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CHEMISTRY (616 journals)                  1 2 3 4 | Last

Showing 1 - 200 of 735 Journals sorted alphabetically
2D Materials     Hybrid Journal   (Followers: 14)
Accreditation and Quality Assurance: Journal for Quality, Comparability and Reliability in Chemical Measurement     Hybrid Journal   (Followers: 26)
ACS Catalysis     Hybrid Journal   (Followers: 43)
ACS Chemical Neuroscience     Hybrid Journal   (Followers: 21)
ACS Combinatorial Science     Hybrid Journal   (Followers: 23)
ACS Macro Letters     Hybrid Journal   (Followers: 25)
ACS Medicinal Chemistry Letters     Hybrid Journal   (Followers: 41)
ACS Nano     Hybrid Journal   (Followers: 280)
ACS Photonics     Hybrid Journal   (Followers: 14)
ACS Symposium Series     Full-text available via subscription  
ACS Synthetic Biology     Hybrid Journal   (Followers: 24)
Acta Chemica Iasi     Open Access   (Followers: 5)
Acta Chimica Slovaca     Open Access   (Followers: 2)
Acta Chimica Slovenica     Open Access   (Followers: 1)
Acta Chromatographica     Full-text available via subscription   (Followers: 9)
Acta Facultatis Medicae Naissensis     Open Access  
Acta Metallurgica Sinica (English Letters)     Hybrid Journal   (Followers: 7)
Acta Scientifica Naturalis     Open Access   (Followers: 3)
adhäsion KLEBEN & DICHTEN     Hybrid Journal   (Followers: 7)
Adhesion Adhesives & Sealants     Hybrid Journal   (Followers: 9)
Adsorption Science & Technology     Open Access   (Followers: 6)
Advanced Functional Materials     Hybrid Journal   (Followers: 57)
Advanced Science Focus     Free   (Followers: 5)
Advances in Chemical Engineering and Science     Open Access   (Followers: 67)
Advances in Chemical Science     Open Access   (Followers: 18)
Advances in Chemistry     Open Access   (Followers: 21)
Advances in Colloid and Interface Science     Full-text available via subscription   (Followers: 19)
Advances in Drug Research     Full-text available via subscription   (Followers: 24)
Advances in Environmental Chemistry     Open Access   (Followers: 5)
Advances in Enzyme Research     Open Access   (Followers: 10)
Advances in Fluorine Science     Full-text available via subscription   (Followers: 9)
Advances in Fuel Cells     Full-text available via subscription   (Followers: 16)
Advances in Heterocyclic Chemistry     Full-text available via subscription   (Followers: 11)
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Advances in Nanoparticles     Open Access   (Followers: 15)
Advances in Organometallic Chemistry     Full-text available via subscription   (Followers: 16)
Advances in Polymer Science     Hybrid Journal   (Followers: 44)
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Advances in Protein Chemistry and Structural Biology     Full-text available via subscription   (Followers: 20)
Advances in Quantum Chemistry     Full-text available via subscription   (Followers: 6)
Advances in Science and Technology     Full-text available via subscription   (Followers: 12)
African Journal of Bacteriology Research     Open Access  
African Journal of Chemical Education     Open Access   (Followers: 3)
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  
Alkaloids: Chemical and Biological Perspectives     Full-text available via subscription   (Followers: 2)
AMB Express     Open Access   (Followers: 1)
Ambix     Hybrid Journal   (Followers: 3)
American Journal of Biochemistry and Biotechnology     Open Access   (Followers: 65)
American Journal of Biochemistry and Molecular Biology     Open Access   (Followers: 20)
American Journal of Chemistry     Open Access   (Followers: 30)
American Journal of Plant Physiology     Open Access   (Followers: 11)
American Mineralogist     Hybrid Journal   (Followers: 15)
Analyst     Full-text available via subscription   (Followers: 38)
Angewandte Chemie     Hybrid Journal   (Followers: 169)
Angewandte Chemie International Edition     Hybrid Journal   (Followers: 247)
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)
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Annual Review of Chemical and Biomolecular Engineering     Full-text available via subscription   (Followers: 12)
Annual Review of Food Science and Technology     Full-text available via subscription   (Followers: 13)
Anti-Infective Agents     Hybrid Journal   (Followers: 3)
Antiviral Chemistry and Chemotherapy     Open Access   (Followers: 2)
Applied Organometallic Chemistry     Hybrid Journal   (Followers: 9)
Applied Spectroscopy     Full-text available via subscription   (Followers: 23)
Applied Surface Science     Hybrid Journal   (Followers: 32)
Arabian Journal of Chemistry     Open Access   (Followers: 6)
ARKIVOC     Open Access   (Followers: 1)
Asian Journal of Biochemistry     Open Access   (Followers: 2)
Atomization and Sprays     Full-text available via subscription   (Followers: 4)
Australian Journal of Chemistry     Hybrid Journal   (Followers: 7)
Autophagy     Hybrid Journal   (Followers: 2)
Avances en Quimica     Open Access  
Biochemical Pharmacology     Hybrid Journal   (Followers: 10)
Biochemistry     Hybrid Journal   (Followers: 359)
Biochemistry Insights     Open Access   (Followers: 6)
Biochemistry Research International     Open Access   (Followers: 6)
BioChip Journal     Hybrid Journal  
Bioinorganic Chemistry and Applications     Open Access   (Followers: 10)
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: 2)
Biomacromolecules     Hybrid Journal   (Followers: 21)
Biomass Conversion and Biorefinery     Partially Free   (Followers: 10)
Biomedical Chromatography     Hybrid Journal   (Followers: 7)
Biomolecular NMR Assignments     Hybrid Journal   (Followers: 3)
BioNanoScience     Partially Free   (Followers: 5)
Bioorganic & Medicinal Chemistry     Hybrid Journal   (Followers: 132)
Bioorganic & Medicinal Chemistry Letters     Hybrid Journal   (Followers: 87)
Bioorganic Chemistry     Hybrid Journal   (Followers: 10)
Biopolymers     Hybrid Journal   (Followers: 18)
Biosensors     Open Access   (Followers: 2)
Biotechnic and Histochemistry     Hybrid Journal   (Followers: 2)
Bitácora Digital     Open Access  
Boletin de la Sociedad Chilena de Quimica     Open Access  
Bulletin of the Chemical Society of Ethiopia     Open Access   (Followers: 1)
Bulletin of the Chemical Society of Japan     Full-text available via subscription   (Followers: 24)
Bulletin of the Korean Chemical Society     Hybrid Journal   (Followers: 1)
C - Journal of Carbon Research     Open Access   (Followers: 3)
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: 10)
Canadian Mineralogist     Full-text available via subscription   (Followers: 6)
Carbohydrate Research     Hybrid Journal   (Followers: 26)
Carbon     Hybrid Journal   (Followers: 70)
Catalysis for Sustainable Energy     Open Access   (Followers: 8)
Catalysis Reviews: Science and Engineering     Hybrid Journal   (Followers: 7)
Catalysis Science and Technology     Free   (Followers: 8)
Catalysis Surveys from Asia     Hybrid Journal   (Followers: 3)
Catalysts     Open Access   (Followers: 10)
Cellulose     Hybrid Journal   (Followers: 7)
Cereal Chemistry     Full-text available via subscription   (Followers: 4)
ChemBioEng Reviews     Full-text available via subscription   (Followers: 1)
ChemCatChem     Hybrid Journal   (Followers: 8)
Chemical and Engineering News     Free   (Followers: 20)
Chemical Bulletin of Kazakh National University     Open Access  
Chemical Communications     Full-text available via subscription   (Followers: 74)
Chemical Engineering Research and Design     Hybrid Journal   (Followers: 26)
Chemical Research in Chinese Universities     Hybrid Journal   (Followers: 3)
Chemical Research in Toxicology     Hybrid Journal   (Followers: 22)
Chemical Reviews     Hybrid Journal   (Followers: 191)
Chemical Science     Open Access   (Followers: 25)
Chemical Technology     Open Access   (Followers: 26)
Chemical Vapor Deposition     Hybrid Journal   (Followers: 5)
Chemie in Unserer Zeit     Hybrid Journal   (Followers: 56)
Chemie-Ingenieur-Technik (Cit)     Hybrid Journal   (Followers: 24)
ChemInform     Hybrid Journal   (Followers: 8)
Chemistry & Biodiversity     Hybrid Journal   (Followers: 7)
Chemistry & Biology     Full-text available via subscription   (Followers: 32)
Chemistry & Industry     Hybrid Journal   (Followers: 7)
Chemistry - A European Journal     Hybrid Journal   (Followers: 159)
Chemistry - An Asian Journal     Hybrid Journal   (Followers: 16)
Chemistry and Materials Research     Open Access   (Followers: 21)
Chemistry Central Journal     Open Access   (Followers: 4)
Chemistry Education Research and Practice     Free   (Followers: 5)
Chemistry in Education     Open Access   (Followers: 9)
Chemistry International     Open Access   (Followers: 2)
Chemistry Letters     Full-text available via subscription   (Followers: 43)
Chemistry of Materials     Hybrid Journal   (Followers: 259)
Chemistry of Natural Compounds     Hybrid Journal   (Followers: 9)
Chemistry World     Full-text available via subscription   (Followers: 19)
Chemistry-Didactics-Ecology-Metrology     Open Access   (Followers: 1)
ChemistryOpen     Open Access   (Followers: 1)
Chemkon - Chemie Konkret, Forum Fuer Unterricht Und Didaktik     Hybrid Journal  
Chemoecology     Hybrid Journal   (Followers: 4)
Chemometrics and Intelligent Laboratory Systems     Hybrid Journal   (Followers: 14)
Chemosensors     Open Access  
ChemPhysChem     Hybrid Journal   (Followers: 12)
ChemPlusChem     Hybrid Journal   (Followers: 2)
ChemTexts     Hybrid Journal  
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: 11)
Chromatographia     Hybrid Journal   (Followers: 24)
Chromatography     Open Access   (Followers: 2)
Chromatography Research International     Open Access   (Followers: 6)
Clay Minerals     Full-text available via subscription   (Followers: 10)
Cogent Chemistry     Open Access   (Followers: 1)
Colloid and Interface Science Communications     Open Access  
Colloid and Polymer Science     Hybrid Journal   (Followers: 11)
Colloids and Interfaces     Open Access  
Colloids and Surfaces B: Biointerfaces     Hybrid Journal   (Followers: 6)
Combinatorial Chemistry & High Throughput Screening     Hybrid Journal   (Followers: 4)
Combustion Science and Technology     Hybrid Journal   (Followers: 22)
Comments on Inorganic Chemistry: A Journal of Critical Discussion of the Current Literature     Hybrid Journal   (Followers: 2)
Communications Chemistry     Open Access  
Composite Interfaces     Hybrid Journal   (Followers: 7)
Comprehensive Chemical Kinetics     Full-text available via subscription   (Followers: 1)
Comptes Rendus Chimie     Full-text available via subscription  
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Computers & Chemical Engineering     Hybrid Journal   (Followers: 10)
Coordination Chemistry Reviews     Full-text available via subscription   (Followers: 4)
Copernican Letters     Open Access   (Followers: 1)
Corrosion Series     Full-text available via subscription   (Followers: 6)
Critical Reviews in Biochemistry and Molecular Biology     Hybrid Journal   (Followers: 6)
Croatica Chemica Acta     Open Access  
Crystal Structure Theory and Applications     Open Access   (Followers: 4)
CrystEngComm     Full-text available via subscription   (Followers: 13)
Current Catalysis     Hybrid Journal   (Followers: 2)
Current Chromatography     Hybrid Journal  
Current Green Chemistry     Hybrid Journal  
Current Metabolomics     Hybrid Journal   (Followers: 5)
Current Microwave Chemistry     Hybrid Journal  
Current Opinion in Colloid & Interface Science     Hybrid Journal   (Followers: 9)
Current Opinion in Molecular Therapeutics     Full-text available via subscription   (Followers: 14)
Current Research in Chemistry     Open Access   (Followers: 8)
Current Science     Open Access   (Followers: 69)
Current Trends in Biotechnology and Chemical Research     Open Access   (Followers: 3)
Dalton Transactions     Full-text available via subscription   (Followers: 23)
Detection     Open Access   (Followers: 2)
Developments in Geochemistry     Full-text available via subscription   (Followers: 2)
Diamond and Related Materials     Hybrid Journal   (Followers: 12)
Dislocations in Solids     Full-text available via subscription  
Doklady Chemistry     Hybrid Journal  

        1 2 3 4 | Last

Journal Cover
Applied Surface Science
Journal Prestige (SJR): 1.093
Citation Impact (citeScore): 4
Number of Followers: 32  
  Hybrid Journal Hybrid journal (It can contain Open Access articles)
ISSN (Print) 0169-4332
Published by Elsevier Homepage  [3159 journals]
  • Carbon quantum dots (CQDs) and Co(dmgH)2PyCl synergistically promote
           photocatalytic hydrogen evolution over hexagonal ZnIn2S4
    • Abstract: Publication date: 31 December 2018Source: Applied Surface Science, Volume 462Author(s): Yao Ding, Yanhong Gao, Zhaohui LiCQDs/ZnIn2S4 nanocomposites (CQDs stands for carbon quantum dot) prepared by a microwave method in the presence of performed CQDs were impregnated with Co(dmgH)2PyCl (dmgH = dimethylglyoxime, Py = pyridine) to form ternary Co(dmgH)2PyCl/CQDs/ZnIn2S4 nanocomposites (Co/CQDs/ZnIn2S4). The photocatalytic performance for hydrogen evolution in the presence of TEOA as a sacrificial agent over the as-obtained Co/CQDs/ZnIn2S4 under visible light was investigated. It was found that ternary Co/CQDs/ZnIn2S4 show significantly superior photocatalytic activity for hydrogen evolution than both Co(dmgH)2PyCl/ZnIn2S4 and CQDs/ZnIn2S4. An optimum activity was realized over Co/CQDs/ZnIn2S4 with the loading amount of 5.0 wt% CQDs and 1.0 wt% Co(dmgH)2PyCl, in which 703.9 μmol of hydrogen was evolved in 8 h. The superior photocatalytic activity for hydrogen evolution over ternary Co/CQDs/ZnIn2S4 can be ascribed to the synergistic effect played by CQDs and Co(dmgH)2PyCl, in which CQDs acts as a mediator to promote the transfer of the photogenerated electrons to Co(dmgH)2PyCl, the hydrogen evolution cocatalyst. This work provides some guidance for the design of noble metal free photocatalysts for hydrogen generation and highlights the potential of using CQDs to promote the charge transfer in semiconductor-based photocatalysis.Graphical abstractGraphical abstract for this article
  • Construction of robust superhydrophobic film combing povidone iodine for
           high efficient self-cleaning and durable bactericidal properties
    • Abstract: Publication date: 31 December 2018Source: Applied Surface Science, Volume 462Author(s): Hao Chen, Yingying Jin, Lei Lei, Xiaoxu Ding, Xi Li, Yuqin Wang, Lin Sun, Liyan Shen, Mei Yang, Bailiang WangAbstractBacteria can easily colonize on the biomaterials surface which leads to biofilm formation and serious bacterial infections. In this work, a new raspberry structured core-shell nanoparticles were developed through two-step emulsion polymerization method. Robust superhydrophobic film formed on the substrate showed both high efficient self-cleaning and bactericidal properties.
  • Effect of anodic T phase on surface micro-galvanic corrosion of
           biodegradable Mg-Zn-Zr-Nd alloys
    • Abstract: Publication date: 31 December 2018Source: Applied Surface Science, Volume 462Author(s): Changhong Cai, Renbo Song, Luanxiang Wang, Jingyuan LiAbstractA complete understanding of the role of Mg-Zn-Nd (T) phase in surface micro-galvanic corrosion of Mg alloys has not been fully developed. Therefore, the microstructure evolution and corrosion behavior in simulated body fluid (SBF) of Mg-2Zn-0.6Zr-xNd alloys (x = 0, 0.2, 0.6 and 1 wt%) were investigated. It was found that the MgZn phase in Mg-2Zn-0.6Zr alloy changed to Mg60Zn32Nd8 (T2) and Mg35Zn40Nd25 (T3) phases after adding 0.2–1 wt% Nd. With the formation of T phases, the grain size increased first and then decreased. By using scanning kelvin probe force microscopy (SKPFM), the Volta potentials of second phases relative to Mg matrix were measured. T2 and T3 phases with a relative Volta potential of about −400 mV acted as micro-anodes, so that they were corroded preferentially during the corrosion process. Because of the appropriate amount of anodic T phases and their discontinuous distribution, the alloy with 0.2 wt% Nd addition showed a uniform surface corrosion characteristic and exhibit the best corrosion resistance.
