT electrode attained is 890 Fg−1 at 1 Ag−1 and capacitance retention of 91% over 4000 cycles which is greater than 205 Fg−1 and 80% of pristine Co3O4 in 2 M KOH. Furthermore, an asymmetric SC is assembled with NiCo2O4/RGO/CNT electrode exhibits an excellent energy density of 34.5 Whkg−1 at a power density of 799 Wkg−1, high specific capacitance (94.2 Fg−1 at 1 Ag−1) and outstanding cyclic stability (9.8% loss over 5000 cycles) at 1.6 V. These experimental findings may open new perspectives for the design of future competitive hybrid energy storage devices.Graphical abstractGraphical abstract for this article
  • Decent efficiency improvement of organic photovoltaic cell with low acidic
           hole transport material by controlling doping concentration
    • Abstract: Publication date: 15 May 2020Source: Applied Surface Science, Volume 512Author(s): Swarup Biswas, Young-Jun You, Jisoo Kim, Su Ryong Ha, Hyosung Choi, Soon-Hwan Kwon, Kyoung-Kook Kim, Jae Won Shim, Hyeok KimPresently, poly (3, 4-ethylenedi-oxythiophene): polystyrene sulfonic acid (PEDOT:PSS) is most commonly used hole transport material (HTM) in photovoltaic (PV) cells but its higher acidity, hygroscopicity, high price have motivated people to develop a good substitute. Here, we prepare a series of PSS doped polyaniline (PANI) with synergic (around 90%) transmittance and work function value (within 5.09–5.16 eV) varying PSS concentrations to check the possible utility as HTM in a poly (3-hexylthiophene): [6,6]-indene-C60 bisadduct based organic photovoltaic (OPV) cell. Here, it is observed that, because of change in conductivity, the PV performance of those OPV devices is strongly dependent on the doping concentration of the HTM and, at optimized PSS concentration, PANI:PSS has higher conductivity. This facilitates better hole extraction efficiency into the PV device and results in higher short circuit current density (JSC). Therefore, the PANI:PSS-based OPV device with optimized PSS concentration exhibits same level of power conversion efficiency (PCE: 4.5 ± 0.2%) as a PEDOT:PSS based OPV device. Thus, a lower acidic (pH = 2.2) p-type semiconductor PANI:PSS (weight ratio = 1:1 and) can be a good alternative to highly acidic (pH = 1.7) PEDOT:PSS (weight ratio = 1:6, Clevious Al 4083) for using as HTM in an OPV device.Graphical abstractGraphical abstract for this article
  • Photocatalytic properties of atomic layer deposited TiO2 inverse opals and
           planar films for the degradation of dyes
    • Abstract: Publication date: 15 May 2020Source: Applied Surface Science, Volume 512Author(s): P. Birnal, M.C. Marco de Lucas, I. Pochard, B. Domenichini, L. ImhoffThe pollution of waste water due to organic dyes used in textile and chemical industries is an important environmental issue. Inverse opals (IO) offer a great potential for increasing the efficiency of semiconductor photocatalysts as TiO2 by the synergy of high specific surface and photonic crystal properties.In this work, we report the synthesis of both IO and planar TiO2 films by Atomic Layer Deposition and a comparative study of their photocatalytic activity for the degradation of methylene blue in water under UV irradiation. The porosity of planar TiO2 films was modified by a pre-treatment of the substrate to analyze its effect on the photocatalytic activity. A rutile single-crystal was also used for comparison. The kinetics of the MB degradation process was studied for long times to investigate the eventual effect of the progressive increase of degradation products in the solution.A degradation percentage about 90% was obtained after 10 h using IO films, and only about 60% by using planar and dense films. A first-order reaction kinetics was shown in the case of IO films. For the other catalysts, a slowing-down of the reaction kinetics was shown above 8 h. The adsorption of the degradation products at the catalyst surface was addressed to explain this effect. The results highlight the potential of IO films synthesized by ALD for photocatalytic applications.Graphical abstractGraphical abstract for this article
  • Formation of periodic superhydrophilic microstructures by infrared
           nanosecond laser processing of single-crystal silicon
    • Abstract: Publication date: 15 May 2020Source: Applied Surface Science, Volume 512Author(s): Sergey V. Starinskiy, Alexey A. Rodionov, Yuri G. Shukhov, Alexey I. Safonov, Eugene A. Maximovskiy, Veronica S. Sulyaeva, Alexander V. BulgakovThe evolution of the morphology and composition of the single-crystal silicon surface irradiated by infrared and visible nanosecond laser pulses is investigated as a function of processing parameters (laser fluence, irradiation spot size, the number of pulses, background gas pressure and composition). Two types of periodic surface microstructures are obtained with IR (1064 nm) laser pulses in a narrow fluence range of 3–6 J/cm2. At a relatively low number of laser pulses applied, a grid of cleavage cracks is produced within the irradiation spot along the crystal orientation. With further Si irradiation, periodic microhillocks are formed in the nodes of the crack grid. Silicon surface with such microhillocks exhibits superhydrophilic properties which are retained during prolonged storage in air. The cracks are produced in any environment (including vacuum) but the microhillocks are observed only in the presence of oxygen. No periodic structures were observed with visible (532 nm) laser pulses. Mechanisms of nanosecond laser-induced periodic microstructure formation on silicon are discussed.Graphical abstractGraphical abstract for this article
  • Laser Induced Backward Transfer of ultra-thin metal structures
    • Abstract: Publication date: 15 May 2020Source: Applied Surface Science, Volume 512Author(s): Adamantia Logotheti, Filimon Zacharatos, Marina Makrygianni, Ioanna ZergiotiUltra-thin, flexible and stretchable interfaces comprising thin metal films and polymers are attracting increasing interest for applications in sensors and optoelectronics. The transfer of ultra-thin gold films for the digital fabrication of such interfaces was investigated in this study using the Laser-Induced Backward Transfer (LIBT) technique. In particular, the transfer of thin and ultra-thin gold films (60, 10 and 5 nm thick) on Polydimethylosiloxane substrate has been achieved using ps pulses and low laser fluences for controllable material transfer. As the size of the nanograins comprising the Au films decreases, their melting point also decreases, enabling the transfer of intact disk-shaped Au nanostructures at low laser fluence values, with form factors and thickness equal to the pristine films. Moreover, the contribution of the substrate has been clarified: the two substrates (silicon, glass) which were used in this work, have significantly different reflectivity to the selected laser wavelength (532 nm), which can considerably influence the thickness and the quality of the transferred disk. The results presented in this work clearly demonstrate the compatibility of LIBT with ultra-thin metal film/ polymer interfaces and highlight the potential application of this digital process for a variety of optoelectronic applications.Graphical abstractGraphical abstract for this article
  • Hierarchical Pt/WO3 nanoflakes assembled hollow microspheres for
           room-temperature formaldehyde oxidation activity
    • Abstract: Publication date: 15 May 2020Source: Applied Surface Science, Volume 512Author(s): Yao Le, Lifang Qi, Chao Wang, Shaoxian SongHierarchical tungsten trioxide (WO3) hollow microspheres were successfully fabricated via a facile solution method and heat treatment, followed by platinum (Pt) deposition. The Pt/WO3 composite showed superior catalytic activity for formaldehyde (HCHO) removal under ambient condition, resulting from the synergistic effect between Pt and WO3. The optimal Pt loading amount is determined to be 1.0 wt%. The hierarchical hollow architecture endowed Pt/WO3 with relatively large SBET and opened porous architecture. These promote the diffusion and adsorption of HCHO on the Pt/WO3 composite. The present work affords new route to design highly effective catalyst for environmental protection.Graphical abstractGraphical abstract for this article
  • Improved corrosion resistance of hydroxyapatite coating on carbon fiber by
           applying SiC interlayer
    • Abstract: Publication date: 15 May 2020Source: Applied Surface Science, Volume 512Author(s): Yeye Liu, Leilei Zhang, Lina Pei, Hongchao ShengA hydroxyapatite (HA, Ca10(PO4)6(OH)2) coating is successfully fabricated on carbon fiber (CF) with SiC interlayer prepared via pack cementation method at 1773 K, 1873 K, 2073 K and 2273 K. The morphologies and microstructures of the SiC interlayer and HA coating are analyzed. The corrosion performance is evaluated by electrochemical behavior in simulated body fluid (SBF). The results show that the morphologies and crystalline structures of SiC interlayers vary with temperatures. The SiC interlayer improves the surface wettability for CF. The HA coating deposited on SiC interlayer modified CF exhibits denser and more uniform structure than that on the CF. Corrosion test shows that the corrosion potential (Ecorr) and corrosion current density (Icorr) for HA coated CF with SiC interlayer are −0.13 V and 0.64 × 10−5 A/cm2, respectively. For HA coated CF, the Ecorr and Icorr are −0.15 V and 1.25 × 10−5 A/cm2, respectively. The Ecorr increases and the Icorr decreases resulting from the introduction of SiC interlayer. The corrosion resistance of HA coated CF with SiC interlayer in SBF is better than that of HA coated CF. The HA coated CF with SiC interlayer would be possible for biological application.Graphical abstractGraphical abstract for this article
  • Prediction of corrosion inhibition efficiency of pyridines and quinolines
