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  Subjects -> CHEMISTRY (Total: 924 journals)
    - ANALYTICAL CHEMISTRY (57 journals)
    - CHEMISTRY (657 journals)
    - CRYSTALLOGRAPHY (21 journals)
    - ELECTROCHEMISTRY (27 journals)
    - INORGANIC CHEMISTRY (43 journals)
    - ORGANIC CHEMISTRY (48 journals)
    - PHYSICAL CHEMISTRY (71 journals)

CHEMISTRY (657 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: 31)
ACS Applied Polymer Materials     Hybrid Journal  
ACS Catalysis     Hybrid Journal   (Followers: 53)
ACS Chemical Neuroscience     Hybrid Journal   (Followers: 22)
ACS Combinatorial Science     Hybrid Journal   (Followers: 21)
ACS Macro Letters     Hybrid Journal   (Followers: 29)
ACS Medicinal Chemistry Letters     Hybrid Journal   (Followers: 46)
ACS Nano     Hybrid Journal   (Followers: 361)
ACS Photonics     Hybrid Journal   (Followers: 15)
ACS Symposium Series     Full-text available via subscription   (Followers: 1)
ACS Synthetic Biology     Hybrid Journal   (Followers: 24)
Acta Chemica Iasi     Open Access   (Followers: 6)
Acta Chimica Slovaca     Open Access   (Followers: 2)
Acta Chimica Slovenica     Open Access   (Followers: 1)
Acta Chromatographica     Full-text available via subscription   (Followers: 8)
Acta Facultatis Medicae Naissensis     Open Access  
Acta Metallurgica Sinica (English Letters)     Hybrid Journal   (Followers: 7)
Acta Scientifica Naturalis     Open Access   (Followers: 2)
adhäsion KLEBEN & DICHTEN     Hybrid Journal   (Followers: 8)
Adhesion Adhesives & Sealants     Hybrid Journal   (Followers: 9)
Adsorption Science & Technology     Open Access   (Followers: 7)
Advanced Functional Materials     Hybrid Journal   (Followers: 62)
Advanced Science Focus     Free   (Followers: 5)
Advances in Chemical Engineering and Science     Open Access   (Followers: 85)
Advances in Chemistry     Open Access   (Followers: 28)
Advances in Colloid and Interface Science     Full-text available via subscription   (Followers: 20)
Advances in Drug Research     Full-text available via subscription   (Followers: 26)
Advances in Environmental Chemistry     Open Access   (Followers: 8)
Advances in Enzyme Research     Open Access   (Followers: 11)
Advances in Fluorine Science     Full-text available via subscription   (Followers: 9)
Advances in Fuel Cells     Full-text available via subscription   (Followers: 17)
Advances in Heterocyclic Chemistry     Full-text available via subscription   (Followers: 11)
Advances in Materials Physics and Chemistry     Open Access   (Followers: 28)
Advances in Nanoparticles     Open Access   (Followers: 17)
Advances in Organometallic Chemistry     Full-text available via subscription   (Followers: 18)
Advances in Polymer Science     Hybrid Journal   (Followers: 49)
Advances in Protein Chemistry     Full-text available via subscription   (Followers: 19)
Advances in Protein Chemistry and Structural Biology     Full-text available via subscription   (Followers: 20)
Advances in Quantum Chemistry     Full-text available via subscription   (Followers: 6)
Advances in Science and Technology     Full-text available via subscription   (Followers: 13)
African Journal of Bacteriology Research     Open Access  
African Journal of Chemical Education     Open Access   (Followers: 5)
African Journal of Pure and Applied Chemistry     Open Access   (Followers: 8)
Agrokémia és Talajtan     Full-text available via subscription   (Followers: 2)
Al-Kimia : Jurnal Penelitian Sains Kimia     Open Access  
Alchemy : Journal of Chemistry     Open Access   (Followers: 3)
Alkaloids: Chemical and Biological Perspectives     Full-text available via subscription   (Followers: 2)
Alotrop     Open Access  
AMB Express     Open Access   (Followers: 1)
Ambix     Hybrid Journal   (Followers: 3)
American Journal of Biochemistry and Biotechnology     Open Access   (Followers: 71)
American Journal of Biochemistry and Molecular Biology     Open Access   (Followers: 22)
American Journal of Chemistry     Open Access   (Followers: 34)
American Journal of Plant Physiology     Open Access   (Followers: 13)
American Mineralogist     Hybrid Journal   (Followers: 15)
Anadolu University Journal of Science and Technology A : Applied Sciences and Engineering     Open Access  
Analyst     Full-text available via subscription   (Followers: 37)
Angewandte Chemie     Hybrid Journal   (Followers: 190)
Angewandte Chemie International Edition     Hybrid Journal   (Followers: 282)
Annales Universitatis Mariae Curie-Sklodowska, sectio AA – Chemia     Open Access   (Followers: 1)
Annals of Clinical Chemistry and Laboratory Medicine     Open Access   (Followers: 4)
Annual Reports in Computational Chemistry     Full-text available via subscription   (Followers: 3)
Annual Reports Section A (Inorganic Chemistry)     Full-text available via subscription   (Followers: 4)
Annual Reports Section B (Organic Chemistry)     Full-text available via subscription   (Followers: 8)
Annual Review of Chemical and Biomolecular Engineering     Full-text available via subscription   (Followers: 12)
Annual Review of Food Science and Technology     Full-text available via subscription   (Followers: 15)
Antiviral Chemistry and Chemotherapy     Open Access   (Followers: 2)
Applied Organometallic Chemistry     Hybrid Journal   (Followers: 9)
Applied Spectroscopy     Full-text available via subscription   (Followers: 26)
Applied Surface Science     Hybrid Journal   (Followers: 33)
Arabian Journal of Chemistry     Open Access   (Followers: 6)
ARKIVOC     Open Access   (Followers: 1)
Asian Journal of Biochemistry     Open Access   (Followers: 3)
Asian Journal of Chemistry and Pharmaceutical Sciences     Open Access   (Followers: 2)
Atomization and Sprays     Full-text available via subscription   (Followers: 5)