  • Study of iron oxide magnetic nanoparticles obtained via pulsed laser
           ablation of iron in air
    • Abstract: Publication date: 31 December 2018Source: Applied Surface Science, Volume 462Author(s): Valery A. Svetlichnyi, Anastasiia V. Shabalina, Ivan N. Lapin, Darya A. Goncharova, Dmitry A. Velikanov, Aleksey E. SokolovMagnetic nanoparticles were obtained using the nanosecond pulsed laser ablation (Nd:YAG laser, 1064 nm, 7 ns) of an iron target in air at atmospheric pressure. The particles obtained were further annealed at four different temperatures. The composition, structure and properties of all obtained powders were investigated using X-ray diffraction (XRD), DSC, attenuated total reflection Fourier-transform infrared spectroscopy (ATR-FTIR), Raman spectroscopy, TEM, SAED and other techniques. The initial sample was found to contain monoclinic magnetite and iron nitrides. Presumably, magnetite presents in the form of spherical particles with the distribution maximum of 12–15 nm, and nitrides take the form of lamellas and rolls. Thermal treatment of the sample led to particle enlargement and phase transformations, first, to cubic magnetite, then to a Fe3O4, α-Fe2O3 and γ-Fe2O3 mixture, and finally to the pure hematite phase. Zeta-potential, BET surface area and magnetic properties changed with the annealing as well. The obtained materials exhibited different properties that make them in demand in different fields, from biomedicine to technology.Graphical abstractGraphical abstract for this article
  • Well-regulated nickel nanoparticles functional modified ZIF-67 (Co)
           derived Co3O4/CdS p-n heterojunction for efficient photocatalytic hydrogen
    • Abstract: Publication date: 31 December 2018Source: Applied Surface Science, Volume 462Author(s): Yongke Zhang, Zhiliang Jin, Hong Yuan, Guorong Wang, Bingzhen MaWell-designed functional noble metal-free Ni nanoparticles as co-catalyst to modified ZIF-67(Co) derived Co3O4 framework materials/CdS p-n heterojunction photocatalyst for efficient hydrogen evolution was successfully synthesized via photo-assisted in-situ method. The obtained noble metal-free defect-induced [Co3O4(3 wt%)/CdS/Ni] mesoporous photocatalyst exhibit excellent photocatalytic activity, namely, the maximum amount of hydrogen evolution reaches about 512 μmol for 5 h over the [Co3O4(3 wt%)/CdS/Ni] photocatalyst under visible light irradiation, which is 14.2 times higher than that of the pure CdS. Deeper further research confirms that the red shift of absorption band edge, the enhancement of light absorption intensity, the short fluorescence lifetime (2.61 ns), the faster electron injection rate (KET = 1.17 × 108 s−1), the larger efficiency of electron injection (ηinj = 30.6%), the high photocurrent response and the smaller R1 (22.3 Ω) and R2 (16,207 Ω) together accelerate the efficient spatial charges separation and transfer. The deeper characterization study results such as TEM, SEM, XPS, XRD, UV–vis DRS, Transient photocurrent and FT-IR etc. shown that the Ni nanoparticles modified on the Co3O4/CdS provided the more active sites and improved the efficiency of photo-generated charge separation, the results of which were in good agreement with each other.Graphical abstractGraphical abstract for this article
  • Silver palladium bimetallic core-shell structure catalyst supported on
           TiO2 for toluene oxidation
    • Abstract: Publication date: 31 December 2018Source: Applied Surface Science, Volume 462Author(s): Yongfeng Li, Fangfang Liu, Yun Fan, Gao Cheng, Wei Song, Junli ZhouWe show that silver palladium bimetallic core-shell structure catalysts supported on TiO2 substrate (Ag@Pd/TiO2) are highly active with a low palladium loading for toluene purification in oxidation reaction. The Ag@Pd catalysts were synthesized by galvanic replacement of Pd coating on Ag nanoparticles. Transmission electron microscopy (TEM), high-resolution TEM, and scanning TEM with energy dispersive spectrometer confirmed that the catalysts have a core-shell configuration, and are spherical in shape with an average diameter size of about 9.0 nm. The UV–vis absorption spectroscopy and selected area electron diffraction further proved that the intimate contact and different electronegativity of Ag and Pd in core-shell structure result in electrons transferring from Ag core to Pd shell, which increases local electron density around Pd atom. In addition, X-ray photoelectron spectroscopy reveals that such an increase of electron density on Pd active site in Ag@Pd/TiO2 catalyst can substantially strengthen the chemisorption with reactant of O2, further promote the phase transformation from Pd0 metal to PdO oxidation state, and finally maintain the normal operation of Pd0-PdO synergic mechanism during toluene oxidation reaction. Hence, compared to monometallic Pd/TiO2 catalyst, the as-prepared bimetallic core-shell Ag@Pd/TiO2 catalyst exhibits greatly higher toluene oxidation activity as a whole although its palladium loading value is just one third of Pd/TiO2. The high catalytic oxidation activity with a low Pd loading makes the Ag@Pd/TiO2 a promising catalyst for use in VOCs purification.Graphical abstractGraphical abstract for this article
  • NiCoCrAlYTa coatings on nickel-base superalloy substrate: Deposition by
           high velocity oxy-fuel spraying as well as investigation of mechanical
           properties and wear resistance in relation to heat-treatment duration
    • Abstract: Publication date: 31 December 2018Source: Applied Surface Science, Volume 462Author(s): Enkang Hao, Yulong An, Xiaoqin Zhao, Huidi Zhou, Jianmin ChenNiCoCrAlYTa coating, a metal-based coating, was prepared on Inconel 718 Ni-base superalloy substrate by high velocity oxy-fuel (HVOF) spraying. The as-polished NiCoCrAlYTa coating was heated at 1000 °C for different durations to afford coatings C1, C2, C3, and C4. The microstructure, element distribution, phase composition and crystalline structure of the as-deposited coating and heat-treated ones were analyzed by transmission electron microscopy, scanning electron microscopy-energy dispersive spectrometry, X-ray diffraction and electron back-scattered diffraction. Moreover, the oxidation behavior of the NiCoCrAlYTa coatings was evaluated based on isothermal oxidation kinetics as well as weight loss measurements; and the effects of surface oxide layers on the microstructure, mechanical properties as well as friction and wear behavior of the NiCoCrAlYTa coatings were investigated. Results show that the as-sprayed coating exhibits dense and uniform microstructure as well as excellent oxidation resistance. Oxide layers, mainly composed of Al2O3, Cr2O3, NiO, Y2O3, Ta2O5, NiCr2O4, and CoCr2O4, are formed on the surface of the coating upon heat-treatment in air; and the microstructure and mechanical properties of the NiCoCrAlYTa coatings as well as oxide layers are governed by heat-treatment time. Particularly, coating C3, obtained after heat-treatment of the as-polished NiCoCrAlYTa coating at 1000 °C for 50 h, exhibits greatly increased indentation hardness, elastic modulus, and wear resistance. This is because the joint functions of a compact and continuous surface oxide layer with gradient nanostructure formed after heat-treatment, and the amorphous protective layer generated on the rubbed surface of coating C3.Graphical abstractNiCoCrAlYTa coating, which possesses excellent oxidation resistance was prepared by HVOF spraying technology on the Inconel 718 substrate. And an oxidative layer with double-levels nanostructure formed on the surface of coating after different isothermal oxidation time, which presents excellent mechanical properties as well as friction and wear behaviors rate due to the the coupling effects of the gradient nanostructure of oxidative layer and the formation of amorphous protective layer on its worn surface.Graphical abstract for this article
  • The promoted performance of CeO2 catalyst for NH3-SCR reaction by NH3
    • Abstract: Publication date: 31 December 2018Source: Applied Surface Science, Volume 462Author(s): Xiao Sun, Rui-tang Guo, Shuai-wei Liu, Jian Liu, Wei-guo Pan, Xu Shi, Hao Qin, Zhong-yi Wang, Zhong-zhu Qiu, Xing-yu LiuIn this study, NH3 treatment of CeO2 was found to significantly enhance its NH3-SCR performance. The NH3-treated CeO2 was characterized by BET, XRD, TPR and XPS. The obtained results revealed the excellent SCR activity and stability of CeO2 catalyst treated by NH3 should be originated from the dropped crystallinity, better reducibility, along with the production of more Ce3+ and surface adsorbed oxygen. Furthermore, in situ DRIFT study has been carried out and the results indicated that the Langmuir-Hinshelwood (L-H) mechanism could be applied for explaining the SCR reaction route over CeO2-N.Graphical abstractGraphical abstract for this article
  • Delamination and self-assembly of layered double hydroxides for enhanced
           loading capacity and corrosion protection performance
    • Abstract: Publication date: 31 December 2018Source: Applied Surface Science, Volume 462Author(s): Ang Liu, Huiwen Tian, Weihua Li, Wei Wang, Xiang Gao, Peng Han, Rui DingAbstractLayered double hydroxides (LDHs) nanocontainers intercalating with corrosion inhibitors are considered as a great platform to deliver corrosion inhibitors to the corroding sites. However, the small interlayer spacing and strong interaction between hydrotalcite laminates and interlayer anions impede the loading of macromolecular species into LDHs via a conventional anion-exchange process. This work devises a new paradigm for the preparation of LDHs in corrosion protection. A new method combining delamination and self-assembly to increase the loading of the organic corrosion inhibitor —5-Methyl-1,3,4-thiadiazole-2-thiol (MTT) into LDHs is applied and exhibits remarkable corrosion protection effects. The SEM, EDS, TEM, XRD, XPS and FT-IR were used to characterize the LDHs and LDH nanosheets. UV–vis absorption spectra and thermogravimetric analysis (TGA) experiments indicate an enhanced loading of MTT which is slowly released to the chloride media. The electrochemical experiments indicate that the release of MTT from their LDHs host can efficiently inhibit the corrosion on the surface of mild steel in 3.5 wt% NaCl solution. Furthermore, surface analysis experiments were carried out to probe into the anticorrosion mechanism of LDHs.
  • Superhydrophobic coating from fluoroalkylsilane modified natural rubber
           encapsulated SiO2 composites for self-driven oil/water separation
    • Abstract: Publication date: 31 December 2018Source: Applied Surface Science, Volume 462Author(s): Jittraporn Saengkaew, Duy Le, Chanatip Samart, Hideo Sawada, Masakazu Nishida, Narong Chanlek, Suwadee Kongparakul, Suda KiatkamjornwongA superhydrophobic/superoleophilic mesh was successfully prepared in a simple and environmentally friendly process by coating with fluoroalkylsilane-modified natural rubber-encapsulated silica latex (FAS-modified NR/SiO2). TEM images confirmed the formation of a core-shell morphology, in which the rubber core was fully covered by a silica shell. This improved the thermal stability of the composites. Coating with FAS-modified NR/SiO2 enhanced both the hydrophobicity and surface roughness of the mesh. The depth profile of the XPS spectra revealed the presence of fluoroalkylsilane on the superhydrophobic mesh and Ar gas ion etching confirmed migration of the fluoroalkylsilane, SiO2, and carbon to the mesh surface. SEM and AFM results quantified the surface roughness of the coated mesh. Meshes coated with FAS-modified NR/SiO2 exhibited superhydrophobic/superoleophilic properties. Surfaces coated with these encapsulated particles were successfully applied to oil/water separation. They exhibited a separation efficiency of up to 100% and were reusable across 30 cycles.Graphical abstractGraphical abstract for this article
  • Sb2S3/Sb2O3 modified TiO2 photoanode for photocathodic protection of 304
           stainless steel under visible light
    • Abstract: Publication date: 31 December 2018Source: Applied Surface Science, Volume 462Author(s): Xinran Li, Xiutong Wang, Xiaobo Ning, Jing Lei, Jing Shao, Wencheng Wang, Yanliang Huang, Baorong HouAbstractA series of Sb2S3/Sb2O3/TiO2 (SS/SO/T) composites with different reactant concentrations were synthesized via anodic oxidation and a one-pot hydrothermal method. The chemical compositions, morphologies, and optical absorption properties of prepared samples were characterized by X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy, energy disperse spectroscopy, elemental mapping and ultraviolet–visible diffuse reflectance spectroscopy. Photocathodic protection performances of these samples were studied using time-dependent open circuit potential, time-dependent photoinduced current density, and photoinduced volt-ampere characteristic. The SS/SO/T composite with a 48 mmol/L antimony source exhibited optimal performance for 304 stainless steel (304SS). This excellent performance origins from the synergistic effect of the ternary system. The narrow band gap Sb2S3 promoted visible light harvesting. The p-n junction between p-type Sb2S3 and n-type SO/T provides a driving force for the separation and transfer of carriers. Well crystallized Sb2O3 rods offer a direct pathway for the carriers migration.
  • Shape-dependent photogenerated cathodic protection by hierarchically
           nanostructured TiO2 films
    • Abstract: Publication date: 31 December 2018Source: Applied Surface Science, Volume 462Author(s): Juan Zuo, Hao Wu, Ajiao Chen, Junqiu Zhu, Meidan Ye, Jidong Ma, Zhengbin QiAbstractTiO2 films with different nanostructures were prepared by means of hydrothermal technique by adjusting the concentration of reactant components and reaction time. The flower-like, rod-like and sphere-like of the TiO2 films were observed by scanning electron microscopy. The shape-dependent photogenerated cathodic protection activity of such films were investigated. The flower-like film presents the largest drop of open circuit potential and the maximum magnitude of the photocurrent once irradiated by UV light. The 304 stainless steel coupled with it has the most negative potential Ecorr in comparison with other nanostructure films as well. The electrochemical impedance spectroscopy analysis of 304 stainless steel also shows the minimum charge transfer resistance when coupled with flower-like nanostructure films. To understand the effect of nanostructure on the properties, possible schematic diagrams of UV incident light passage in the three flower-like, rod-like and sphere-like nanostructures films are proposed to explain the absorption difference. The flower-like structure with a large amount of voids is beneficial to enhance light scattering and trapping for efficient UV light harvesting.
  • TiMoN nano-grains embedded into thin MoS x -based amorphous matrix: A
           novel structure for superhardness and ultra-low wear
    • Abstract: Publication date: 31 December 2018Source: Applied Surface Science, Volume 462Author(s): Lina Yang, Mao Wen, Jianhong Chen, Jia Wang, Xuan Dai, Xinlei Gu, Xiaoqiang Cui, Kan ZhangMolybdenum disulfide (MoS2) represents a highly sought lubricant for reducing friction based on intrinsic layered structure, unfortunately, practical applications have been greatly restricted due to the fact that its low hardness would cause severe wear. Here, a novel TiMoN/a-MoSx composite coatings with TiMoN solid solution grains embedded into MoSx-based amorphous matrix has been successfully designed and synthesized, through magnetron co-sputtering technology. Desirably, in virtue of such special microstructure, superhardness and excellent toughness can be well achieved, along with an ultra-low wear rate at ∼2 × 10−11 mm3/Nm in air. Simultaneously, a low friction at ∼0.1 is maintained. It should be noted that this wear level is almost two orders of magnitude lower than that of pure TiN coating, and is, as we known, the lowest wear rate in dry sliding. Investigations of tribofilm reveal that it is amorphous MoSx in nature, and its formation arises directly from the transfer of MoSx amorphous matrix to frictional interface. Which contributes to effective lubrication behavior, coupled with excellent mechanical performances of such composite coating, exceptionally low wear can be guaranteed. The designed special structure makes it possible for the synthesis of super-hard and super-durable lubricative coating for industrial application.Graphical abstractGraphical abstract for this article
  • Experimental and simulation studies of strontium/zinc-codoped
           hydroxyapatite porous scaffolds with excellent osteoinductivity and
           antibacterial activity
    • Abstract: Publication date: 31 December 2018Source: Applied Surface Science, Volume 462Author(s): Qun Wang, Pengfei Tang, Xiang Ge, Pengfei Li, Chen Lv, Menghao Wang, Kefeng Wang, Liming Fang, Xiong LuThe porous scaffold of hydroxyapatite (HA) is highly promising for application in clinics owing to its interconnected porous structure, excellent mechanical properties, biocompatibility, and biological activity; however, the effectiveness of its antibacterial properties and osteoinductivity limits its wide usage. In the present study, strontium (Sr), zinc (Zn), and Sr/Zn-codoped porous scaffolds of HA were prepared by an ion-exchange method and a foaming method. The results based on the density functional theory (DFT) and experimental methods suggested that Sr and Zn were successfully doped into the HA lattice structure, thereby changing the lattice parameters of HA. Sr-doped, Zn-doped, and codoped porous HA scaffolds promoted the proliferation of bone marrow stromal cells (BMSCs), and Sr-doped and codoped porous HA scaffolds promoted BMSC differentiation. In addition, Zn-doped and codoped porous HA scaffolds exhibited excellent antibacterial properties. In short, the codoped HA porous scaffolds, prepared using the simple, facile, and mild ion-exchange, and foaming methods, had good biocompatibility, osteoinductivity, and antibacterial properties, which could effectively inhibit microbial infection and promote bone tissue regeneration in the process of bone repair. Moreover, they are hopeful to be good bone replacement material in clinical application.Graphical abstractGraphical abstract for this article
  • Pd nanonetwork decorated on rGO as a high-performance electrocatalyst for
           ethanol oxidation
    • Abstract: Publication date: 31 December 2018Source: Applied Surface Science, Volume 462Author(s): Mehdi Zareie Yazdan-Abad, Meissam Noroozifar, Nafiseh Alfi, Ali Reza Modarresi-Alam, Hamideh SaravaniA three-dimensional palladium nanonetwork decorated on reduced graphene oxide (rGO) is synthesized by a simple and rapid method. In this method, graphene oxide (GO) is reduced on a glassy carbon electrode by Zn/HCl system. After reduction of GO to rGO, three dimensional Pd nanonetwork is fabricated on rGO by reduction of deposited PdCl2 using Zn/HCl system. The morphology and chemical composition of as-prepared 3-D Pd/rGO catalyst are characterized by scanning electron microscopy and energy dispersive spectroscopy, respectively. We revealed that the as-synthesized 3-D Pd nanonetwork shows excellent electrocatalytic activity and durability toward ethanol oxidation due to the formation of the 3-D nanonetwork and porous structure. The specific activity of 3-D Pd/rGO toward ethanol oxidation is 12.3 times higher than commercial Pd/C. Durability and tolerance to carbonaceous intermediates accumulation of the as-prepared catalyst are also greatly improved.Graphical abstractGraphical abstract for this article
  • Multiscale array antireflective coatings for improving efficiencies of
           solar cells
    • Abstract: Publication date: 31 December 2018Source: Applied Surface Science, Volume 462Author(s): Yijie Li, Yaoju Zhang, Jie Lin, Chaolong Fang, Yongqi Ke, Hua Tao, Weiji Wang, Xuesong Zhao, Zhihong Li, Zhenkun LinAbstractMultiscale array (MSA) structures are present to reduce the front-side surface reflection loss of solar cells, which consists of nanostructure patterns spanned across the curved surface of micrometer-sized plano-concave cylindrical arrays. The MSAs are fabricated using flexible polydimethylsiloxane (PDMS) polymer by simple template replication together with surface modification technique and characterized by atomic force microscopy (AFM) and scanning electron microscopy (SEM). Optical characterization shows the MSA structure can reduce 3.85% integrated reflectivity of multicrystalline silicon solar cell encapsulated by the flat epoxy resin polymer (ERP) coating. Importantly, the MSA antireflective coating can improve the photovoltaic conversion efficiency of the ERP-encapsulated solar cell from 17.50% to 18.34% and can increase the contact angle of a 2 μL water droplet on the solar cell surface from 110.5° to 153.1°. These improvements have great significance for commercial Si solar cell devices.
  • Superhydrophobic and superoleophilic surfaces prepared by spray-coating of
           facile synthesized Cerium(IV) oxide nanoparticles for efficient oil/water
    • Abstract: Publication date: 31 December 2018Source: Applied Surface Science, Volume 462Author(s): Asif Matin, Umair Baig, M.A. Gondal, Sultan Akhtar, S.M. ZubairAbstractIn this work, we report the preparation of superhydrophobic and superoleophilic surfaces on stainless steel meshes by spray-coating of Cerium(IV) oxide (CeO2) nanoparticles obtained by a co-precipitation method. The synthesized particles and the coated meshes were characterized using advanced techniques. Scanning electron microscopy images showed the particles to be present in distinct lumps; merged with each other on calcination to give a homogeneous structure. Transmission electron microscopy analyses showed the agglomeration of individual particles to form the clusters. Contact angle measurements revealed the superhydrophobic and superoleophilic nature of the modified mesh surface in air. Fourier transform infra-red analyses of the synthesized particles showed the characteristics peaks of CeO2 found in commercial samples. X-ray photoelectron spectroscopy of the glass coated with ceria confirmed the predominant presence of Ce4+ that also explained the wetting behavior. Oil-water separation studies using a simple gravity-driven setup showed high separation efficiency of an oil water mixture. An analytical model is discussed in detail to account for the wetting behavior and efficacy of the prepared surfaces in separating the two fluids. To summarize, this work presents a very simple and effective route for oil-water separation with high efficiency.
  • Formation of extended thermal etch pits on annealed Ge wafers
    • Abstract: Publication date: 31 December 2018Source: Applied Surface Science, Volume 462Author(s): L. Persichetti, M. Fanfoni, M. De Seta, L. Di Gaspare, L. Ottaviano, C. Goletti, A. SgarlataAbstractAn extended formation of faceted pit-like defects on Ge(0 0 1) and Ge(1 1 1) wafers was obtained by thermal cycles to T > 750 °C. This temperature range is relevant in many surface-preparation recipes of the Ge surface. The density of the defects depends on the temperature reached, the number of annealing cycles performed and correlates to the surface-energy stability of the specific crystal orientation. We propose that the pits were formed by preferential desorption from the strained regions around dislocation pile-ups. Indeed, the morphology of the pits was the same as that observed for preferential chemical etching of dislocations while the spatial distribution of the pits was clearly non-Poissonian in line with mutual interactions between the core dislocations.
  • Qualitative analysis of growth mechanism of polycrystalline InAs thin
           films grown by molecular beam epitaxy
    • Abstract: Publication date: 31 December 2018Source: Applied Surface Science, Volume 462Author(s): Arpana Agrawal, Youngbin Tchoe, Heehun Kim, Joon Young ParkAbstractThe mechanism of surfaces/interfaces and precise control of growth morphology is a key parameter for any specific device application. Herein, we report on a qualitative growth study of molecular beam epitaxy-grown polycrystalline InAs thin films on a lattice-mismatched Si(1 0 0) substrate using atomic force microscopy. The height-height correlation function (HHCF) and power spectral density function (PSDF) were employed to analyze the surface structures. Clear oscillatory behavior in the HHCF for sufficiently larger lateral distances suggests a mound-like morphology, which was confirmed by the existence of a characteristic frequency peak in the PSDF. The growth mechanism is described qualitatively by the Schwoebel barrier (roughening) effect coupled with the Mullins diffusion model (smoothing effect).