           on an iron surface using machine learning-powered quantitative
           structure-property relationships
    • Abstract: Publication date: 15 May 2020Source: Applied Surface Science, Volume 512Author(s): Cher Tian Ser, Petar Žuvela, Ming Wah WongLinear and non-linear quantitative structure–property relationship (QSPR) models were developed to predict corrosion inhibition efficiency for a series of 41 pyridine and quinoline N-heterocycles. Out of 20 physicochemical and quantum chemical variables related to the surface adsorption behaviour of the inhibitors, consensus models were constructed using the genetic algorithm-partial least squares (GA-PLS) and genetic algorithm-artificial neural network (GA-ANN) methods. The consensus GA-PLS model comprised of eight variables (exponential of the calculated adsorption energy, LUMO, van der Waals surface area and volume, polarizability, electron affinity, electrophilicity, electron donor capacity) exhibited an %RMSECV of 16.5% and mean %RMSE of 14.9%. Such a model moderately captured the complex relationships between inhibition efficiency and the quantum chemical variables. The consensus GA-ANN model comprised of nine input variables (exponential of the calculated adsorption energy, HOMO, LUMO, HOMO-LUMO Gap, electronegativity, softness, electrophilicity, electron donor capacity and N atomic charge) exhibited an %RMSECV of 16.7 ± 2.3% and mean %RMSE (training/testing/validation) of 8.8%, performing better than its linear counterpart in terms of predictive ability. Both models revealed the importance of adsorption to the metal surface, and electronic parameters quantifying electron acceptance/donation to/from the iron surface, suggesting key corrosion inhibition design principles.Graphical abstractGraphical abstract for this article
  • Surface substitution of polyanion to improve structure stability and
           electrochemical properties of lithium-rich layered cathode oxides
    • Abstract: Publication date: 15 May 2020Source: Applied Surface Science, Volume 512Author(s): Jianjian Zhong, Zhe Yang, Yang Yu, Yanying Liu, Jianling Li, Feiyu KangAbstractLithium-rich layered cathode oxides attract enormous attention due to their superior capacity, high voltage and environmentally friendliness. However, it is considerable that they suffer from serious capacity fade, voltage attenuation and phase transition deriving from inevitable oxygen evolution. In this work, polyanions are induced on the surface of the oxides via the method of surface substitution, considering synergy effects of bulk substitution and surface modification to stabilize crystal structure and promote electrochemical properties. The material doped with 5 wt% PO43− exhibits excellent specific capacity of 217.1 mAh g−1 with capacity retention of 88.43% and average discharge voltage drop of 0.4846 V after 200 cycles at 0.5 C significantly superior to the pristine material. And the discharge capacity of the material can reach 105.6 mAh g−1 at 10 C owing to enlarged interlayer spacing and improved ionic conductivity. Transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and electrochemical impedance spectroscopy (EIS) of the material before and after cycle verify that polyanions are beneficial to supply more active oxygen, restrain transition metal migration, reduce surface microstrain, and enhance electronic and ionic conductivities. All above indicate that it is effective for polyanions to promote lithium-rich cathode oxides to give full play to their electrochemical advantages.
  • Remarkable enhancement of PdAg/rGO catalyst activity for formic acid
           dehydrogenation by facile boron-doping through NaBH4 reduction
    • Abstract: Publication date: 15 May 2020Source: Applied Surface Science, Volume 512Author(s): Xi Zhao, Dongyan Xu, Kai Liu, Ping Dai, Jun GaoA novel boron-doped PdAg alloy anchored on reduced graphene oxide (rGO) was synthesized via a facile aqueous chemical reduction method using NaBH4 as the reducing agent. The characterization results confirm the formation of ultrafine PdAgB alloy nanoparticles that are uniformly dispersed on the surface of rGO. The as-prepared PdAgB/rGO catalysts show composition-dependent catalytic activity for the hydrogen generation from formic acid/sodium formate aqueous solution, with Pd0.90Ag0.10B/rGO exhibiting the highest activity at 298 K. Compared to Pd0.90Ag0.10/rGO prepared by using N2H4·H2O as the reductant, Pd0.90Ag0.10B/rGO displays higher activity towards dehydrogenation of formic acid irrespective of its relatively larger particle size, suggesting the significant promotion of B to the catalytic performance. The superior performance of Pd0.90Ag0.10B/rGO could be attributed to the combination of engineered alloy nanostructure and electronic modification effect of boron species.Graphical abstractThe ultrafine PdAgB nanoparticles supported on reduced graphene oxide (rGO) can be facilely synthesized. The PdAgB/rGO exhibits high catalytic activity towards hydrogen generation from FA/SF system because of its more electron-rich Pd active sites.Graphical abstract for this article
  • Surfactant and catalyst free facile synthesis of Al-doped ZnO nanorods –
           An approach towards fabrication of single nanorod electrical devices
    • Abstract: Publication date: 15 May 2020Source: Applied Surface Science, Volume 512Author(s): Preetam Guha Ray, Madhurima Das, Meher Wan, Chacko Jacob, Somenath Roy, Piyali Basak, Santanu DharaClassical models illustrate the genesis of bottom-up techniques for synthesis of pristine ZnO or Al-doped ZnO nanoparticles via surfactant aided or hydrothermal chemistry, to constitute the fundamental modules of nanotechnology and nanodevices. The present study demonstrates a facile as well as surfactant and catalyst free route for synthesis of morphology controlled Al-doped ZnO nanorods. Morphological evaluation (via FESEM and TEM characterization) clearly verifies the successful synthesis of ZnO and Al-doped ZnO nanorods. Moreover, crystallographic and FTIR studies ratified presence of multiple different planes as well as phases of ZnO and Al-doped ZnO nanostructures, eventually confirming the doping process. Further, the alteration in mode of electronic transition and surface charge of ZnO nanorods post doping with Al was witnessed from its UV–visible or photoluminescence spectra and zeta potential measurements, respectively. Electrical measurements were performed on prepared Al-doped ZnO nanorods which were fabricated as single nanorod devices. Owing to substitutional and interstitial doping, the electrical conductivity of the devices was drastically enhanced after doping. Excellent electrical attribute of the nanorods when fabricated into single nanorod device was indicative of its potential to be deployed as next generation nano-biosensors or piezo-electric devices.Graphical abstractGraphical abstract for this article
  • Wear resistance of FeCoCrNiMnAlx high-entropy alloy coatings at
           high temperature
    • Abstract: Publication date: 15 May 2020Source: Applied Surface Science, Volume 512Author(s): Yan Cui, Junqi Shen, Sunusi Marwana Manladan, Keping Geng, Shengsun HuThe FeCoCrNiMnAlx high-entropy alloy (HEA) coatings were produced on 4Cr5MoSiV steel by laser cladding, which can improve the high temperature oxidation resistance and wear resistance of the substrate steel in its service environment. The effects of Al addition on the microstructure and properties of the coatings were systematically investigated. The addition of Al element promoted the transition of FCC to FCC + BCC (B2) phases in the cladding layer and also refined the grains. Thereby, with the Al addition from 0 to 0.75, the micro-hardness and room-temperature wear weight loss of the HEA coatings increased and decreased, respectively, i.e. from 224.4 HV0.5 and to 344.2 HV0.5 and from 6.0 mg to 1.1 mg, compared with those of the base metal (227.1 HV0.5 and 10.5 mg). In the high-temperature oxidation process, fine and dense α-Al2O3 was preferentially generated because of its lowest absolute Gibbs free energy compared to the other oxides. The generation of α-Fe2O3 and Cr2O3 also promoted the heterogeneous nucleation of α-Al2O3. The high-temperature oxidation weight gain and wear weight loss of the FeCoCrNiMnAl0.75 cladding layer was approximately 58% and 17% of those of the base metal, respectively, and the wear mechanism was mainly abrasive wear.Graphical abstractFeCoCrNiMnAlx cladding layers were prepared by laser cladding technique. Al element obviously improved the high temperature wear resistance of coating metals, and the wear morphology was mainly abrasive wear. Al element promoted the formation of hard B2 (BCC) phase in grain boundary and refined the grains. Therefore, the effect of fine grain strengthening and dispersion strengthening improved the micro-hardness and wear properties of the cladding layers. The oxidation weight gain curve showed that the high temperature oxidation resistance of the cladding layers increased with the addition of aluminum element, and the oxidation weight gain was only 17% of that of the 4Cr5MoSiV substrate. The Gibbs free energy of oxidation reaction, lattice structure and PBR of oxides were comprehensively analyzed. Fine and dense α-Al2O3 was preferentially generated on the surface of cladding layer. The lattice type of α-Fe2O3 and Cr2O3 was similar to the α-Al2O3 that would promote the formation of α-Al2O3 in the outermost layer of the oxide film. This effectively improved the high temperature oxidation resistance of cladding layer.Graphical abstract for this article
  • π -plasmon+as+a+monitor+of+the+thermal+reduction+of+graphene+oxide&rft.title=Applied+Surface+Science&rft.issn=0169-4332&">The evolution of hydrogen induced defects and the restoration of
           π -plasmon as a monitor of the thermal reduction of graphene oxide