Australian Journal of Chemistry     Hybrid Journal   (Followers: 7)
Autophagy     Hybrid Journal   (Followers: 4)
Avances en Quimica     Open Access  
Biochemical Pharmacology     Hybrid Journal   (Followers: 11)
Biochemistry     Hybrid Journal   (Followers: 394)
Biochemistry Insights     Open Access   (Followers: 7)
Biochemistry Research International     Open Access   (Followers: 7)
BioChip Journal     Hybrid Journal  
Bioinorganic Chemistry and Applications     Open Access   (Followers: 11)
Bioinspired Materials     Open Access   (Followers: 5)
Biointerface Research in Applied Chemistry     Open Access   (Followers: 2)
Biointerphases     Open Access   (Followers: 1)
Biology, Medicine, & Natural Product Chemistry     Open Access   (Followers: 2)
Biomacromolecules     Hybrid Journal   (Followers: 25)
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: 6)
Bioorganic & Medicinal Chemistry     Hybrid Journal   (Followers: 180)
Bioorganic & Medicinal Chemistry Letters     Hybrid Journal   (Followers: 92)
Bioorganic Chemistry     Hybrid Journal   (Followers: 10)
Biopolymers     Hybrid Journal   (Followers: 17)
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 Institute of Chemistry and Chemical Technology, Mongolian Academy of Sciences     Open Access  
Bulletin of the Chemical Society of Ethiopia     Open Access   (Followers: 1)
Bulletin of the Chemical Society of Japan     Full-text available via subscription   (Followers: 25)
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: 12)
Canadian Mineralogist     Full-text available via subscription   (Followers: 7)
Carbohydrate Research     Hybrid Journal   (Followers: 24)
Carbon     Hybrid Journal   (Followers: 72)
Catalysis for Sustainable Energy     Open Access   (Followers: 10)
Catalysis Reviews: Science and Engineering     Hybrid Journal   (Followers: 10)
Catalysis Science and Technology     Hybrid Journal   (Followers: 10)
Catalysis Surveys from Asia     Hybrid Journal   (Followers: 3)
Catalysts     Open Access   (Followers: 14)
Cellulose     Hybrid Journal   (Followers: 14)
Cereal Chemistry     Full-text available via subscription   (Followers: 5)
ChemBioEng Reviews     Full-text available via subscription   (Followers: 2)
ChemCatChem     Hybrid Journal   (Followers: 8)
Chemical and Engineering News     Free   (Followers: 23)
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: 27)
Chemical Physics Letters : X     Open Access   (Followers: 2)
Chemical Research in Chinese Universities     Hybrid Journal   (Followers: 3)
Chemical Research in Toxicology     Hybrid Journal   (Followers: 22)
Chemical Reviews     Hybrid Journal   (Followers: 229)
Chemical Science     Open Access   (Followers: 32)
Chemical Technology     Open Access   (Followers: 46)
Chemical Vapor Deposition     Hybrid Journal   (Followers: 5)
Chemie in Unserer Zeit     Hybrid Journal   (Followers: 56)
Chemie-Ingenieur-Technik (Cit)     Hybrid Journal   (Followers: 21)
ChemInform     Hybrid Journal   (Followers: 8)
Chemistry     Open Access  
Chemistry & Biodiversity     Hybrid Journal   (Followers: 7)
Chemistry & Biology     Full-text available via subscription   (Followers: 32)
Chemistry & Industry     Full-text available via subscription   (Followers: 8)
Chemistry - A European Journal     Hybrid Journal   (Followers: 189)
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: 3)
Chemistry Letters     Full-text available via subscription   (Followers: 45)
Chemistry of Heterocyclic Compounds     Hybrid Journal   (Followers: 4)
Chemistry of Materials     Hybrid Journal   (Followers: 282)
Chemistry of Natural Compounds     Hybrid Journal   (Followers: 10)
Chemistry World     Full-text available via subscription   (Followers: 21)
Chemistry-Didactics-Ecology-Metrology     Open Access   (Followers: 1)
ChemistryOpen     Open Access   (Followers: 1)
Chemkon - Chemie Konkret, Forum Fuer Unterricht Und Didaktik     Hybrid Journal  
Chemoecology     Hybrid Journal   (Followers: 3)
Chemometrics and Intelligent Laboratory Systems     Hybrid Journal   (Followers: 15)
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: 12)
Chromatographia     Hybrid Journal   (Followers: 22)
Chromatography     Open Access   (Followers: 3)
Chromatography Research International     Open Access   (Followers: 5)
Clay Minerals     Hybrid Journal   (Followers: 10)
Cogent Chemistry     Open Access   (Followers: 2)
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: 8)
Combinatorial Chemistry & High Throughput Screening     Hybrid Journal   (Followers: 4)
Combustion Science and Technology     Hybrid Journal   (Followers: 24)
Comments on Inorganic Chemistry: A Journal of Critical Discussion of the Current Literature     Hybrid Journal   (Followers: 2)
Communications Chemistry     Open Access   (Followers: 2)
Composite Interfaces     Hybrid Journal   (Followers: 8)
Comprehensive Chemical Kinetics     Full-text available via subscription   (Followers: 1)
Comptes Rendus Chimie     Full-text available via subscription  
Comptes Rendus Physique     Full-text available via subscription   (Followers: 2)
Computational and Theoretical Chemistry     Hybrid Journal   (Followers: 9)
Computational Biology and Chemistry     Hybrid Journal   (Followers: 13)
Computational Chemistry     Open Access   (Followers: 3)
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: 7)
Critical Reviews in Biochemistry and Molecular Biology     Hybrid Journal   (Followers: 8)
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   (Followers: 2)
Current Metabolomics     Hybrid Journal   (Followers: 6)
Current Microwave Chemistry     Hybrid Journal  
Current Opinion in Colloid & Interface Science     Hybrid Journal   (Followers: 10)
Current Opinion in Molecular Therapeutics     Full-text available via subscription   (Followers: 13)
Current Research in Chemistry     Open Access   (Followers: 9)