  • TiNb2O7 nanoparticle-decorated graphite felt as a high-performance
           electrode for vanadium redox flow batteries
    • Abstract: Publication date: 31 December 2018Source: Applied Surface Science, Volume 462Author(s): Daniel Manaye Kabtamu, Anteneh Wodaje Bayeh, Tai-Chin Chiang, Yu-Chung Chang, Guan-Yi Lin, Tadele Hunde Wondimu, Shuenn-Kung Su, Chen-Hao WangA novel, low-cost, safe, highly catalytic, and stable TiNb2O7 nanoparticle-modified graphite felt (TNO-modified GF) electrode was successfully fabricated using a simple solvothermal method for vanadium redox flow batteries (VRFBs). The TNO-modified GF electrode showed the highest electrocatalytic activity toward the VO2+/VO2+ redox couple among all samples measured. According to charging-discharging results, the average energy efficiency of the cell using TNO-modified GF electrode reached 79.06% at 100 mA cm−2, which is 4.43% and 15.73% higher than the cells constructed with heat-treated GF (HT-GF) and pristine GF (P-GF) electrodes, respectively. Moreover, cycling tests revealed no observable decay in the efficiencies after 100 cycles, indicating that the TNO-modified GF electrode is stable over repetitive cycling. The superior electrochemical performance of the cell with the TNO-modified GF electrode is attributed to the introduction of uniformly distributed TNO nanoparticles. The modification increased oxygen-containing functional groups on the surface of GF, thus making it more hydrophilic. It also lowered the activation barrier for electrochemical reactions within vanadium ions, leading to facilitate the charge transfer process on the surface of GF.Graphical abstractGraphical abstract for this article
  • Self-assembly porous metal-free electrocatalysts templated from sulfur for
           efficient oxygen reduction reaction
    • Abstract: Publication date: 31 December 2018Source: Applied Surface Science, Volume 462Author(s): Qin Xiang, Sha Li, Xuefeng Zou, Yujie Qiang, Bingbing Hu, Yuan Cen, Chuanlan Xu, Lijun Liu, Yan Zhou, Changguo ChenAcetylene black (AB) was exfoliated and functionalized through a single-pot method then be assembled to a novel porous carbon material by utilizing sulfur as both template and sulfur source. The defect-rich structures of the obtained AB play a critical role in providing more appropriate sites for sulfur atom doping. After a pyrolysis process in the presence of melamine as N doping agent, the sulfur template was decomposed and yielded the N,S-codoped porous carbon material with additional porosity. The synergistic effects between the defect-projecting and heteroatoms-doping boost the activity of electrocatalysts in terms of the enhanced oxygen reduction efficiency and optimized kinetic process, both are better than that of commercial Pt/C. And the improved reactivity between carbon atoms and heteroatoms as well as sulfur and nitrogen atoms greatly suppress the loss of active ingredient of the catalyst, the mechanism yields a striking long-term stability for the unique metal-free OAB@S-N electrocatalyst.Graphical abstractGraphical abstract for this article
  • First-principles calculations on wetting interface between Ag-Cu-Ti filler
           metal and SiC ceramic: Ag (1 1 1)/SiC (1 1 1) interface and Ag
           (1 1 1)/TiC (1 1 1) interface
    • Abstract: Publication date: 31 December 2018Source: Applied Surface Science, Volume 462Author(s): Jian Yang, Zheng Ye, Jihua Huang, Shuhai Chen, Yue ZhaoInterfacial properties of Ag (1 1 1)/SiC (1 1 1) interface and Ag (1 1 1)/TiC (1 1 1) interface were researched by first-principles calculations to investigate the reason that Ag-Cu-Ti filler metal shows the superior reactive wettability on SiC ceramic. The calculated results show that, 7 atom-layers Ag (1 1 1) surface, 11 atom-layer SiC (1 1 1) surface and 9 atom-layer TiC (1 1 1) surface can represent the Ag bulk, SiC bulk and TiC bulk, effectively. Ag (1 1 1)/SiC (1 1 1) interface and Ag (1 1 1)/TiC (1 1 1) interface with C-terminated structure and TL stacking sequence show the highest interfacial stability. Chemical bonds at Ag (1 1 1)/SiC (1 1 1) interface and Ag (1 1 1)/TiC (1 1 1) interface are mainly formed by the interaction between 1st layer C atoms in SiC (or TiC) slab and 1st layer Ag atoms in Ag slab. Interfacial energy of Ag (1 1 1)/SiC (1 1 1) interface is much larger than that of Ag (1 1 1)/TiC (1 1 1) interface, which indicates that the formed TiC reaction layer between Ag-Cu-Ti filler metal and SiC ceramic indeed plays the positive role on improving the wettability of Ag-Cu-Ti filler metal on SiC ceramic.Graphical abstractGraphical abstract for this article
  • Sequential liquid separation using meshes with hierarchical
           microcube–nanohole structure and controlled surface wettability
    • Abstract: Publication date: 31 December 2018Source: Applied Surface Science, Volume 462Author(s): Seeun Woo, Wonshik Kwak, Woonbong HwangAbstractIn actual industrial processes, in addition to separation of just water and oil, separation of multiphase liquids and separation of organic solvents are also required. Here, we demonstrate successful multiphase liquid separation by simply applying different coating materials to aluminum meshes with a hierarchical microcubic and nanohole structure. A gravity-driven multiphase separation system was designed using these meshes as the separation media, and it showed high collection rate (99%) and high content ratio (95%). The fabricated separation system could sequentially separate liquids with surface tension of ≤21.6, 21.6–32.0, and ≥32.0 mN/m by choosing a filter with the proper surface energy. Given the small differences in the surface tension of the liquids used in this study, the separation system with a surface-energy-controlled filter can be an impressive tool to separate numerous liquid mixtures.
  • Melamine-functionalized graphene oxide: Synthesis, characterization and
           considering as pseudocapacitor electrode material with intermixed POAP
    • Abstract: Publication date: 30 November 2018Source: Applied Surface Science, Volume 459Author(s): Farshad Boorboor Ajdari, Elaheh Kowsari, Ali Ehsani, Liudmyla Chepyga, Milan Schirowski, Sebastian Jäger, Olga Kasian, Frank Hauke, Tayebeh AmeriIn this study, Melamine functionalized graphene oxide (FGO-Melamine) was synthesized by chemical route. The prepared functionalized graphene oxide was characterized by different analytical techniques such as FT-IR, Raman spectroscopy, thermogravimetry coupled with mass spectrometry (TG-MS), X-Ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM), and X-ray photoelectron spectroscopy (XPS). To improve electrochemical properties of polyorthoaminophenol (POAP), the electropolymerized POAP/FGO-Melamine films, employed as an active electrode regarding electrochemical performance. In terms of electrochemical measurements, galvanostatic charge–discharge evaluation, EIS (electrochemical impedance spectroscopy) and CV (cyclic voltammetry) were employed for conducting an enquiry into supercapacitive performance of nanocomposite of POAP/FGO-Melamine. This graphene-based electrode showed a specific capacitance (SC) by 273 F g−1 and high energy of 37.91 W kg−1 at power density of 500 W kg−1. The novel materials synthesized in the current work show higher efficiency compared to the carbon-based ones concerning redox reactions of capacitors consisting of good stability in the existence of aqueous electrolyte, large active surface area and ease synthesis method.Graphical abstractGraphical abstract for this article
  • Surface chemical characterization of model glycan surfaces and shelf life
           studies of glycan microarrays using XPS, NEXAFS spectroscopy, ToF-SIMS and
           fluorescence scanning
    • Abstract: Publication date: 30 November 2018Source: Applied Surface Science, Volume 459Author(s): C. Nietzold, P.M. Dietrich, M. Holzweber, A. Lippitz, A. Kamalakumar, V. Blanchard, S. Ivanov-Pankov, W. Weigel, U. Panne, W.E.S. UngerCovalent modification of surfaces with carbohydrates (glycans) is a prerequisite for a variety of glycomics-based biomedical applications, including functional biomaterials, carbohydrate-arrays, and glycan-based biosensors. The chemistry of glycan immobilization plays an essential role in the bioavailability and function of surface bound carbohydrate moieties. For biomedical applications the stability over time (shelf life) of glycan arrays is a crucial factor. Herein we report on approaches for surface and interface characterization relevant to the needs of production of glycan microarrays which were tested using model carbohydrate surfaces. For detailed characterization of glycan model surfaces we used a combination of X-ray photoelectron spectroscopy (XPS), near edge X-ray absorption fine structure spectroscopy (NEXAFS) and ToF SIMS which are complementary techniques of surface chemical analysis. Links to fluorescence spectroscopy often used for characterization in the microarray community were established as well. In detail, amine-reactive silicon oxide and glass surfaces were used for anchoring oligosaccharides with an amino linker. The amount of surface bound carbohydrates was estimated by X-ray photoelectron spectroscopy (XPS). Glycan immobilization was investigated using lectins, which are glycan-binding molecules. A shelf life study of model glycan microarrays on epoxy-coated glass surfaces was done over a period of 160 days under different storage conditions utilizing fluorescence, ToF-SIMS and XPS analysis. It was shown that glycan activity of the models used can be maintained at least for half a year of storage at 4 °C.Graphical abstractGraphical abstract for this article
  • Removal of surface states on Si(1 0 0) by valence-mending
    • Abstract: Publication date: 31 December 2018Source: Applied Surface Science, Volume 462Author(s): Meng TaoSurface states are a classic obstacle in semiconductor technologies dating back to the John Bardeen era. We propose a generic approach, i.e., valence-mending passivation, to remove surface states. This paper reviews valence-mending passivation of the Si(1 0 0) surface, which is accomplished by depositing a monolayer of chalcogen atoms on Si(1 0 0). Methods for preparing an atomically-clean surface and depositing a self-limited monolayer of chalcogen atoms on Si(1 0 0) are developed in molecular beam epitaxy, solution passivation, and chemical vapor deposition. The passivated surface exhibits unprecedented electrical and chemical properties that are atypical of three-dimensional bulk semiconductors. The Schottky barrier heights for various metals now obey the Mott-Schottky theory on valence-mended Si(1 0 0). Metals of very-low and very-high workfunctions produce record-high and record-low Schottky barriers on the passivated surface. The record-high barrier demonstrated is 1.14 eV for an Al/sulfur-passivated p-type Si(1 0 0) junction, which exceeds the bandgap of Si. The record-low barrier is lower than 0.08 eV for an Al/sulfur-passivated n-type Si(1 0 0) junction and that barrier is likely negative at –0.02 eV. These record Schottky barriers show good thermal stability up to 500 °C upon annealing. Potential applications of valence-mending passivation include: (1) new approaches to Ohmic contacts for both heavily- and lightly-doped semiconductors, (2) a new diode that is an intermediate between a Schottky junction and a p-n junction, (3) suppressed surface and grain boundary recombination in optoelectronics and photovoltaics, and (4) the ideal substrate for van der Waals epitaxy of two-dimensional materials. The limitations of the current methods in characterizing extremely-low and negative Schottky barriers are outlined.Graphical abstractGraphical abstract for this article
  • Fabrication of Mo2C coating on molybdenum by contact solid
    • Abstract: Publication date: 31 December 2018Source: Applied Surface Science, Volume 462Author(s): Ziyuan Zhao, Pengfei Hui, Tao Wang, Yunhua Xu, Lisheng Zhong, Mingxuan Zhao, Dexin Yang, Ran WeiRecently a contact solid carburization method to fabricate carbide coatings on refractory metals was proposed. The principle is to hot-press the refractory metal with a “carbon sponge” (e.g. cast iron or high-carbon steel) which contains interstitial carbon atoms. When they contact in atomic scale at high temperatures, the carbon atoms diffuse into the refractory metal matrix and then dense carbide coatings on the substrates can be obtained since most refractory metals are carbide forming elements. In this article, we apply this method to prepare carbide coating on molybdenum (Mo). Cast iron is used as the “carbon sponge” and hot-pressed with textured Mo at constant temperature and pressure (18 MPa). We set the temperature at 1100 °C and 900 °C separately, we found that coatings containing Fe-Mo-C layer and Mo-C layer are generated at 1100 °C while coatings containing only Mo-C layer are formed at 900 °C. We then hot-pressed the samples at 900 °C for 2–10 h and systematically investigated the microstructure and some basic properties of the coatings obtained at 900 °C. The coating grows inward, it is pure ceramic and completely dense. The coating is composed of columnar Mo2C grains whose grain orientations are randomly distributed. The metal and carbide phases are metallurgically bonded with incoherent interfaces. The coating thickness reaches 1.8 μm when annealed for 10 h. As expected, the surface hardness is remarkably improved and the coating adhesion is strong. This technique is also expected to be used to improve the wear resistance, oxidation resistance for molybdenum and Mo based alloys and may also provide a new strategy to prepare Mo2C superconductors and catalysts.Graphical abstractGraphical abstract for this article
  • Synthesis and characterization of Ag/α-Fe2O3 microspheres and their
           application to highly sensitive and selective detection of ethanol
    • Abstract: Publication date: 31 December 2018Source: Applied Surface Science, Volume 462Author(s): Xiaohua Jia, Xiaojing Yu, Linxuan Xia, Yali Sun, Haojie SongAbstractHierarchical oxide nanostructures had proved their promising features in gas sensing due to their high surface areas and well-aligned nanoporous structures containing less agglomerated configurations. In this study, a facile method was developed to prepare Ag/α-Fe2O3 microspheres using α-FeOOH microspheres as precursor and AgNO3 as Ag resource. Various characterization techniques were employed to identify the structures and morphologies of the hybrid nanostructures. The results revealed that Ag nanoparticles with diameters of 5 nm formed on the surface of hollow α-Fe2O3 spheres were composed of primary nano-sized particles. The ethanol sensing properties of pure α-Fe2O3 and Ag/α-Fe2O3 microspheres were evaluated and Ag/α-Fe2O3 microspheres showed higher responses towards ethanol when compared to other gases, such as toluene, ammonia, acetone, and formaldehyde. The response of Ag/α-Fe2O3 microspheres to 50 ppm ethanol was estimated to ∼11.2, which was 1.7 folds higher than that of pure α-Fe2O3 at 240 °C. Furthermore, the sensor could easily be recovered to its initial state in short periods after exposure to fresh air. The addition of Ag served as an active catalyst, creating more active sites believed crucial for enhancing sensitivity.
  • Synthesis of g-C3N4/Bi5O7I microspheres with enhanced photocatalytic
           activity under visible light
    • Abstract: Publication date: 31 December 2018Source: Applied Surface Science, Volume 462Author(s): Xueqi Geng, Shuai Chen, Xiang Lv, Wei Jiang, Tianhe WangNovel g-C3N4/Bi5O7I heterojunction microspheres having excellent photocatalytic activity were successfully prepared by a one-pot ethylene glycol (EG)-assisted hydrothermal method followed by calcination in air. Bi5O7I microspheres grafted with g-C3N4 nano-sheets were formed and studied by electron microscopy. The morphological effects on g-C3N4/Bi5O7I photocatalytic capability with varied g-C3N4 contents were investigated and discussed. The g-C3N4/Bi5O7I microspheres exhibited much improved photocatalytic degradation performance under visible light irradiation compared with bare Bi5O7I and g-C3N4. The preparation conditions of g-C3N4/Bi5O7I microspheres with optimal photocatalytic ability for degrading methyl orange (MO) and rhodamine (RhB) were established. Analyses by both photoluminescence (PL) and photocurrent independently confirmed that photo-induced electron-hole pairs in the g-C3N4/Bi5O7I composite have been effectively created which was responsible for the observed photocatalysis. Based on the analysis of the experiment results, a Z-Scheme heterojunction photocatalytic mechanism was proposed. The excellent photocatalytic performance could be attributed to the effective charge separation at the interface between g-C3N4 and Bi5O7I and the enhanced visible light absorption. In addition, the photocatalytic mechanism was discussed on the basis of the relative band positions of these two semiconductor materials.Graphical abstractGraphical abstract for this article
  • Anchoring of Ag nanoparticles on Fe3O4 modified polydopamine
           sub-micrometer spheres with enhanced catalytic activity
    • Abstract: Publication date: 31 December 2018Source: Applied Surface Science, Volume 462Author(s): Na Li, Zhenyuan Ji, Lizhi Chen, Xiaoping Shen, Yifei Zhang, Shiqing Cheng, Hu ZhouIn this study, highly dispersed Ag nanoparticles anchored on Fe3O4 modified polydopamine sub-micrometer spheres (PSS) nanocomposites were fabricated by a facile two-step approach. The catalytic properties of the as-obtained PSS/Fe3O4/Ag ternary nanocomposites were evaluated with the reduction of 4-nitrophenol by NaBH4 as a model reaction. It is shown that the presence of Fe3O4 can significantly decrease the particle size of the in-situ formed Ag nanoparticles on PSS, and optimize the catalytic performance of PSS/Ag nanocomposites. Additionally, the as-synthesized PSS/Fe3O4/Ag ternary nanocomposites exhibit high catalytic stability for recycle. Magnetic study reveals that the ternary nanocomposites display room-temperature superparamagnetic behavior. It is believed that this simple and effective method can be extended for the preparation of other polydopamine-based multicomponent nanocomposites with intriguing property, which would hold great promise for a variety of applications.Graphical abstractGraphical abstract for this article
  • Nucleation and adhesion of ultra-thin copper films on amino-terminated
           self-assembled monolayers
    • Abstract: Publication date: 31 December 2018Source: Applied Surface Science, Volume 462Author(s): J. Bogan, A. Brady-Boyd, S. Armini, R. Lundy, V. Selvaraju, R. O'ConnorAbstractIn this work, we report on the effect of amino-terminated self-assembled monolayers (SAMs) on the growth and adhesion of copper on a dielectric surface in ultra-high vacuum. The nucleation and adhesion of copper is studied for a range of self-assembled monolayers both with and without nitrogen containing terminal groups, and as a function chain length using X-ray photoelectron spectroscopy, dynamic water contact angle, sheet resistance, and adhesion testing measurements.In-situ X-ray photoelectron spectroscopy studies of ultra-thin copper films show that the presence of nitrogen significantly improves the nucleation of copper to the surface, particularly those coated with long chain SAMs. However, upon thermal annealing short chain amino-terminated SAMs retain much of the deposited copper while significant desorption occurs for longer chains.Results consistent with these observations are obtained during conventional tape test measurements to determine adhesion. As such, for CMOS interconnect applications which require copper trenches with a nano-scale cross section, short chain SAMs offer excellent nucleation and adhesion, as well as the potential to act as a pore-sealant for low-k materials, without impacting significantly on the cross-sectional area of the copper lines.
  • Ultraviolet-light-driven photoresponse of chemical vapor deposition grown
           molybdenum disulfide/graphene heterostructured FET
    • Abstract: Publication date: 30 November 2018Source: Applied Surface Science, Volume 459Author(s): Muhammad Zahir Iqbal, Sana Khan, Salma SiddiqueAbstractTwo dimensional materials such as graphene and transition metal dichalcogenides (TMDC) have gained profound research interest as novel optical material owing to their remarkable optical and electrical properties. The formation of atomically controlled van der Waals (vdW) heterostructured architectures facilitates comprehending innovative photosensing and optoelectronic devices exhibiting unique properties than conventional counterparts. We have demonstrated the use of MoS2/graphene heterostructured field effect transistor (FET) for photosensing applications. For different drain to source voltages (Vds), the effect of DUV irradiations is studied, revealing an increased photoresponse. Optical performance of FET is studied by evaluating photoresponsivity (Rλ), detectivity (D∗) and external quantum efficiency (EQE). Optical response with Rλ and D∗ approaching 3.34 × 103 AW−1 and 1.004 × 1012 jones, respectively is obtained. This approach of creating TMDCs/graphene based heterostructured devices provide new insights for development of high performance photosensors for next generation optical and sensing applications.