    • Abstract: Publication date: 15 May 2020Source: Applied Surface Science, Volume 512Author(s): Gianluca Di Filippo, Andrea Liscio, Alessandro RuoccoIn this article, we study the modification of the optical, chemical and electronic properties of graphene oxide (GO) during thermal reduction in ultra-high-vacuum by combining the results of several electron spectroscopies. We find that the fraction of oxygen moieties on the surface, as deduced from the evolution of C 1s core level in photoemission, is progressively reduced upon increasing the annealing temperature from 150 to 650 °C. The intensity of the CH stretching mode, associated with CH defects on GO surface and measured in the low energy region of electron energy loss spectra (EELS), decreases as a function of the annealing temperature. The removal or the reduction of such hydrogen or oxygen defects induces a restoration of sp2 carbon hybridization. The presence of such hybridization is confirmed by the capability to excite π-plasmon as observed in the EELS spectra. In particular we find a critical annealing temperature (Tann = 300 °C) at which π-plasmon excitation via electron scattering is accessible suggesting the formation of graphene-like domains with size comparable with the plasmon wavelength (λp~5 nm). The linear dispersion of π-band close to Fermi level, as measured in UPS, confirms the formation of graphene-like domains.Graphical abstractGraphical abstract for this article
  • Remarkably enhanced first hyperpolarizability and nonlinear refractive
           index of novel graphdiyne-based materials for promising optoelectronic
           applications: A first-principles study
    • Abstract: Publication date: 15 May 2020Source: Applied Surface Science, Volume 512Author(s): Xiaojun Li, Yunguang Zhang, Jun LuA new functionalized graphdiyne-based structure was designed by adsorbing single and double AM3O (AM = Li, Na, K) on graphdiyne (GDY) surface, namely (AM3O)n@GDY (AM = Li, Na, K; n = 1, 2). Density-functional theory calculations have been used to unravel the relations between the geometric structure and nonlinear optical (NLO) properties, e.g., Hyper-Rayleigh Scattering coefficient (βHRS) and nonlinear refractive index (n2). The frequency-dependent electro-optic Pockel's effect (EOPE) and second-harmonic generation (SHG) were explored to design the efficient NLO materials. Our calculations reveal that the AM3O molecule has the strong interactions with the GDY unit, and the intramolecular charge transfer is significant for determining the NLO properties. Large first hyperpolarizabilities (βtot) for single-adsorbed GDY have been found, especially for K3O@GDY (∼3.06 × 105 a.u.), rather than double-adsorbed GDY. Moreover, the small transition energies with large oscillator strength are a decisive factor for enhancing the βtot values. In the dynamic NLO process, the EOPE and SHG resonances can be enhanced at ω = 0.10 a.u., while single-adsorbed GDY clusters have large nonlinear refractive index and improved Hyper-Rayleigh Scattering response. All of these results will inevitably stimulate further synthesis of GDY-based optoelectronic materials with high NLO properties for future applications.Graphical abstractGraphical abstract for this article
  • An atomically flat single–crystalline gold film thermometer on mica to
           study energy (heat) exchange at the nano–scale
    • Abstract: Publication date: 15 May 2020Source: Applied Surface Science, Volume 512Author(s): S. Veronesi, T. Papa, Y. Murata, S. HeunThere is a great interest in the scientific community to perform calorimetry on samples having mass in the nanogram range. A detailed knowledge of the energy (heat) exchange in the fast growing family of micro– and nano–systems could provide valuable information about the chemistry and physics at the nano–scale. The possibility to have an atomically flat thermal probe represents an added value, because it provides the unique opportunity to perform Scanning Probe Microscopy (SPM) together with calorimetry. Here we report the fabrication, characterization, and calibration of atomically flat, single–crystalline gold film thermometers on mica substrate. Gold re–crystallization has been obtained, and successively the thermometer surface has been studied by Low Energy Electron Diffraction (LEED) and Scanning Tunneling Microscopy (STM). The thermometer calibration demonstrates a heat exchange coefficient of 2.1×10-7 W/K and a performance about 10 times better than previous sensors based on Si substrates. The experimental setup allows the simultaneous investigation of heat exchange and surface physics on the same sample.Graphical abstractGraphical abstract for this article
  • Modification of polyvinyl chloride ion-selective membrane for nitrate
           ISFET sensors
    • Abstract: Publication date: 15 May 2020Source: Applied Surface Science, Volume 512Author(s): Woraphan Chaisrirattanakua, Win Bunjongpru, Apirak Pankiew, Awirut Srisuwan, Wutthinan Jeamsaksiri, Ekalak Chaowicharat, Nutthaphat Thornyanadacha, Putapon Pengpad, Mati Horprathum, Darinee PhromyothinAbstractIn this work, a Polyvinyl Chloride (PVC) ion-selective membrane was modified to detect nitrate based on Ion Selective Field Effect Transistor (ISFET) sensing technology in order to eliminate chloride interference. A modification was done with ethylenediamine solution to achieve animated PVC, which was then oxidized with sodium tungstate to form nitrone coated PVC membrane. The modified PVC was characterized using FTIR, 1H NMR, GPC, FE-SEM and EIS. The FTIR spectrum of animate PVC demonstrated -NH2 bending at 1580 cm−1, NO2 asymmetric stretching at 1650 cm−1 and NO out-of-plane deformation vibration at 837 cm−1. GPC analysis of the modified PVC showed that the PVC molecular weight was shifted to a high molecular weight. The PVC ion-selective membrane was immobilized on the ISFET to create nitrate sensors with the following characteristics. The Nitrate-Nitrogen detection limit is 1.20 ppm with linear range from 3−20 ppm at sensitivity of 56 ± 2 mV/dec. The sensor is useful for detecting small amount of nitrate in a mixed solution, which usually is the case in most situations. This sensor could be applied in many applications, such as agricultural industry, water reserve management and medical field as well.
  • Formation of SnO and SnO2 phases during the annealing of SnO(x) films
           obtained by molecular beam epitaxy
    • Abstract: Publication date: 15 May 2020Source: Applied Surface Science, Volume 512Author(s): Alexander Nikiforov, Vyacheslav Timofeev, Vladimir Mashanov, Ivan Azarov, Ivan Loshkarev, Vladimir Volodin, Dmitry Gulyaev, Igor Chetyrin, Ilya KorolkovSnO and SnO2 films were obtained on the SiO2 surface by the molecular-beam epitaxy method. The initial films are in the polycrystalline phase. The annealing of SnO(x) films at a temperature of 300 °C resulted in the formation of the tetragonal SnO phase. Three vibration modes Eg, A1g, and B1g with the frequencies of SnO bond vibrations of 113, 211 and ~360 cm−1, respectively, which correspond to the SnO phase, were first observed by the Raman spectroscopy method. The orthorhombic SnO2 films were obtained by increasing the annealing temperature to 500 °C. Based on the valence band XPS (X-ray photoelectron spectroscopy) spectrum, several features with the binding energy approximately 5 eV, 7.5 eV and 11 eV, which are the same with the valence band of SnO2, were identified. The refractive index and absorption coefficient were investigated by the spectral ellipsometry technique. The high absorption coefficients correspond to the high Sn content. The film dielectric properties were revealed at the temperature higher than 300 °C. The refractive index values lie in the range of 1.5–2.6 for the visible spectral region. The pronounced absorption edges at 2.85 eV and 3.6 eV corresponding to those of stannous oxide (SnO) and stannic oxide (SnO2) were observed. The photoluminescence (PL) from the SnO(x) films was observed at room temperature. The increase of the annealing temperature resulted in the increase of PL intensity. Such PL intensity behavior is likely due to the Sn nanoislands.Graphical abstractGraphical abstract for this article
  • Impact of grain growth of silver reflective electrode by electron
           bombardment on external quantum efficiency of III-nitride
           micro-light-emitting diode arrays
    • Abstract: Publication date: 15 May 2020Source: Applied Surface Science, Volume 512Author(s): In Yeol Hong, Abu Bashar Mohammad Hamidul Islam, Tae Kyoung Kim, Yu-Jung Cha, Joon Seop KwakThe effect of electron-beam irradiation (EBI) on Ag reflector is investigated in order to improve the efficiency of flip-chip InGaN/GaN multiple-quantum-wells micro light-emitting diode (μ-LED) arrays. After EBI, small size grains are diffused and then become larger grain. Therefore, grain boundaries are reduced which originates both the crystal quality and the reflectance of Ag reflect to improve. Grain size of Ag reflector is increased with the increase in EBI time that is consistently observed by different kinds of material characterizations. 5 min EBI-based Ag reflector shows higher reflectance (~91%) at 450 nm than without EBI sample (~84%). Finally, without and with EBI on Ag reflector-based μ-LED arrays are fabricated. After EBI, there is no change in forward bias voltage except optical performances. At driving current, Ag reflector with EBI-based μ-LEDs has higher light-output-power, electroluminescence intensity and electroluminescence distribution over the chip area compared to without EBI-based μ-LEDs. Usually, increased light-extraction-efficiency causes the external-quantum-efficiency of the μ-LEDs to increase. These enhanced optoelectronic performances are consistently described by using microscopic and macroscopic characterizations.Graphical abstractGraphical abstract for this article
