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  Subjects -> CHEMISTRY (Total: 849 journals)
    - ANALYTICAL CHEMISTRY (50 journals)
    - CHEMISTRY (598 journals)
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CHEMISTRY (598 journals)                  1 2 3 | Last

Showing 1 - 200 of 735 Journals sorted alphabetically
2D Materials     Hybrid Journal   (Followers: 8)
Accreditation and Quality Assurance: Journal for Quality, Comparability and Reliability in Chemical Measurement     Hybrid Journal   (Followers: 26)
ACS Catalysis     Full-text available via subscription   (Followers: 32)
ACS Chemical Neuroscience     Full-text available via subscription   (Followers: 17)
ACS Combinatorial Science     Full-text available via subscription   (Followers: 23)
ACS Macro Letters     Full-text available via subscription   (Followers: 23)
ACS Medicinal Chemistry Letters     Full-text available via subscription   (Followers: 39)
ACS Nano     Full-text available via subscription   (Followers: 227)
ACS Photonics     Full-text available via subscription   (Followers: 11)
ACS Synthetic Biology     Full-text available via subscription   (Followers: 21)
Acta Chemica Iasi     Open Access   (Followers: 2)
Acta Chimica Sinica     Full-text available via subscription   (Followers: 1)
Acta Chimica Slovaca     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: 5)
Acta Scientifica Naturalis     Open Access   (Followers: 2)
adhäsion KLEBEN & DICHTEN     Hybrid Journal   (Followers: 5)
Adhesion Adhesives & Sealants     Hybrid Journal   (Followers: 7)
Adsorption Science & Technology     Full-text available via subscription   (Followers: 5)
Advanced Functional Materials     Hybrid Journal   (Followers: 50)
Advanced Science Focus     Free   (Followers: 3)
Advances in Chemical Engineering and Science     Open Access   (Followers: 53)
Advances in Chemical Science     Open Access   (Followers: 13)
Advances in Chemistry     Open Access   (Followers: 14)
Advances in Colloid and Interface Science     Full-text available via subscription   (Followers: 18)
Advances in Drug Research     Full-text available via subscription   (Followers: 22)
Advances in Enzyme Research     Open Access   (Followers: 9)
Advances in Fluorine Science     Full-text available via subscription   (Followers: 8)
Advances in Fuel Cells     Full-text available via subscription   (Followers: 15)
Advances in Heterocyclic Chemistry     Full-text available via subscription   (Followers: 8)
Advances in Materials Physics and Chemistry     Open Access   (Followers: 19)
Advances in Nanoparticles     Open Access   (Followers: 14)
Advances in Organometallic Chemistry     Full-text available via subscription   (Followers: 15)
Advances in Polymer Science     Hybrid Journal   (Followers: 41)
Advances in Protein Chemistry     Full-text available via subscription   (Followers: 18)
Advances in Protein Chemistry and Structural Biology     Full-text available via subscription   (Followers: 19)
Advances in Quantum Chemistry     Full-text available via subscription   (Followers: 5)
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: 2)
African Journal of Pure and Applied Chemistry     Open Access   (Followers: 7)
Agrokémia és Talajtan     Full-text available via subscription   (Followers: 2)
Alkaloids: Chemical and Biological Perspectives     Full-text available via subscription   (Followers: 3)
AMB Express     Open Access   (Followers: 1)
Ambix     Hybrid Journal   (Followers: 3)
American Journal of Biochemistry and Biotechnology     Open Access   (Followers: 67)
American Journal of Biochemistry and Molecular Biology     Open Access   (Followers: 14)
American Journal of Chemistry     Open Access   (Followers: 26)
American Journal of Plant Physiology     Open Access   (Followers: 13)
American Mineralogist     Hybrid Journal   (Followers: 13)
Analyst     Full-text available via subscription   (Followers: 38)
Angewandte Chemie     Hybrid Journal   (Followers: 164)
Angewandte Chemie International Edition     Hybrid Journal   (Followers: 212)
Annales UMCS, Chemia     Open Access   (Followers: 1)
Annals of Clinical Chemistry and Laboratory Medicine     Open Access   (Followers: 1)
Annual Reports in Computational Chemistry     Full-text available via subscription   (Followers: 3)
Annual Reports Section A (Inorganic Chemistry)     Full-text available via subscription   (Followers: 3)
Annual Reports Section B (Organic Chemistry)     Full-text available via subscription   (Followers: 8)
Annual Review of Chemical and Biomolecular Engineering     Full-text available via subscription   (Followers: 12)
Annual Review of Food Science and Technology     Full-text available via subscription   (Followers: 14)
Anti-Infective Agents     Hybrid Journal   (Followers: 3)
Antiviral Chemistry and Chemotherapy     Hybrid Journal  
Applied Organometallic Chemistry     Hybrid Journal   (Followers: 7)
Applied Spectroscopy     Full-text available via subscription   (Followers: 23)
Applied Surface Science     Hybrid Journal   (Followers: 28)
Arabian Journal of Chemistry     Open Access   (Followers: 6)
ARKIVOC     Open Access   (Followers: 2)
Asian Journal of Biochemistry     Open Access   (Followers: 1)
Atomization and Sprays     Full-text available via subscription   (Followers: 3)
Australian Journal of Chemistry     Hybrid Journal   (Followers: 7)
Autophagy     Hybrid Journal   (Followers: 2)
Avances en Quimica     Open Access   (Followers: 1)
Biochemical Pharmacology     Hybrid Journal   (Followers: 10)
Biochemistry     Full-text available via subscription   (Followers: 285)
Biochemistry Insights     Open Access   (Followers: 5)
Biochemistry Research International     Open Access   (Followers: 6)
BioChip Journal     Hybrid Journal  
Bioinorganic Chemistry and Applications     Open Access   (Followers: 9)
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: 1)
Biomacromolecules     Full-text available via subscription   (Followers: 19)
Biomass Conversion and Biorefinery     Partially Free   (Followers: 10)
Biomedical Chromatography     Hybrid Journal   (Followers: 6)
Biomolecular NMR Assignments     Hybrid Journal   (Followers: 3)
BioNanoScience     Partially Free   (Followers: 4)
Bioorganic & Medicinal Chemistry     Hybrid Journal   (Followers: 110)
Bioorganic & Medicinal Chemistry Letters     Hybrid Journal   (Followers: 93)
Bioorganic Chemistry     Hybrid Journal   (Followers: 10)
Biopolymers     Hybrid Journal   (Followers: 18)
Biosensors     Open Access   (Followers: 2)
Biotechnic and Histochemistry     Hybrid Journal   (Followers: 1)
Bitácora Digital     Open Access  
Boletin de la Sociedad Chilena de Quimica     Open Access  
Bulletin of the Chemical Society of Ethiopia     Open Access   (Followers: 2)
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: 3)
Carbohydrate Research     Hybrid Journal   (Followers: 26)
Carbon     Hybrid Journal   (Followers: 67)
Catalysis for Sustainable Energy     Open Access   (Followers: 6)
Catalysis Reviews: Science and Engineering     Hybrid Journal   (Followers: 8)
Catalysis Science and Technology     Free   (Followers: 6)
Catalysis Surveys from Asia     Hybrid Journal   (Followers: 3)
Catalysts     Open Access   (Followers: 7)
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: 12)
Chemical Bulletin of Kazakh National University     Open Access  
Chemical Communications     Full-text available via subscription   (Followers: 70)
Chemical Engineering Research and Design     Hybrid Journal   (Followers: 23)
Chemical Research in Chinese Universities     Hybrid Journal   (Followers: 3)
Chemical Research in Toxicology     Full-text available via subscription   (Followers: 19)
Chemical Reviews     Full-text available via subscription   (Followers: 174)
Chemical Science     Open Access   (Followers: 21)
Chemical Technology     Open Access   (Followers: 16)
Chemical Vapor Deposition     Hybrid Journal   (Followers: 5)
Chemical Week     Full-text available via subscription   (Followers: 8)
Chemie in Unserer Zeit     Hybrid Journal   (Followers: 55)
Chemie-Ingenieur-Technik (Cit)     Hybrid Journal   (Followers: 25)
ChemInform     Hybrid Journal   (Followers: 8)
Chemistry & Biodiversity     Hybrid Journal   (Followers: 6)
Chemistry & Biology     Full-text available via subscription   (Followers: 30)
Chemistry & Industry     Hybrid Journal   (Followers: 5)
Chemistry - A European Journal     Hybrid Journal   (Followers: 150)
Chemistry - An Asian Journal     Hybrid Journal   (Followers: 15)
Chemistry and Materials Research     Open Access   (Followers: 18)
Chemistry Central Journal     Open Access   (Followers: 4)
Chemistry Education Research and Practice     Free   (Followers: 5)
Chemistry in Education     Open Access   (Followers: 9)
Chemistry International     Hybrid Journal   (Followers: 2)
Chemistry Letters     Full-text available via subscription   (Followers: 45)
Chemistry of Materials     Full-text available via subscription   (Followers: 243)
Chemistry of Natural Compounds     Hybrid Journal   (Followers: 9)
Chemistry World     Full-text available via subscription   (Followers: 22)
Chemistry-Didactics-Ecology-Metrology     Open Access  
ChemistryOpen     Open Access   (Followers: 2)
Chemkon - Chemie Konkret, Forum Fuer Unterricht Und Didaktik     Hybrid Journal  
Chemoecology     Hybrid Journal   (Followers: 2)
Chemometrics and Intelligent Laboratory Systems     Hybrid Journal   (Followers: 15)
Chemosensors     Open Access  
ChemPhysChem     Hybrid Journal   (Followers: 9)
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: 10)
Chromatographia     Hybrid Journal   (Followers: 24)
Chromatography Research International     Open Access   (Followers: 7)
Clay Minerals     Full-text available via subscription   (Followers: 9)
Cogent Chemistry     Open Access  
Colloid and Interface Science Communications     Open Access  
Colloid and Polymer Science     Hybrid Journal   (Followers: 10)
Colloids and Surfaces B: Biointerfaces     Hybrid Journal   (Followers: 8)
Combinatorial Chemistry & High Throughput Screening     Hybrid Journal   (Followers: 3)
Combustion Science and Technology     Hybrid Journal   (Followers: 18)
Comments on Inorganic Chemistry: A Journal of Critical Discussion of the Current Literature     Hybrid Journal   (Followers: 2)
Composite Interfaces     Hybrid Journal   (Followers: 6)
Comprehensive Chemical Kinetics     Full-text available via subscription   (Followers: 2)
Comptes Rendus Chimie     Full-text available via subscription  
Comptes Rendus Physique     Full-text available via subscription   (Followers: 1)
Computational and Theoretical Chemistry     Hybrid Journal   (Followers: 9)
Computational Biology and Chemistry     Hybrid Journal   (Followers: 12)
Computational Chemistry     Open Access   (Followers: 2)
Computers & Chemical Engineering     Hybrid Journal   (Followers: 9)
Coordination Chemistry Reviews     Full-text available via subscription   (Followers: 2)
Copernican Letters     Open Access  
Critical Reviews in Biochemistry and Molecular Biology     Hybrid Journal   (Followers: 5)
Crystal Structure Theory and Applications     Open Access   (Followers: 3)
CrystEngComm     Full-text available via subscription   (Followers: 11)
Current Catalysis     Hybrid Journal   (Followers: 2)
Current Metabolomics     Hybrid Journal   (Followers: 5)
Current Opinion in Colloid & Interface Science     Hybrid Journal   (Followers: 9)
Current Research in Chemistry     Open Access   (Followers: 8)
Current Science     Open Access   (Followers: 56)
Dalton Transactions     Full-text available via subscription   (Followers: 19)
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  
Drying Technology: An International Journal     Hybrid Journal   (Followers: 4)
Eclética Química     Open Access   (Followers: 1)
Ecological Chemistry and Engineering S     Open Access   (Followers: 4)
Ecotoxicology and Environmental Contamination     Open Access  
Educación Química     Open Access   (Followers: 1)
Education for Chemical Engineers     Hybrid Journal   (Followers: 5)
EJNMMI Radiopharmacy and Chemistry     Open Access  
Elements     Full-text available via subscription   (Followers: 2)
Environmental Chemistry     Hybrid Journal   (Followers: 9)
Environmental Chemistry Letters     Hybrid Journal   (Followers: 4)
Environmental Science & Technology Letters     Full-text available via subscription   (Followers: 5)