  • Surface N modified 2D g-C3N4 nanosheets derived from DMF for
           photocatalytic H2 evolution
    • Abstract: Publication date: 30 November 2018Source: Applied Surface Science, Volume 459Author(s): Quanguo Hao, Yanhua Song, Haiyan Ji, Zhao Mo, Xiaojie She, Jiujun Deng, Tahir Muhmood, Xiangyang Wu, Shouqi Yuan, Hui Xu, Huaming LiThe two-dimensional graphitic carbon nitride (2D g-C3N4) shows excellent photocatalytic performance due to its graphene-like structure, unique electronic and optical property. However, the 2D g-C3N4 suffers from lower visible light utilization because of the quantum size effect. Herein, a new approach was developed to prepare the surface nitrogen modified 2D g-C3N4 nanosheets (NCNS) through a facile hydrothermal treatment route. The as-obtained NCNS exhibited a high hydrogen evolution rate of 19.8 mmol h−1 g−1 with a turnover number (TON) of 642.39 in 5 h, and the external quantum efficiency (EQE) of 10.7% at 420 nm was superior to the g-C3N4 different morphological regulation. The surface nitrogen modification prompted electron delocalization of two-dimensional electron system, leading to accelerating photon-generated carrier separation and transportation efficiency.Graphical abstractThe as-obtained NCNS photocatalyst both increased the absorption of visible light and exhibited more efficient charge separation compared to the precursor of 2D g-C3N4. It also exhibited superior photocatalytic hydrogen evolution performance with high external quantum efficiency (∼10.7%, λ = 420 nm).Graphical abstract for this article
  • Interface reaction processes and reactive properties of Al/CuO
           nanothermite: An ab initio molecular dynamics simulation
    • Abstract: Publication date: 30 November 2018Source: Applied Surface Science, Volume 459Author(s): Guolin Xiong, Chunhong Yang, Weihua ZhuAbstractAb initio molecular dynamics simulations were performed to investigate the interface reaction processes and reactive properties of the Al/CuO thermite at high temperatures. The results indicate that the redox reactions that produced copper metal and aluminum oxide initiate at both the upper and lower interfaces. The higher the temperature is, the faster the atomic configuration changes. Especially, when the temperature is above 2000 K, the Cu atom starts to penetrate into the aluminum metal layer. The metal copper is ultimately doped by the aluminum atoms at 3000 K. There are significant differences between the propagation rates and time of duration for the upper and lower oxidation fronts. The population analysis of Bader charges were calculated to understand the change in the bonding properties of atoms associated with the redox reactions. At 830 and 1000 K, the interface reactions were done incompletely as shown in the reaction rates. At 2000 K, the interface reaction was finished fast, while at 3000 K, this reaction completed much more quickly; and moreover, the Cu atoms migrate into the aluminum oxide. The present molecular-dynamics study may provide new insight into understanding the reactive properties and characters of fast thermite reaction in atomic details.
  • Low temperature growth of polycrystalline InN films on non-crystalline
           substrates by plasma-enhanced atomic layer deposition
    • Abstract: Publication date: 30 November 2018Source: Applied Surface Science, Volume 459Author(s): Hong Peng, Xingcan Feng, Jinhui Gong, Wei Wang, Hu Liu, Zhijue Quan, Shuan Pan, Li WangIndium nitride (InN) has attracted much attention due to its high electron mobility and peak electron velocity, which make it suitable for fabrication of high-speed electronic devices. In this work, we report the low temperature growth of polycrystalline InN on non-crystalline substrates by plasma-enhanced atomic layer deposition (PE-ALD). InN thin film is amorphous in nature during the initial growth stage. With the increasing growth cycles, the starting nuclei compete for space respectively and select orientations of crystal. After about 800–1200 cycles, the nuclei will grow on the suitable planes and the film turn into polycrystalline. The amorphous to polycrystalline transition of InN film is revealed definitively by the evolution of XRD patterns and the intensity of diffraction peaks with the growth cycles.Graphical abstractGraphical abstract for this article
  • Tailoring properties of nanostructured MoO3−x thin films by aqueous
           solution deposition
    • Abstract: Publication date: 30 November 2018Source: Applied Surface Science, Volume 459Author(s): Katherine Inzani, Mohammadreza Nematollahi, Sverre M. Selbach, Tor Grande, Magnus Langøien Waalekalv, Thomas Brakstad, Turid Worren Reenaas, Morten Kildemo, Fride Vullum-BruerAbstractMolybdenum oxide films are required for a large range of optical, electronic and catalytic applications, and optimal film characteristics are similarly broad. Furthermore, the layered crystal structure of MoO3 is suited to nanostructuring, which can be adapted to enhance the film properties. Here, we present a simple, aqueous route to MoO3 thin films and attain nanostructured morphologies by control of solution parameters. Smooth and homogeneous thin films were achieved by control of the molecular species in solution by pH. The sensitivity of film quality to pH was demonstrated with the addition of PVA to the solution, which resulted in large spherical particulates on the surface. Film thickness was adjusted from 10 to 60 nm, whilst maintaining good film quality, by changing the solution concentration. Moreover, the grain size and nanocrystallite orientation varied with solution concentration. The importance of film morphology is revealed in the compositional changes of the films during hydrogen reduction, with differences in breakdown of film coverage and growth of reduced phases. Furthermore, spectroscopic ellipsometry was used to determine the optical properties of the films. This revealed changes in the dielectric function and band gap that were dependent on the level of reduction. The nanoscale morphologies presented demonstrate the potential to precisely control film morphology, dimensions, oxygen stoichiometry and phase composition by a low-cost wet chemical route.
  • Steering reduction and decomposition of peroxide compounds by interface
           interactions between MgO thin film and transition-metal support
    • Abstract: Publication date: 30 November 2018Source: Applied Surface Science, Volume 459Author(s): Zhenjun Song, Bin Zhao, Qiang Wang, Peng ChengThe detection, removal and reduction of hydrogen peroxide and organic peroxides is of significant importance for its increasing application in the areas of environment, food, electrochemistry and clinical laboratory. Herein the dissociative adsorption behavior of H2O2 and organic peroxides on ultrathin magnesia (0 0 1) films deposited on transition metal is uncovered for the first time by employing periodic density-functional theory calculations with van der Waals corrections. Splitting of H2O2 on bulk MgO(0 0 1) is highly endothermic process with activation barrier 1.85 eV, indicating it is extraordinarily difficult to dissociate H2O2 on pristine MgO(0 0 1). The H2O2 is dissociated smoothly and reduced to surface hydroxyls on MgO(0 0 1)/TM, and the dissociative adsorption energies of all the considered fragmentation configurations are substantially negative, demonstrating dissociation and reduction of H2O2 is thermodynamically favorable. The mechanism of reactivity enhancement for energetically and dynamically favorable decomposition of H2O2 on supported magnesia is elucidated by characterizing the geometric structures and electronic properties. The fragmentation and reduction of diethyl peroxide and peroxyacetone are also studied to reveal the catalytic activity of ultrathin magnesia toward splitting organic peroxides. The results are wished to provide useful clue for detecting and reducing hydrogen peroxide and organic peroxides by employing oxide-metal hybrid nanostructure.Graphical abstractDecomposition and reduction of hydrogen peroxide and organic peroxides on bulk MgO(0 0 1) and single crystalline MgO(0 0 1) films grown on TM substrates has been exploited systematically for the first time.Graphical abstract for this article
  • A novel natural SERS system for crystal violet detection based on graphene
           oxide wrapped Ag micro-islands substrate fabricated from Lotus leaf as a
    • Abstract: Publication date: 30 November 2018Source: Applied Surface Science, Volume 459Author(s): Guochao Shi, Mingli Wang, Yanying Zhu, Yuhong Wang, Haijun XuA stable biomimetic surface enhanced Raman scattering (SERS) system was fabricated by covering graphene oxide (GO) on the Ag micro-islands substrate using micro/nanostructured Lotus leaf (L.l.) as a template via the simple magnetron sputtering system and dip-coated method. The Raman signals of crystal violet (CV) on the GO-Ag-L.l.-30 substrate (the sputtering time was 30 min) showed far better SERS performances than Ag-L.l.-30 hybrids in terms of signal enhancement, sensitivity and stability. The results suggested that the SERS activity of the bio-inspired GO-Ag-L.l.-30 substrate using CV as probe molecules showed an enhancement factor (EF) of ∼1.52 × 106. Sensitivity tests indicated that the limit of detection (LOD) for CV was as low as 5 × 10−10 M, which was two orders of magnitude lower than Ag-L.l.-30 substrate. Time-stability for 30 days was also reported which revealed that the Raman intensity of CV on GO-Ag-L.l.-30 substrate only reduced by 18.2% after aging for 30 days. Moreover, the maximum relative standard deviations (RSD) of Raman intensities was less than 7.09%, demonstrating outstanding reproducibility and uniformity of GO-Ag-L.l.-30 substrate. Therefore, the cost-efficient and high-performance SERS system shows great application prospects in biochemical sensing and attracts broad attention to many other natural materials which can be prepared as multifarious novel SERS systems.Graphical abstractGraphical abstract for this article
  • Controlled surface/interface structure and spin enabled superior
           properties and biocompatibility of cobalt ferrite nanoparticles
    • Abstract: Publication date: 30 November 2018Source: Applied Surface Science, Volume 459Author(s): Sumayya M. Ansari, Bhavesh B. Sinha, Kalpana R. Pai, Suresh K. Bhat, Yuan-Ron Ma, Debasis Sen, Yesh D. Kolekar, C.V. RamanaAbstractHigh quality, crystalline, well-dispersed, and stable magnetic oxide nanoparticles (NPs) of inverse spinel cobalt ferrite (CoFe2O4; CFO) were prepared by a facile, reproducible, and simple hydrothermal route. The transmission electron microscopy, small-angle scattering and X-ray diffraction analyses demonstrate the structural quality of CFO NPs with a controlled size of ∼12 nm. Small-angle scattering experiments demonstrate that the pristine CFO NPs have the individual size ∼8.5 nm and spherical shape. The Raman and infrared spectroscopic measurements further confirm their high chemical quality and cubic symmetry. CFO NPs exhibit a remarkable, maximum coercivity (HC) value of 18.92 kOe, which is the highest value achieved to date. Surface spins and spins canting along with a weak dipolar interaction accounts for the giant HC and large effective anisotropy (11.45 × 106 erg/cm3) of these CFO NPs. The magnetic grain size of NPs reveals that the canted surface spins exist around the magnetic particles. Reorientation of surface spins and interparticle interaction causes the jumping behaviour in M-H hysteresis loops at H = 0. The cell viability of CFO NPs against the cancer (cisplatin resistant ovarian cancer – A2780/CP70) was evaluated to determine their potential application in biomedicine and health science. The mild response of CFO NPs in terms of their anti-proliferative nature against cancer cells and negligible cytotoxicity suggests their human-safe-and-friendly nature which makes them suitable for biomedical/health-related applications. Assessment of toxicity toward human red blood cells (RBC) revealed that hemolysis is less than 5% compared to the positive control confirming the potential applications of CFO NPs targeting human cells and making relevant for adopting them in biomedicine.
  • Generating more Mn4+ ions on surface of nonstoichiometric MnO2 nanorods
           via microwave heating for improved oxygen electroreduction
    • Abstract: Publication date: 30 November 2018Source: Applied Surface Science, Volume 459Author(s): Kebin Xu, Xiuxia Lin, Xiufang Wang, Ligui Li, Zaisheng Zhu, Yong TianCatalytic activities of transition metal oxides are usually influenced by their surface states. Herein, microwave heating is exploited as a fast and economic alternative approach to conventional postsynthesis calcination to effectively tune the surface states of nonstoichiometric MnO2 nanorods. After heating with microwave for 30 min, although the crystalline phase and morphology of nonstoichiometric MnO2 nanorods are largely reserved, the content of high-valent Mn cations, i.e. Mn4+, on the surface of nonstoichiometric MnO2 is maximized, which leads to a remarkably reduced charge transfer resistance for ORR, and the corresponding catalytic activity of oxygen reduction reaction (ORR) is markedly enhanced and becomes close to that of commercial Pt/C catalyst, within the context of onset potential, diffusion-limiting current density and average electron transfer number. The present work not only enriches the way to tune the ORR activity of catalysts, but also provides a deeper insight into the influence of surface state on electrochemically catalytic activity of manganese oxides.Graphical abstractGraphical abstract for this article
  • Electrodeposited Mo-doped WO3 film with large optical modulation and high
           areal capacitance toward electrochromic energy-storage applications
    • Abstract: Publication date: 30 November 2018Source: Applied Surface Science, Volume 459Author(s): Sijie Xie, Zhijie Bi, Yongbo Chen, Xiaoli He, Xiangxin Guo, Xiangdong Gao, Xiaomin LiAmorphous Mo-doped WO3 films are successfully synthesized via an electrodeposition method. In comparison with the reported time-consuming and costly techniques involving heating or vacuuming steps, the proposed electrodeposition method achieves the preparation of Mo-doped WO3 in a simple and economic all-solution route. By optimizing the dopant concentration of Mo, the as-prepared 2 at% Mo-doped WO3 film exhibits excellent electrochromic and energy-storage properties with large optical modulation of 83.3% at 633 nm and high pseudocapacitance of 117.1 mF cm−2 (334.6 mF g−1), greatly superior to those of pure WO3 films. These great electrochemical properties could be attributed to the amorphous state and the proper structure distortion caused by doped atoms. Furthermore, bifunctional devices on various substrates contained the 2 at% Mo-doped WO3 films are demonstrated with satisfactory electrochromic and energy-storage properties as well, indicating the practical applications of the Mo-doped WO3 films in both energy-saving and energy-storage fields.Graphical abstractGraphical abstract for this article
  • Capacitive deionization from reconstruction of NiCoAl-mixed metal oxide
           film electrode based on the “memory effect”
    • Abstract: Publication date: 30 November 2018Source: Applied Surface Science, Volume 459Author(s): Chengzhi Hu, Ting Wang, Jingjing Dong, Ruiping Liu, Huijuan Liu, Jiuhui QuThe ternary-component NiCoAl-mixed metal oxides (NiCoAl-MMOs), which are expected to have a high capacitance, were successfully prepared as film electrode for capacitive deionization (CDI). Hexagonal NiCoAl-MMOs nanoplatelets with a lateral size between 250 and 400 nm densely covered the surface of the nickel foam substrate. With the optimal Ni/Co/Al ratio (1.5:1.5:1), NiCoAl-MMOs displayed a more well-distributed surface, better crystallinity, and higher specific surface area, while the Ni/Co/Al ratio of 1.5:1.5:1 was also optimal for the NiCoAl-MMOs film electrodes to achieve maximum capacitance of 1167 F/g. The NiCoAl-MMOs film electrodes possessed ideal pseudocapacitive behavior and good capacitive reversibility, and showed outstanding performance in CDI from the concomitant reconstruction of the layered double hydroxides by intercalating anions. The desalination capacity of the NiCoAl-MMOs film electrodes was 108.8 mg NaCl/g, which was significantly higher than that of binary-component NiAl-MMOs and carbon-based electrodes. The NiCoAl-MMOs electrodes were quickly regenerated by reversing the voltage, with a desorption rate of 81.36%. The electrosorption capacity was about 2.5 times higher than that of adsorption without bias, indicating that the intercalation of ions into NiCoAl-MMOs nanoplatelets was enhanced by applying an electric field. NiCoAl-MMOs showed great promise as a CDI electrode in desalination.Graphical abstractGraphical abstract for this article
  • Self-assembly behavior of amphiphilic poly(ethylene glycol)-conjugated
           10-hydroxycamptothecin in water and its cytotoxicity assay
    • Abstract: Publication date: 30 November 2018Source: Applied Surface Science, Volume 459Author(s): Yongfang Zhang, Xiaoxia Yang, Zhenning Lu, Haiping Li, Xiuli Guo, Wanguo HouA PEGylated 10-hydroxycamptothecin (HCPT) conjugate, an amphiphilic prodrug, in which two hydrophobic HCPT molecules were conjugated to the two ends of a hydrophilic poly(ethylene glycol) bis(carboxymethyl) ether (PEG-biCOOH) molecule, was synthesized by esterification of the terminal carboxylic groups of PEG-biCOOH and the 10-OH groups of HCPT molecules. The obtained conjugate, denoted as PEG-bi(COO-HCPT), was characterized using NMR, MALDI-TOF MS, HPLC, elemental analyses, FT-IR, and UV–Vis spectroscopy. Especially, the surface activity and self-assembly behavior of the amphiphilic conjugate in water were examined using equilibrium surface tension and fluorescence techniques. The prodrug exhibits a high drug content of ∼52.7 wt% and the significantly enhanced water-solubility of HCPT from ∼1.41 μmol/L to ∼2.04 mmol/L. The PEG-bi(COO-HCPT) in water can self-assemble into vesicles with ∼130 nm in size at a concentration higher than ∼23 μmol/L, as evidenced using negative-staining, freeze-fracture, and cryogenic TEM, AFM, conductivity, fluorescence, and dynamic light scattering techniques. Furthermore, the cytotoxicity of the prodrug was evaluated against A549 non-small cell lung cancer (NSCLC) cells (Sensitive cells), human hepatoma (HepG2) cells (Non-sensitive cells), human umbilical vein endothelial cells (HUVEC, Normal cells), showing excellently improved cytotoxicity in comparison with pristine HCPT. This work provides a better understanding of self-assembly behavior of amphiphilic prodrugs in solutions and demonstrates that PEGylation of HCPT might be one of the promising strategies to improve its therapeutic efficacy.Graphical abstractA PEGylated 10-hydroxycamptothecin (HCPT) conjugate with a high drug content of 52.7 wt% was synthesized, which can self-assemble into vesicles in water and significantly enhance the water-solubility and cytotoxicity of HCPT.Graphical abstract for this article
  • A molecular dynamics study on the dependence of phase behaviors and
           structural properties of two-dimensional interfacial monolayer on surface
    • Abstract: Publication date: 30 November 2018Source: Applied Surface Science, Volume 459Author(s): Yaoyao Wei, Honglei Wang, Qiying Xia, Shiling YuanAbstractThe packing state and structure of monolayer at the air/water interface have important effect on its wide application. Using molecular dynamics (MD) simulation, phase transitions of sodium dodecyl sulfate (SDS) monolayer, dependent on the surface area per molecule, have been studied in the view of configuration entropy. With the reduction of surface area per molecule, three two-dimensional (2D) phases are defined, including gaseous, liquid expanded and liquid condensed phases. At small surface area per molecule, the 2D monolayer will collapse and 3D aggregates are formed in the bulk solution. We give a detailed description of the collapse mode from interfacial monolayer at the air/water interface to micelle in the solution at the molecular level. Using the quasi-harmonic (QH) approximation, the entropic change of SDS for 2D phase transition are first introduced, which is around −29.7 J mol−1 K−1 for the transition from 2D gaseous film to 2D liquid expanded film and −42.0 J mol−1 K−1 for the transition from 2D liquid expanded film to 2D liquid condensed film. The effect of different surface coverages on the dynamical and structural properties of SDS monolayer at the air/water interface is evaluated. Based on simulated results, a schematic diagram of 2D monolayer in different phases is proposed.