  • Exponential promotion and suppression of bubble nucleation in carbonated
           liquid by modification of surface wettability
    • Abstract: Publication date: 15 May 2020Source: Applied Surface Science, Volume 512Author(s): Jeong-Won Lee, Seongmin Kim, Seungchul Lee, Woonbong HwangWhen carbon dioxide is supersaturated in a liquid, carbon dioxide gas gets nucleated, expands, and floats on the surface of the liquid. This is a well-known phenomenon and is generally observed in carbonated drinks. This bubble generation phenomenon can be activated or suppressed by changing the properties of the solid surface in contact with the carbonated liquid. In this study, a method of exponentially increasing or suppressing the bubble generation of carbonated liquids by modifying the surface wettability is proposed. Equal amounts of carbonated liquid were poured into bare, superhydrophilic, and superhydrophobic cups to compare the amount of overflow and generated gas. In the superhydrophobic cup, bubbles were generated only at the start of pouring the carbonated liquid, after which no more bubbles were generated. When the same amount of liquid was poured into the bare cup, about 4.1% of the total mass overflowed, while in the case of superhydrophilic surfaces, about 34% overflowed. The generated gas from each cup also showed significant difference according to the surface properties. From the experimental results, it was concluded that the superhydrophobic surface can suppress bubble nucleation, thus, preventing the soda from overflowing. Furthermore, a fall in carbon dioxide concentration can be prevented.Graphical abstractGraphical abstract for this article
  • Synthesis of 3D mesoporous g-C3N4 for efficient overall water splitting
           under a Z-scheme photocatalytic system
    • Abstract: Publication date: 15 May 2020Source: Applied Surface Science, Volume 512Author(s): Wei Chen, Mei Liu, Xiying Li, Liqun MaoPhotocatalytic overall water splitting (H2/O2 = 2) on graphitic polymeric carbon nitride (g-C3N4) is still a challenge due to the presence of an insufficient number of active sites and the weak oxidative capacity of the valence band towards H2O. Herein, a 3D porous g-C3N4 photocatalyst was prepared by the SiO2 hard template method, and overall water splitting was achieved with a Z-scheme system. With the confinement effect of SiO2, 3D porous g-C3N4 possesses a large specific area and thin walls compared to bulk g-C3N4, which not only provides more active sites but also shortens the charge migration distance, thus enhancing the photocatalytic activity. With a specific surface area of 159.7 m2·g−1 and a 12.4 nm pore size, the mesoporous g-C3N4-15 showed the highest H2 evolution rate, reaching 2.5 (under full-wavelength light: λ > 320 nm) and 4.7 (under visible light: λ > 420 nm) times that of bulk g-C3N4. Under a Z-scheme system where BiVO4 and Fe2+/Fe3+ are used as the O2 evolution photocatalyst and carrier transfer mediator, respectively, the mesoporous g-C3N4-15 achieved overall water splitting under both full-wavelength (H2: 81.6 μmol∙h−1, O2: 40.4 μmol∙h−1) and visible (9.8 μmol∙h−1 and 4.4 μmol∙h−1) light irradiation with 1.8% apparent quantum yield (AQY) at λ = 420 nm. Besides high photocatalytic activity, the large specific surface area of g-C3N4-15 is beneficial for the adsorption and redox capability of Fe2+/Fe3+, which facilitates the formation of the Z-scheme system and promotes the photocatalytic activity.Graphical abstractGraphical abstract for this article
  • Enhancing the adsorption performance and sensing capability of Ti-doped
           MoSe2 and MoS2 monolayers by applying electric field
    • Abstract: Publication date: 15 May 2020Source: Applied Surface Science, Volume 512Author(s): Yafeng Yang, Muhammad Aqeel Ashraf, Kittisak Jermsittiparsert, Lilin Jiang, Dangquan ZhangOn the basis of recent findings reported, gas sensors constructed from MoS2 and MoSe2 monolayers have superior sensing performance compared to the gas sensors fabricated from graphene. In this work, we scrutinized the adsorption of NO, and CO gas molecules on the perfect and Ti-doped MoS2 and MoSe2 monolayers by means of the density functional theory method. The obtained results revealed that the Ti-doped MoS2 and MoSe2 monolayers have more sensitivity towards NO and CO detection than the pristine systems with substantial adsorption energies of gas molecules on these surfaces. The higher sensitivity and larger adsorption energy of Ti-doped systems are responsible for the strong interaction between NO/CO molecules and MoS2/MoSe2 systems. There are considerable electronic density between the metal site of substrates and N/C atoms of NO/CO molecules, which can be attributed to the strong interaction between them. Moreover, the effect of external electric field on the adsorption process was evaluated, which indicates that the sensitivity of gas sensor can substantially be modulated via applying external electric field. This work aims at suggesting a promising material based on Ti-doped MoS2 and MoSe2 systems for sensing toxic NO and CO gases in the atmosphere.Graphical abstractGraphical abstract for this article
  • Ultralow lattice thermal conductivity and anisotropic thermoelectric
           performance of AA stacked SnSe bilayer
    • Abstract: Publication date: 15 May 2020Source: Applied Surface Science, Volume 512Author(s): Shagun Nag, Anuradha Saini, Ranber Singh, Ranjan KumarAbstractThe low-temperature bulk phase of SnSe has a layered structure with AB-type of stacking of two-atom-thick SnSe monolayers. However, in the case of bilayers the AA-stacked SnSe bilayer structure is most stable. Similar to bulk SnSe, AA-stacked SnSe bilayer has ultralow lattice thermal conductivity of 0.90 Wm−1 K−1 at room temperature which is quite low as compared to other two dimensional materials. Our results show that n-type SnSe bilayer has good thermoelectric performance as compared to that of the p-type bilayer.
  • Adsorption and sensing behaviors of SF6 decomposed species on Ni-doped C3N
           monolayer: A first-principles study
    • Abstract: Publication date: 15 May 2020Source: Applied Surface Science, Volume 512Author(s): Hao Cui, Chao Yan, Pengfei Jia, Wen CaoTo give a first insight into the transition metal (TM) doped C3N monolayer for application of chemical gas sensors, we using first-principles theory in this paper investigated the adsorption performance of Ni-doped C3N (Ni-C3N) monolayer upon three SF6 decomposed species, including SO2, SOF2, and SO2F2. We first analyzed the stability of Ni-doping on the C3N monolayer where two sites were considered, namely the N-vacancy and C-vacancy site. It is found that N-vacancy would be the preferred site with higher binding energy for anchoring Ni atom, which is thereafter defined as the model to perform the adsorption processes. The results of gas adsorption indicated that Ni-C3N monolayer possesses strong adsorption ability towards three gaseous molecules, making them stably adsorbed on the Ni site with strong chemical bonds. Besides, the analyses of band structure and density of state (DOS) not only verify these findings but also expound the underlying mechanism for gas sensing using Pd-C3N monolayer. In addition, the analysis of the optical property for Ni-C3N monolayer suggests its potential to be optical gas nanosensors based on ultraviolet spectrum method. Our calculations would be meaningful to explore the chemical sensing application of Ni-C3N monolayer as a novel member in the sensor family.Graphical abstractGraphical abstract for this article
  • Quantification and mapping of elastic strains in ferroelectric
           [BaZrO3]xᴧ/[BaTiO3](1-x)ᴧ superlattices
    • Abstract: Publication date: 15 May 2020Source: Applied Surface Science, Volume 512Author(s): J. Belhadi, F. Ravaux, H. Bouyanfif, M. Jouiad, M. El MarssiWe report on quantification and elastic strain mapping in two artificial [BaZrO3]xᴧ/[BaTiO3](1-x)ᴧ (BZxᴧ/BT(1-x)ᴧ) superlattices having periods of Λ = 6.6 nm and Λ = 11 nm respectively, grown on (0 0 1) SrTiO3 single crystal substrate by pulsed laser deposition technique. The methodology consists of a combination of high-resolution scanning transmission electron microscopy and nanobeam electron diffraction associated with dedicated algorithm for diffraction patterns processing originally developed for semiconductors to record the strains at atomic scale. Both in-plane and out-of-plane elastic strains were then determined at 2 nm spatial resolution and their average values were used to map the strains along and transverse to the epitaxial growth direction of both samples to determine its variation along several BZ/BT interfaces. In addition, the variation of the width of the inter-diffusion BT/BZ interfaces and intermixing between different layers are estimated. The obtained width average value measured in these inter-diffusion interfaces vary from 8 to 12% and from 9 to 11% for both superlattices having Λ = 6.6 nm and Λ = 11 nm respectively. These inter-diffusion interfaces and the inherent elastic strains due to the confined layers of the superlattices are known to be the most important parameters, responsible of the change in their functional properties.Graphical abstractGraphical abstract for this article
  • Controlled synthesis and photocatalytic performance of biocompatible
           uniform carbon quantum dots with microwave absorption capacity