        1 2 3 | Last

Journal Cover Applied Surface Science
  [SJR: 0.93]   [H-I: 125]   [28 followers]  Follow
    
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
   ISSN (Print) 0169-4332
   Published by Elsevier Homepage  [3042 journals]
  • Correlation between oxidant concentrations, morphological aspects and
           etching kinetics of silicon nanowires during silver-assist electroless
           etching
    • Abstract: Publication date: 15 December 2017
      Source:Applied Surface Science, Volume 425
      Author(s): Besma Moumni, Abdelkader Ben Jaballah
      Silicon porosification by silver assisted chemical etching (Ag-ACE) for a short range of H2O2 concentration is reported. We experimentally show that porous silicon (PSi) is obtained for 1% H2O2, whereas silicon nanowires (SiNWs) appeared by simply tuning the concentration of H2O2 to relatively high concentrations up to 8%. The morphological aspects are claimed by scanning electron microscopy proving that the kinetics of SiNWs formation display nonlinear relationships versus H2O2 concentration and etching time. A semi-qualitative electrochemical etching model based on local anodic, Ic, and cathodic, Ia, currents is proposed to explain the different morphological changes, and to unveil the formation pathways of both PS and SiNWs. More importantly, an efficient antireflective character for silicon solar cell (reflectance close to 2%) is realized at 8% H2O2. In addition, the luminescence of the prepared Si-nanostructures is claimed by photoluminescence which exhibit a large enhancement of the intensity and a blue shift for narrow and deep SiNWs.
      Graphical abstract image

      PubDate: 2017-07-23T12:52:10Z
       
  • Combined DFT and XPS investigation of enhanced adsorption of sulfide
           species onto cerussite by surface modification with chloride
    • Abstract: Publication date: 15 December 2017
      Source:Applied Surface Science, Volume 425
      Author(s): Qicheng Feng, Shuming Wen, Jiushuai Deng, Wenjuan Zhao
      This study systematically investigates the enhanced adsorption of sulfide species onto cerussite by surface modification with chloride through density functional theory calculations and X-ray photoelectron spectroscopy (XPS) measurements. Calculation results demonstrate obvious differences in the surface structures and electronic properties of cerussite after HS− adsorption in the absence and presence of chloride species. Surface modification with chloride promotes the stable adsorption of HS− onto the cerussite surface, and the hybridization of Pb 6p orbital at the surface layer and S 3p orbital from HS− is enhanced. Moreover, the reactivity of cerussite surfaces is enhanced by the occurrence of new DOS peaks of Pb 6p and S 3p near the Fermi level and by the transfer of additional electrons between the bonding atoms in the presence of chloride. Meanwhile, Mulliken population and XPS analysis results indicate that a slight oxidation is involved in the interaction between sulfide species and cerussite surfaces because of the presence of disulfide and polysulfide in the sulfidization products. In addition, a higher proportion of disulfide and polysulfide relative to the overall S is exhibited in the presence of chloride, facilitating the sulfidization flotation of cerussite.
      Graphical abstract image

      PubDate: 2017-07-23T12:52:10Z
       
  • Interfacial characterization and supercapacitive properties of
           polyaniline—Gum arabic nanocomposite/graphene oxide LbL modified
           electrodes
    • Abstract: Publication date: 15 December 2017
      Source:Applied Surface Science, Volume 425
      Author(s): Rafaela D. Oliveira, Cleverson S. Santos, Rodolfo T. Ferreira, Gustavo Marciniuk, Luís F. Marchesi, Jarem R. Garcia, Marcio Vidotti, Christiana A. Pessoa
      In this manuscript, we describe the synthesis and electrochemical characterization of polyaniline—gum arabic nanocomposites and graphene oxide (PANI-GA/GO) modified electrodes with a detailed study concerning their supercapacitive properties. The electrode modification was carried out by using the Layer-by-Layer technique (LbL), where the PANI-GA nanocomposite dispersion was used as polycation and the GO colloidal dispersion as polyanion. The bilayer growth was followed by both UV–vis spectroscopy and cyclic voltammetry, and an increase in the characteristic PANI absorption and in the electrochemical signal was verified, confirming the electrode build up. Galvanostatic charge-discharge curves (GCDC) were performed to evaluate the supercapacitive properties of the modified electrodes, these results showed the dependence of the specific capacitance with the number of bilayers, where values of CS around 15mFcm−2 (i=0.1mAcm−2) were found. Electrochemical impedance spectroscopy confirmed the pseudocapacitive properties of the modified electrodes, showing an increase in the low-frequency capacitance with the number of bilayers. Hereby the (PANI-GA/GO)-LbL electrodes were shown to be good candidates for active materials in supercapacitors.

      PubDate: 2017-07-23T12:52:10Z
       
  • The optimization of a Mo bilayer and its application in Cu(In, Ga)Se2
           solar cells
    • Abstract: Publication date: 15 December 2017
      Source:Applied Surface Science, Volume 425
      Author(s): P.C. Huang, C.C. Sung, J.H. Chen, C.H. Huang, C.Y. Hsu
      Molybdenum (Mo) back contact films for Cu(In, Ga)Se2 (CIGS) solar cells are deposited on soda-lime glass (SLG) substrates by direct current (DC) magnetron sputtering with a Mo target in a pure Ar atmosphere. The effect of the DC power (in the range, 100–500W) and the sputtering pressure (in the range, 0.2–1.8Pa) on the morphology, the electrical resistivity, the optical reflectance and the adhesive properties of Mo films is determined. The optimum properties for the Mo bilayer are obtained. The quality of the SLG/Mo bilayers/CIGS samples that are selenized at 560°C is confirmed to be dense and relatively smooth, with very good adherence. No cracking or peeling off is observed after selenization. The X-ray diffraction patterns for the CIGS absorbers film have a chalcopyrite crystal structure with a preferred orientation of (112), (204)/(220) and (312)/(116). The chemical composition of the Cu-In-Ga precursor films and CIGS absorbers are determined using X-ray fluorescence spectroscopy. The secondary ion mass spectroscopy surface chemical analysis for the CIGS films shows that the Ga element moves away from the surface and accumulates at the bottom of the sample and Se diffuses into the Mo surface, which indicates the possible completion of selenization. The CIGS solar cells that are produced have a maximum photo-conversion efficiency of 12.83%.
      Graphical abstract image

      PubDate: 2017-07-23T12:52:10Z
       
  • Effect of free Cr content on corrosion behavior of 3Cr steels in a CO2
           environment
    • Abstract: Publication date: 15 December 2017
      Source:Applied Surface Science, Volume 425
      Author(s): Wei Li, Lining Xu, Lijie Qiao, Jinxu Li
      The corrosion behavior of 3Cr steels with three microstructures (martensite, bainite, combined ferrite and pearlite) in simulated oil field formation water with a CO2 partial pressure of 0.8MPa was investigated. The relationships between Cr concentrations in corrosion scales and corrosion rates were studied. The precipitated phases that contained Cr were observed in steels of different microstructures, and free Cr content levels were compared. The results showed that steel with the martensite microstructure had the highest free Cr content, and thus had the highest corrosion resistance. The free Cr content of bainite steel was lower than that of martensite steel, and the corrosion rate of bainite steel was higher than that of martensite steel. Because large masses of Cr were combined in ferrite and pearlite steel, the corrosion rates of ferrite and pearlite steel were the highest. Free Cr content in steel affects its corrosion behavior greatly.
      Graphical abstract image

      PubDate: 2017-07-23T12:52:10Z
       
  • Superhydrophobicity construction with dye-sensitised TiO2 on fabric
           surface for both oil/water separation and water bulk contaminants
           purification
    • Abstract: Publication date: 15 December 2017
      Source:Applied Surface Science, Volume 425
      Author(s): Linfeng Yu, Shengmiao Zhang, Meng Zhang, Jianding Chen
      For the promising material for both oil/water separation and water-soluble contaminants, the Dye@TiO2-TEOS/VTEO hybrid modified polyester fabric is developed by a simple dip-coating process, which combines Dye-sensitised TiO2 with silicon contained superhydrophobic coating to guarantee the long-term stability of Dye-sensitised TiO2 system as well as material’s sustainability. The modified fabric possesses selective oil/water seperation properties towards water and oil, besides, mechanical, acid and alkali durability shows this material’s appropriate performance on oil/water separation. UV–Vis absorption spectrum reveals the Dye 4-(2H-imidazol-2-ylazo) benzoic acid could sensitize the semiconductor TiO2 for visible light catalytic organic pollutant degradation that is also confirmed by methylene blue degradation experiment. Density Functional calculation (DFT) witnesses that HOMO, HOMO-1 of Dye contributed by oxygen bonding to TiO2 can insert into TiO2 band gap and result in low energy electron excitation. The ability of oil/water separation and water-soluble contaminants purification provides the material opportunity to practical applications in environmental restoration and human life.
      Graphical abstract image