        1 2 3 4 | Last

Similar Journals
Journal Cover
Applied Surface Science
Journal Prestige (SJR): 1.093
Citation Impact (citeScore): 4
Number of Followers: 33  
 
  Hybrid Journal Hybrid journal (It can contain Open Access articles)
ISSN (Print) 0169-4332
Published by Elsevier Homepage  [3183 journals]
  • Biosynthesis of Ag deposited phosphorus and sulfur co-doped g-C3N4 with
           enhanced photocatalytic inactivation performance under visible light
    • Abstract: Publication date: 31 January 2020Source: Applied Surface Science, Volume 501Author(s): Xiuquan Xu, Songmei Wang, Xiaofeng Yu, Jila Dawa, Dongliang Gui, Ronghui Tang Photocatalytic inactivation has been proved to be an effective strategy for controlling biohazards. Herein, the novel Ag deposited phosphorus and sulfur co-doped g-C3N4 (PSCN) composites with different Ag content were constructed via a facile calcination combining with biogenic-reduction method for inactivating Escherichia coli (E. coli). The detailed characterization results indicated that P and S elements were successfully co-doped into g-C3N4 (CN) lattice and Ag nanoparticles (NPs) were evenly deposited on the surface of PSCN with diameter range of 4–20 nm. The Ag/PSCN at depositing amount of 4 wt% (Ag/PSCN-4) achieved the strongest photocatalytic inactivation along with excellent stability, which could completely inactivate 7.0 log cells of E. coli within 60 min of visible light irradiation. This improved bactericidal performance was mainly attributed to the synergistic effects of P-S co-doped together with Ag deposition, which resulted in the increased visible light utilization, the improved separation and transfer efficiency of photo-induced charge carriers. Moreover, active species trapping experiments revealed that the generated superoxide radicals (O2−) and holes (h+) played the significant roles in photocatalytic inactivation process. Our present work presented a promising and environmentally friendly strategy to enhance the photocatalytic capacities of CN based composites for pathogens inactivation.Graphical abstractThe Ag deposited P, S co-doped g-C3N4 with considerably enhanced photocatalytic inactivation performance was fabricated via a facile calcination combining with biogenic-reduction method.Graphical abstract for this article
       