    • Abstract: Publication date: 15 May 2020Source: Applied Surface Science, Volume 512Author(s): Hanqi Zhang, Hong Wang, Ying Wang, Baifu XinCarbon quantum dots (CQDs) were successfully prepared via a facile microwave-assisted method combined with a controlled drainage time using glucose as the carbon source. XRD analysis, FT-IR spectroscopy, UV spectroscopy, XPS, and PL spectroscopy were performed to characterize the structures and properties of the samples. The results showed that the average particle size of the prepared CQDs was about 2 nm, and there were two UV absorption at the wavelengths of 228 nm and 280 nm, respectively, corresponding to the π-π* transition of CC (atomic group) and the n-π* transition of the oxygen containing group (CO) on the surface of the carbon core. According to the unique optical and microwave absorption properties of the CQDs, a suitable photocatalytic system, namely, a microwave electrodeless discharge lamp (MEDL) system was used. In the MEDL system, the degradation rate of rhodamine B (RhB, 50 mL, 30 mg L−1) by 0.02 g CQDs-2 in 10 min could reach 85.79%. The photocatalytic activity of CQDs-2 was about twice that of P25. In addition, the biocompatibility of the CQDs was investigated, which revealed that the CQDs could be absorbed by microorganisms as a carbon source. The prepared CQDs are a promising environmentally friendly photocatalyst.Graphical abstractGraphical abstract for this article
  • Component synergistic catalysis of Ce-Sn-W-Ba-Ox/TiO2 in selective
           catalytic reduction of NO with ammonia
    • Abstract: Publication date: 15 May 2020Source: Applied Surface Science, Volume 512Author(s): Qijie Jin, Mengmeng Chen, Xingjun Tao, Bingxu Lu, Jianyu Shen, Yuesong Shen, Yanwei ZengThe component synergistic catalysis of the Ce-Sn-W-Ba-Ox/TiO2 in selective catalytic reduction of NO (in the presence/absence of H2O and SO2) was investigated. Results verified that CeO2 was an essential primary active component, and WO3, SnO2 and BaO were essential cocatalyst. TiO2 provided enough acid sites, CeO2 enhanced redox properties, weakened acid strength and increased chemisorbed oxygen concentration, which was beneficial to accelerate the activation and desorption of NH3. SnO2 increased chemisorbed oxygen concentration, enhanced redox properties and improved activation rate of NH3. WO3 increased acid amount and BaO enhanced the anti-influences to water vapor and SO2. Their synergistic effects made Ce-Sn-W-Ba-Ox/TiO2 exhibit excellent catalytic performance for NH3-SCR, reaching the highest value about 100% at 350 °C in presence of H2O and SO2. Moreover, in situ DRIFTS study showed that the reaction followed L-H mechanism at high temperature and tended to simultaneously follow E-R and L-H mechanisms at low temperature.Graphical abstractGraphical abstract for this article
  • Strength enhancement of magnesium alloy through equal channel angular
           pressing and laser shock peening
    • Abstract: Publication date: 15 May 2020Source: Applied Surface Science, Volume 512Author(s): T.R. Praveen, H. Shivananda Nayaka, S. Swaroop, K.R. GopiAbstractAM80 magnesium alloy was processed by Equal Channel Angular Pressing up to 2 passes under route BC and C, to study the effect of change in microstructure. Microstructures were examined under optical microscope. Samples processed by route BC showed heterogeneous grain structure with good tensile strength compared to that processed by route C. Tensile tests of 2-pass equal channel angular pressed samples showed high tensile strength under route BC. Laser shock peening without coating was carried out on route BC sample for further grain refinement on the surface. Laser pulses with power density of 8 GW cm−2, under different percentages of cover, were used to peen the surface at high strain rate. Microstructures were analysed through scanning and transmission electron microscope, and fine grains of less than 100 nm were observed. Tensile tests indicated that the laser shock peened samples had increased strength and ductility. Fracture details from tensile tested specimens, were examined under SEM. Mixed mode of brittle and ductile fractures was observed in ECAP processed samples. Fracture surface of Laser shock peening without coating treated on equal channel angular pressed samples showed small dimples near the peened surface and intensity of dimples increased with increase in percentage of cover. Wear test was carried out on before and after Laser shock peening without coating processed samples, on pin-on-disc wear test machine. Increase in friction coefficients and wear rate was observed due to roughness induced by peening effect and it decreased after increase in sliding distance due to increase in hardness. Nano indentation experiments were carried out to examine the mechanical characterization at nano level, and it expose the effect of LSPwC in terms of increase in hardness at peened region.
  • Effect of Cd source on photocatalytic H2 evolution over CdS/MoS2
           composites synthesised via a one-pot hydrothermal strategy
    • Abstract: Publication date: 15 May 2020Source: Applied Surface Science, Volume 512Author(s): Zheng Guo, Weisong Li, Yongchao He, Guoning Li, Kaitian Zheng, Chunjian XuAs a prototypical non-noble metal photocatalytic composite, CdS/MoS2 has attracted increasing attention for its efficient visible-light H2 evolution. Owing to the simplicity and high reliability, the one-pot hydrothermal strategy has been widely used for CdS/MoS2 synthesis. However, Cd source effect on the hydrothermal synthesis of CdS/MoS2 composites has rarely been investigated. In this study, CdS/MoS2 is synthesised by the one-pot hydrothermal strategy using different Cd sources (CdCl2, Cd(Ac)2, Cd(NO3)2, and CdSO4), and the corresponding visible-light photocatalytic performances of resulting composites are evaluated by hydrogen evolution experiments. The results reveal that Cd source strongly influences the crystallisation, morphology, MoS2 loading, and visible-light absorption of the resulting CdS/MoS2 composites. The CdS/MoS2 composite synthesised using Cd(Ac)2 as precursor exhibited the highest hydrogen evolution rate of 19.34 mmol‧g−1‧h−1, which could be attributed to its larger specific surface area, stronger visible light absorption, and inhibited recombination of photogenerated carriers. In contrast, the use of cadmium nitrate as the Cd source hinders the formation of MoS2 because of the oxidation ability of nitrate groups in the hydrothermal process, which results in its low photocatalytic efficiency. We believe that these findings will provide guidance for the one-pot hydrothermal synthesis of CdS/MoS2 or related composites.Graphical abstractGraphical abstract for this article
  • Enabling highly effective underwater oxygen-consuming reaction at
           solid-liquid-air triphasic interface
    • Abstract: Publication date: 15 May 2020Source: Applied Surface Science, Volume 512Author(s): Jie Bai, Qiang Wang, Hailing Yu, Lei Yang, Jiecai Han, Bing Dai, Jiaqi ZhuElectrode surfaces with superhydrophobic and conductive properties exhibit a unique energy-mass transfer behavior in electrolytes. Therefore, the rational design of electrode surface structures, conductivity, and infiltration performance is expected to yield more efficient electrochemical reactions and solve the gas-deficit problem that hinders many underwater gas-consuming reaction systems. In this paper, hydrogenated carbon nano-onions displaying superhydrophobicity and conductivity were prepared by microwave plasma-enhanced chemical vapor deposition, which exhibited remarkable transferability and designability. The fabricated carbon nano-onions were used to modify the surfaces of various materials and structures toward their application to self-cleaning, oil-water separation, and enabling highly effective underwater oxygen-consuming reactions. Systematic analyses of the different wetting states of the superhydrophobic electrodes coated with the fabricated carbon nano-onions indicated that the different wetting states have important effects on their behaviors for underwater nucleation reactions, thus changing the efficiency of underwater oxygen-consuming reaction systems. The results reveal that designing a superhydrophobic electrode with a Wenzel-Cassie coexistent underwater wetting state, rather than a Cassie state or Wenzel state, is the key to enabling highly effective underwater oxygen-consuming reactions.Graphical abstractThe Wenzel-Cassie coexistent underwater wetting state is the key to enabling highly effective underwater oxygen-consuming reactions.Graphical abstract for this article
  • Effect of overlapped adjacent tracks on surface morphology in plasma beam
           polishing of austenitic stainless steel
    • Abstract: Publication date: 15 May 2020Source: Applied Surface Science, Volume 512Author(s): Tiantian Deng, Fei Xie, Jianjun Li, Zhizhen Zheng, Weikang ZhangThe adoption of high energy beam in the area of metallic surface polishing is a novel technique to produce glossy surfaces. In particularly, plasma beam finishing is emerging as a workable and economical option to realize high quality irradiated surfaces. In this paper, effect of overlap between the adjacent tracks on surface morphology during plasma beam finishing was researched through using different offset distances, and AISI 304 austenitic stainless steel was selected to be the test material. Based on considering surface roughness, certain statistic features (e.g. material ratio function and power spectral density function) were analyzed to comprehensively reflect the influence of offset distance. To aid a deeper understanding of the molten pool flow and surface evolution during polishing process, a two-dimension transient model, which consists of magnetic field, electric field, laminar flow and heat transfer, was developed by means of the finite element approach. The multi-track polishing tests showed that although the irradiated surface became smoother, significant bulges were found in the overlapped region between adjacent tracks. The simulation model then verified that these bulges varied with different offset distances, reflecting different dynamic processes. Therefore, the selection of offset distance is important for the optimization of plasma beam polishing.Graphical abstractGraphical abstract for this article