  • Efficient assembly of high-performance reduced graphene oxide/silver
           nanowire transparent conductive film based on in situ light-induced
           reduction technology
    • Abstract: Publication date: 30 November 2018Source: Applied Surface Science, Volume 459Author(s): Lingying Li, Wanli Li, Jinting Jiu, Katsuaki SuganumaSilver nanowires (AgNWs) show great potential in the fabrication of high-flexible transparent conductive films (TCFs) and reduced graphene oxide (rGO) has been considered as one of the most promising overcoating materials for improving the long-term stability of AgNW TCFs. However, transmittance, conductivity, and flexibility of AgNW TCFs are often compromised during the assembly of rGO film. Herein, a highly efficient process of preparing a high-performance and highly stable AgNW TCF is proposed. Firstly, a water-based, self-assembled coating method is used to achieve GO/AgNW TCFs. Then, the light absorption property of AgNWs is utilized to assist the reduction of the graphene oxide (GO) layer through the use of a microsecond intense pulsed light (IPL) irradiation treatment, resulting in a high-performance rGO/AgNW TCF. The instantaneous high-temperature rising from AgNWs provides additional and abundant thermal energy during the irradiation to reduce the ultra-thin GO film without damage to the nanostructure of the GO layer or to the AgNW TCFs itself. The achieved rGO/AgNW TCFs have a low sheet resistance to 8 Ω/sq and a high transmittance of 86.2% owing to the in-situ reduction of rGO film from thin GO film and welding between the AgNWs. In addition, this technique presents a robust enhancement of AgNW TCFs, not only with regard to their electrical stability in high-temperature and high-humidity atmospheres but also to their overall mechanical stability, which significantly enhances the application prospects of AgNW TCFs for use in flexible optoelectronic devices.Graphical abstractGraphical abstract for this article
  • Implementation of AFM tip-based nanoscratching process on single crystal
           copper: Study of material removal state
    • Abstract: Publication date: 30 November 2018Source: Applied Surface Science, Volume 459Author(s): Yongda Yan, Jiqiang Wang, Yanquan Geng, Zhuo Fang, Yang HeThe material removal state, which is closely related to machining quality, is an important factor in any machining process. During the machining using a non-rotational symmetric cutting tool, scratching direction manifests significant influence on the material removal state. In the present study, the relationship between material removal mode and scratching direction was investigated during the nanoscratching process on single crystal copper using an atomic force microscopy (AFM) tip. Considering the installation angle of the cantilever and the height of pile-up, a theoretical model was developed to relate machining depth with normal load for the machining of a single groove. Experimental results revealed that the theoretical normal load model was more suitable when materials were expelled in constant chip formation with small pile-ups. In addition, based on the scratching tests in different directions, the critical included cutting angle determined whether materials were expelled in chip formation or not. The height of pile-up was also influenced by the included cutting angle during the scratching in face-forward direction; however, during the machining in edge-forward direction, the distance between the cutting swept faces formed by the lateral and front edges determined the height of pile-up. Finally, an optimal machining direction is selected based on the quality of the machined grooves, which can be used in the potential application.Graphical abstractGraphical abstract for this article
  • Design and synthesis of surface-controlled CuOx/rGO nanocomposites with
           unusually high efficiency in catalytic conversion of organic reactants in
           the presence of NaBH4
    • Abstract: Publication date: 30 November 2018Source: Applied Surface Science, Volume 459Author(s): Xu Liang, Xiaowen Chen, Zhiling Xiang, Rui Yan, Hui Xi, Ting Bian, Jingjia Zhang, Jingxiang Zhao, Qinghai Cai, Hongxia WangAbstractSurface-controlled CuOx/rGO nanocomposite has been successfully fabricated in this study using a simple hydrothermal method. In addition to the characterization by X-ray diffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and N2 adsorption/desorption, the catalytic conversions of 4-nitrophenol (4-NP), methylene blue (MB) or rhodamine B by the CuOx/rGO nanocomposite in the presence of NaBH4 were carried out. The results demonstrate that all the selected probe reactants show no adsorption on the as-prepared CuOx/rGO nanocomposite, however, their conversions are close to 100% and can be carried out within several minutes. The excellent catalytic activities may be associated with the multi-valenced copper species and the controlled surface of the CuOx/rGO nanocomposite. In the meantime, the CuOx/rGO nanocomposite has a better stability and can be reused for many times without obvious decrease in activity, suggesting a great potential of the as-prepared CuOx/rGO nanocomposite for catalytic degradation of organic pollutants.
  • Cu nanoparticles encapsulated with hollow carbon spheres for methanol
           oxidative carbonylation: Tuning of the catalytic properties by particle
           size control
    • Abstract: Publication date: 30 November 2018Source: Applied Surface Science, Volume 459Author(s): Ruina Shi, Juan Wang, Jinxian Zhao, Shusen Liu, Panpan Hao, Zhong Li, Jun RenCu nanoparticles (NPs) encapsulated within a hollow carbon spheres (Cu@HCS) is an effective catalyst with optimal structural design for the oxidative carbonylation of methanol to dimethyl carbonate (DMC). Control of the structural properties of both the shell and the core plays a vital role in determining the catalytic properties. In this study, mesoporous HCS with an average diameter of 190 nm and a shell thickness of 15 nm were obtained using silica micropheres as a hard template and by tuning the amount of resorcinol and formaldehyde. Cu@HCS catalysts were fabricated by hydrothermal impregnation followed by hydrogen reduction, and the size of Cu NPs was delicately controlled by varying heating rate of reduction process. The results show that a thin mesoporous carbon shell of Cu@HCS is beneficial to the diffusion of reactants and products, and that Cu NPs with very small size can provide a large active specific surface area. In comparison with the commercial CuCl catalyst, the Cu@HCS-5 catalyst displays superior catalytic activity; its turnover frequency and apparent activation energy reaches 23.1 h−1 and 20.5 kJ·mol−1, respectively. In addition, it exhibits higher stability than that of CuCl because the carbon shell prevents the aggregation and leaching of copper NPs during the reaction. With the advantages in catalytic activity, corrosion effect, and recovery performance, the Cu@HCS catalyst has a promising potential for realizing the cleaner production of DMC.Graphical abstractGraphical abstract for this article
  • Study of sputtered Cu2ZnSnS4 thin films on Si
    • Abstract: Publication date: 30 November 2018Source: Applied Surface Science, Volume 459Author(s): Ning Song, Martin A. Green, Jialiang Huang, Yicong Hu, Xiaojing HaoAbstractIntegrating commercialized Si solar cells with eco-friendly and earth-abundant Cu2ZnSnS4 (CZTS) film is a promising method to increase power conversion efficiency and hence reduce the levelized cost of electricity. However, synthesis of CZTS thin film on Si as well as the study of the interaction between the two materials, which are crucial for good performance of CZTS/Si two-terminal devices, are areas that have been less investigated. Here, we grow polycrystalline CZTS thin films on Si (1 0 0) substrate by sputtering and study the properties of the CZTS thin film and interface between the CZTS and Si. The CZTS shows uniform microstructure and optimal optical properties. A CZTS solar cell which is fabricated on Si shows a photovoltaic response although subjected to high serious resistance, and Cu diffusion was found from CZTS into Si, which caused needle-like dislocations in Si. Therefore, an effective conductive barrier layer between CZTS and Si is desirable to inhibit Cu from diffusing into Si for tandem solar cell purposes. The study offers valuable input for understanding the properties of CZTS thin film sputtered from single target sputtering and the impact on the interfaces and underlying Si, suggesting concerns that manufacturers need to be aware of for its application in tandem solar cells based on Si.
  • Adsorption and dissociation of CH4 on graphene: A density
           functional theory study
    • Abstract: Publication date: 30 November 2018Source: Applied Surface Science, Volume 459Author(s): Kun Li, Hejun Li, Ningning Yan, Tiyuan Wang, Zhigang ZhaoTo investigate the mechanism of the heterogenous reactions during the Chemical vapor infiltration (CVI) process of carbon/carbon composites, the dissociation of CH4 on graphene was calculated by density functional theory (DFT). Graphene was used as the adsorption surface in the course of the heterogenous reactions. Based on the energy analysis, the preferred adsorption sites of CHx(x = 0–4) and H on graphene were obtained. Then, the stable co-adsorption configurations of CHx/H(x = 0–3) on graphene were located. The calculation results show that CH4, CH3 and H prefer to be adsorbed at the top of a carbon atom of graphene, while CH2, CH and C are favorable on the midpoint of a CC bond of graphene. Transition state (TS) calculation shows that the dissociation of CH4 into CH3 and H is a rate-determining step. Additionally, by comparing the dissociation of CH3 into CH2 and H and the formation of C2H6 during the dissociation of CH4, it is obvious that the CH3 groups are more likely to produce ethane rather than dissociating into CH2 and H.Graphical abstractGraphical abstract for this article
  • Ratiometric fluorescence detection of phosphate in human serum with a
           metal-organic frameworks-based nanocomposite and its immobilized agarose
    • Abstract: Publication date: 30 November 2018Source: Applied Surface Science, Volume 459Author(s): Nan Gao, Jian Huang, Liyuan Wang, Jiayu Feng, Pengcheng Huang, Fangying WuWe report a metal-organic frameworks (MOFs)-based nanocomposite by incorporating a fluorescent dye, rhodamine B (RhB), into a stable Zr-based MOF, UiO-66-NH2. Based on weakened the LMCT process resulted from the strong binding of phosphate with Zr-O node in UiO-66-NH2 and the unchangable fluorescence of RhB as the reference, this nanocomposite can be employed as a novel fluorescent sensing platform for ratiometric detection of phosphate in the range from 80 to 400 µM with a detection limit of 2.0 µM. It is particularly suitable for accurate quantification of phosphate in complex samples like human serum. Furthermore, this sensing platform is well recyclable due to reversible interaction with phosphate. Finally, this nanocomposite was encapsulated into agarose hydrogels for direct detection of phosphate in human serum with the naked eye. Thanks to the robust, portable, and instrument-free characteristics, it is expected to show great potential for on-site clinical diagnosis.Graphical abstractGraphical abstract for this article
  • Tailoring surface and structural properties of composite materials by
           coupling Pt-decorated graphene oxide and ZIF-8-derived carbon
    • Abstract: Publication date: 30 November 2018Source: Applied Surface Science, Volume 459Author(s): Barbara Szczęśniak, Jerzy Choma, Mietek JaroniecUltrasonication is used to obtain new nanoporous composites consisting of Pt-decorated graphene oxide (Pt-GO) and zeolitic imidazolate framework (ZIF-8)-derived carbon with improved surface and structural properties as evidenced by high hydrogen uptake of 0.44 mmol/g at 25 °C and 1 bar. At the same conditions, the bare ZIF-8-derived carbon (CZIF-8) and ZIF-8 showed hydrogen uptakes of 0.13 mmol/g and 0.05 mmol/g, respectively. This significant enhancement in hydrogen adsorption on Pt-GO/CZIF-8 is attributed to spillover mechanism. Moreover, adsorption affinity of CZIF-8 toward diverse gases is examined. CZIF-8 adsorbed larger amounts of CH4 (1.8 mmol/g at 20 °C), CO2 (5.7 mmol/g at 0 °C) and H2 (9.9 mmol/g at cryogenic temperature) at 1 bar in comparison to those obtained for parent ZIF-8. This study shows that the ultrasonication-assisted coupling of Pt-GO and MOF-derived carbons can be used for fabrication of composites with tailored surface and structural properties for adsorption, catalytic and photocatalytic applications.Graphical abstractGraphical abstract for this article
  • Observing the evolution of regular nanostructured indium phosphide after
           gas cluster ion beam etching
    • Abstract: Publication date: 30 November 2018Source: Applied Surface Science, Volume 459Author(s): Anders J. Barlow, Naoko Sano, Billy J. Murdoch, Jose F. Portoles, Paul J. Pigram, Peter J. CumpsonIndium phosphide (InP) surfaces develop a pronounced nanostructured texture upon irradiation by energetic ion beams. We have observed the mechanism of nanostructure evolution of InP under irradiation by an Ar gas cluster ion beam (GCIB) using helium ion microscopy (HIM). Initially, metallic indium nanoparticles form on the surface after removal of the top-most oxide layer. These nanoparticles form a mask which shadows the underlying InP. As the ion dose is increased, the masking effect results in substantial nanostructured topography in the form of pillars or nanocones, oriented along the axis of the incident GCIB. The surface sensitivity and high resolution of the HIM facilitates the direct observation of the metallic indium cap at the top of the pillars.Graphical abstractGraphical abstract for this article
  • The microstructural evolution of chemical disorder and ferromagnetism in
           He+ irradiated FePt3 films
    • Abstract: Publication date: 30 November 2018Source: Applied Surface Science, Volume 459Author(s): Grace L. Causer, Hanliang Zhu, Joel Davis, Mihail Ionescu, Gary J. Mankey, Xiaolin L. Wang, Frank KloseAbstractThis paper investigates the role of ion-induced disorder on the morphology and magnetic properties of chemically ordered FePt3 films. The effects are studied for 15 keV He+ ions as a function of the ion fluence for 0, 2 × 1016 and 2 × 1017 ions cm−2. Substitutional mixing of the L12-type Fe-Pt sites takes place within the region of the chemically ordered FePt3 film affected by the irradiation. This accompanies a paramagnetic-to-ferromagnetic transition, as determined by room-temperature magnetometry. Dark-field transmission electron microscopy (TEM) measurements confirm that the 15 keV He+ ions induce a 120 nm-thick chemically disordered layer into the sub-surface region of the nominally 280 nm-thick ordered FePt3 film. The average domain size and the fractional density of the chemically ordered domains within the irradiated FePt3 microstructure are found to mutually decrease with increasing ion fluence. Selected-area electron diffraction results demonstrate that the film’s single crystallinity is preserved after irradiation, irrespective of the ion fluence. High-resolution TEM elucidates the coexistence of ordered domains and precipitate disordered domains in the near-surface, low-ion impacted regions of the FePt3 film. Collectively, this work provides detailed insights into the material-science relationship between ion-induced disorder and ferromagnetism in FePt3, as a step towards creating fully customisable, ion-beam-synthesised magnetic nano-elements.
  • Hierarchical Co2P microspheres assembled from nanorods grown on reduced
           graphene oxide as anode material for Lithium-ion batteries
    • Abstract: Publication date: 30 November 2018Source: Applied Surface Science, Volume 459Author(s): Chi Zhang, Guanghua Jiao, Fanjun Kong, Jian Wang, Shi Tao, Lei Zhang, Bin Qian, Yimin ChaoTransition metal phosphides (TMPs) have been studied as promising electrodes for energy storage and conversion due to their large theoretical capacities and high activities. Herein, a hierarchically structured Co2P coupling with the reduced graphene oxide (RGO) composite (Co2P/RGO) was synthesized by a simple solid state method for Li storage. The Co2P/RGO hybrid composite exhibits a high reversible capacity of 61 mAh g−1 at 60 mA g−1, good rate capability of 327 mAh g−1 at 3000 mA g−1 and long cycle life (397 mAh g−1 at 500 mA g−1 for after 1000 cycles). The excellent electrochemical performance can be attributed to the synergistic effect of Co2P micro/nano architecture and graphene modulation, which provide more activity sites for Li+-ions and maintain the structural integrity of active material. This work may provide a new path for preparation of other metal phosphides as potential electrode materials for application in energy storage fields.Graphical abstractReduced graphene oxides (RGO) decorating Co2P microspheres with hierarchically structure are synthesized, using a simple solid-state method. The hybrids with small Co2P nanorods are well incorporated with RGO. Such unique micro/nano structure can effectively provide more contact between Co2P nanoparticles each other and alleviate the volume expansion and enhance the electrochemical performance.Graphical abstract for this article
  • Porous carbon materials based on biomass for acetone adsorption: Effect of
           surface chemistry and porous structure
    • Abstract: Publication date: 30 November 2018Source: Applied Surface Science, Volume 459Author(s): Xiancheng Ma, Liqing Li, Ruofei Chen, Chunhao Wang, Ke Zhou, Hailong LiThe relative influence of porous structure and functional groups of porous carbon materials for acetone adsorption is presented in this article. Here, we have successfully prepared oxygen and nitrogen doping porous carbons (ONPCs) by a hydrothermal method using waste tobacco stem as the carbon precursor and ethylenediamine as a nitrogen source. The resulting ONPCs have high specific surface (906–2940 m2 g−1) and chemical compositions (1.80–5.22% N and 5.81–11.77% O). This carbon shows high acetone adsorption capacity (i.e., 16.91 mmol g−1 at 25 °C and 18 kPa). The pore volume and specific surface area of ONPCs were found to be determinative factors for acetone adsorption at high pressure, and the introduction of oxygen and nitrogen into carbon surface can improve acetone adsorption at low pressure. Molecular simulations results suggest that adsorption capacity of acetone is improved at low pressure after doping of oxygen and nitrogen functional groups, but equilibrium adsorption capacity is unchanged. This is in good agreement with the experimental results that these functional groups are primarily responsible for the materials’ low-pressure acetone adsorption capacity. This work provides insights into material design and further development for acetone adsorption.Graphical abstractGraphical abstract for this article
  • Basalt fiber fabric synergistically decorated by MnO2 nanosheets/stearic
           acid for the enhancement of oil-recovery and anti-icing behavior
    • Abstract: Publication date: 30 November 2018Source: Applied Surface Science, Volume 459Author(s): Xinshan Rong, Lu Zhang, Xiaoying Zhang, Jian Rong, Xiangtong Zhou, Haifei Chen, Shuang Liu, Fengxian Qiu, Zhiren WuCross-weaved basalt fiber fabric (CBFF) woven from basalt fiber (BF), as a natural inorganic product, which presented a highly research value and widely application field, due to its high chemical stability, non-toxic, non-combustible and sound mechanical property. (Super)hydrophobic surface has recently received extraordinary attention, focusing both on novel preparation-used materials and application. In this work, cross-weaved basalt fiber fabric was synergistically decorated by MnO2 nanosheets/stearic acid (SA) and the superhydrophobic inorganic/organic composite (CBFF@MnO2/SA) was obtained by hydrothermal processes. MnO2 nanosheets self-assembled on the surface of CBFF (CBFF@MnO2) presented honeycomb roughness with the micro/nanometer-sized spaces among the MnO2 nanosheets. The water contact angles of CBFF, CBFF@MnO2 and CBFF@MnO2/SA samples were 21.6, 120.0 and 155.5°, respectively. The result indicated that cross-weaved basalt fiber fabric exhibited an obvious superhydrophobic property after the modification by MnO2 nanosheets and stearic acid. The as-prepared materials were applied in the simulation of oil/water separation and anti-icing process. Oil/water separation results not only displayed the separation efficiency up 95.0% by selective absorption for light oil/water system, but also showed the separation efficiency above 97.2% by filtration of oil for heavy oil/water system. Furthermore, CBFF@MnO2/SA could be used as the filter membrane in dynamic suction filtration device for oil recovery in oil spill accidents. Anti-icing experiments demonstrated that prepared CBFF@MnO2/SA had an obviously ice-over delay with the value of 166.6%.Graphical abstractA natural inorganic basalt fiber fabric exhibits the excellent superhydrophobic property in oil/water separation and anti-icing by surface modification.Graphical abstract for this article
  • The effects of tungsten and hydrothermal aging in promoting NH3-SCR
           activity on V2O5/WO3-TiO2 catalysts
    • Abstract: Publication date: 30 November 2018Source: Applied Surface Science, Volume 459Author(s): Hongfeng Chen, Yang Xia, Ruyi Fang, Hui Huang, Yongping Gan, Chu Liang, Jun Zhang, Wenkui Zhang, Xuesong LiuThe fresh catalysts of V2O5-TiO2 (VTi) and V2O5/WO3-TiO2 (VWTi) were prepared via an impregnation method. The hydrothermal aged samples were obtained at 750 °C for 24 h under airflow with 10 vol% water vapor. Compared to the fresh catalysts, the catalytic performance of the aged catalysts (VTi-A and VWTi-A) has been significantly improved. Particularly, VWTi-A displayed the best activity over a wide temperature range (NOx conversion:>90% @ 250–550 °C). Structural characterizations indicated that the surface area of the aged catalysts was dramatically decreased, and the morphologies of catalysts also changed. The X-ray photoelectron spectroscopy (XPS), H2 temperature-programmed reduction (H2-TPR), and Raman results demonstrated that hydrothermal aging greatly influenced the migration and agglomeration of vanadium species. As a result, numerous active polymeric VOx species were emerged on the surface of catalysts. More importantly, XPS results revealed that more low valence vanadium species (V4+ and V3+) was produced on the VWTi-A catalysts than that of VTi-A after hydrothermal aging. These low valence vanadium species resulted in considerably higher SCR activity than the high valence vanadium species (V5+). Consequently, both polymeric surface VOx species and low valence vanadium species determined the enhanced low-temperature SCR behavior of the aged catalysts.Graphical abstractThe formation mechanism of polymeric surface VOx and low valence vanadium on hydrothermal aged V2O5/WO3-TiO2 catalysts to improve the low temperature SCR activity.Graphical abstract for this article
  • Enhanced sensing performance and mechanism of CuO nanoparticle-loaded ZnO
           nanowires: Comparison with ZnO-CuO core-shell nanowires
    • Abstract: Publication date: 30 November 2018Source: Applied Surface Science, Volume 459Author(s): Kaidi Diao, Jia Xiao, Zhou Zheng, Xudong CuiAbstractThe synergism of nanocomposite heavily impacts the performance of gas sensing materials, that need to be systematically and deeply investigated to meet the high application requirement. In this work, we present gas sensors developed by ZnO-CuO core-shell nanowires (C-S NWs) and ZnO/CuO NWs (ZnO NWs modified by CuO nanoparticles) synthesized by a facile three-step process. The sensing performances for both structures were investigated toward the oxidizing gas NO2 and the reducing gas benzene. Results show that compared with pure ZnO NWs, ZnO/CuO NWs exhibits enhanced sensing performance and a n-type response behavior, while ZnO-CuO C-S NWs shows reduced sensing property and a p-type response behavior. The phenomenon is closely associated with the charge transfer at the p-n junctions contributing to adsorb the target gases for materials. Our study indicates that the construction method and their synergism are key factors to the effective design of gas sensors with MOS sensing materials.