      PubDate: 2017-07-23T12:52:10Z
       
  • CO2-assisted fabrication of novel heterostructures of h-MoO3/1T-MoS2 for
           enhanced photoelectrocatalytic performance
    • Abstract: Publication date: 15 December 2017
      Source:Applied Surface Science, Volume 425
      Author(s): Chuanhui Zhu, Qun Xu, Wei Liu, Yumei Ren
      Combining the peculiar properties of different ingredients in one ultimate material is an efficient route to achieve the desired functional materials. Compared to 2H-MoS2, 1T-MoS2 nanosheets display the perfect performance of hydrogen evolution reaction (HER) because of the excellent electronic conductivity. However, how to further realize HER in the visual and near-infrared (NIR) region is a great challenge. Herein, we develop an efficient method to locally pattern h-MoO3 on the ultrathin metallic 1T-MoS2 nanosheets and obtain the novel heterostructures of h-MoO3/1T-MoS2. The enhanced photoelectrochemical performance of the as-prepared heterostructures has been demonstrated. Our study indicates it is originated from the synergistic effect between h-MoO3 and 1T-MoS2, i.e., the strong optical absorption of h-MoO3 in the visible and NIR region, the excellent electronic conductivity of 1T-MoS2 and as well as the efficient separation of the photo-induced carriers from the heterostructures.
      Graphical abstract image

      PubDate: 2017-07-23T12:52:10Z
       
  • Multifaceted adsorption of α-cyano-4-hydroxycinnamic acid on silver
           colloidal and island surfaces
    • Abstract: Publication date: 15 December 2017
      Source:Applied Surface Science, Volume 425
      Author(s): Dawoon Jung, Kooknam Jeon, Juhyun Yeo, Shafqat Hussain, Yoonsoo Pang
      The surface adsorption of organic nitrile compounds on the silver colloidal and island surfaces has been studied using surface-enhanced Raman scattering (SERS). α-Cyano-4-hydroxycinnamic acid (CHCA) with nitrile and carboxyl groups shows various surface adsorption on the silver surfaces. In acidic conditions, the surface adsorption of CHCA via the nitrile group with a more or less tilted geometry to the surface was found. When the solution pH increases, the carboxylate and nitrile groups of deprotonated CHCA participate in the surface adsorption, whereas the molecular plane of CHCA becomes more parallel to the surface. The ν(CN) band in SERS of CHCA is the indicator of the surface adsorption geometry. The strongly red-shifted and broadened ν(CN) band in SERS represents the surface adsorption via π-electrons of the CN bond (side-on geometry; π-coordination). Nitriles adsorbed on the surface via the nonbonding electron pair of the nitrogen atom (end-on geometry; σ-coordination) often cause the blue-shifts and small band broadening in ν(CN) in SERS. The surface adsorption geometry of organic nitriles based on many previous experimental results was further confirmed by the surface adsorption of CHCA on the silver island surfaces and dinitrile compounds on the silver colloidal surfaces.
      Graphical abstract image

      PubDate: 2017-07-23T12:52:10Z
       
  • Synthesis of uniform discrete cage-like nitrogen-doped hollow porous
           carbon spheres with tunable direct large mesoporous for ultrahigh
           supercapacitive performance
    • Abstract: Publication date: 15 December 2017
      Source:Applied Surface Science, Volume 425
      Author(s): Mingming Fang, Zhimin Chen, Qiuge Tian, Yanxia Cao, Chong Wang, Yuan Liu, Jianwei Fu, Jianan Zhang, Lichen Zhu, Chong Yang, Jiafu Chen, Qun Xu
      Uniform discrete cage-like nitrogen-doped hollow porous carbon spheres (CN-HPCS) with tunable direct large mesoporous (18–30nm) have been successfully synthesized for the first time by using the carboxylated polystyrene spheres and silica particles as a dual-template and dopamine as the carbon and nitrogen sources. When they are used as the electrode for supercapacitors, these CN-HPCS exhibit a high specific capacitance of 257Fg−1 at 1Ag−1 and 194Fg−1 at 10Ag−1 with excellent rate capability and cycling stability.
      Graphical abstract image

      PubDate: 2017-07-23T12:52:10Z
       
  • Rapid synthesis of dendritic Pt/Pb nanoparticles and their
           electrocatalytic performance toward ethanol oxidation
    • Abstract: Publication date: 15 December 2017
      Source:Applied Surface Science, Volume 425
      Author(s): Ke Zhang, Hui Xu, Bo Yan, Jin Wang, Zhulan Gu, Yukou Du
      This article reports a rapid synthetic method for the preparation of dendritic platinum–lead bimetallic catalysts by using an oil bath for 5min in the presence of hexadecyltrimethylammonium chloride (CTAC) and ascorbic acid (AA). CTAC acts as a shape-direction agent, and AA acts as a reducing agent during the reaction process. A series of physical techniques are used to characterize the morphology, structure and electronic properties of the dendritic Pt/Pb nanoparticles, indicating the Pt/Pb dendrites are porous, highly alloying, and self-supported nanostructures. Various electrochemical techniques were also investigated the catalytic performance of the Pt/Pb catalysts toward the ethanol electrooxidation reaction. Cyclic voltammetry and chronoamperometry indicated that the synthesized dendritic Pt/Pb nanoparticles possessed much higher electrocatalytic performance than bulk Pt catalyst. This study may inspire the engineering of dendritic bimetallic catalysts, which are expected to have great potential applications in fuel cells.

      PubDate: 2017-07-23T12:52:10Z
       
  • Influence of square wave anodization on the electronic properties and
           structures of the passive films on Ti in sulfuric acid solution
    • Abstract: Publication date: 15 December 2017
      Source:Applied Surface Science, Volume 425
      Author(s): Y. Long, D.G. Li, D.R. Chen
      Two types of square wave anodization (type 1 and type 2) were employed in this work to form a passive film on Ti in a 0.5M H2SO4 solution. The influences of the anodization potential and duration on the electronic properties and structures of the passive films were studied by Mott-Schottky plots, auger electron spectroscopy (AES) and X-ray photoelectron spectroscopy (XPS). The results showed that the donor density, ND, of the passive film decreased and the flat band potential, EFB, shifted to the positive direction with the increase of the anodization duration and high anodization potential irrespective of whether type 1 or type 2 was used. Moreover, the passive film that formed on Ti using type 1 had a lower donor density and a more positive flat band potential than that on Ti using type 2 at one fixed anodization duration (only exchanging the anodization order of 1V and the high potential). XPS analysis revealed that the outmost passive film was only composed of TiO2, the inner passive film was mainly composed of TiO2 with some amount of TiO and Ti2O3, and the TiO2 concentration in the outermost passive film increased with the increase of the anodization duration and the high potential in the case of using type 1 or type 2, implying an increased degree of crystallinity. The AES results showed that the O/Ti atomic ratio of the passive film obviously increased with the increasing anodization duration and high potential, demonstrating the increased homogeneous characteristic of the passive film; this was in agreement with the Mott-Schottky and XPS results.

      PubDate: 2017-07-23T12:52:10Z
       
  • Kinetics of plasma oxidation of germanium-tin (GeSn)
    • Abstract: Publication date: 15 December 2017
      Source:Applied Surface Science, Volume 425
      Author(s): Wei Wang, Dian Lei, Yuan Dong, Zheng Zhang, Jisheng Pan, Xiao Gong, Eng-Soon Tok, Yee-Chia Yeo
      The kinetics of plasma oxidation of GeSn at low temperature is investigated. The oxidation process is described by a power-law model where the oxidation rate decreases rapidly from the initial oxidation rate with increasing time. The oxidation rate of GeSn is higher than that of pure Ge, which can be explained by the higher chemical reaction rate at the GeSn-oxide/GeSn interface. In addition, the Sn atoms at the interface region exchange positions with the underlying Ge atoms during oxidation, leading to a SnO2-rich oxide near the interface. The bandgap of GeSn oxide is extracted to be 5.1±0.2eV by XPS, and the valence band offset at the GeSn-oxide/GeSn heterojunction is found to be 3.7±0.2eV. Controlled annealing experiments demonstrate that the GeSn oxide is stable with respect to annealing temperatures up to 400°C. However, after annealing at 450°C, the GeO2 is converted to GeO, and desorbs from the GeSn-oxide/GeSn, leaving behind Sn oxide.