  • Nanoflakes of zinc oxide:cobalt oxide composites by pulsed laser
           fragmentation for visible light photocatalysis
    • Abstract: Publication date: 31 January 2020Source: Applied Surface Science, Volume 501Author(s): Sreed S. Kanakkillam, S. Shaji, B. Krishnan, S. Vazquez-Rodriguez, J.A. Aguilar Martinez, M.I. Mendivil Palma, D.A. Avellaneda Metal oxide nanomaterials as visible light photocatalysts are of special interest for the research community. We report synthesis and properties of nanocomposites of zinc oxide with cobalt oxide by cryomilling followed by pulsed laser fragmentation technique for the first time. Structure, morphology, composition, optical properties and visible light photocatalysis of these nanocomposites are investigated. Morphological analysis showed that pulsed laser fragmentation in water resulted with nanoflakes. The optical absorption in visible range was enhanced by addition of cobalt oxide. Chemical states and mapping studies of the sample surfaces showed their uniformity of elemental composition. They were used for photocatalytic studies under visible light from a solar simulator (200 W) using methylene blue dye as the contaminant. These nanocomposites showed good stability and cyclic photocatalytic activity under visible light irradiation. The results show enhanced and cyclic visible light photocatalytic activities of metal oxide nanocomposites designed by pulsed laser fragmentation.Graphical abstractGraphical abstract for this article
       
  • Microstructures and corrosion resistance of Zircaloy-4 after surface
           alloying with copper by high-current pulsed electron beam
    • Abstract: Publication date: 31 January 2020Source: Applied Surface Science, Volume 501Author(s): Shen Yang, Zuoxing Guo, Liang Zhao, Qingfeng Guan, Lei Zhao, Yuhua Liu In present paper, Zircaloy-4 surface alloying with copper (Cu) using a high-current pulsed electron beam (HCPEB) device was firstly studied. For investigating the changes in microstructures and corrosion resistance prior and after surface alloying, a series of characterization methods were adopted. Results revealed that, after surface alloying by HCPEB, a Cu-riched alloying layer with a thickness of about 3 μm was formed within the melted layer, inside which martensitic transformation was largely inhibited and large numbers of ultra-fine equiaxed β grains were generated. Most of the Cu elements in the alloying layer were uniformly distributed in the β-Zr supersaturated solid solution, others were existed in the form of fine dispersed ZrCu SPPs. Besides, Zr(Fe,Cr)2 SPPs were dissolved into the Zr-matrix within the HCPEB affect area. Compared with initial and directly irradiated specimens, the specimen after surface alloying exhibited extremely excellent anti-corrosion performance at 500 °C/10.3 MPa superheated steam, which was mainly attributed to those supersaturated Cu elements.Graphical abstractGraphical abstract for this article
       
  • Substrate effect on the structural phase formation and magnetic properties
           of α-Fe2O3 and Ti doped α-Fe2O3 thin films
    • Abstract: Publication date: 31 January 2020Source: Applied Surface Science, Volume 501Author(s): R.N. Bhowmik, Priyanka Mitra, R.J. Choudhury, V.R. Reddy We report the synthesis and magnetic properties of hematite (α-Fe2O3) and Ti doped hematite (α-Fe1.4Ti0.6O3) films. The films have been grown at 400 °C on different substrates by using Pulsed Laser Deposition technique. The as-grown film has been heated in the temperature range 600–730 °C either in air or vacuum. Microstructure of the films has been studied using X-ray diffraction pattern, Atomic force microscope, Field effect Scanning Electron Microscope, and magneto-optic Kerr effect (MOKE). Crystalline structure of the films has been stabilized either in rhombohedral phase or in cubic spinel phase depending on the type of substrates. The crystalline films have been found highly oriented on specific directions. Magnetic order of the films at room temperature has been studied using MOKE. The films on selected substrates have been used for a detailed study of low temperature magnetic properties. The temperature dependent magnetization of the films has exhibited bifurcation between zero field cooled and field cooled magnetic curves at all measurement temperatures (5–350 K). Magnetic spin order of the films has been affected by the nature of substrates. Some of the films with room temperature ferromagnetism or canted antiferromagnetism seem to be useful for spintronics applications.
       
  • Novel two-dimensional MOF as a promising single-atom electrocatalyst for
           CO2 reduction: A theoretical study
    • Abstract: Publication date: 15 January 2020Source: Applied Surface Science, Volume 500Author(s): Qianyi Cui, Gangqiang Qin, Weihua Wang, K.R. Geethalakshmi, Aijun Du, Qiao Sun The conversion of CO2 is very important for alleviating environmental and resource crisis. Herein, we have systemically investigated a family of emerging 2D metal-organic frameworks (MOFs) utilizing density functional theory (DFT) calculations. The 2D MOFs possess characteristics of single-atom catalysts (SACs), and present higher maneuverability and practicability than modifying materials by doped single metal atoms. Our results show that the Mo-based MOF presents the promising capability of CO2 activation and reduction under ambient conditions. The value of energy cost for CO2 selectively reduced to methane is low with a value of only 0.42 eV. Moreover, the energy input can be further decreased to 0.27 eV with MoO based MOF. These energy inputs are substantially lower than classical pure metal catalysts and some novel SACs based on noble metals. This study provides insights at the atomic level that novel Mo-based MOF, in which molybdenum is an earth-abundant metal, can be used as a cost-effective single-atom electrocatalyst for CO2 reduction at mild conditions.Graphical abstractThe study provides insights at atomic level that novel Mo-based two-dimensional MOF with metallic properties can be used as an efficient single-atom electrocatalyst for CO2 reduction at mild conditions.Graphical abstract for this article
       