  • Glass-on-LiNbO3 heterostructure formed via a two-step plasma activated
           low-temperature direct bonding method
    • Abstract: Publication date: 30 November 2018Source: Applied Surface Science, Volume 459Author(s): Jikai Xu, Chenxi Wang, Yanhong Tian, Bin Wu, Shang Wang, He ZhangLithium niobate (LiNbO3) crystal has been widely used in integrating optical and acoustic devices. However, direct bonding of LiNbO3 to Si-based materials is still a challenge due to the large coefficient of thermal expansion mismatches. In this paper, strong bonding strength of the LiNbO3/glass pair was obtained via the optimized O2 plasma activation followed by N2 plasma treatment. After the pre-bonding was accomplished at room temperature, the bonded pair was annealed at 150 °C for 12 h. A defect-free and tight bonding interface was confirmed by the scanning electron microscopy and transmission electron microscopy. Based on atomic force microscopy, water contact angle and X-ray photoelectron spectroscopy characterizations, both LiNbO3 and glass surfaces became smoother and more hydrophilic due to the densities of OH and N-related groups increased. Additionally, combined with the bonding strength obtained via different plasma activated processes, we demonstrated that the mechanism of the enhanced bonding strength could be attributed to N-related covalent bonds formed across the bonding interface. Furthermore, the excellent optical transmittance of LiNbO3/glass bonded pairs indicated this facile bonding process can meet the demand of high-performance glass-on-LiNbO3 devices.Graphical abstractGlass-on-LiNbO3 heterostructure was fabricated by the two-step plasma activated direct bonding at 150 °C.Graphical abstract for this article
  • Experimental and theoretical investigations of some pyrazolo-pyrimidine
           derivatives as corrosion inhibitors on copper in sulfuric acid solution
    • Abstract: Publication date: 30 November 2018Source: Applied Surface Science, Volume 459Author(s): Yue Xu, Shengtao Zhang, Wenpo Li, Lei Guo, Shenying Xu, Li Feng, Loutfy H. MadkourThe anticorrosion performance of three pyrazolo-pyrimidine derivatives, namely, 4-amino pyrazolo-pyrimidine (APP), 4-hydroxy pyrazolo-pyrimidine (HPP), and 4-mercapto pyrazolo-pyrimidine (MPP) on copper in 0.5 M H2SO4 solution have been investigated using electrochemical, surface analysis, as well as theoretical techniques. The results indicate that these inhibitors have largely inhibited the corrosion of copper and the inhibition efficiency increased with increasing concentration. Moreover, the inhibitors adsorb on copper surface following Langmuir adsorption isotherm. XPS analysis were performed for describing the bonding characteristics between inhibitors and copper substrate. Furthermore, DFT and molecular dynamics simulation calculations were applied to further explain the anti-corrosion mechanism.Graphical abstractGraphical abstract for this article
  • TiO2 nanoscale ionic materials using mussel adhesive proteins
           inspired ligand
    • Abstract: Publication date: 30 November 2018Source: Applied Surface Science, Volume 459Author(s): Junjie Wu, Dongdong Li, Huifang Zeng, Zhou Zhou, Shijia Yang, Ning Zhao, Jian XuInspired by mussel adhesive proteins, solvent-free nanoscale ionic materials (NIMs) were prepared using Tiron as bridging ligand, which could coordinate with titanium dioxide nanoparticles (TiO2 NPs) through ligand exchange, and then bridged with nonylphenyl poly(ethylene glycol) quaternary ammonium salt via ion exchange. The obtained homogenous TiO2-NIMs showed liquid-like behavior at room temperature. UV-visible and FT-IR spectra confirmed the coordination interaction between Tiron and TiO2 NPs. The size and crystal structure of TiO2 NPs were preserved during the modification. The well dispersion of NPs in the organic component, and the high content, low crystallization and melting temperature of the organic component guaranteed the unique properties of TiO2-NIMs. Moreover, TiO2-NIMs showed amphiphilic nature with good solubility and long-term stability in polar and nonpolar solvents. This research offers a useful and versatile approach to prepare NIMs and expands the gallery of bio-inspired materials.Graphical abstractGraphical abstract for this article
  • Low-temperature direct synthesis of high quality WS2 thin films by
           plasma-enhanced atomic layer deposition for energy related applications
    • Abstract: Publication date: 30 November 2018Source: Applied Surface Science, Volume 459Author(s): Seungmin Yeo, Dip K. Nandi, R. Rahul, Tae Hyun Kim, Bonggeun Shong, Yujin Jang, Jong-Seong Bae, Jeong Woo Han, Soo-Hyun Kim, Hyungjun KimTungsten disulfide (WS2) thin films are grown on several types of substrates by plasma-enhanced atomic layer deposition (PEALD) technique using tungsten hexacarbonyl [W(CO)6] and H2S plasma at a relatively low temperature of 350 °C. The method delivers polycrystalline WS2 film with (0 0 2) preferential growth and the high quality films could be successfully grown with as low as 30 ALD cycles (corresponding to ∼3 nm of thickness). Density functional theory (DFT) calculation results reveal that both adsorption of W(CO)6 and removal of CO ligand would be facilitated by usage of H2S plasma by generating the different defect sites on the basal plane. The typical self-limiting film growth (growth rate of ∼0.1 nm/cycle), characteristic of ideal ALD, is clearly observed with both the precursor and reactant pulsing time. X-ray diffractometry (XRD), Raman spectroscopy, transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and Rutherford backscattering spectrometry (RBS) are performed in details to study the as-grown WS2 film on Si/SiO2 substrate. The analysis results confirm the formation of polycrystalline film, with high purity and well-defined stoichiometry. The as-deposited WS2 films are then explored as an electrode in the field of energy generation as well as energy storage. The films are uniformly and conformally grown on high surface-area 3 dimensional Ni-foam that show excellent activity towards hydrogen evolution reaction (HER). Significantly low overpotential of ∼280 mV is observed at a high operational current density of 100 mA cm−2 during HER in acid electrolyte. In addition, the as-grown films on stainless steel substrate also reveal the stable electrochemical performances in Na-ion battery as an anode with reasonably high areal capacity of ∼44.5 μAh cm−2 at the end of 50 charge-discharge cycles.Graphical abstractGraphical abstract for this article
  • Rapid synthesis of MoS2-PDA-Ag nanocomposites as heterogeneous catalysts
           and antimicrobial agents via microwave irradiation
    • Abstract: Publication date: 30 November 2018Source: Applied Surface Science, Volume 459Author(s): Guangjian Zeng, Long Huang, Qiang Huang, Meiying Liu, Dazhuang Xu, Hongye Huang, Zhenyu Yang, Fengjie Deng, Xiaoyong Zhang, Yen WeiTwo dimensional nanomaterials have attracted great interest for diverse applications due to their unique structure feature, small size and high specific surface areas. Among them, the two-dimensional metal dichalcogenides have recently emerged as the outstanding ones for various applications ranged from biosensing, energy conversion and storage, and cancer photothermal treatment. In this work, a fast, facile and environmentally benign microwave irradiation method was developed to fabricate MoS2-PDA-Ag nanocomposites. To obtain MoS2-PDA-Ag nanocomposites, MoS2 nanosheets were first coated with polydopamine (PDA) films via self-polymerization of dopamine in alkaline aqueous solution. Then Ag nanoparticles were facilely deposed onto the surface of MoS2-PDA via in situ reduction by using microwave irradiation. Here, the PDA thin films were as the ad-layers for reduction and stabilizing the Ag nanoparticles simultaneously. The successful preparation of MoS2-PDA-Ag nanocomposites was characterized by means of transmission electron microscope, thermogravimetry analysis and X-ray photoelectron spectroscopy. We demonstrated that MoS2-PDA-Ag nanocomposites can be facilely fabricated via combination of mussel inspired chemistry and microwave irradiation. The resultant composites exhibited high catalytic activity towards 4-nitrophenol reduction and great antibacterial activity compared with pure MoS2 and MoS2-PDA.Graphical abstractGraphical abstract for this article
  • Anodic oxidation of Al/Ge/Al multilayer films
    • Abstract: Publication date: 30 November 2018Source: Applied Surface Science, Volume 459Author(s): A.N. Beltiukov, E.V. Stashkova, O.V. BoytsovaAbstractWe report the effect of an intermediate germanium layer on the process of anodic oxidation of an Al/Ge/Al multilayer film in oxalic acid solution and the morphology of the formed oxide membrane. The anodization of the upper and lower aluminum layers is performed in accordance with the classical mechanism of formation of porous anodic alumina and does not depend on the germanium layer. Whereas the anodization of the germanium layer is particularly sensitive to its structure and conductivity. In the case of amorphous germanium with low intrinsic conductivity, anodic dissolution of the layer is observed. A layer of porous germanium oxide is formed to occur from crystal germanium with high conductivity.
  • Template-free synthesis of biomass-derived carbon coated Li4Ti5O12
           microspheres as high performance anodes for lithium-ion batteries
    • Abstract: Publication date: 30 November 2018Source: Applied Surface Science, Volume 459Author(s): Keqiang Li, Yang Zhang, Yunong Sun, Yunlong Xu, Huang Zhang, Pan Ye, Mengdan Zheng, Nan Zhou, Di WangAbstractThe hierarchical Li4Ti5O12/C microspheres based on the waste biomass of phoenix tree leaf are synthesized as anodes for lithium-ion batteries. The phoenix tree leaf derived activated carbon (CPTL) are uniformly coated on the surface of acanthosphere-like Li4Ti5O12 (LTO) microspheres using a facial hydrothermal method to fabricate hierarchical porous structures with conductive interconnected 3D networks. Results show that the LTO-CPTL composite with 3 wt% carbon delivers the best electrochemical performance at both ambient and low temperatures with an initial discharge capacity of 212 mAh g−1 at 1 C and capacity retention of 95% after 500 cycles. The present study demonstrates a facile and cost-efficient way to fabricate high performance electrode materials for batteries.
  • Solution phase surface functionalization of PbS nanoparticles with organic
           ligands for single-step deposition of p-type layer of quantum dot solar
    • Abstract: Publication date: 30 November 2018Source: Applied Surface Science, Volume 459Author(s): Hossein Beygi, Seyed Abdolkarim Sajjadi, Abolfazl Babakhani, Jeff F. Young, Frank C.J.M. van VeggelSemiconducting p-type layers of heterojunction quantum dot solar cells (QDSCs) are often prepared by the layer-by-layer (LBL) method. Due to the intermittent nature of quantum dot (QD) deposition, solid-state ligand exchange and washing steps, the LBL process typically involves a high waste of materials and a relatively low surface quality of the applied layers. To introduce a simplified method for deposition of QD layer, this paper investigates the preparation of pre-exchanged QD inks for the single-step deposition of QD layers of QDSCs. Various pre-exchanged QD inks were prepared through the solution phase exchange of oleate ligands with organic ligands of different functional groups, chain lengths and chain structures. Oxidation and colloidal stability of the prepared inks during long-time air exposure storage were investigated by the means of UV–Vis-NIR spectroscopy, photoluminescence (PL) and zeta potential measurements. Transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier transform infrared (FT-IR), nuclear magnetic resonance (NMR) and combustion CHNS analyses were used to study the surface chemistry of the exchanged QDs and the mechanism of ligand exchange. Various inks of pre-exchanged QDs were deposited on different substrates in a single-step method. The best surface topography and the lowest oxidation rate were achieved for layers prepared by the single-step deposition of 3-mercaptopropionic acid (MPA)-capped QD ink. The QDSCs fabricated by such layers had higher efficiency than those fabricated by the common LBL method. Furthermore, annealing the MPA-capped QD layer increases the power conversion efficiency of the ink based solar cells up to 3.22% under simulated AM1.5 solar illuminations.Graphical abstractGraphical abstract for this article
  • Promoting sensitivity and selectivity of HCHO sensor based on strained
           InP3 monolayer: A DFT study
    • Abstract: Publication date: 30 November 2018Source: Applied Surface Science, Volume 459Author(s): Huiru Yang, Zeping Wang, Huaiyu Ye, Kai Zhang, Xianping Chen, Guoqi ZhangSensitive materials for formaldehyde (HCHO) sensor need high sensitivity and selectivity. The research on two dimensional (2D) sensitive material is growing, and most studies focus on the pristine or modified graphene. So it is essential to introduce other 2D materials into HCHO gas sensor. In this report, the adsorption behaviors of organic gas molecules including C2H6, C2H4, C2H2, C6H6, C2H5OH and HCHO over indium triphosphide (InP3) monolayer were studied by using first-principle atomistic simulations. The calculation results demonstrate that InP3 monolayer has a high sensitivity and selectivity to HCHO than others. By comparing the structures and adsorption results of InP3 monolayer, graphene and single-layered MoS2, it was found that the polarity bonds and steric effect of the site on monolayer play an important role in the detection of HCHO. The effect of strain on the gas/substrate adsorption systems was also studied, implying that the stained InP3 monolayer could enhance the sensitivity and selectivity to HCHO. This study provides useful insights into the gas-surface interaction that may assist future experimental development of 2D material for HCHO sensing and performance optimization based on strain.Graphical abstractInP3 monolayer is sensitive and selective to HCHO than graphene and MoS2, and its performance can be enhanced by applying strain.Graphical abstract for this article
  • One-step fabrication of β-cyclodextrin modified magnetic graphene oxide
           nanohybrids for adsorption of Pb(II), Cu(II) and methylene blue in aqueous
    • Abstract: Publication date: 30 November 2018Source: Applied Surface Science, Volume 459Author(s): Ying-Xia Ma, Wen-Jie Shao, Wen Sun, Ya-Lan Kou, Xin Li, Hai-Peng YangIn this study, using graphene oxide (GO) as carrier, ferrous sulfate heptahydrate (FeSO4·7H2O) and ferric chloride hexahydrate (FeCl3·6H2O) as iron sources, sodium hydroxide (NaOH) as precipitant, β-cyclodextrin (β-CD) as a modifier, β-cyclodextrin modified magnetic graphene oxide (β-CD/MGO) nanohybrids were fabricated by a simple one-step reverse phase co-precipitation method. The as-prepared β-CD/MGO nanohybrids were characterized by transmission electron microscope (TEM), scanning electron microscope (SEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), vibrating sample magnetometer (VSM), N2 adsorption/desorption isotherm, X-ray photoelectron spectroscopy (XPS) and Zeta potential analysis. Simultaneously, the adsorption properties of the β-CD/MGO nanohybrids for Pb(II), Cu(II) heavy metal ions and methylene blue (MB) in single aqueous solution were explored by batch experiments. The results revealed that the β-CD/MGO nanohybrids with high superparamagnetism were successfully fabricated, the maximum adsorption capacities of β-CD/MGO nanohybrids for Pb(II), Cu(II) and MB were 279.21, 51.29 and 93.97 mg·g−1 at 298 K, respectively. The adsorption process could be better fitted by pseudo-second-order model and Langmuir model.Graphical abstractGraphical abstract for this article
  • Surface effects on the magnetocaloric properties of perovskites
           ferromagnetic thin films: A Monte Carlo study
    • Abstract: Publication date: 30 November 2018Source: Applied Surface Science, Volume 459Author(s): A.S. Erchidi Elyacoubi, R. Masrour, A. JabarAbstractWe have used the Monte Carlo simulations to study the surface effects on the magnetocaloric properties of perovskites ferromagnetic thin films. We have determined the magnetization, the transition temperatures, magnetic entropy change, the relative cooling power (RCP), and the magnetic hysteresis cycle temperature as functions of the film thickness, and surface exchange coupling. The reduced critical temperature tC of the perovskites ferromagnetic thin films is studied as a function of film thickness L and the exchange interactions in the bulk JB, in the surface JS and between surface. We have shown that maximal entropy change in thin film systems can be observed at temperatures well below the magnetic phase transition temperature. The maximal entropy change increases with increasing the external magnetic field. RCP increases with increasing the external magnetic field and it is dependent of thickness film. The RCP decreases with increasing the value of surface exchange coupling. The magnetic coercive field decreases with increasing the temperatures values when the surface exchange coupling is inferior to bulk exchange coupling. The magnetic coercive field hC of the perovskites ferromagnetic thin films is studied as a function of reduced surface exchange coupling.