      PubDate: 2017-07-23T12:52:10Z
       
  • Synergetic effect of MoS2 and graphene as cocatalysts for enhanced
           photocatalytic activity of BiPO4 nanoparticles
    • Abstract: Publication date: 15 December 2017
      Source:Applied Surface Science, Volume 425
      Author(s): Hua Lv, Yumin Liu, Haibo Tang, Peng Zhang, Jianji Wang
      The photodegradation of organic pollutants is an attractive green chemistry technology for water pollution control. Here we prepared a new composite material consisting of BiPO4 nanocrystals grown on layered graphene and MoS2 as a high-performance photocatalyst for the photodegradation of organic pollutants. This composite material was synthesized by a facile one-pot microwave-assisted hydrothermal technique in the presence of layered graphene and MoS2. Through optimizing the loading content of each component, the BiPO4-MoS2/graphene nanocomposite exhibited the highest photocatalytic activity for the degradation of Rhodamine (RhB) when the content of MoS2 and graphene was 2wt% and 7wt%, respectively. The enhanced photocatalytic activity of the new composite photocatalyst was attributed to the positive synergetic effect of the layered graphene and MoS2 as cocatalyst, which acted as electron collector and transporter for the interfacial electron transfer from BiPO4 to electron acceptor in the aqueous solution and thus suppressed the charge recombination and made the photogenerated holes more available to participated in the oxidation process. Moreover, the presence of layered MoS2/graphene hybrid could offer more reactive sites and activated the O2 molecular in water to form superoxide radical, thereby resulting in the enhanced photocatalytic activity.
      Graphical abstract image

      PubDate: 2017-07-23T12:52:10Z
       
  • Metal organic framework g-C3N4/MIL-53(Fe) heterojunctions with enhanced
           photocatalytic activity for Cr(VI) reduction under visible light
    • Abstract: Publication date: 15 December 2017
      Source:Applied Surface Science, Volume 425
      Author(s): Wenyuan Huang, Ning Liu, Xiaodong Zhang, Minghong Wu, Liang Tang
      In this study, hybrid nanocomposites based on Fe-based MOF and graphitic carbon nitride (g-C3N4) were developed by a facile solvothermal method. The as-prepared materials were characterized by XRD, FESEM, TEM, XPS and PL analysis. It was showed that the introduction of a certain amount of g-C3N4 on the surface of MIL-53(Fe) would improve the separation and migration rate of photo-induced charges, consequently resulting in the boost of photocatalytic efficiency. Compared with g-C3N4 and MIL-53(Fe), the CMFe composites displayed more excellent visible light-resposive photocatalytic activity for the reduction of Cr(VI). The optimal doping content of g-C3N4 in g-C3N4/MIL-53(Fe) composite was determined to be 3.0wt%, and it showed about 2.1 and 2.0 times as high photocatalytic efficiency for the reduction of Cr(VI) as that of pure g-C3N4 and MIL-53(Fe), respectively. Meanwhile, the composite exhibited good reusability and stability in the process of cyclic experiments. A possible photocatalytic reaction mechanism was also investigated in detail by the related electrochemical analysis.
      Graphical abstract image

      PubDate: 2017-07-23T12:52:10Z
       
  • Microstructure and temperature stability of highly strained
           tetragonal-like BiFeO3 thin films
    • Abstract: Publication date: 15 December 2017
      Source:Applied Surface Science, Volume 425
      Author(s): Yizhong Guo, Ying Liu, Yajun Qi, Jinzhao Wang, Kun Liang, Tianjin Zhang
      A highly strained tetragonal (T)-like BiFeO3 (BFO) phase interspersed between two rhombohedral (R)-like phase regions in BFO films grown on LaAlO3 substrates was confirmed by transmission electron microscopy (TEM). The typical width of the T-like phase was about 5–35nm and the areal fraction of the T-like phase was estimated to be 35%. A lattice misalignment of 3.8° between adjacent R- and T-like phases was observed in both high-resolution TEM images and selected-area electron diffraction patterns. Superlattice reflection spots were observed along the [110] direction in the R-like phase, which were attributed to the antiphase tilting of oxygen octahedra about the pseudocubic [111] axis of the R-like phase. A structural phase transition from the T-like phase to the R-like one at around 435°C was observed by TEM during in situ heating and cooling experiments.

      PubDate: 2017-07-23T12:52:10Z
       
  • Nanoscale domains of ordered oxygen-vacancies in LaCoO3 films
    • Abstract: Publication date: 15 December 2017
      Source:Applied Surface Science, Volume 425
      Author(s): Guiju Liu, Xiaotian Li, Yiqian Wang, Wenshuang Liang, Bin Liu, Honglei Feng, Huaiwen Yang, Jing Zhang, Jirong Sun
      High-quality LaCoO3 (LCO) thin films were epitaxially grown on SrTiO3 (STO), (La,Sr)(Al,Ta)O3 (LSAT) and LaAlO3 (LAO) substrates using pulsed laser deposition technique. Nanoscale domains with either horizontally or vertically modulated dark stripes are observed in the LCO films on STO and LSAT substrates, whereas only horizontally-modulated domains are found in the films on LAO substrate. The domain sizes and directions strongly depend on the strain state of the films due to lattice mismatch between film and substrate. The lattice strains in the films are mainly relaxed through change of the domain directions. The oxygen deficiency of the films has been revealed by X-ray photoelectron spectroscopy. As confirmed by high-angle annular dark field (HAADF) observations and high-resolution transmission electron microscopy (HRTEM) image simulations, the modulated dark stripes stem from oxygen-vacancy ordering, which causes local lattice expansion. The saturation magnetization increases with the tensile strain in the films. The ferromagnetic character is correlated with the oxygen deficiency, strain state and vertically modulated domains.
      Graphical abstract image

      PubDate: 2017-07-23T12:52:10Z
       
  • Surface characterization studies of walnut-shell biochar catalysts for
           
    • Abstract: Publication date: 15 December 2017
      Source:Applied Surface Science, Volume 425
      Author(s): Xin Song, Kai Li, Ping Ning, Chi Wang, Xin Sun, Lihong Tang, Haotian Ruan, Shuang Han
      The influences of different preparation conditions for surface characteristics on removing organic sulfur were studied. From BET, XRD, FTIR, DRIFTS, TG/DTA, CO2-TPD results, it can be seen that these preparation conditions had great influences on the pore structure, specific surface area, crystal structure and surface functional groups. The micropore volume, amorphous structure and alkalinity site strength played major roles in desulfurization process. H2S was oxidized by oxygen containing functional groups, such as COO, CO. H2O molecule could be converted into some groups, such as CH and COH groups, and promoted the hydrolysis reaction. The strong alkalinity site was the key factor for chemical adsorption and hydrolysis. H2O molecule, CH, COH groups promoted the hydrolysis reaction and COO, CO groups promoted the oxidation of H2S on the surface of WSB. Meanwhile, the main desulfurization process over WSB after carbonization was adsorption and it changed to hydrolysis reaction after activation on the surface of WSB. Furthermore, the reaction mechanism was investigated by DRIFTS measurement according to the change of surface functional groups.
      Graphical abstract image

      PubDate: 2017-07-23T12:52:10Z
       
  • Study on the influence of thiolation on the adsorption and magnetic
           recovery of superparamagnetic nanoadsorbents for Cd2+ removal
    • Abstract: Publication date: 15 December 2017
      Source:Applied Surface Science, Volume 425
      Author(s): Sen Lin, Yong Yang, Gong Chen, Xin Chen, Wei Zhang, Meng Xu, Lili Liu, Kualngfei Lin
      In the study, the influence resulting from thiol-functionalization on Fe3O4-based superparamagnetic nanoadsorbents was investigated in detail, involving various physicochemical properties, especially, the contradiction between adsorption performance and magnetic recovery. The experimental results demonstrated clearly that the aqueous dispersibility and stability of the Fe3O4-SH nanoparticles were positively related with the thiolation while the magnetic response and recovery efficiency in aqueous solution had negative correlations with the amount of SH-groups on the surface. In addition, the adsorption performances for Cd2+ using the Fe3O4-SH nanoparticles with different thiolation degrees were also studied comprehensively, which were all sensitive to pH and ionic strength and varied with a similar trend. Meanwhile, the adsorption kinetics and isotherms manifested that the initial adsorption rates and adsorption capacities could also be positively correlated with higher thiolation degree on the nanoadsorbent surface.

      PubDate: 2017-07-23T12:52:10Z
       
  • First-principles calculation of hydrogen adsorption and diffusion on
           Mn-doped Mg2Ni (010) surfaces
    • Abstract: Publication date: 15 December 2017
      Source:Applied Surface Science, Volume 425
      Author(s): Ziying Zhang, Jiarui Jin, Huizhen Zhang, Xiaoxiao Qi, Yang Bian, Hui Zhao
      Effects of Mn doping on the hydrogen adsorption and diffusion on the Mg2Ni (010) surface are studied using first-principles density functional theory. The results show that the Mg2Ni (010) surface becomes more uneven and the thermodynamical stability of Mg2Ni (010) system is lowered after Mn doping. Analysis of the hydrogen adsorption energies on the pure and Mn-doped Mg2Ni (010) surfaces shows that Mn-doped Mg2Ni (010) surface has more sites for hydrogen to adsorb stably. Further calculation of the hydrogen diffusion indicates that the substitution of Mg with Mn lowers the energy barrier for hydrogen to diffuse from the (010) surface to the subsurface.

      PubDate: 2017-07-23T12:52:10Z
       
  • Inverted polymer solar cell based on MEH-PPV/PC61BM coupled with ZnO
           nanoparticles as electron transport layer
    • Abstract: Publication date: 15 December 2017
      Source:Applied Surface Science, Volume 425
      Author(s): A.M.S. Salem, S.M. El-Sheikh, Farid A. Harraz, S. Ebrahim, M. Soliman, H.S. Hafez, I.A. Ibrahim, M.S.A. Abdel-Mottaleb
      In this work, we demonstrate the use of annealed sol-gel derived ZnO nanoparticles acting as electron transport layer (ETL) in inverted bulk heterojunction (BHJ) polymer solar cells (PSCs). We have examined the photovoltaic performance of devices based on poly(2-methoxy-5-(2-ethylhexyloxy)-p-phenylenevinylene) (MEH-PPV):(6,6)-phenyl-C61-butyric acid methyl ester (PC61BM) blend system employing the ZnO nanoparticles as an ETL with CuI as hole transport layer (HTL) in comparison to the case of using the conventional HTL of poly(3,4-ethylenedioxythiophene)/poly(styrene sulfonate) sulfonic acid (PEDOT:PSS). The effect of the presence of another layer of ZnO macrospheres attached to the ZnO nanoparticles is also investigated. The highest power conversion efficiency (PCE) value of 1.35% was achieved for device: ITO/ZnO nanoparticles/MEH-PPV:PC61BM/CuI/Ag, which is 275% more the value obtained when CuI was replaced by PEDOT:PSS. The comprehensive analyses on structural and optical characteristics including SEM, XRD, FTIR, PL and UV–vis spectroscopy indicated that the use of the ZnO nanoparticles alone as ETL, together with the CuI as HTL could effectively reduce trap-assisted recombination and charge accumulation at the interface, which is beneficial for the enhanced device performance.
      Graphical abstract image