  • In-situ surface functionalization of superparamagnetic reduced graphene
           oxide – Fe3O4 nanocomposite via Ganoderma lucidum extract for targeted
           cancer therapy application
    • Abstract: Publication date: 15 May 2020Source: Applied Surface Science, Volume 512Author(s): Xin Jie Lee, Hong Ngee Lim, N.S.K. Gowthaman, Mohd Basyaruddin Abdul Rahman, Che Azurahanim Che Abdullah, Kasturi MuthoosamyA superparamagnetic graphene-based magnetite nanocomposite (rGO-Fe3O4) was synthesized via a simple in-situ chemical approach. This rGO-Fe3O4 nanocomposite can be used as a drug carrier that is able to be guided by external magnetic fields to the specific site of interest for targeted drug delivery application to treat cancer. Ganoderma lucidum extract (GL) was employed, which successfully stabilized the rGO-Fe3O4 via hydrogen bonding and resulted in enhancement of water dispersibility and stability of the prepared nanocomposite, while Pluronic F-127 (PF) was introduced to reduce the overall cytotoxicity. The presence of both GL and PF on the surface of nanocomposite was successfully validated by cyclic voltammetry (CV). Quercetin (Que), a naturally-available polyphenolic flavonoid with anti-cancer properties was utilized to study the potential of rGO-Fe3O4-GL-PF for controlled drug delivery application. The loading capacity of Que on rGO-Fe3O4-GL-PF was determined to be 11 wt% through UV–visible spectroscopy. The Que was loaded on rGO plane via π-π stacking and hydrophobic interaction, which was validated through CV. Furthermore, the in-vitro cytotoxicity of the synthesized nanocomposite showed obvious cytotoxicity toward A549 cells due to the anti-cancer properties of GL which has high potential to be developed into a targeted drug delivery carrier for cancer therapeutics.Graphical abstractA superparamagnetic graphene-based nanocomposite stabilized via edible Ganoderma lucidum extract is prepared for targeted drug delivery application.Graphical abstract for this article
  • Mechanism of surface hydration of potassium carbonate: Insights from
           first-principles simulations
    • Abstract: Publication date: 15 May 2020Source: Applied Surface Science, Volume 512Author(s): Jianquan Lin, Yimin Xiao, Qian Zhao, Wenqi Qu, Haotian Huang, Tiecheng Zhou, Qing Wu, Hongzhi MaoIn this work, the density functional theory simulations were performed to analyze the hydration mechanism of single and multiple water molecules over K2CO3(0 0 1) surface. A single water molecule preferentially adsorbed on the hollow site through a hydrogen bond and an ionic bond. Mulliken charge analysis showed that electrons were transferred from the potassium atom on K2CO3(0 0 1) surface to the H2O molecule. To investigate the impact of water molecule coverage, the configurations of multiple water molecules adsorbed on K2CO3(0 0 1) surface at different coverages (from 0.5 to 1.5 monolayers) were optimized. The results indicated that one monolayer of water molecules adsorbed on K2CO3(0 0 1) surface is the most stable configuration because of well water-water and water-surface interactions, where four water molecules generate a head-to-tail water chain by hydrogen bonding. Interestingly, the distances between the adjacent molecule layers increased with increasing water coverage, suggesting that the potassium carbonate expands during the earlier hydration process. In addition, the geometric parameters of the hydrogen bonds were obtained and we found that the hydrogen bonds formed by the combination of water molecules on substrate obeyed the bond valence model.Graphical abstractGraphical abstract for this article
  • Selective pulsed chemical vapor deposition of water-free HfOx on Si in
           preference to SiCOH and passivated SiO2
    • Abstract: Publication date: 15 May 2020Source: Applied Surface Science, Volume 512Author(s): Jong Youn Choi, Christopher F. Ahles, Yunil Cho, Ashay Anurag, Keith T. Wong, Srinivas D. Nemani, Ellie Yieh, Andrew C. KummelHfOx was selectively deposited on Si in preference to SiCOH using an oxygen-containing precursor, Hf(OtBu)4, via a pulsed chemical vapor deposition. The water-free process avoids nucleation by water on passivated oxide surfaces. The uniform HfOx film was deposited on Si by the thermal decomposition of the precursor, and the inherent selectivity of HfOx was retained over SiCOH until ~ 2 nm of HfOx was deposited on Si at 250 °C. Additional selectivity enhancement was demonstrated by employing molecular surface passivation and reversible adsorption/desorption of the precursor via control of the purge time. 1,1,3,3-tetramethyldisilazane (TMDS) and Bis(dimethylamino)dimethylsilane (DMADMS) were employed to passivate reactive –OH sites on SiO2 and SiCOH to increase the selectivity to ~ 7 nm HfOx deposition on Si before any significant nucleation occurred on TMDS passivated SiCOH. It is expected that the selective water-free HfOx deposition can be used for patterning nanoscale structures in MOSFET devices.Graphical abstractGraphical abstract for this article
  • Molecular investigations of tripeptide adsorption onto TiO2 surfaces:
           Synergetic effects of surface nanostructure, hydroxylation and bioactive
    • Abstract: Publication date: 15 May 2020Source: Applied Surface Science, Volume 512Author(s): Ting Zheng, Yu Zhang, Chunya Wu, Lin Zhou, Peter T. CummingsMicro-/nano-topographies on the surface of titanium-based biomaterials are critical features responsible for protein adsorptions, and investigations into the underlying molecular mechanisms are essential to improving the biocompatibility of titanium-based biomaterials. In the present work, classical molecular dynamics simulations were conducted to study the synergetic influences of surface nanostructures, hydroxylation states and bioactive ions on the adsorption of collagen tripeptides onto the TiO2 surfaces. The nanostructures on the non-hydroxylated surface, i.e., grooves or ridges, favor the formation of highly ordered layers of water molecules at the surface, which create strong barriers for stable adsorptions of tripeptides. Surface hydroxylation, however, makes the water distribution less ordered and more dispersive on hydroxylated surfaces. Thus, tripeptides are able to adsorb stably on the hydroxylated grooves, by passing through the loosely packed water layers and forming hydrogen bonds with the surface hydroxyls. Moreover, the hydroxylation on the grooved surfaces also facilitates the aggregation of calcium/phosphate ions. Consequently, the intermediate calcium/phosphate ions reduce the energy barriers of compact water layers and provide active sites for tripeptide adsorption. The present computational study provides insights into the intrinsic mechanisms of peptide adsorptions on the nanostructured Ti-based biomaterial surface.Graphic abstractSynergetic adsorption of collagen tripeptides and calcium/phosphate ions onto the grooved surface with hydroxylation.Graphical abstract for this article
  • Component regulation and crystallization mechanism of CsPbBr3/Cs4PbBr6
           perovskite composite quantum dots-embedded borosilicate glass for light
           emitting application
    • Abstract: Publication date: 15 May 2020Source: Applied Surface Science, Volume 512Author(s): Bobo Yang, Fei Zheng, Shiliang Mei, Zhihao Chen, Yu Xie, Hanqing Dai, Xian Wei, Wanlu Zhang, Fengxian Xie, Jiaqi Ju, Yaoqing Chu, Jun Zou, Ruiqian GuoCesium lead bromide CsPbBr3/Cs4PbBr6 perovskite composite QDs-embedded borosilicate glass (QDs@glass) have been prepared by using the conventional melting-quenching and heat-treatment technique. The effect of raw components and melting condition on the crystallization process, phase transition and crystal growth of CsPbBr3/Cs4PbBr6 QDs in the glass matrix were discussed in details. The formation of Cs4PbBr6 in glass has a significant impact on the optical properties of CsPbBr3 QDs. Excellent QDs@glass with high photoluminescence quantum yield (PLQY) of ~58% was achieved by optimizing the raw components and melting condition. The obtained QDs@glass shows outstanding thermal stability, photostability and water resistance stability. The PL intensity of QDs@glass remains 80% of the original one after being stored in a chamber with high-temperature and high-humidity (85 °C/RH 85%) for 70 h, and shows little decrease (2%) after being soaked into deionized water for 70 h. The white LED fabricated by using the as-synthesized green QDs@glass powder and red K2SiF6: Mn4+ phosphor on the surface of a blue LED chip displays luminous efficiency of 25 lm/W with CIE coordinates of (0.3328, 0.3442) at 100 mA and exhibits a wide color gamut (130% of the National Television System Committee standard).Graphical abstractGraphical abstract for this article
  • Hydrophilic nano-porous carbon derived from egg whites for highly
           efficient capacitive deionization
    • Abstract: Publication date: 15 May 2020Source: Applied Surface Science, Volume 512Author(s): Runan Zhang, Xiao Gu, Yihan Liu, Di Hua, Meng Shao, Zhida Gu, Jiansheng Wu, Bing Zheng, Weina Zhang, Sheng Li, Fengwei Huo, Wei HuangThe design and preparation of electrode material with advanced desalination properties are key factors to the capacitive deionization (CDI) technique. Herein, a nitrogen (N) doped porous carbon has been successfully fabricated using whipped egg foam as precursor. It possesses a unique micro-mesopore structure with ultra-high specific surface area of 3277.96 m2 g−1, and abundant active adsorption sites from the surface doping. These features could not only provide hydrophilic property, but also good electronic/ions conductivities during the deionization processes, facilitating the pseudo-capacitance and total CDI performance. As a result, the obtained electrode material could deliver a high salt adsorption capacity of 26.67 mg g−1 and fast salt adsorption rate in 500 mg L−1 NaCl solution at an applied voltage of 1.2 V, which could be considered a feasible electrode material for CDI.Graphical abstractGraphical abstract for this article