  • Ag SPR-promoted 2D porous g-C3N4/Ag2MoO4 composites for enhanced
           photocatalytic performance towards methylene blue degradation
    • Abstract: Publication date: 30 November 2018Source: Applied Surface Science, Volume 459Author(s): Yao Huo, Zhongliao Wang, Jinfeng Zhang, Changhao Liang, Kai DaiRapid recombination of photogenerated carriers has always been an important factor limiting advanced photocatalyst design. In this work, two-dimensional (2D) composites were successfully synthesized. Besides, crystal structure, micromorphology, optical properties, electrochemical properties, along with the photocatalytic methylene blue (MB) performance and photostability have been systematically explored. Porous graphite carbon nitride (Pg-C3N4) was composited with Ag2MoO4 forming a large-scale heterojunction interfaces, which is not only beneficial to supply more reaction active sites for catalytic reaction, but reduce the distance during the photoexcited carriers transfer. In addition, Ag surface plasmon resonance (SPR) effect acts as a very important role in photodegradation process, which makes great contributions to boosting the separation of photoexcited electron-hole pairs. The Pg-C3N4/Ag2MoO4 composites exhibit an excellent photocatalytic MB degradation and photostability, which can degrade MB solution by 99.5% in 12 min. The kapp of 40%Pg-C3N4/Ag2MoO4 is 0.33065 min−1, which is much higher than that of Pg-C3N4 (0.01606 min−1) and Ag2MoO4 (0.00933 min−1). Moreover, trapping experiment was employed to determine the specific reactive species, indicating that hole plays a major role in MB photodegradation. This work provides an available method to conduct a 2D photocatalyst with large-scale heterojunction, which is a promising material for the application in photocatalytic water pollution treatment.Graphical abstractGraphical abstract for this article
  • First-principle investigation on charge carrier transfer in
           transition-metal single atoms loaded g-C3N4
    • Abstract: Publication date: 30 November 2018Source: Applied Surface Science, Volume 459Author(s): Tong Tong, Bowen He, Bicheng Zhu, Bei Cheng, Liuyang ZhangThe decoration by transition-metal single atoms shows great potential in enhancing the photocatalytic performance of semiconductors. Nevertheless, the factors accounting for this enhancement remain unknown. Herein, single atoms (Fe, Co, Ni, Cu, Zn) loaded g-C3N4 were used as prototypes to investigate the mechanism through density functional theory (DFT). The results indicate that Fe, Co and Ni single atoms are inclined to penetrate into g-C3N4, prolonging the charge carrier migration distance. Furthermore, these single atoms can act as bridge to promote charge carrier transfer across g-C3N4 interlamination through the reconstitution of molecular orbitals. Among these five metals, built-in electric field is created in Fe/g-C3N4 and Co/g-C3N4 models, effectively suppressing the recombination of electron–hole pairs. In contrast, Cu and Zn atoms can only be loaded on the g-C3N4 surface, contributing trivial to the interlayer charge carrier migration. Our work provides theoretical support for the study of transition-metal single atom/g-C3N4 systems and gives new insight into the photocatalytic performance enhancement.Graphical abstractGraphical abstract for this article
  • Oxidation and ablation protection of multiphase Hf0.5Ta0.5B2-SiC-Si
           coating for graphite prepared by dipping-pyrolysis and reactive
           infiltration of gaseous silicon
    • Abstract: Publication date: 30 November 2018Source: Applied Surface Science, Volume 459Author(s): Yan Jiang, Tianyu Liu, Hongqiang Ru, Wei Wang, Cuiping Zhang, Lu WangAbstractA novel monolayer Hf0.5Ta0.5B2-SiC-Si coating with defect-free structure for protecting graphite materials was prepared by dipping-pyrolysis combined with reactive infiltration of gaseous silicon. The phase synthesis, microstructure, oxidation and ablation resistance properties of the prepared Hf0.5Ta0.5B2-SiC-Si coating were studied. Results demonstrated that the as-prepared coating exhibited excellent low and high temperature oxidation resistance, after isothermal oxidation at 900 °C and 1500 °C for 1320 h and 2080 h, respectively, the mass gains were 0.14% and 1.74%, respectively. The excellent anti-oxidation performance at 900 °C was ascribed to the defect-free structure of coating, while the formed compound Hf-Ta-Si-O glassy oxide layer on the coating surface was responsible for the excellent oxidation resistance at 1500 °C. Moreover, the Hf0.5Ta0.5B2-SiC-Si coating had good ablation resistance, after ablation for 60 s, the mass and linear ablation rates of the coated sample were 1.05 mg/s and −10.2 μm/s, respectively. The ablation behaviors of the coated sample mainly included thermal-physical and thermal-chemical erosion along with thermos-mechanical denudation.
  • Fabrication of CdSe/CaTiO3 nanocomposties in aqueous solution for improved
           photocatalytic hydrogen production
    • Abstract: Publication date: 30 November 2018Source: Applied Surface Science, Volume 459Author(s): Jishu Han, Ying Liu, Fangxu Dai, Ruiyang Zhao, Lei WangNovel CdSe/CaTiO3 nanocomposites are prepared in aqueous phase and used for photocatalytic hydrogen production. The modification of CdSe QDs on the surface of CaTiO3 sheet-like structure effectively increases visible light absorption of nanocomposites, improves the separation and transfer of photoinduced electrons and prevents the recombination of electron-hole pairs. Experimental results show that obtained CdSe/CaTiO3 nanocomposites possess significantly enhanced photocatalytic hydrogen production performance. The photocatalytic hydrogen production amount of CdSe/CaTiO3 is 48 times higher than that of pure CaTiO3 and 4.14 times higher than that of CdSe QDs. Meanwhile, CdSe/CaTiO3 nanocomposites display high stability and recyclability, which is beneficial for photocatalytic hydrogen production application.Graphical abstractGraphical abstract for this article
  • Co-solvent induced self-roughness superhydrophobic coatings with
           self-healing property for versatile oil-water separation
    • Abstract: Publication date: 30 November 2018Source: Applied Surface Science, Volume 459Author(s): Shouwei Gao, Xiuli Dong, Jianying Huang, Jianing Dong, Yan Cheng, Zhong Chen, Yuekun LaiDespite of the extensive effort made to construct a superhydrophobic surface in labs, achieving a short processing time and via a sustainable production route remains a challenge for practical applications. Here, with tetrahydrofuran and n-hexane as co-solvent, we demonstrate that roughness can be induced on polydimethylsiloxane (PDMS) coatings to achieve superhydrophobic coatings on different types of substrates including woven fabrics, non-woven fabrics, and melamine sponge. The sample constructed without adding particles exhibited excellent performance for versatile oil-water separation of mixtures of heavy oil and water, light oil and water, as well as oil-water emulsion. Due to the good solubility of the PDMS in the co-solvent, the dipping solution exhibited a long-time stability. Moreover, the abundant CH3 provided by the self-roughness PDMS coating helped the substrates recover its superhydrophobic property even after destroyed by plasma for 10 times. We believe that this extremely easy dipping-curing method would open up a new direction for fabricating a series of self-roughed superhydrophobic surface with self-healing property. Besides, the developed strategy is fast and easily scalable for industrial applications.Graphical abstractGraphical abstract for this article
  • Reduced bacterial colonisation on surfaces coated with silicone
    • Abstract: Publication date: 30 November 2018Source: Applied Surface Science, Volume 459Author(s): Margrith Meier, Valentin Dubois, Stefan SeegerBacterial adhesion on silicone nano- and microstructures is investigated in stagnant and flow experiments. Static adhesion tests are performed in 0.9% NaCl solution. These experiments reveal that the number of Staphylococcus epidermidis (S. epidermidis) and Escherichia coli (E. coli) adhering to glass surfaces can significantly be reduced if silicone nanofilament and rod coatings are present. Further, flow experiments are conducted in a parallel-plate flow chamber using 0.9% NaCl solution and artificial urine as medium. Silicone nanofilament coated surfaces are compared to uncoated glass surfaces. E. coli colonisation on filament coated surfaces is reduced for at least 24 h in 0.9% NaCl solution, while in artificial urine no reduction is observed after 24 h. S. epidermidis shows converse adhesion behaviour. Here, initial adhesion on nanofilaments is promoted but the number of adherent S. epidermidis seems to decrease after extended contact time. The obtained results demonstrate that superhydrophobic silicone surfaces significantly reduce bacterial colonisation under stagnant and dynamic conditions. However, the bacterial adhesion behaviour depends on the architecture of the silicone nano- and microstructures and the bacterial species investigated.Graphical abstractGraphical abstract for this article
  • Understanding the microstructural evolution of cold sprayed Ti-6Al-4V
           coatings on Ti-6Al-4V substrates
    • Abstract: Publication date: 30 November 2018Source: Applied Surface Science, Volume 459Author(s): Jun Yan Lek, Ayan Bhowmik, Adrian Wei-Yee Tan, Wen Sun, Xu Song, Wei Zhai, Pio J. Buenconsejo, Feng Li, Erjia Liu, Yeng Ming Lam, Chris B. BoothroydRapid development of cold spray technology has made it a viable option to remanufacture and repair damaged engineering components made of Ti-6Al-4V (Ti64). This solid-state deposition process contributes to the distinctive microstructure of Ti64 coatings. In this study, the microstructural evolution of Ti64 from feedstock powder to coating as a result of high strain rate deformation is evaluated. TEM lamellae were extracted from the particle-substrate and particle-particle interfaces of a cold sprayed coating by focused ion beam milling and a comprehensive microstructural analysis was carried out. The feedstock powder is predominantly composed of martensitic lathes. The microstructure of the coating at the particle-substrate interface is noticeably different from the microstructure of the feedstock powder. Narrow regions consisting of nanometre-sized grains are observed in both the particle and substrate in the vicinity of the interface. Adiabatic shear instability under localized high strain rate deformation and heat accumulation are believed to be responsible for this observation. However, the martensitic structure is partially retained in the less deformed region of the particles, further away from the interfaces. The formation mechanism of the microstructure observed from the inner region of particle, at the vicinity of the particle-substrate and particle-particle interfaces respectively is discussed in the light of microstructural observations and finite element modelling.Graphical abstractGraphical abstract for this article
  • Efficiently enhancing the tracking and erosion resistance of silicone
           rubber by the synergism of fluorine-containing polyphenylsilsesquioxane
           and ureido-containing MQ silicone resin
    • Abstract: Publication date: 30 November 2018Source: Applied Surface Science, Volume 459Author(s): Tongyi Wu, Xuejun Lai, Fengjiao Liu, Hongqiang Li, Xingrong ZengIt is of great interest and challenge to simultaneously improve the anti-pollution and tracking resistance of silicone rubber for its application in outdoor high voltage insulation. In this work, we proposed an efficient approach to address this issue by incorporating fluorine-containing polyphenylsilsesquioxane (F-PPSS) and ureido-containing MQ silicone resin (U-MQ) into addition-cure liquid silicone rubber (ALSR). F-PPSS/U-MQ significantly improved the tracking resistance and hydrophobicity of ALSR. By adding 2 phr F-PPSS and 1 phr U-MQ, ALSR passed the 1A 4.5 level inclined plane test with merely 0.2% eroded mass, and had a water contact angle as high as 121°. The synergism of F-PPSS and U-MQ on suppressing the ALSR degradation was further revealed and demonstrated. Our findings exhibited great potentials for fabricating silicone rubber with prominent tracking and erosion resistance by the combination of prevention and inhibition of tracking damage, endowing it with excellent long-term stable service performance.Graphical abstractGraphical abstract for this article
  • Nitrogen doping in Ta2O5 and its implication for photocatalytic H2
    • Abstract: Publication date: 30 November 2018Source: Applied Surface Science, Volume 459Author(s): Wei-Szu Liu, Sheng-Hsin Huang, Chia-Fen Liu, Chih-Wei Hu, Tsan-Yao Chen, Tsong-Pyng PerngAbstractNitrogen-doped Ta2O5 (N-Ta2O5) powders were fabricated by nitridation of Ta2O5 in NH3 for 1 h at 600–700 °C. The concentration of nitrogen doping increased as the nitridation temperature increased, and a small amount of Ta3N5 appeared when nitridized at 700 °C. Pure Ta3N5 was obtained by nitridation at 800 °C for 6 h. They were characterized by X-ray diffraction, Raman spectroscopy, X-ray absorption spectroscopy, X-ray photoelectron spectroscopy, UV–vis spectrometry, and photoluminescence spectroscopy. It is concluded that in the N-Ta2O5 samples nitrogen ions have substituted for oxygen ions, creating some oxygen vacancies and extra energy levels within the band gap. Further, Ta3N5 prefers to form on the surface and acts as the recombination center for electrons and holes. Among all samples, nitridation at 650 °C resulted in the best photocatalytic hydrogen production efficiency that can be explained by more nitrogen doping and no formation of Ta3N5.
  • Fabrication and characterization of novel powder reconstitution derived
           nanostructured spherical La2(Zr0.75Ce0.25)2O7 feedstock for plasma
    • Abstract: Publication date: 30 November 2018Source: Applied Surface Science, Volume 459Author(s): Feifei Zhou, You Wang, Wenlong Chen, LiangWang, Changxiang Huang, Yaming Wang, Min LiuHigh-performance thermal spraying feedstock is of great significance for obtaining high quality plasma-sprayed thermal barrier coatings (TBCs). Rare-earth zirconates TBCs have attracted much more attention so far. In this paper, the nanostructured La2(Zr0.75Ce0.25)2O7 (LCZ) feedstock was fabricated by the nanopowder reconstitution method. The microstructures of the LCZ feedstock were characterized by transmission electron microscopy, X-ray diffraction, Raman spectroscopy and scanning electron microscopy. Moreover, the thermo-physical properties of the LCZ feedstock were also evaluated. The results indicate that the spherical LCZ feedstock with the median particle size (d50) of 37.40 μm consists of only pyrochlore phase. Compared with the nanostructured La2Zr2O7 (LZ) feedstock, the tap density and flowability of the LCZ feedstock are enhanced considerably. As for the LCZ coating, the thermal conductivity is much lower and the thermal expansion coefficient (TEC) is relatively higher than the LZ coating. Therefore, the nanostructured LCZ feedstock can be a promising advanced thermal spraying feedstock used for double ceramic layer TBCs in future.Graphical abstractGraphical abstract for this article
  • The effect of surface texture on the oxidation behaviour of
           polycrystalline Fe-Cr
    • Abstract: Publication date: 30 November 2018Source: Applied Surface Science, Volume 459Author(s): G. Zijlstra, L.T.H. de Jeer, V. Ocelík, J.Th.M. De HossonGrain-direction dependent oxidation at the surface of polycrystalline Fe-Cr steel is not well understood, as most of the described systems in literature focus on single crystals of either Fe or Cr. We found through electron backscatter diffraction that surface oxidation in air at temperatures between 260 and 450 °C depends severely on grain orientations at the outer surface. Subsequently electron microscopy was combined with X-ray photoelectron spectroscopy (XPS) and X-ray Diffraction (XRD) to characterize the oxide film further in detail. In particular we have observed the following sequence in oxidation rate of crystal planes parallel to the surface for Fe-Cr steel, {0 0 1} 
  • N-doped hollow carbon nanospheres as platinum anchoring material for
           efficient hydrogen evolution
    • Abstract: Publication date: 30 November 2018Source: Applied Surface Science, Volume 459Author(s): Lili Fan, Xinxin Du, Zixi Kang, Hailing Guo, Wenpei Kang, Ming Xue, Daofeng SunPlatinum-based materials remain as the most effective electrocatalysts for hydrogen evolution reaction. Smarter material and strategy for anchoring platinum with enhanced utilization efficiency are highly demanded. In this work, N-doped hollow carbon nanospheres are prepared targetedly from a metal-organic framework for in-situ platinum dispersion. Through a simple electrochemical method, platinum nanoparticles are successfully anchored on the surface of the carbon nanospheres decorated electrode, which exhibits exceptional HER performance in H2SO4 with low onset overpotential, small Tafel slope (33 mV decade−1), high current density (overpotentials of 40 mV to reach the current density of 10 mA cm−2) and high stability (4000 cyclic voltammetry (CV) cycles and total 30 h of high current density (10, 50 and 100 mA cm−2) chronoamperometric electrolysis). The superior electrocatalytic activity and durability can be attributed to the facilitated electron transport and synergistic effects between platinum and carbon nanospheres. This work provides an insight into the development of efficient support materials from MOFs to design efficient platinum-based electrocatalysts for future water splitting.Graphical abstractN-rich hollow carbon nanospheres are designed and synthesized as platinum anchoring material for efficient hydrogen evolution.Graphical abstract for this article
  • Electrochemical synthesis of anisole on platinum anode surface: Experiment
           and first-principle study
    • Abstract: Publication date: 30 November 2018Source: Applied Surface Science, Volume 459Author(s): Zhengwei Zhang, Qiang WangThe anisole is synthesized by electrolyzing of phenol (or sodium phenate) and tetramethylammonium chloride (TMAC). The production forms on the Pt anode surface and not in the solution. There are adequate supplies of methyl radicals in all solutions. The phenoxyl radical is difficult to form in phenol-TMAC solution, and thus the yield is low. The sodium phenate is easily oxidized into phenoxyl radical, and hence there is high yield.Graphical abstractThe tetramethylammonium chloride (TMAC) is reduced on the cathode and supplies methyl radical. The phenol (or sodium phenate) is oxidized on the anode and supplies phenol radical. The two kinds of radicals bond together and form anisole.Graphical abstract for this article
  • In-situ preparation of amino-terminated dendrimers on TiO2 films by
    • Abstract: Publication date: 30 November 2018Source: Applied Surface Science, Volume 459Author(s): Peichuang Li, Wenjuan Zheng, Wenyong Ma, Xin Li, Shiqi Li, Yuancong Zhao, Jin Wang, Nan HuangDendrimers, with their unique structure and polyfunctionality, have shown excellent performance in many biomedicinal applications, such as drug carriers and gene transfection. In this study, titanium dioxide (TiO2) films with four generations (G1, G2, G3, G4) of amino-terminated dendrimers were prepared in situ using a simple iterative Michael addition and aminolysis reaction for generational growth. The TiO2 films with different generations of dendrimers were characterized using X-ray diffraction, water contact angle measurements, and scanning electron microscopy. The chemical compositions of these films were confirmed by Fourier-transform infrared spectroscopy and X-ray photoelectron spectroscopy. Blood compatibility was evaluated using platelet adhesion and activation assays utilizing platelet-rich plasma. The results indicated that the dendrimers immobilized on the surface of the TiO2 films effectively reduced platelet adhesion and aggregation. Endothelial cell culturing on the dendrimer-immobilized surfaces showed that the amino-terminated dendrimers exhibited a certain degree of cytotoxicity due to the positive charges of the amino groups. These results indicated that amino-terminated dendrimers immobilized on TiO2 films provided numerous functional groups for the future immobilization of specific biological molecules and may be used for manufacturing future blood-contacting implants.Graphical abstractGraphical abstract for this article
  • Enlarged working potential window for MnO2 supercapacitors with neutral
           aqueous electrolytes
    • Abstract: Publication date: 30 November 2018Source: Applied Surface Science, Volume 459Author(s): Yun-Zhao Wu, Yong Ding, Tasawar Hayat, Ahmed Alsaedi, Song-Yuan DaiManganese oxide (MnO2) has been comprehensively studied as one high-voltage electrode material in the neutral aqueous supercapacitors, whereas the working potential window (WPW) for the device hasn’t exceeded 2.0 V in most reports. Here, interlaced ultrathin MnO2 nanoflakes were vertically aligned on the carbon cloth (CC) via a facial potentiostatic electrochemical deposition method. A stable WPW for the MnO2/CC electrodes in three electrolytes of 0.5 M A2SO4 (A = Li, Na, K) was defined as 0–1.1 V, which was attributed to the nanoporous morphology of the MnO2 nanosheets and high content of structure water within it. Furthermore, the MnO2 nanoflakes with 0.5 M Na2SO4 have achieved a high specific capacitance of 272.2 F/g at 2 mV/s, and the retention of the performance was 83.8% (5 A/g) after 5000 cycling tests. As for the flexible asymmetric MnO2 supercapacitors (FAMSC), the MnO2/CC electrode was used as a cathode and a self-assembled rGO film was developed as an anode. Working in an extended WPW of 0–2.2 V, the FASMC exhibited a large energy density of 49.8 Wh/kg and the retention of the performance was 88.7% at 5 A/g after 5000 cycles. This work provides a stable WPW for the MnO2 electrodes, which may promote further development of the high-voltage neutral aqueous supercapacitors.Graphical abstractGraphical abstract for this article
  • Synthesis of MoS2/Ni3S2 heterostructure for efficient electrocatalytic
           hydrogen evolution reaction through optimizing the sulfur sources
    • Abstract: Publication date: 30 November 2018Source: Applied Surface Science, Volume 459Author(s): Xiaolei Liu, Peng Wang, Qianqian Zhang, Baibiao Huang, Zeyan Wang, Yuanyuan Liu, Zhaoke Zheng, Ying Dai, Xiaoyan Qin, Xiaoyang ZhangThe electrocatalysts with low-cost, good stabilities, rich reserves and efficient activities are required to replace Pt-based materials for the hydrogen evolution reaction. Herein, we synthesize the low-cost MoS2/Ni3S2 heterostructure on Ni foam with efficient HER activity and good stability through optimizing the sulfur sources selection among thioacetamide (TAA), L-cysteine and thiourea. The different sulfur sources have a very important influence on the structures and morphologies of NF-MoS2/Ni3S2 composites, which may attribute to the different selective combining capacities of sulfur sources with Na2MoO4 and Ni foam. By contrast, NF-MoS2/Ni3S2-TAA shows relatively lower overpotential of 91 mV at 10 mA cm−2 and Tafel slope of 48.62 mV dec−1 than those of NF-MoS2/Ni3S2-L-cysteine (overpotential of 148 mV at 10 mA cm−2 and Tafel slope of 68.81 mV dec−1) or NF-MoS2/Ni3S2-thiourea (overpotential of 187 mV at 10 mA cm−2 and Tafel slope of 93.41 mV dec−1). The superior HER activity of NF-MoS2/Ni3S2-TAA is benefit from the higher MoS2 content and larger electrochemically active surface area. Optimizing the sulfur source selection can realize the efficient electrocatalytic hydrogen evolution of MoS2/Ni3S2 heterostructure which has an important guiding significance for the practical application in the future.Graphical abstractGraphical abstract for this article
  • Tribological behaviors of fluid-lubricated DLC films under sliding and
           fretting conditions
    • Abstract: Publication date: 30 November 2018Source: Applied Surface Science, Volume 459Author(s): Hanmin Fu, Xiaoqiang Fan, Wen Li, Hao Li, Zhenbing Cai, Minhao ZhuAbstractTo meet the ever–increasing performance requirements of mechanical equipment under various working conditions, lubrication schemes have been transformed from onefold to synergistic lubrication. Here we introduced the synergistic lubrication systems consisting of DLC film as anti–wear supporting layer and two high–performance fluids (ionic liquids (ILs) and multiply–alkylated cyclopentanes (MACs)) as lubricating layer, and their tribological properties were conducted under sliding and fretting conditions. Results show that ILs and MACs can improve the friction reduction and wear resistance of DLC film under sliding condition because a boundary lubrication film was formed by physical adsorption film and tribo–transfer film, which could minimize the shear and adhesion. Under fretting condition, the lubrication function of ILs and MACs is not superior to that under sliding condition partly because intact fluid-film has difficulty in formation on the fretting regime, and also partly because fretting conditions induce the transformation of fretting running regime from partial slip to gross slip.