      PubDate: 2017-07-23T12:52:10Z
       
  • Micro-tube biotemplate synthesis of Fe3O4/C composite as anode material
           for lithium-ion batteries
    • Abstract: Publication date: 15 December 2017
      Source:Applied Surface Science, Volume 425
      Author(s): Jun Du, Yu Ding, Liangui Guo, Li Wang, Zhengbing Fu, Caiqin Qin, Feng Wang, Xinyong Tao
      Kapok fibres were used as micro-tube biotemplate and bio-carbon source to synthesise Fe3O4/C composites, which were then utilised as anode materials. Fe3O4 nanoparticles were grown uniformly onto the external surface and internal channel of kapok carbon fibres. The flexibility, high specific surface area and electronic conduction of kapok fibres can buffer the volume expansion as well as inhibit the aggregation of Fe3O4 nanoparticles. Thus, the electrical integrity and structural of the Fe3O4/C composites electrode during lithiation/delithiation processes. The Fe3O4/C composites electrode delivers a high reversible capacity of 596mAhg−1 after 100 cycles and an ultra-high coulombic efficiency approaching 100%. The high electrochemical performance of the Fe3O4/C composites can be caused by the synergistic effect of the Fe3O4 nanoparticles and the structure of kapok carbon fibres.
      Graphical abstract image

      PubDate: 2017-07-23T12:52:10Z
       
  • One-step hydrothermal synthesis of sandwich-type NiCo2S4@reduced graphene
           oxide composite as active electrode material for supercapacitors
    • Abstract: Publication date: 15 December 2017
      Source:Applied Surface Science, Volume 425
      Author(s): Fangping Wang, Guifang Li, Qianqian Zhou, Jinfeng Zheng, Caixia Yang, Qizhao Wang
      A facile one step hydrothermal process is developed for the synthesis of NiCo2S4@reduced graphene oxide (NiCo2S4@RGO) composite as electrode for electrochemical supercapacitors. This NiCo2S4@RGO electrode exhibits an ultrahigh specific capacitance of 2003Fg−1 at 1Ag−1 and 1726Fg−1 at 20Ag−1 (86.0% capacitance retention from 1Ag−1 to 20Ag−1), excellent cycling stabilities (86.0% retention after 3500 cycles). Moreover, an asymmetric supercapacitor is successfully assembled by using NiCo2S4@RGO nanoparticle as the positive electrode and active carbon(AC) as the negative electrode in 2M KOH electrolyte. The fabricated NiCo2S4@RGO//AC asymmetric supercapacitor exhibits a high energy density of 21.9 Wh kg−1 at a power density of 417.1Wkg−1 and still remains an impressive energy density of 13.5Whkg−1 at a large power density of 2700Wkg−1. The results demonstrate that the NiCo2S4@RGO composite is a promising electrode material as supercapacitors in energy storage.

      PubDate: 2017-07-23T12:52:10Z
       
  • Electron-ion coupling and ambipolar diffusion in dense electron-hole
           plasma in thin amorphous Si films studied by single-shot, pulse-width
           dependent ultrafast laser ablation
    • Abstract: Publication date: 15 December 2017
      Source:Applied Surface Science, Volume 425
      Author(s): Pavel Danilov, Andrey Ionin, Roman Khmelnitskii, Irina Kiseleva, Sergey Kudryashov, Nikolay Mel’nik, Andrey Rudenko, Nikita Smirnov, Dmitry Zayarny
      Single-shot ablation of amorphous silicon films of 50-, 100- and 150-nm thickness by laser pulses of variable (0.2–6ps) widths demonstrates non-monotonous variation of ablation thresholds and characteristic ablation 1/e-radii with their minima at the 0.6-ps pulse-width and the following increase. For the shorter laser pulses the increased thresholds and enhanced transport can be related to fast ambipolar electron-hole plasma diffusion and other electronic energy losses in dense transient plasma prior its energy transfer to the ionic subsystem (electron-ion thermalization) at 0.6ps, while for the longer laser pulses slower ambipolar diffusion in moderate-density electron-hole plasma, ionic heat conduction and other thermal losses may predominate.
      Graphical abstract image

      PubDate: 2017-07-23T12:52:10Z
       
  • Self-assembled monolayer assisted binding of partially oxidized graphene
           on gold: Tunable electron-transfer mediation and in-situ electrochemical
           disassembly
    • Abstract: Publication date: 15 December 2017
      Source:Applied Surface Science, Volume 425
      Author(s): Qing Zheng, Kejian Ding, Ximing Huang, Huibo Shao
      In this research a class of graphene modified electrodes based on self-assembled monolayer assisted binding of partially oxidized graphene on gold was achieved. The electrodes show two features: (1) the tunable electron-transfer mediation ability which is controlled by the oxidation degree of the graphene, and (2) the ability of in-situ electrochemical disassembly. The tunable electron-transfer mediation ability was investigated by interpreting the cyclic voltammogram recorded with the classic redox couple, potassium ferricyanide/ferrocyanide. The ability of in-situ electrochemical disassembly was investigated by cyclic voltammetry and electrochemical impedance spectroscopy in the case of enzyme adsorption. It was found that the “on” and “off” conditions of the partially oxidized graphene correspond to the assembly and disassembly of the mercaptosuccinic acid self-assembled monolayer respectively, endowing the electrodes with the ability of in-situ electrochemical disassembly. In addition, the experimental results on glucose sensing illustrate the potential applications of the graphene modified electrodes.

      PubDate: 2017-07-23T12:52:10Z
       
  • Hydrothermal synthesis of Mn-doped ZnCo2O4 electrode material for
           high-performance supercapacitor
    • Abstract: Publication date: 15 December 2017
      Source:Applied Surface Science, Volume 425
      Author(s): A. Juliet Christina Mary, A. Chandra Bose
      Mn-doped ZnCo2O4 nanoparticle has been synthesized by hydrothermal method without adding any surfactants. Structural, morphological and electrochemical performances have been studied for the pure and various concentration of Mn-doped ZnCo2O4 nanoparticles. XRD and Raman studies demonstrate the crystalline structure of the material. Specific capacitance of the 10wt% Mn doped ZnCo2O4 nanomaterial is analysed using the three-electrode system. 10wt% Mn-doped ZnCo2O4 has a maximum capacitance of 707.4Fg−1 at a current density of 0.5Ag−1. Coulombic efficiency of the material is 96.3% for 500 cycles in the KOH electrolyte medium. A two-electrode device using 10wt% Mn-doped ZnCo2O4 exhibits the highest specific capacitance of 6.5Fg−1 at a current density of 0.03Ag−1 which is the suitable material for supercapacitor application.
      Graphical abstract image

      PubDate: 2017-07-23T12:52:10Z
       
  • Illuminate the active sites of γ-FeOOH for low-temperature
           desulfurization
    • Abstract: Publication date: 15 December 2017
      Source:Applied Surface Science, Volume 425
      Author(s): Lijuan Shen, Yanning Cao, Zhongjie Du, Wentao Zhao, Ke Lin, Lilong Jiang
      FeOOH has been explored as a promising adsorbent for low-temperature H2S adsorption. However, the nature of the active sites toward the desulfurization has remained elusive. Here, a series of γ-FeOOH is prepared with well-defined lath-like and rod-like shapes by adjusting the pH value of the reaction system. The two shapes of γ-FeOOH have identical bulk structures but expose different distributions of surface OH groups, namely singly (FeOH, OH), doubly (Fe2OH, μOH), and triply coordinated (Fe3OH, μ3 OH) hydroxyls, allowing us to investigate the geometrical-site-dependent desulfurization activity of γ-FeOOH at molecular-scale level. Following a thorough analysis by X-ray diffraction (XRD), transmission electron microscope (TEM), X-ray photoelectron spectroscopy (XPS), and in situ Fourier transform infrared spectroscopy (In situ FT-IR), we demonstrate that singly hydroxyl (FeOH, OH) site is responsible for H2S adsorption, which acts as the active site for low-temperature desulfurization.
      Graphical abstract image

      PubDate: 2017-07-23T12:52:10Z
       
  • Improving the oxidation resistance and stability of Ag nanoparticles by
           coating with multilayered reduced graphene oxide
    • Abstract: Publication date: 15 December 2017
      Source:Applied Surface Science, Volume 425
      Author(s): Yahui Li, Huayu Zhang, Bowen Wu, Zhuo Guo
      A kind of coating nanostructure, Ag nanoparticles coated with multilayered reduced graphene oxide (RGO), is fabricated by employing a three-step reduction method in an orderly manner, which is significantly different from the conventional structures that are simply depositing or doping with Ag nanoparticles on RGO via chemical reduction. The as-prepared nanostructure is investigated by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), selected-area electronic diffraction (SEAD), scanning electron microscopy (SEM), and Fourier transform infrared spectroscopy (FTIR). The results show that the obtained Ag/RGO nanostructure is observed to be a perfect coating structure with well dispersed Ag particles, which is responsible for the remarkable oxidation resistance. The results of XPS spectra indicate the content of metallic Ag is far greater than that of Ag oxides despite of prolonged exposure to the air, which fully demonstrate the excellent stability of thus coating nanostructure.
      Graphical abstract image

      PubDate: 2017-07-23T12:52:10Z
       
  • The investigation of Ga-doped ZnO as an interlayer for ohmic contact to
           Cd1−xZnxTe films
    • Abstract: Publication date: 15 December 2017
      Source:Applied Surface Science, Volume 425
      Author(s): Yibin Shen, Jian Huang, Qingmiao Gu, Hua Meng, Ke Tang, Yue Shen, Jijun Zhang, Linjun Wang, Yicheng Lu
      In this work, high quality Cd1−x Zn x Te films were prepared on fluorine doped tin oxide (FTO) glass substrates by close-spaced sublimation (CSS) method. A low resistivity sputtered Ga-doped ZnO (GZO) film was used as an interlayer between Au electrodes and Cd1−x Zn x Te films try to reduce the contact resistance and contribute to bring about a better Ohmic contact. Circular transmission line model (CTLM) was adopted to investigate the effects of GZO intermediate layer on the contact properties of Au/GZO/Cd1−x Zn x Te structure. The results show a low contact resistivity of 0.37Ωcm2 for Au/GZO contacts on Cd1−x Zn x Te films. Cd1−x Zn x Te film radiation detectors were also fabricated using Au/GZO contacts and an energy resolution of about 28% was obtained from a 60KeV 241Am γ-ray source for the first time.