  • Cu-Mn-Ce mixed oxides catalysts for soot oxidation and their mechanistic
    • Abstract: Publication date: 15 May 2020Source: Applied Surface Science, Volume 512Author(s): Shafqat Ali, Xiaodong Wu, Zareen Zuhra, Yue Ma, Yasir Abbas, Baofang Jin, Rui Ran, Duan WengA series of flower-like CuxMnyCez mixed oxides catalysts for soot removal were prepared via a facile co-precipitation approach followed by calcination. The structural and surface properties of these catalysts were investigated by powder X-ray diffraction, N2 physisorption, transmission electron microscopy, scanning electron microscopy, X-ray photoelectron spectroscopy, hydrogen temperature-programmed reduction, oxygen temperature-programmed desorption and NO temperature-programmed oxidation. Superior soot oxidation performance was obtained over these ternary mixed oxides catalysts and the corresponding mechanism was explored. In particular, the Cu1Mn1Ce1 catalyst showed a remarkable improvement in soot oxidation activity in both NO + O2 and O2 atmospheres. The reusability and durability of these catalysts were assessed, and these materials showed high soot oxidation activity after the hydrothermal stability test.Graphical abstractGraphical abstract for this article
  • Achieving controllable friction of ultrafine-grained graphite HPG510 by
           tailoring the interfacial nanostructures
    • Abstract: Publication date: 15 May 2020Source: Applied Surface Science, Volume 512Author(s): Wei Qi, Peng Huang, Xinchun Chen, Jie Jin, Jianbin LuoGraphite is an effective solid lubricant due to its self-lubricating properties. However, in practical environments such as ambient air and vacuum, the coefficient of friction (COF) of graphite is still high, resulting in serious wear that limits applications. In this study, two methods are proposed to improve the tribological properties of HPG510, including alcohol-processed two-dimensional (2D) nanomaterials as surface lubricating additives and deposition of a diamond-like carbon (DLC) film on the graphite surfaces. The results show that the COF of graphite decreases from 0.25 to 0.06 when lubricated by graphene oxide (GO)-processed alcohol solution. Similar performance is also observed for fluorinated graphene (GF), and tungsten disulfide (WS2) plus graphene (G) processed solutions. The identified mechanism is the combined lubrication effect of anhydrous alcohol and 2D lubricant materials. Meanwhile, the DLC-deposited graphite not only has a lower COF (~0.10) but also possesses a significant enhancement of the wear resistance. An interesting finding about the anti-friction phenomenon is that some bulk DLC blocks are embedded in the lubricating tribolayer. The present work can provide reliable experimental evidence and a theoretical basis to expand the application field of bulk graphite.Graphical abstractGraphical abstract for this article
  • Tuning of the electronic band structure of fibrous silica titania with
           g-C3N4 for efficient Z-scheme photocatalytic activity
    • Abstract: Publication date: 15 May 2020Source: Applied Surface Science, Volume 512Author(s): M.S. Azami, A.A. Jalil, C.N.C. Hitam, N.S. Hassan, C.R. Mamat, R.H. Adnan, N. ChanlekGraphitic carbon nitride (g-C3N4)/fibrous silica titania (CNFST) catalysts are successfully synthesized via a simple solid-state microwave-assisted method under various loadings of g-C3N4 and then characterized by XPS, ESR, FTIR, TEM, UV–Vis DRS, FESEM, XRD and N2 adsorption-desorption analysis. The catalytic activity towards visible-light photodegradation of 2-chlorophenol is of the following order: 10 wt% CNFST (93%) ˃ 15 wt% CNFST (70%) ˃ g-C3N4 (67%) ˃ 5 wt% CNFST (49%) ˃ fibrous silica titania (40%). The highest activity of 10 wt% CNFST is due to high amount of defect sites, including SiON and SiOC bonds, oxygen vacancies and metal defects. These features narrow the band gap and tune the electronic band structure of fibrous silica titania, as well as acting as electron mediators which can induced charge carriers recombination and strong redox ability for the Z-scheme mechanism. Consequently, photogenerated holes play a major role in the degradation, as confirmed by a scavenger study. It is believed that the Z-scheme interfacial heterojunction of CNFST demonstrates an excellent potential toward the photocatalytic degradation of numerous phenolic compounds in wastewater treatment.Graphical abstractGraphical abstract for this article
  • Adsorption of gas molecules on the defective stanene nanosheets with
           single vacancy: A DFT study
    • Abstract: Publication date: 15 May 2020Source: Applied Surface Science, Volume 512Author(s): Yu Yang, Hao Zhang, Lihong Song, Zhenling LiuUsing the first-principles calculations, we have systematically examined the adsorption of gas molecules on the pristine and vacancy defective stanene monolayers. The adsorption of gas molecules on the defective monolayers is much stronger than that on the perfect ones, indicating the suitability of defective stanene nanosheets for adsorption processes. The large adsorption energies for SO2 and SO3 adsorbed complexes indicate the strong reactivity of stanene systems with adsorbed gas molecules, leading to the formation of multiple contacting points at the interface. The formation energies for the defective stanene systems were calculated. Our results indicated that the single vacancy defective stanene monolayers are thermodynamically stable, and can be used as effective gas sensors. The charge density difference calculations indicate that the electronic densities were largely accumulated between the atoms interacting with each other. This strong chemical interaction was also evidenced by the large overlaps of the density of states between the interacting atoms. The band structure calculations reveal the semiconductor features for defective stanene monolayers with adsorbed gas molecules. Our obtained results would be useful to search for promising gas sensor devices based on vacancy defective stanene monolayers.Graphical abstractGraphical abstract for this article
  • Effects of alloy elements on adsorption of fibrinogen on biodegradable
           magnesium alloys surfaces: The MD simulations and experimental studies
    • Abstract: Publication date: 15 May 2020Source: Applied Surface Science, Volume 512Author(s): Hongyan Wang, Zhe Fang, Yu Zhao, Shichang Yao, Jingan Li, Jianfeng Wang, Shijie Zhu, Chunyao Niu, Yu Jia, Shaokang GuanThe interactions between fibrinogen (Fg) and biodegradable Mg alloy are of great significance in the fields of vascular stents and bone implants. In this work, the effects of eight alloy elements (Ca, Li, Ce, Y, Zr, Mn, Zn and Cu) on the adsorption behavior of C-terminal fragment of Fg on Mg alloy surfaces are systematically investigated using molecular dynamic (MD) simulations and experimental methods. It was revealed by MD simulations that the adsorption energy of Fg on Mg alloys surfaces could be greatly enhanced and more residues were anchored to the surfaces when the alloy elements with lower electronegativity than that of Mg were added. Addition of alloy elements with higher electronegativity than that of Mg slightly reduced the adsorption capacity of proteins and fewer residues were anchored to the surfaces. Furthermore, the MD simulation results of Fg adsorption on Mg alloy samples were further confirmed by the corresponding experiments. Our studies contribute a deep understanding on the adsorption behavior of Fg on various Mg alloy surfaces, which would provide a significant guidance on the design of Mg-based biomaterials.Graphical abstractGraphical abstract for this article
  • Cd-free Cu(InGa)Se2 solar cells with eco-friendly a-Si buffer
    • Abstract: Publication date: 15 May 2020Source: Applied Surface Science, Volume 512Author(s): Jieyi Chen, Honglie Shen, Zihao Zhai, Yufang Li, Shubing LiCdS, In2S3 and ZnO-based materials are typically adopted as buffer layers in high efficiency CIGS solar cells. However, the drawbacks involved toxicity, complicated synthesis process and environmental damage of aforementioned materials would someday limit the development themselves. Here, for the first time, eco-friendly and low-cost a-Si thin films prepared by e-beam evaporation were used as buffer layers in CIGS solar cells. Thickness of a-Si films was changed to optimize the performance of CIGS solar cells through investigating their optical, structural and electrical properties. It revealed that the conduction band alignment of CIGS and a-Si is a favorable spike and a 60 nm a-Si film is optimal for CIGS/a-Si interface properties. Following the SCAPS simulation, bandgaps and conduction band energy level of CIGS films were facilely modulated through altering the Ga/(Ga + In) ratios. The conversion efficiency of solar cell with modified CIGS film was relatively improved by over 30% compared to the pristine one. The present work provides a new and eco-friendly strategy for fabrication of CIGS solar cells and expands the application of a-Si thin films as buffer layers for solar cells.Graphical abstractGraphical abstract for this article
  • Significant improved interfacial properties of PBO fibers composites by
           in-situ constructing rigid dendritic polymers on fiber surface