  • Curvature induced improvement of Li storage in Ca2N nanotubes
    • Abstract: Publication date: 30 November 2018Source: Applied Surface Science, Volume 459Author(s): Wenwei Luo, Hewen Wang, Junping Hu, Sanqiu Liu, Chuying OuyangAbstractRecently, Hu et al. reported that Ca2N monolayer is a good anode material for Na storage, but Li storage is not allowed since Li adsorption on Ca2N monolayer is energetically unfavorable. In this paper, from first-principles calculations, we predict that Li storage becomes possible when the Ca2N monolayer is rolling up into nanotubes. The curvature effect of the Ca2N nanotube decreases the Li adsorption energy to a level below 0 eV, corresponding to positive charge/discharge potential. As a result, Li storage in Ca2N nanotubes becomes feasible and a theoretical capacity of about 426.9 mAh/g is predicted for the Ca2N-(14, 0) nanotube. The metallic electronic structure and very fast Li/Na diffusion in the Ca2N nanotubes ensure that the rate performance of the Ca2N nanotubes can be good. This study offers an example of designing electrode materials for Li/Na ion batteries through curvature effect, and the strategy is applicable to other 2D materials.
  • Anti-irreversible fouling of precisely-designed PVDF-ZnO membrane: Effects
           of ion strength and co-existing cations
    • Abstract: Publication date: 30 November 2018Source: Applied Surface Science, Volume 459Author(s): Ning Li, Yu Tian, Jianhui Zhao, Lingchao Kong, Jun Zhang, Wei Zuo, Hao Cui, Qingyuan LinIn this work, the atomic layer deposition-zinc oxide (ALD-ZnO) modified membrane was fabricated and the effects of ionic strength, co-existing Ca2+ and Mg2+ on its fouling potential were systematically investigated. Results showed excellent anti-irreversible fouling performance of PVDF-ZnO modified membrane with co-existing cations. Attractively, the values of declined membrane flux dropped by 25.7%, 25.9% and 22.3% after ZnO modification in the presence of 50 mM NaCl, 1.0 mM Ca2+ and 1.0 mM Mg2+, respectively. Besides, Ca2+ was prone to cause membrane fouling than Mg2+. Furthermore, fitting of multistage filtration models revealed that membrane fouling was ascribed to dynamic adsorption initially, followed by surface and pores deposition when filtrating BSA with or without Mg2+. However, the modified membrane experienced reverse process with higher ionic strength or Ca2+ addition due to BSA molecular cluster. Moreover, the reduced repulsive energy induced by charge screening and calcium bridging resulted in slight aggravation of membrane fouling. Interestingly, the flux of PVDF-ZnO fouled membrane was easily recovered after physical cleaning. These findings provided deep insight into practical application of ALD modified membrane in wastewater remediation.Graphical abstractGraphical abstract for this article
  • Gram-scale solution-based synthesis of SnSe thermoelectric nanomaterials
    • Abstract: Publication date: 30 November 2018Source: Applied Surface Science, Volume 459Author(s): Subrata Kundu, Su-In Yi, Choongho YuGram-scale SnSe nanomaterials have been prepared by exploiting a simple wet-chemical route at ambient environments in which a transparent NaHSe solution was mixed with SnCl2 and sodium ascorbate, followed by hydrothermal heating for 24 h. It is notable that phase-pure crystalline SnSe nanorods having aspect ratios of ∼5 were obtained within a short period of time and without any sophisticated instruments or inert environment. The key steps and conditions to obtain pure SnSe nanorods in the synthesis process were identified and discussed. The SnSe powder was sintered using a facile spark plasma sintering method to form polycrystalline pellets for thermoelectric property measurements. According to the thermopower measurement results, the pristine SnSe pellets are p-type, and showed slightly higher electrical conductivities compared to that of single crystalline SnSe. The counterpart n-type SnSe pellets were also fabricated by doping Bi with a high energy ball milling process. The thermal conductivity of our polycrystalline SnSe was found to be in between that of single crystalline SnSe along a- and b- axis (or c-axis) direction. The facile and new synthesis route, high reproducibility and cost-effectiveness are easily adaptable for the formation of other doped and un-doped metal selenide nanomaterials with a short reaction time for various applications beyond thermoelectrics.Graphical abstractGram scale SnSe nanomaterials having rod shaped morphology with aspect ratios of ∼5 has been prepared by exploiting a simple wet-chemical route at ambient environment within a short time without need of any inert atmosphere. The pristine SnSe pellets are p-type, and showed slightly higher electrical conductivities compared to those of single crystalline SnSe. Subsequent Bi doping via high energy ball milling process convert p-type SnSe to n-type SnSe. The thermal conductivity of our polycrystalline SnSe was found in between those of single crystalline SnSe along a- and b-axis (or c-axis) direction.Graphical abstract for this article
  • Facile synthesis of Pt assisted Bi-Bi2WO6−x with oxygen vacancies for
           the improved photocatalytic activity under visible light
    • Abstract: Publication date: 30 November 2018Source: Applied Surface Science, Volume 459Author(s): Shuoshuo Zhang, Wenhong Pu, Hao Du, Yunyang Wang, Changzhu Yang, Jianyu GongPt assisted self-modified microflower like Bi2WO6 composites (Pt/Bi-Bi2WO6−x) were prepared using a simple in-situ NaBH4 reduction method. The characterization of these samples was systematically studied and the photocatalytic activity of as-prepared samples was evaluated through the degradation of bisphenol A (BPA) under visible light illumination. The results indicated that the self-modified Bi-Bi2WO6−x presented the high separation efficiency of photo-generated carriers due to the introduction of the oxygen vacancies and metallic Bi. Furthermore, because of the presence of Pt on Bi-Bi2WO6−x, a higher concentration of generated oxygen vacancies was also obtained, resulting in the excellent photocatalytic performance. The 2%Pt/0.2Bi-Bi2WO6−x sample exhibited the highest degradation efficiency of BPA under visible light illumination, which was approximately 2.88 times and 1.52 times as high as that of Bi2WO6 and 0.2Bi-Bi2WO6−x, respectively. In addition, the degradation efficiency clearly improved at high pH value. The highest degradation efficiency was obtained at alkaline solution (pH = 9). According to the mechanism study, the enhanced photocatalytic property on 2%Pt/0.2Bi-Bi2WO6−x should be attributed to the presence of oxygen vacancies on the material surface, since oxygen vacancies states were partly overlapping of with the valence band (VB), and increased the width of VB, reducing the band gap of Bi2WO6. The possible photocatalytic mechanism was also simulated by chemical calculations, which was proposed to guide further related studies.Graphical abstractGraphical abstract for this article
  • DFT study on the electronic structure and optical properties of N, Al, and
           N-Al doped graphene
    • Abstract: Publication date: 30 November 2018Source: Applied Surface Science, Volume 459Author(s): Xi Zhou, Cuihua Zhao, Guofei Wu, Jianhua Chen, Yuqiong LiAbstractThe electronic structures and optical properties of pure, N-doped, Al-doped, and N-Al co-doped graphenes were studied by the first-principle calculation. The pure graphene is a zero bandgap semiconductor. The energy gaps were opened after N, Al, and N-Al doping. The gap value of N-Al co-doped graphene is the largest, 0.47 eV, then Al-doped graphene, 0.40 eV, and N-doped graphene, 0.21 eV. For N-doped graphene, carbon atom loses electrons, nitrogen atom gains electrons, while carbon gains electrons, aluminum atom loses electrons for Al-doped graphene. For N-Al co-doped graphene, aluminum atom loses a bit more electrons (2.31 e) than that in Al-doped graphene (2.27 e), while nitrogen atom gains a lot more electrons (−0.76 e) than that in N-doped graphene (−0.27 e). After N, Al, N-Al doping, the absorption peaks of graphene become weak, especially low frequency peaks of N and Al doping. The absorption curve of N-Al doped graphene is similar with that of pure graphene. However, the absorption peak of low frequency for N-Al doped graphene shifts to low energy relative to pure graphene, showing that it is easier for the transitions between π and π∗, and lead to the opened gap.
  • Fluorinated tin oxide (FTO) deposited at room temperature: Influence of
           hydrogen and oxygen in the sputtering gas on the optical and electrical
    • Abstract: Publication date: 30 November 2018Source: Applied Surface Science, Volume 459Author(s): María Morán-Pedroso, Jorge Sánchez-Marcos, Alicia de Andrés, Carlos PrietoAbstractThe optical and electrical properties of fluorinated tin oxide (FTO) films deposited at room temperature by sputtering were investigated. In addition to small amount of oxygen to preserve highly transparent films, electrical resistivity become decreased two orders of magnitude by using appropriate hydrogen content in the sputtering gas. Films deposited with Ar(93%)/O2(5%)/H2(2%) gas mixture show maximal values of conductivity, charge carrier density and mobility as well as excellent transparency. Taking into account the film characterization carried out by Rutherford backscattering spectrometry (RBS), a mechanism is proposed to explain the observed optical and electrical dependence with the hydrogen content in the film.
  • Sulfur doping in multivacancy graphene systems
    • Abstract: Publication date: 30 November 2018Source: Applied Surface Science, Volume 459Author(s): Dominique Mombrú, Ricardo Faccio, Alvaro W. MombrúAbstractThe conformational, magnetic and electronic study of one and two sulfur atoms doping on multivacancy graphene systems, using first principles calculations is presented. The location for the addition of the sulfur atoms is ruled by the presence of pentagonal figures in the optimized multivacancy graphene system or, in case of the absence of such figures, by the concave four membered structures in the vacancy. The electronic structure and the magnetism in these systems are strongly affected by the cancellation of dangling bonds due to the inclusion of sulfur atoms. Finally, it was possible to demonstrate that the inclusion of one and even a second sulfur atoms in the multivacancy graphene systems is favorable.
  • Morphology controlled synthesis of hierarchical structured Fe2O3 from
           natural ilmenite and its high performance for dyes adsorption
    • Abstract: Publication date: 30 November 2018Source: Applied Surface Science, Volume 459Author(s): Dongjuan Kang, Chaoquan Hu, Qingshan ZhuA facile method using acid leachate of ilmenite as the precursor has been successfully developed to tailor the structure of Fe2O3. The morphology and structure of the final product can be controlled from nanoparticles, microcubes, rhombohedrons to microspheres by varying the synthetic parameters. Detailed characterization showed that the microspheres had a hierarchical structure and was actually consisted of nanoblocks subunits. A possible mechanism was proposed for the formation of the hierarchically structured Fe2O3 microspheres. Due to its large surface area and abundant functional groups, the Fe2O3 microspheres could efficiently remove organic dyes in aqueous solution. The measured maximum adsorption capacities were 723.8, 150.7, and 54.5 mg/g for Congo red, Methyl orange, and Methylene blue, respectively, which were generally higher than those for Fe2O3 with other structures reported in literature. This work provides a novel approach to using waste as the resource for the preparation of low-cost and efficient adsorbent materials.Graphical abstractThis work provides a novel approach for “waste eliminates waste, turning waste to treasure”, which not only can achieve the goal of cleanup waste water, but also reusing waste and reducing environmental pollution.Graphical abstract for this article
  • Adsorption of polythiophene/TiO2 composite for Zn (II), Pb (II) and Cu
           (II): Selectivity and synergistic effect investigation
    • Abstract: Publication date: 30 November 2018Source: Applied Surface Science, Volume 459Author(s): Jie Chen, Lin Zhang, Jinwei Zhu, Ning Wang, Jiangtao Feng, Wei YanA composite with self-doping nature, polythiophene (PTh)/TiO2 with impressive selectivity was synthesized in the aqueous medium to support the mechanism on synergistic effect between PTh and TiO2. An interesting self-doping of TiO2(O−) on the polythiophene in the PTh+/TiO2(O−) composite was also prepared with tunable heterojunction structure by adjusting the solution pH. An impressive selective adsorption property with an ascending order of Zn2+> Pb2+≫ Cu2+ was achieved in the single and competitive adsorption study, where the adsorption for Cu2+ could be almost suppressed. This interesting selective adsorption was confirmed to be caused by the dedoping of TiO2(O−) in the heavy metal ion solution due to the metastable doping form of PTh in non-acid solution from the TGA and electrochemical point of view. While the selective adsorption of the composite was also determined on TiO2. The general mechanisms on synergistic effect and on selective adsorption were successfully convinced through the designed experiment, providing some reliable guidelines for designing adsorbents with selectivity towards specific heavy metal ions. In addition, PTh+/TiO2(O−) composite with high adsorption capacity for Zn2+ and Pb2+ can be readily applied in the practical application, especially in the Cu2+ rich waste water without capacity loss.Graphical abstractGraphical abstract for this article
  • Mesoporous reduced graphene oxide/WSe2 composite particles for efficient
           sodium-ion batteries and hydrogen evolution reactions
    • Abstract: Publication date: 30 November 2018Source: Applied Surface Science, Volume 459Author(s): Jung Sang Cho, Seung-Keun Park, Kyung Min Jeon, Yuanzhe Piao, Yun Chan KangAbstractMesoporous WSe2-reduced graphene oxide (WSe2-rGO) composite particles were prepared by spray pyrolysis and subsequent selenization. The WSe2-rGO composite particles had both well-dispersed rGO nanosheets and well-faceted WSe2 nanocrystals with plenty of folded edges. As a comparison sample, hierarchical structured WSe2 particles were produced by selenization of the bare WO3 particles obtained by spray pyrolysis. The WSe2-rGO composite particles showed superior electrochemical properties for sodium-ion batteries (SIBs) and electrocatalytic efficiencies for hydrogen evolution reactions (HERs) compared to those of the bare WSe2 particles. The discharge capacities of the WSe2-rGO composite particles and bare WSe2 particles for the 100th cycle at a current density of 0.5 A g−1 for sodium-ion storage were 238 and 36 mA h g−1, respectively; their corresponding capacity retentions measured from the third cycle were 80% and 13%. The WSe2–rGO composite particles showed much lower onset potential and larger current density (36.5 mA cm−2 at η = 300 mV) than those of the bare WSe2 particles (0.61 mA cm−2 at η = 300 mV). The Tafel slopes for the WSe2–rGO composite and bare WSe2 particles were approximately 60 and 115 mV dec−1, respectively.
  • Titanium doped zinc oxide thin film transistors fabricated by cosputtering
    • Abstract: Publication date: 30 November 2018Source: Applied Surface Science, Volume 459Author(s): Wen Yu, Dedong Han, Huijin Li, Junchen Dong, Xiaobin Zhou, Zhuang Yi, Zhen Luo, Shengdong Zhang, Xing Zhang, Yi WangTitanium doped zinc oxide (TiZO) thin-film transistors (TFTs) were fabricated with the active layer deposited by the cosputtering of Ti and ZnO targets. We fabricated TiZO TFTs under various sputtering powers, effects of which on the performance of TiZO TFTs were investigated. The results suggest that the effective Ti doping concentration is significant for excellent electrical properties. The optimal electrical performance was obtained at 60 W of ZnO sputtering power and 80 W of Ti sputtering power. The changes in the crystalline structure, surface morphology and optical transmittance of TiZO thin films were examined according to the sputtering power, which agreed well with the variation of device performance.Graphical abstractThe transfer curves of TiZO TFTs (a) as a function of Ti sputtering power with ZnO sputtering power fixed at 50 W and (b) as a function of ZnO sputtering power with Ti sputtering power fixed at 80 W.Graphical abstract for this article
  • Effects of Y doping with point defects on the ferromagnetic properties of
           ZnO(0001)-Zn polar surface
    • Abstract: Publication date: 30 November 2018Source: Applied Surface Science, Volume 459Author(s): Cong Li, Qingyu HouAbstractThe ferromagnetic properties of Y-doped ZnO(0001)-Zn polar surface with and without point defects, including oxygen vacancy (VO), hydrogen interstitial (Hi), and zinc vacancy (VZn), are calculated using the first-principles method. Results show that Y-doped ZnO with or without VO is nonmagnetic. Hi in Y-doped ZnO with VO can combine adjacent O atoms to form a bound magnetic polaron. Adjacent H–O bound magnetic polaron (BMPs) create an interconnected BMP cluster, which induces the ferromagnetism of ZnO. Unpaired O-2p electrons induced by VZn causes ZnO to have a long-range ferromagnetic order through the double-exchange mechanism. Ferromagnetic quenching occurs in the ZnO lattice when the ratio of Y to VZn is 2:1. Both ferromagnetic mechanism can be achieved at room temperature.
School of Mathematical and Computer Sciences
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