  • First principle study of feasibility of dinitrogen reduction to ammonia on
           two-dimensional transition metal phthalocyanine monolayer
    • Abstract: Publication date: 15 January 2020Source: Applied Surface Science, Volume 500Author(s): Shiqiang Liu, Yawei Liu, Xiaoping Gao, Yujia Tan, Zhemin Shen, Maohong Fan The current remarkable catalysts for natural and artificial ammonia (NH3) synthesis are transition-metal (TM) atoms as binding site and catalytic center. Herein several TM atoms were embedded regularly and separately on phthalocyanine monolayer as N2 capture and reduction catalysts and theirs catalytic activity were investigated in this work by performing density functional theory simulations. The results showed that single molybdenum atom embedded phthalocyanine monolayer exhibited outstanding performances on N2 capture and reduction to NH3 at ambient conditions. N2 reduction reaction prefers to proceed through distal reaction pathway with a rate determining barrier 0.70 V, suggesting its good catalytic performance for N2 reduction. Our work also demonstrated the Pc monolayers can act as an excellent substrate for the design of single-atom catalysts. Our study provides a novel pathway for achieving conversion of N2 into NH3 at ambient conditions.Graphical abstractGraphical abstract for this article
       
  • Yttrium doped graphene oxide as a new adsorbent for H2O, CO, and ethylene
           molecules: Dispersion-corrected DFT calculations
    • Abstract: Publication date: 15 January 2020Source: Applied Surface Science, Volume 500Author(s): Leila Tabari, Davood Farmanzadeh A Grimme dispersion-corrected density functional theory (DFT-D) calculations are performed to explore the electronic structures and adsorption behaviors of graphene oxide (GO) and Yttrium doped graphene oxide (Y doped GO) toward the adsorption of H2O, CO, and C2H4 molecules. The HOMO and LUMO spatial distributions, the electrostatic potential charges, and the field that corresponds to the electrostatic potential are evaluated to understand the effect of the Yttrium doping on the electronic properties of the pristine graphene oxide. Calculated molecular and thermodynamic parameters indicate that the electronic structure of GO is obviously affected by the presence of yttrium atom. It can be seen that the adsorption energies of H2O, CO, and C2H4 molecules adsorption increase from 69.5, 17.4 and 34.7 kJ/mol over the pristine GO to 133.1, 182.4 and 214.2 kJ/mol for the Yttrium doped GO. We believe that the obtained results will provide beneficial insights for experimental research about the potential application of metal-doped graphene oxides as nanoscale adsorbents for water, carbon monoxide, and ethylene molecules.Graphical abstractGraphical abstract for this article
       
  • Removal of mercury by magnetic nanomaterial with bifunctional groups and
           core-shell structure: Synthesis, characterization and optimization of
           adsorption parameters
    • Abstract: Publication date: 15 January 2020Source: Applied Surface Science, Volume 500Author(s): Zhenzong Zhang, Kai Xia, Ziwei Pan, Chenxiao Yang, Xi Wang, Ganwei Zhang, Yongfu Guo, Renbi Bai In this study, a magnetic nanomaterial CoFe2O4@SiO2@m-SiO2-SH/NH2 with bifunctional groups and core-shell structure was successfully synthesised and employed to remove mercury ions [Hg(II)] for enhancing the corrosion resistance of magnetic iron-based nanomaterials. Furthermore, the grafting conditions were improved for amino (NH2) and thiol groups (SH), while increasing the capacity of iron-based adsorbent. The grafting of NH2 and SH was conducted through a relatively safe, mild and facile hydrothermal method at low temperature (353 K) without using any toxic and harmful solvents. Adsorption-related variables including solution pH, adsorbent dosage, initial concentration (C0) and reaction temperature were studied by response surface methodology analysis, wherein maximum adsorption capacity was used as a response variable. The optimal results indicate that the maximum adsorption capacity of 504.34 mg Hg(II)/g was obtained at a pH of 7.2. The magnetic nanoparticles exhibited high adsorption capacity for Hg(II) ions, i.e., 464.7 mg/g, by pseudo-second-order fitting. In addition, the maximum adsorption capacity calculated from Langmuir fitting was 517.4 mg/g at pH 7. Thermodynamic data showed that the adsorption of Hg(II) was endothermic and spontaneous. Moreover, the adsorption capacity of Hg(II) ions still reached over 300 mg/g after five adsorption–desorption cycles. Finally, the probable adsorption mechanism was discussed.Graphical abstractGraphical abstract for this article
       