      PubDate: 2017-07-23T12:52:10Z
       
  • Necklace-like fiber composite membrane for high-efficiency particulate
           matter capture
    • Abstract: Publication date: 15 December 2017
      Source:Applied Surface Science, Volume 425
      Author(s): Yingchun Su, Zhijia Zhang, Zegao Wang, Menglin Chen, Mingdong Dong, Xiaojun Han
      The necklace-like fiber membranes are fabricated using electrospinning technique for high-efficiency PM (particulate matter) capture. Poly-N,N′-[(4,5-dihydroxy-1,2 phenylene)bis(methylene)]bisacrylamide (POHABA) nanospheres as “pearls” are embedded in poly(ethylene oxide) (PEO) and poly(vinylpyrrolidone) (PVP) matrix substrates to make necklace-like fibers. The reason for choosing POHABA nanospheres is due to their broad-spectrum inhibitory effect on bacteria. The diameters of three POHABA nanospheres are controlled to be 190±50, 364±39 and 467±65nm, respectively. The necklace-like structures become more pronounced with the increase of POHABA diameter. The PM2.5 removal efficiencies of PEO necklace-like fiber membranes obtained with electrospinning time of half an hour are in the range from 88.0 to 92.5%. Under the same fabrication conditions, the PEO/POHABA-467 fiber membrane displays better capture efficiency than that of PVP/POHABA-467 fiber membrane. Using thicker PEO/POHABA-467 filter membrane (electrospinning for one hour), excellent removal efficiency of PM2.5 (99.2%) is achieved, which is better than that obtained from other membranes and even commercial QMA filter (Whatman). The necklace-like fiber membranes have a great potential in the fields of aero filter and mask.
      Graphical abstract image

      PubDate: 2017-07-23T12:52:10Z
       
  • Site-controlled fabrication of silicon nanotips by indentation-induced
           selective etching
    • Abstract: Publication date: 15 December 2017
      Source:Applied Surface Science, Volume 425
      Author(s): Chenning Jin, Bingjun Yu, Xiaoxiao Liu, Chen Xiao, Hongbo Wang, Shulan Jiang, Jiang Wu, Huiyun Liu, Linmao Qian
      In the present study, the indentation-induced selective etching approach is proposed to fabricate site-controlled pyramidal nanotips on Si(100) surface. Without any masks, the site-controlled nanofabrication can be realized by nanoindentation and post etching in potassium hydroxide (KOH) solution. The effect of indentation force and etching time on the formation of pyramidal nanotips was investigated. It is found that the height and radius of the pyramidal nanotips increase with the indentation force or etching time, while long-time etching can lead to the collapse of the tips. The formation of pyramidal tips is ascribed to the anisotropic etching of silicon and etching stop of (111) crystal planes in KOH aqueous solution. The capability of this fabrication method was further demonstrated by producing various tip arrays on silicon surface by selective etching of the site-controlled indent patterns, and the maximum height difference of these tips is less than 10nm. The indentation-induced selective etching provides a new strategy to fabricate well site-controlled tip arrays for multi-probe SPM system, Si nanostructure-based sensors and high-quality information storage.

      PubDate: 2017-07-23T12:52:10Z
       
  • Transparent optically vanadium dioxide thermochromic smart film fabricated
           via electrospinning technique
    • Abstract: Publication date: 15 December 2017
      Source:Applied Surface Science, Volume 425
      Author(s): Yuan Lu, Xiudi Xiao, Ziyi Cao, Yongjun Zhan, Haoliang Cheng, Gang Xu
      The monoclinic phase vanadium dioxide VO2 (M) based transparent thermochromic smart films were firstly fabricated through heat treatment of opaque VO2-based composite nanofibrous mats, which were deposited on the glass substrate via electrospinning technique. Noteworthily, the anti-oxidation property of VO2 smart film was improved due to inner distribution of VO2 in the polymethylmethacrylate (PMMA) nanofibers, and the composite mats having water contact angle of 165° determined itself good superhydrophobic property. Besides, PMMA nanofibrous mats with different polymer concentrations demonstrated changeable morphology and fiber diameter. The VO2 nanoparticles having diameter of 30–50nm gathered and exhibited ellipse-like or belt-like structure. Additionally, the solar modulation ability of PMMA-VO2 composite smart film was 6.88% according to UV–Vis-NIR spectra. The research offered a new notion for fabricating transparent VO2 thermochromic material.

      PubDate: 2017-07-23T12:52:10Z
       
  • Molecular adsorption properties of CO and H2O on Au-, Cu-, and
           AuxCuy-doped MoS2 monolayer
    • Abstract: Publication date: 15 December 2017
      Source:Applied Surface Science, Volume 425
      Author(s): Yelda Kadioglu, Gökhan Gökoğlu, Olcay Üzengi Aktürk
      In this study, we investigate the adsorption properties of Au, Cu, and Au x Cu y nanoclusters on MoS2 sheet and the interactions of the adsorbed systems with CO and H2O molecules by using first principles calculations. Results indicate that Au, Cu, or Au x Cu y strongly binds to MoS2 monolayer resulting in enhanced chemical activity and sensitivity toward CO and H2O molecules compared to bare MoS2 monolayer. Although both CO and H2O molecules bind weakly to pristine MoS2 monolayer, CO strongly binds to MoS2 sheet in the presence of Au, Cu atoms or Au x Cu y clusters. Semiconductor MoS2 monolayer turns into metal upon Au or Cu adsorption. Au x Cu y nanocluster adsorption decreases the band gap of MoS2 monolayer acting as a n-type dopant. Au x Cu y -doped MoS2 systems have improved adsorption properties for CO and H2O molecules, so the conclusions provided in this study can be useful as a guide for next generation device modeling.
      Graphical abstract image

      PubDate: 2017-07-23T12:52:10Z
       
  • Interface and stability analysis of Tantalum- and Titanium nitride thin
           films onto Lithiumniobate
    • Abstract: Publication date: 15 December 2017
      Source:Applied Surface Science, Volume 425
      Author(s): U. Vogel, S. Oswald, J. Eckert
      Modern surface-acoustic-wave (SAW) devices are characterized by their trend to higher frequencies, power densities and new applications. For this, a shrinking of the dimensions is necessary resulting in an increased power density and temperature within the metallization. To reduce the emerging damaging effects (acustomigration, diffusion etc.) additional barrier layers between substrates and electrodes are necessary, especially for high temperature applications. In this context, we present results of detailed chemical interface analysis of sputtered TaN and TiN thin films as potential barrier layers onto SAW-substrate material (LiNbO3) with respect to their temporal (up to 8h) and thermal stability up to 600°C in vacuum. We report good stability of both systems. The main technique for analysis was non-destructive and surface sensitive angle-resolved X-ray photoelectron spectroscopy (AR-XPS).

      PubDate: 2017-07-23T12:52:10Z
       
  • Preparation of magnetic Ni-P amorphous alloy microspheres and their
           catalytic performance towards thermal decomposition of ammonium
           perchlorate
    • Abstract: Publication date: 15 December 2017
      Source:Applied Surface Science, Volume 425
      Author(s): Yi Deng, Yuanyi Yang, Liya Ge, Weizhong Yang, Kenan Xie
      In this work, a series of amorphous Ni-P alloys with diverse microspheric structures and magnetic properties were successfully prepared through a facile aqueous solution reduction using sodium hypophosphite as reducing agent with the assistance of polyvinylpyrrolidone (PVP). Scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and laser particle size analysis were used to investigate the structure of Ni-P alloy particles, which demonstrated that the as-prepared alloys possessed spherical morphologies and tunable compositions. We investigated the effects of the synthesis conditions including reaction temperature, initial Ni2+ concentration, pH value, and surfactant type on the morphologies and chemical constitutes of Ni-P alloy particles. Compared with other microsphere counterparts (ferromagnetism), the spherical Ni-P alloy powders with diameter of about 500nm exhibited apparent paramagnetism. In addition, the catalytic performance of the products on the thermal decomposition of ammonium perchlorate (AP) was further investigated via thermogravimetric analysis (TG) and differential scanning calorimetry (DSC). These Ni-P noncrystalline alloy particles with different magnetic properties and good catalytic activities would broaden the technological and industrial applications of Ni-P alloys in petrochemical reaction, soft magnetic devices, and burning rate catalysts.

      PubDate: 2017-07-23T12:52:10Z
       
  • Synthesis and properties of a high-capacity iron oxide adsorbent for
           fluoride removal from drinking water
    • Abstract: Publication date: 15 December 2017
      Source:Applied Surface Science, Volume 425
      Author(s): Chang Zhang, Yingzhen Li, Ting-Jie Wang, Yanping Jiang, Jason Fok
      A novel iron oxide adsorbent with a high fluoride adsorption capacity was prepared by a facile wet-chemical precipitation method and ethanol treatment. The ethanol-treated adsorbent was amorphous and had a high specific surface area. The adsorption capacity of the treated adsorbent was much higher than that of untreated adsorbent. The Langmuir maximum adsorption capacity of the adsorbent prepared at a low final precipitation pH (≤9.0) and treated with ethanol reached 60.8mg/g. A fast adsorption rate was obtained, and 80% of the adsorption equilibrium capacity was achieved within 2min. The adsorbent had high fluoride-removal efficiency for water in a wide initial pH range of 3.5–10.3 and had a high affinity for fluoride in the presence of common co-anions. The ethanol treatment resulted in structure transformation of the adsorbent by inhibiting the crystallization of the nano-precipitates. The adsorption was confirmed to be ion exchange between fluoride ions and the hydroxyl groups on the adsorbent surface.
      Graphical abstract image

      PubDate: 2017-07-23T12:52:10Z
       
  • Kinetic and theoretical studies of novel biodegradable thermo-sensitive
           xerogels based on PEG/PVP/silica for sustained release of enrofloxacin
    • Abstract: Publication date: 15 December 2017
      Source:Applied Surface Science, Volume 425
      Author(s): Azra Ebadi, Amir Abbas Rafati, Sadeghali Bavafa, Masoumah Mohammadi
      This study involves the synthesis of a new silica-based colloidal hybrid system. In this new hybrid system, poly (ethylene glycol) (PEG) and thermo-sensitive amphiphilic biocompatible poly (vinyl pyrrolidone) (PVP) were used to create suitable storage for hydrophobic drugs. The possibility of using variable PVP/PEG molar ratios to modulate drug release rate from silica nanoparticles was a primary goal of the current research. In addition, an investigation of the drug release kinetic was conducted. To achieve this, silica nanoparticles were synthesized in poly (ethylene glycol) (PEG) and poly (vinyl pyrrolidone) (PVP) solution incorporated with enrofloxacin (EFX) (as a model hydrophobic drug), using a simple synthetic strategy of hybrid materials which avoided waste and multi-step processes. The impacts of PVP/PEG molar ratios, temperature, and pH of the release medium on release kinetic were investigated. The physicochemical properties of the drug-loaded composites were studied by Fourier transform infrared (FT-IR) spectra, scanning electron microscopy (SEM), and thermogravimetric analysis (TGA). In vitro drug release studies demonstrated that the drug release rate, which was evaluated by analyzing the experimental data with seven kinetic models in a primarily non-Fickian diffusion-controlled process, aligned well with both Ritger-Peppas and Sahlin-Peppas equations.
      Graphical abstract image