    • Abstract: Publication date: 15 May 2020Source: Applied Surface Science, Volume 512Author(s): Zhide Liu, Bo Song, Tingting Wang, Li WangIn this study, the interfacial properties of PBO fiber were enhanced significantly through constructing the rigid dendritic polymers on its surface. The rigid branched structure and massive functional groups of dendritic polymers endowed the interphase with more powerful physical entanglement and mechanical interlocking, abundant chemical bonding, improved interfacial compatibility and moderate mechanical properties. Compared with untreated PBO fiber composites, the interfacial shear strength and interlaminar shear strength of modified PBO fiber (PBO-M2) composites increased by 81.49 and 42.17%, respectively. Meanwhile, the impact strength raised from 68.15 to 103.28 kJ/m2 due to the construction of rigid dendritic polymers. Dynamic mechanical evaluation also indicated that the storage modulus (at 30 °C) of PBO-M2 composites increased from 34 ± 2 to 47 ± 3 GPa. Moreover, the hydrothermal aging resistance of PBO-M2 composites was also markedly improved.Graphical abstractGraphical abstract for this article
  • Electrochemical detection of amikacin sulphate using reduced graphene
           oxide and silver nanoparticles nanocomposite
    • Abstract: Publication date: 15 May 2020Source: Applied Surface Science, Volume 512Author(s): Neha Sharma, Sathish Panneer Selvam, Kyusik YunThis work examined the electrochemical detection of amikacin sulphate by utilizing a nano composite of green synthesized silver nanoparticles and reduced graphene oxide (AgNPs/rGO) on a nickel foam (NiF) electrode. The average size of AgNPs was 35 nm. The transmission electron microscopic and field emission scanning electron microscopic images of the rGO-AgNPs composite confirmed that the AgNPs stiffly adhered to the rGO sheets. The cyclic voltammetry (CV) and differential pulse voltammograms (DPVs) were employed for the characterization of electrodes. The electrochemical behavior of the (NiF-AgNPs/rGO) electrode and the surface confined oxidation of amikacin sulphate were confirmed by CV. The developed sensor showed a linear electrochemical response in the range of 0.05–15 μM with a detection limit of 38 nM. The developed sensor exhibited reproducibility with a relative standard deviation of 1.01% and storage stability over four weeks. The results revealed that owing to the uniform distribution of AgNPs on rGO; the fabricated sensor had high selectivity and response to amikacin sulphate detection. Moreover, the practical viability of the developed sensor was evaluated in spiked human urine samples under validated conditions. The recovery rate was in the range of 99%–102%, which indicates the sensor’s effectiveness in the detection of amikacin sulphate.Graphical abstractGraphical abstract for this article
  • Microstructures and properties of novel nanocomposite WNx coatings
           deposited by reactive magnetron sputtering
    • Abstract: Publication date: 15 May 2020Source: Applied Surface Science, Volume 512Author(s): Yang Deng, Shiheng Yin, Yue Hong, Yi Wang, Yi Hu, Gaopeng Zou, Tongchun Kuang, Kesong ZhouNovel nanocomposite tungsten nitrides (WNx) coatings were deposited on cemented carbides by direct current (dc) reactive magnetron sputtering under different deposition powers. The microstructures and related mechanical properties of the coatings were carefully investigated. At deposition power of 2 kW, the WNx coating is entirely composed of well-developed columnar fcc-W2N grains, showing the strongest (2 0 0)W2N preferred orientation, whereas the coatings deposited at other conditions are composed of nanocomposite structures consisting of nanocrystalline bcc-W and fcc-W2N embedded into amorphous-phase matrix, showing weak (2 0 0)W2N and (1 1 1)W2N preferred orientations. Moreover, there is an orientation relationship between bcc-W and fcc-W2N: (−1 0 −1)w//(1 1 −1)W2N + 2.1° and [−1 1 1]w//[0 1 1]W2N. The amorphous films with thickness of several nanometers always occur in a special periodic multilayer structure or in the large angle grain boundaries of bcc-W. Such amorphous films are resulted from the intensive bombardment of sputtered W atoms, which leads to the densification of the coating and further restrains the diffusion of W atoms for crystallization growth. Moreover, strong ion bombardment can interrupt the W-W metallic bond, and further restrain crystallization growth. Therefore, the nanocomposite structure shows the higher hardness and fracture toughness when compared with columnar W2N coating mainly due to the fine-grained strengthening and solution strengthening.Graphical abstractGraphical abstract for this article
  • Lithium-selenium sulfide batteries with long cycle life and high energy
           density via solvent washing treatment
    • Abstract: Publication date: 15 May 2020Source: Applied Surface Science, Volume 512Author(s): Wonhee Kim, Jiyeon Lee, Seungmin Lee, KwangSup Eom, Chanho Pak, Hyeong-Jin KimAbstractSeS2 is a promising cathode material that has both advantages of S and Se. In a carbonate-based electrolyte, Li-SeS2 batteries show good cycle performance but work at low discharge voltage due to slow Li-ion diffusion. Here, we report a simple solvent treatment method for synthesizing cathode composite materials to overcome the disadvantage of carbonate-based electrolytes. The solvent washing treatment can effectively remove excess SeS2 that blocks carbon pores, which act as an electrolyte pathway. Additionally, the SeS2/OMC composite (w-SeS2/OMC) maintains the SeS2 configuration, thus leading to both the advantages of S and Se. As a result, enhanced Li-ion diffusion helps to reduce polarization and elevate the discharge voltage to ~2 V. In addition, it shows excellent capacity retention (360 mAh g−1) for 2,000 cycles at a 1C rate.
  • Vibrational fingerprint of the catalytically-active FeO2-x iron
           oxide phase on Pt(111)
    • Abstract: Publication date: Available online 14 February 2020Source: Applied Surface ScienceAuthor(s): Marija Stojkovska, Rocco Davì, Giovanni Carraro, Marco Smerieri, Mikołaj Lewandowski, Mario Rocca, Luca Vattuone, Letizia SavioWe report here on the oxidation of monolayer FeO islands on Pt(111) into the highly-reactive FeO2-x phase by high-temperature oxidation under Ultra High Vacuum (UHV) conditions. The chemical composition and characteristic phonon modes of both FeO and FeO2-x films were investigated by X-ray photoemission Spectroscopy (XPS) and High Resolution Electron Energy Loss Spectroscopy (HREELS). The reactivity and thermal stability of the “oxygen-rich” FeO2-x phase were studied with respect to the CO oxidation reaction at 450 K and to annealing in UHV at 563 K, respectively. By performing repeated oxidation/reduction cycles, we have identified the vibrational mode at 76 meV as the unique signature of the FeO2-x phase and confirmed the already reported ability of CO to reduce such oxide at 450 K. The latter process is not fully reversible, suggesting a modification of the active sites upon CO adsorption.Graphical abstractGraphical abstract for this article
  • Influence of oxidizing conditions on the condensation of aluminum oxide
           nanoparticles: Insights from atomistic modeling
    • Abstract: Publication date: 15 May 2020Source: Applied Surface Science, Volume 512Author(s): Georg Daniel Förster, Florent CalvoThe condensation of aluminum and aluminum oxide nanoclusters in a cooling gas of the two elements were computationally investigated at the atomistic level of details using molecular dynamics simulations based on a reactive many-body potential. The formation kinetics for particles containing up to several thousands atoms and their final morphology were scrutinized, in comparison with the oxidation of preformed aluminum nanodroplets at the same composition. In both cases the amount of oxygen in the system is found to directly control the shape, crystalline character and extent of chemical ordering, the finally obtained nanoparticles showing homogeneous or core-shell character depending on composition. Particle growth is limited under the conditions of high oxygen content. The generic role of oxidation is found to be non trivial but in satisfactory agreement with recent experimental X-ray scattering measurements of particles formed in a laser ablation plume notably probing the surface ruggedness. The ability of the simulations to unravel nanostructure morphologies at or away from equilibrium is discussed.Graphical abstractGraphical abstract for this article
  • Electrochemical performances of asymmetric aqueous supercapacitor based on
           porous Cu3Mo2O9 petals and La2Mo3O12 nanoparticles fabricated through a
           simple co-precipitation method
    • Abstract: Publication date: 15 May 2020Source: Applied Surface Science, Volume 512Author(s): V. Gajraj, C.R. MariappanPresent work shows the electrochemical performances of asymmetric aqueous supercapacitor device based on Cu3Mo2O9 and La2Mo3O12 as a positive and a negative electrode respectively. The Cu3Mo2O9 and La2Mo3O12 were prepared by a simple co-precipitation route within 20 min and post annealing method. Crystalline phase purity of the electrodes is confirmed with powder X-ray diffraction, Raman and X-ray photoelectron spectroscopy techniques. The agglomerated nanoparticles and porous petals-like microstructures are observed for La2Mo3O12 and Cu3Mo2O9 respectively. The specific capacity of La2Mo3O12 and Cu3Mo2O9 is found to be 195.85 and 71.94 C g−1 at 2.5 A g−1 respectively. Charge storage mechanism of the electrodes is elucidated via Dunn’s and Trasatti’s approaches. The asymmetric supercapacitor (ASC) device exhibits a specific capacitance of 61.45 F g−1 at 2 A g−1. The ASC shows retention of 119.4% of initial specific capacitance after 5000 charging and discharging cycles and exhibits coulombic efficiency of 95.5% throughout the 5000 cycles. The ASC stores energy density of 21.84 Wh kg−1 at power density of 1.61 kW kg−1 and sustains the energy density as 2.92 Wh kg−1 at high power density of 10.86 kW kg−1.Graphical abstractGraphical abstract for this article
School of Mathematical and Computer Sciences
Heriot-Watt University
Edinburgh, EH14 4AS, UK
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