  • Uncovering the electrochemical mechanisms for hydrogen evolution reaction
           of heteroatom doped M2C MXene (M = Ti, Mo)
    • Abstract: Publication date: 15 January 2020Source: Applied Surface Science, Volume 500Author(s): Bo Ding, Wee-Jun Ong, Jizhou Jiang, Xingzhu Chen, Neng Li Half-reaction of water splitting is hydrogen evolution reaction (HER), which requires low cost and high activity catalysts. Two-dimensional (2D) transition metal carbon/nitrides (MXene) materials have shown great potential as highly efficient catalysts due to their excellent properties. In this work, the heteroatom X (X = N, B, P, S) doping effect on the HER of M2C MXene (M = Ti, Mo) with or without oxygen functional groups have been performed by well-defined density functional calculations (DFT). The X doped M2CT2 (M = Mo, Ti; T = O) exhibited better HER catalytic activity than the X doped pristine M2C (M = Mo and Ti). Moreover, the calculated Gibbs free energies of hydrogen adsorption (ΔGH) indicate that the N-doped Ti2CO2 has improved electrocatalytic activity than that of Pt(1 1 1). Additionally, based on the electronic structure of X-doped Ti2CO2, the electrical conductivity of N-doped Ti2CO2 is higher than that of pristine Ti2CO2.Graphical abstractGraphical abstract for this article
       
  • A novel SiC/Zn0.5Cd0.5S solid-state Z-scheme system and its enhanced
           hydrogen production activity
    • Abstract: Publication date: 15 January 2020Source: Applied Surface Science, Volume 500Author(s): Shen-wei Bai, Hui Mei, Zhi-peng Jin, Shan-shan Xiao, Lai-fei Cheng In this article, we for the first time synthesized a series of SiC@Zn0.5Cd0.5S core-shell Z-scheme nanostructure, with the thickness of the shell varies from 12 nm to 60 nm, and the excellent photocatalytic exists because of the Z-scheme heterojunction mechanism. The Z-scheme system of SiC@Zn0.5Cd0.5S core-shell structure was proven by the in situ irradiated X-ray photoelectron spectroscopy, the system separated the photo-generated electron-hole pairs, and the core-shell structure performed better photocatalytic properties than Zn0.5Cd0.5S on the hydrogen production under UV–vis light irradiation. With decreasing of the shell thickness, the transient photocurrent response of the SiC@Zn0.5Cd0.5S increased and the photoluminescence decreased, anticipating the creation, collection, transportation of electrons/holes increased, and the electrons/holes recombination suppressed. The hydrogen production rate enhanced to 334% comparing with pure Zn0.5Cd0.5S, showing the advantage of SiC@Zn0.5Cd0.5S core-shell Z-scheme heterojunction nanostructure.Graphical abstractSchematic illustration of the charge separation and transfer in direct Z-scheme system SiC@Zn0.5Cd0.5S model under light irradiation.Graphical abstract for this article
       
  • Wettability of striped patterned mono-and multilayer graphene supported on
           platinum
    • Abstract: Publication date: 15 January 2020Source: Applied Surface Science, Volume 500Author(s): Hamzeh Yaghoubi, Masumeh Foroutan Wettability of water nanodroplet on graphene and graphene-coated metals in recent years have been the subject of interest. In the present work, the wettability of mono and three-layer graphene supported on underlying platinum was investigated using molecular dynamics simulation. Furthermore, the striped patterns were generated on the substrates by parallel grooves with different widths and depths. Wetting results showed that the Cassie-Baxter state converts into the Wenzel state by increasing the width of the grooves, which was confirmed by free energy results that obtained from free energy perturbation and potential of mean force methods. A chain of water molecules forms at interface by increasing the width of the grooves, which leads to higher hydrogen bond lifetime. Water-platinum interaction in the grooves and nanodroplet pinning cause anisotropy in the wetting and nanodroplet shape. This suggests that such artificial surfaces with anisotropic wetting properties can mimic water anisotropic behavior on some natural structures, which lead water to move in a specific direction.
       
  • Photocatalytic reduction of CO2 into CO over nanostructure Bi2S3 quantum
           dots/g-C3N4 composites with Z-scheme mechanism
    • Abstract: Publication date: 15 January 2020Source: Applied Surface Science, Volume 500Author(s): Rui-tang Guo, Xing-yu Liu, Hao Qin, Zhong-yi Wang, Xu Shi, Wei-guo Pan, Zai-guo Fu, Jun-ying Tang, Peng-yao Jia, Yu-fang Miao, Jing-wen Gu Bi2S3 quantum dots (QDs) /g-C3N4 composites with various Bi2S3 QDs contents were synthesized by hydrothermal reaction method and used in CO2 photocatalytic reduction, which demonstrated much higher photocatalytic activity than pristine g-C3N4. Experimental results indicated that the 20 wt% Bi2S3 QDs/g-C3N4 showed a remarkable photocatalytic activity, which was 4 times the CO yield of that pure g-C3N4. The SEM and TEM results indicated that Bi2S3 QDs had uniformly covered the catalysts surface, which could effectively increase the absorption of visible-light and promote the separation of photogenerated carriers, thereby decrease the recombination rate of photogenerated electron-hole pairs and enhance the performance of photocatalytic reduction.Graphical abstractGraphical abstract for this article
       