      PubDate: 2017-07-23T12:52:10Z
       
  • Density-functional theory study of dimethyl carbonate synthesis by
           methanol oxidative carbonylation on single-atom Cu1/graphene catalyst
    • Abstract: Publication date: 15 December 2017
      Source:Applied Surface Science, Volume 425
      Author(s): Wei Sun, Ruina Shi, Xuhui Wang, Shusen Liu, Xiaoxia Han, Chaofan Zhao, Zhong Li, Jun Ren
      The mechanism for dimethyl carbonate (DMC) synthesis by oxidation carbonylation of methanol on a single-atom Cu1/graphene catalyst was investigated by density-functional theory calculations. Carbon vacancies in graphene can significantly enhance the interaction between Cu atoms and graphene supports, and provide an increased transfer of electrons from Cu atoms to the graphene sheet. Compared with Cu-doped divacancy graphene (Cu/DG), Cu-doped monovacancy graphene (Cu/MG) provides a stronger interaction between adsorbents and the catalyst surface. Among the reaction processes over Cu1/graphene catalysts, CO insertion into methoxide was more favorable than dimethoxide. The rate-limiting step on the Cu/DG surface is the carbomethoxide reaction with methoxide, which is exothermic by 164.6kJmol−1 and has an activation barrier of 190.9kJmol−1 energy. Compared with that on the Cu crystal surface, Cu4 and Cu3Rh clusters, and the Cu2O(111) surface, the rate-determining step for DMC formation on Cu/MG, which is CO insertion into methoxide, needs to overcome the lowest barrier of 73.5kJmol−1 and is exothermic by 44.6kJmol−1. Therefore, Cu/MG was beneficial to the formation of DMC as a single-atom catalyst.
      Graphical abstract image

      PubDate: 2017-07-23T12:52:10Z
       
  • Theoretical investigation of lithium adsorption, diffusion and coverage on
           MX2 (M=Mo, W; X=O, S, Se, Te) monolayers
    • Abstract: Publication date: 15 December 2017
      Source:Applied Surface Science, Volume 425
      Author(s): F. Ersan, H.D. Ozaydin, G. Gökoğlu, E. Aktürk
      It is important to improve the high-efficient anode materials for Li batteries, which require the large capacity, high stability and mobility. In this work, we present the adsorption and diffusion properties of lithium atom on MX2 (M=Mo, W; X=O, S, Se, Te) transition metal dichalcogenide structures using first principles calculations within density functional theory. All the MX2 systems considered are semiconductor in bare state with band gaps between 0.93eV (MoO2) and 1.79eV (WS2). They turn into metal upon single Li adsorption. Li atom is adsorbed on MoO2 and WO2 rather stronger than other systems. The energy barrier for diffusion of single Li on MX2 varies between 0.15eV and 0.28eV which are lower or comparable to that of graphene or silicene. Two Li atoms are preferably adsorbed on MX2 monolayer symmetrically at opposite sides with high adsorption energy. The increasing number of Li atoms does not remarkably affect the adsorption energy per Li atom. This can be attributed to that Li atoms do not accumulate on certain regions of the surface. The systems under investigation provide insights into exploring electronic properties which are rather adequate for possible applications in Li-ion batteries.
      Graphical abstract image

      PubDate: 2017-07-23T12:52:10Z
       
  • Effect of scanning velocity on femtosecond laser-induced periodic surface
           structures on HgCdTe crystal
    • Abstract: Publication date: 15 December 2017
      Source:Applied Surface Science, Volume 425
      Author(s): Hongan Gu, Ye Dai, Haodong Wang, Xiaona Yan, Guohong Ma
      In this paper, a femtosecond laser line-scanning irradiation was used to induce the periodic surface microstructure on HgCdTe crystal. Low spatial frequency laser induced periodic surface structures of 650–770nm and high spatial frequency laser induced periodic surface structures of 152–246nm were respectively found with different scanning speeds. The evolution process from low spatial frequency laser induced periodic surface structures to high spatial frequency laser induced periodic surface structures is characterized by scanning electron microscope. Their spatial periods deduced by using a two-dimensional Fourier transformation partly agree with the predictions of the Sipe-Drude theory. Confocal micro-Raman spectral show that the atomic arrangement of induced low spatial frequency laser-induced structures are basically consistent with the crystal in the central area of laser-scanning line, however a new peak at 164cm−1 for the CdTe-like mode becomes evident due to the Hg vaporization when strong laser ablation happens. The obtained surface periodic ripples may have applications in fabricating advanced infrared detector.

      PubDate: 2017-07-23T12:52:10Z
       
  • LEEM study of high-temperature oxygen structures on W(110) and their
           transformations
    • Abstract: Publication date: 15 December 2017
      Source:Applied Surface Science, Volume 425
      Author(s): Tomasz Giela, Dorota Wilgocka-Ślęzak, Michał Ślęzak, Nika Spiridis, Józef Korecki
      High-temperature reorganization of the adsorbed oxygen on the W(110) surface was investigated using low-energy electron diffraction (LEED) and low-energy electron microscopy (LEEM). Using these two techniques, we have resolved two out of three high-temperature tungsten oxide phases reported in the literature. We verified the structural properties of oxygen adsorbed on tungsten by comparing bright- and dark-field LEEM images. In particular, we determined the relationship between atomic steps and the occurrence of a specific structural domain in different phases. Finally, we described the temperature-induced structural transformation that was directly observed, both in real and reciprocal space, for two oxygen surface phases formed on W(110). By careful examination, it was proven that under specific circumstances, this transition can be conducted in both directions, and it is possible to halt it at any stage.

      PubDate: 2017-07-23T12:52:10Z
       
  • Application of atmospheric-pressure plasma jet processed carbon nanotubes
           to liquid and quasi-solid-state gel electrolyte supercapacitors
    • Abstract: Publication date: 15 December 2017
      Source:Applied Surface Science, Volume 425
      Author(s): Fei-Hong Kuok, Ken-Yuan Kan, Ing-Song Yu, Chieh-Wen Chen, Cheng-Che Hsu, I-Chun Cheng, Jian-Zhang Chen
      We use a dc-pulse nitrogen atmospheric-pressure plasma jet (APPJ) to calcine carbon nanotubes (CNTs) pastes that are screen-printed on carbon cloth. 30-s APPJ treatment can efficiently oxidize and vaporize the organic binders, thereby forming porous structures. As indicated by X-ray photoelectron spectroscopy (XPS) and electron probe microanalysis (EPMA), the oxygen content decreases after APPJ treatment owing to the oxidation and vaporization of ethyl cellulose, terpineol, and ethanol. Nitrogen doping was introduced to the materials by the nitrogen APPJ. APPJ-calcination improves the wettability of the CNTs printed on carbon cloth, as evidenced by water contact angle measurement. Raman spectroscopy indicates that reactive species of nitrogen APPJ react violently with CNTs in only 30-s APPJ processing time and introduce defects and/or surface functional groups on CNTs. Carbon cloths with calcined CNT layers are used as electrodes for liquid and quasi-solid-state electrolyte supercapacitors. Under a cyclic voltammetry test with a 2mV/s potential scan rate, the specific capacitance is 73.84F/g (areal capacitance=5.89 mF/cm2) with a 2M KCl electrolyte and 66.47F/g (areal capacitance=6.10 mF/cm2) with a H2SO4/polyvinyl alcohol (PVA) gel electrolyte.

      PubDate: 2017-07-23T12:52:10Z
       
  • Use of a core-shell composite Ag3PO4@TCNQ to improve photocatalytic
           activity and stability
    • Abstract: Publication date: 15 December 2017
      Source:Applied Surface Science, Volume 425
      Author(s): Panru Hu, Li Liu, Weijia An, Yinghua Liang, Wenquan Cui
      We report a composite photocatalyst with a core-shell structure of Ag3PO4@TCNQ (7,7,8,8-Tetracyanoquinodimethane). TCNQ nano-sheet with a conjugated structure was coated on Ag3PO4 particles to enhanced photocatalysis and the stability of Ag3PO4. This composite catalyst can improve the contact area between semiconductors, promote the separation efficiency of electron and hole, and improve photocatalytic activity and stability. Ag3PO4@TCNQ exhibited a high degradation of phenol under visible light. The degradation rate of Ag3PO4@TCNQ (0.3wt.%) to degradation phenol achieved almost 100% in 12min, which was about 23% higher than that of pure Ag3PO4. In addition, TCNQ wrapped on Ag3PO4 surface, as the core’s protective layer, can effectively improve its stability. After five cycles, the degradation rate still reached 90%, but monomer stability retained only 43%. TCNQ, as a good electron acceptor, can transfer electrons from Ag3PO4 surface well, reduce the reduction of Ag+, and improve the separation efficiency of photogenerated charge, greatly improving the activity and stability of catalyst. TCNQ has a positive position of its energy band relative to Ag3PO4, and the electrons on the Ag3PO4 conduction band can easily transform to the Lowest Unoccupied Molecular Orbital (LUMO) level of TCNQ to realize the efficient separation of charge, which effectively improve quantum efficiency, thus improving activity and stability of catalyst.
      Graphical abstract image