  • Interfacial electronic structure and electrocatalytic performance
           modulation in Cu0.81Ni0.19 nanoflowers by heteroatom doping engineering
           using ionic liquid dopant
    • Abstract: Publication date: 15 January 2020Source: Applied Surface Science, Volume 500Author(s): Jing Sun, Yan-Ru Chen, Keke Huang, Kai Li, Qin Wang Alloy is highly desirable for electrocatalysis due to its superconductivity and structural stability. However, it remains a great challenge to synthesize by a facile synthetic strategy and investigate the synergistic effect for various active components. Herein, a Cu0.81Ni0.19 alloy electrocatalyst doped with N, P, and F heteroatom is constructed by a simple liquid reduction method using ionic liquid as reducing agent and heteroatom dopant. The introduction of ionic liquid not only induces the flower-like morphological characteristics of the Cu0.81Ni0.19 alloy, but also regulates its interfacial electronic structure. This hybrid catalyst exhibits outstanding electrocatalytic performance towards the OER and HER in alkaline medium with ultralow overpotentials of 198 mV and 88 mV at 10 mA·cm−2, respectively, which is among the most efficient Cu-based alloy electrocatalysts up to now. Combined with DFT calculations indicate that both the electronic structure and the reaction energy barrier of the intermediate are regulated by these heteroatoms in electrocatalysis process. This work opens up a facile method to highly efficient and durable alloy electrocatalysts using ionic liquid as a dopant, and is a promising candidate strategy for other alloy catalysts.Graphical abstractGraphical abstract for this article
       
  • The inhibiting effect and mechanisms of smart polymers on the transport of
           fluids throughout nano-channels
    • Abstract: Publication date: 15 January 2020Source: Applied Surface Science, Volume 500Author(s): Yang Zhou, Jingshun Cai, Dongshuai Hou, Honglei Chang, Jiao Yu The transport of ions throughout the nano-channels is vital to the performance of porous materials. Here, a novel smart polymer with both hydrophilic and hydrophobic components was designed by molecular dynamics to regulate the capillary penetration process in cement-based materials, which determines the overall durability. The polymer structure owns carboxyl groups at one end, which are strongly attracted by the surface of a cementitious matrix due to the high polarity, as well as several alkyl groups. The polymer chain acts like a unilateral gate, which is open (lie on the matrix surface) when the nano-pore is anhydrous. However, it can be closed rapidly (stand upright, vertical to the matrix), utilizing the hydrophobic groups to maximize the transport inhibiting effect once in contact with the advancing fluids. Furthermore, a fluid transport inhibitor was fabricated based on the above mechanisms and added to the concrete mixtures. The experimental results indicate after the incorporation of this inhibitor, the water adsorption amount and chloride ion migration rate of concrete experience a huge decrease, indicating a substantial enhancement in the durability of samples. The surface interactions interpreted here may also shed new light on the understandings of smart polymers and their applications onto various matrixes.Graphical abstractGraphical abstract for this article
       
  • Non-destructive evaluation of the strain distribution in selected-area He+
           ion irradiated 4H-SiC
    • Abstract: Publication date: 15 January 2020Source: Applied Surface Science, Volume 500Author(s): Subing Yang, Sakiko Tokunaga, Minako Kondo, Yuki Nakagawa, Tamaki Shibayama Residual strain in silicon carbide (SiC) greatly affects its physical and chemical properties and thus the performance of SiC-based devices. Herein, the detailed strain distribution in selected-area He+ ion-irradiated 4H-SiC was evaluated using the non-destructive techniques of electron backscattering diffraction and confocal Raman microscopy (CRM). In addition to the strain introduced in the irradiated area, excessive strain induced by irradiation-induced swelling also extended into the surrounding substrate. Furthermore, great compressive strain was concentrated around the interface between the irradiated and unirradiated areas. In the strain-introduced substrate, an A1(LO)/A1(LOPC) peak variation was detected by CRM, suggesting a variation of the carrier density.Graphical abstractGraphical abstract for this article
       