      PubDate: 2017-07-23T12:52:10Z
       
  • Roles of cobalt doping on ethanol-sensing mechanisms of flame-spray-made
           SnO2 nanoparticles−electrolytically exfoliated graphene interfaces
    • Abstract: Publication date: 15 December 2017
      Source:Applied Surface Science, Volume 425
      Author(s): Matawee Punginsang, Anurat Wisitsoraat, Chakrit Sriprachuabwong, Ditsayut Phokharatkul, Adisorn Tuantranont, Sukon Phanichphant, Chaikarn Liewhiran
      In this work, the roles of cobalt (Co) and electrolytically exfoliated graphene additives on ethanol gas-sensing properties of flame-spray-made SnO2 nanoparticles were systematically studied. Structural characterizations indicated that Co dopants formed solid solution with SnO2 nanoparticles while multilayer graphene sheets were well dispersed within the Co-doped SnO2 matrix at low graphene loading contents. The sensing films were fabricated by a spin coating process and tested towards 50–1000ppm ethanol at 150–400°C. It was found that the response to 1000ppm ethanol at the optimal working temperature of 350°C was enhanced from 91 to 292 and to 803 by 0.5wt% graphene loading and 0.5wt% Co-doping, respectively. The combination of Co-doping and graphene loading with the same concentration of 0.5wt% led to a synergistic enhancement of ethanol response to 2147 at 1000ppm with a short response time of ∼0.9s and fast recovery stabilization at 350°C, proving the significance of dopant on the gas-sensing performances of graphene/SnO2 composites. Furthermore, the optimal sensor exhibited high ethanol selectivity against C3H6O, NO2, H2S, H2, CH4 and humidity. The mechanisms for the ethanol response enhancement were proposed on the basis of combinative effects of catalytic substitutional p-type Co dopants and active graphene−Co-doped SnO2 M-S junctions with highly accessible surface area of micropores and mesopores in the composites. Therefore, the graphene loaded Co-doped SnO2 sensor is highly potential for responsive and selective detection of ethanol vapor at ppm levels and may be practically useful for drunken driving applications.
      Graphical abstract image

      PubDate: 2017-07-23T12:52:10Z
       
  • Synergetic effect at the interfaces of solution processed MoS2-WS2
           composite for hydrogen evolution reaction
    • Abstract: Publication date: 15 December 2017
      Source:Applied Surface Science, Volume 425
      Author(s): Seong Ku Kim, Wooseok Song, Seulgi Ji, Yi Rang Lim, Young Bum Lee, Sung Myung, Jongsun Lim, Ki-Seok An, Sun Sook Lee
      Recently, the importance of developing an effective catalyst for hydrogen evolution reaction is emphasized because hydrogen fueled energy conversion processes are gaining attention as the next generation energy production method. We propose a transition metal dichalcogenide composite catalyst based on molybdenum disulfide (MoS2) and tungsten disulfide (WS2) on reduced graphene oxide coated nickel (rGO-Ni) foams. The composite exhibited enhanced catalytic activity with observed on-set potential of ∼275mV at −10mA/cm2 and Tafel slope of 54.1mV/dec when the composition of the composite was 50%MoS2-50%WS2. The composite catalyst demonstrated high-stability up to 300 cycles. In order to understand the enhanced catalytic activity, X-ray photoelectron spectroscopy compositional analysis was utilized. We propose that the enhancement of catalytic activities exhibited by the composited samples were achieved due to introduction of new type of interface between MoS2 and WS2 grains, regional transition of 2H phase MoS2 and WS2 to 1T phase, and formation of excess sulfur which depended directly on the composition.
      Graphical abstract image

      PubDate: 2017-07-23T12:52:10Z
       
  • Adsorption and dissociation of H2S on Rh(100) surface by First-principle
           study
    • Abstract: Publication date: 15 December 2017
      Source:Applied Surface Science, Volume 425
      Author(s): Tariq Usman, Hai-jun Luo, Yi Zhang, Xiang-ming Tao, Ming-qiu Tan
      The adsorption and dissociation of H2S on Rh(100) surface have been investigated using self-consistent periodic density functional theory. The adsorption mechanisms on Rh(100) surface of H2S, HS, H and S were examined. It is found that H2S is weakly adsorbed on bridge, top and hollow sites with their adsorption energies of −0.98, −0.86 and −0.82eV, respectively. In contrast to H2S, HS is strongly chemisorbed on Rh(100) surface at hollow, top and bridge site with the adsorption energies of −4.33, −4.31 and −3.85eV, whereas S and H preferred to be absorbed at hollow site. By using climbing nudged elastic band method (CI-NEB), we found the four most feasible paths for H2S dissociation on Rh(100), with energy barriers of 0.19eV, 0.25eV, 44meV and 98 meV, respectively. The energy barrier to break the S-H bond of HS with H co-adsorption or without H co-adsorption was almost the same low. This study reveals that H2S decomposition on Rh(100) surface is a facile process both kinetically and thermodynamically.

      PubDate: 2017-07-23T12:52:10Z
       
  • The photodeposition of surface plasmon Ag metal on SiO2@α-Fe2O3
           nanocomposites sphere for enhancement of the photo-Fenton behavior
    • Abstract: Publication date: 15 December 2017
      Source:Applied Surface Science, Volume 425
      Author(s): Kasimayan Uma, Nadarajan Arjun, Guan-Ting Pan, Thomas C.-K. Yang
      In this study, a simple sol-gel method was used for the synthesis of a core-shell structure of SiO2@α-Fe2O3 nanocomposites for employment as a visible light photocatalyst. It was observed that Ag nanoparticles about 20nm in size were successfully deposited on the surface of the SiO2@α-Fe2O3 nanocomposites. The photocatalytic activity of the Ag-SiO2@α-Fe2O3 nanocomposites catalyst was investigated by observing the degradation of methylene blue (MB) dye in a photo-Fenton process. The results showed that the Ag nanoparticles acted as centers for photo induced electron transfer. The catalytic activity in the SiO2@α-Fe2O3 nanocomposites were enhanced due to the plasmoni c effect of Ag metal under visible light irradiation. The addition of H2O2 played an important role, generating more OH radicals which improved the photo-Fenton catalytic activity, resulting in quicker degradation of the MB dye using the Ag-SiO2@α-Fe2O3 nanocomposite catalyst.
      Graphical abstract image

      PubDate: 2017-07-23T12:52:10Z
       
  • An investigation of the adsorption of potassium stearate molecules on
           diamond-like carbon substrate using molecular dynamics simulation
    • Abstract: Publication date: 15 December 2017
      Source:Applied Surface Science, Volume 425
      Author(s): Shusen Guo, Yongzhi Cao, Junjie Zhang, Le Gu, Chuanwei Zhang, Zhiqiang Xu, Tao Sun
      Molecular dynamics (MD) simulations were performed to investigate the adsorption of potassium stearate molecules on diamond-like carbon (DLC) substrate. The effects of non-bonded interactions and confinement conditions on the adsorption were investigated. The confinement conditions performed herein were achieved by imposing a Z-direction constraint on the movement of molecules in the initial stage of adsorption, and then releasing the molecules from the constraint gradually. Our simulation results show that the polar end groups of molecules tended to accumulate during the adsorption, and the final distribution of adsorptive film without confinement was irregular. Under confinement conditions, the adsorptive film was evenly distributed on the substrate after reaching its equilibrium configuration, and the final inter-subsystem potential of the substrate on adsorptive film was obviously decreased as compared with the results without confinement. These findings provided an effective approach for promoting the adsorption of molecules.

      PubDate: 2017-07-23T12:52:10Z
       
  • Electronic, magnetic properties of transition metal doped Tl2S:
           First-principles study
    • Abstract: Publication date: 15 December 2017
      Source:Applied Surface Science, Volume 425
      Author(s): Nahong Song, Yusheng Wang, Weiyang Yu, Liying Zhang, Yuye Yang, Yu Jia
      In this paper, the structural, electric and magnetic properties of transition metal (TM) doped monolayer Tl2S are investigated by means of first-principles methods The results show that all the considered TM atoms are strongly bonded to the Tl vacancy site. The magnetic moment, the dilute magnetic semiconductor and metal characteristics are varied depending on the specific TM atoms. The TM doped Tl2S (TM-Tl2S) (from Sc to Ni) systems have fractional magnetic moments changing from 0.539μB to 4.479μB. However, Cu- and Zn-Tl2S systems exit the nonmagnetic ground states. The spin polarized metallic states are achieved by Sc, Ti, V, Mn and Fe doping, while spin polarized semiconducting states are realized by Cr, Co and Ni doping. The charge transfer, the total magnetic moment and the band gap obtained with PBE method are less than the values obtained by PBE+U, which suggests that the Hubbard U plays an important role in TM-Tl2S systems. In the case of two same types of TM atoms doped Tl2S systems, there exist AFM in Sc-, V-, Mn-Tl2S systems and FM only in Ti-Tl2S system. Interestingly, the Cr-, Fe-, Co-, Ni-Tl2S systems manifest paramagnetic. These findings may provide a new route for exploring two-dimensional diluted magnetic semiconductors experimentally and theoretically.

      PubDate: 2017-07-23T12:52:10Z
       
  • Polymer supported gold nanoparticles: Synthesis and characterization of
           functionalized polystyrene-supported gold nanoparticles and their
           application in catalytic oxidation of alcohols in water
    • Abstract: Publication date: 15 December 2017
      Source:Applied Surface Science, Volume 425
      Author(s): Babak Kaboudin, Hamid Khanmohammadi, Foad Kazemi
      Sulfonated polystyrene microsphere were functionalized using ethylene diamine to introduce amine groups to the polymer chains. The amine functionalized polymers were used as a support for gold nanoparticles. A thorough structural characterization has been carried out by means of transmission electron microscopy (TEM), scanning electron microscopy (SEM) images, EDS, CHN and atomic absorption spectroscopy. The polymer supported gold nanoparticles was found to be an efficient catalyst for the oxidation of alcohols in water.
      Graphical abstract image

      PubDate: 2017-07-23T12:52:10Z
       
  • Growth and properties of nanostructured titanium dioxide deposited by
           supersonic plasma jet deposition
    • Abstract: Publication date: 15 December 2017
      Source:Applied Surface Science, Volume 425
      Author(s): E.C. Dell’Orto, S. Caldirola, A. Sassella, V. Morandi, C. Riccardi
      Titanium dioxide (TiO2) is a wide gap semiconductor suitable for many applications. In this work, TiO2 nanostructured thin films are deposited by a plasma assisted supersonic deposition technique on silicon and on conductive glass substrates. Optical Emission Spectroscopy (OES) is used to monitor plasma conditions and precursor dissociation reactions. The influence of deposition parameters on TiO2 structure, uniformity, grain size, and optical properties are investigated by atomic force microscopy (AFM), mechanical profilometer, scanning electron microscopy (SEM) and spectroscopic ellipsometry (SE). Experimental results show how employed technique allows obtaining uniform films, with a tunable deposition range. Grains size could be chosen varying precursor flux during the deposition process. Films nanostructure and porosity result to be affected by grains size. Substrate roughness results to affect film morphology.

      PubDate: 2017-07-23T12:52:10Z
       
 
 
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