  • Synthesis of novel and environmental sustainable AgI-Ag2S nanospheres
           impregnated g-C3N4 photocatalyst for efficient degradation of aqueous
           pollutants
    • Abstract: Publication date: 15 January 2020Source: Applied Surface Science, Volume 500Author(s): Sethupathi Velmurugan, Sridharan Balu, Selvakumar Palanisamy, Thomas C.-K. Yang, Vijayalakshmi Velusamy, Shih-Wen Chen, El-Said I. El-Shafey In recent years, synthesis of environmentally sustainable novel photocatalyst materials is of interest to the researchers working in the wide range of applications, including environmental remediation. In the present work, we describe the synthesis of environmentally sustainable and reusable AgI-Ag2S nanospheres impregnated graphitic carbon nitride (AgI-Ag2S@g-C3N4) photocatalyst using the hydrothermal and pyrolysis methods. The as-synthesized AgI-Ag2S@g-C3N4 (ACN) nanocomposite has been utilized for the degradation of organic pollutants in the aqueous solution. This current study confirms the highly active photocatalytic nature of ACN nanocomposite with a more comprehensive visible light absorption property. The ACN photocatalyst shows enhanced degradation efficiency towards Evans Blue (EB) and Congo red (CR) than that of other investigated materials such as g-C3N4 and AgI-Ag2S. The photocatalytic degradation of EB and CR was studied using different wt% containing AgI-Ag2S in ACN. The maximum degradation of EB and CR was achieved by 4 wt% and 2 wt% containing AgI-Ag2S in ACN. The ACN-4 wt% and ACN-2 wt% photocatalyst can able to degrade 98.4 and 94.2% of EB and CR within 50 min and 30 min, respectively. The photoelectrochemical measurements of ACN confirmed its excellent charge separation and the interfacial charge transport resistance.Graphical abstractGraphical abstract for this article
       
  • Effect of nitrogen-doping and post annealing on wettability and band gap
           energy of TiO2 thin film
    • Abstract: Publication date: 15 January 2020Source: Applied Surface Science, Volume 500Author(s): Zhilei Sun, V.F. Pichugin, K.E. Evdokimov, M.E. Konishchev, M.S. Syrtanov, V.N. Kudiiarov, Ke Li, S.I. Tverdokhlebov Titanium dioxide film is one of the most promising self-cleaning materials. The self-cleaning performance is directly related to the photocatalytic activity and surface wettability, which, in turn, depends on the TiO2 film structure parameters. Nitrogen-doping and post annealing are commonly used for TiO2 film treatment. The present paper addresses the mechanisms of N-doping and annealing induced TiO2 film structure transition, band gap narrowing and wettability transition. It is shown that N-doping combined with annealing leads to anatase → rutile phase transition, formation of hierarchical topography, change of surface chemical composition, and consequently results in reduction of band gap energy and water contact angle. N-doping level and N-linkages are found to significantly affect the structure/properties of annealed TiO2 and N-doped TiO2 films. The proposed mechanisms might help optimize TiO2 film synthesis and post treatment procedures. Moreover, annealed N-doped TiO2 film with highest N-content, simultaneously exhibiting anatase-rutile polycrystalline structure, high roughness, as well as lowest band gap energy and water contact angle, is supposed to present optimal self-cleaning performance.Graphical abstractGraphical abstract for this article
       
  • Ab initio study of the adsorption and dissociation of NO2 on pristine and
           Cu decorated ZnO(0001)-3 × 3
    • Abstract: Publication date: 15 January 2020Source: Applied Surface Science, Volume 500Author(s): Erika Camarillo-Salazar, Reyes Garcia-Diaz, Yuliana Avila-Alvarado, J. Guerrero-Sanchez, María Teresa Romero de la Cruz, Gregorio Hernández Cocoletzi Due to the importance of reducing environmental pollution, especially NO2, we have studied the adsorption of this contaminant to eliminate it from the atmosphere. We perform ab initio calculations of the NO2 adsorption on pristine and copper decorated zinc oxide (0001)-3 × 3 surface. Several high symmetry sites have been tested of the NO2 molecule adsorption. The structural and electronic properties of the most stable configurations are reported. The adsorption energies values show that the molecule is chemisorbed. The minimum energy pathways (MEP), to study the NO2 dissociation process, were calculated by the climbing image nudged elastic band (CI-NEB) method. The activation energy of the first stage NO2 dissociation on pristine ZnO surface is 0.14 eV, 1.83 eV lower than the 1.97 eV on the Cu decorated system. On the other hand, for the second dissociation process, the activation energy when Cu is present has a value of 1.16 eV which is 0.8 eV lower than the 1.96 eV needed on the pristine surface. Our results suggest that NO2 adsorption and first dissociation is possible on pristine ZnO(0001), but copper decoration allows a second dissociation stage providing a possible mechanism of the NO2 transformation into harmless substances.Graphical abstractGraphical abstract for this article
       
  • Carbon-coated NiCo2S4 multi-shelled hollow microspheres with porous
           structures for high rate lithium ion battery applications
    • Abstract: Publication date: 15 January 2020Source: Applied Surface Science, Volume 500Author(s): Xintao Zuo, Yue Song, Mengmeng Zhen Carbon-coated multi-shelled hollow nanomaterials with porous structures are regarded as promising anode materials for high performances lithium storage. However, a great challenge to the construction of carbon-coated multi-shelled hollow structures is the need for a facile and template-free route. Herein, we develop a sample solvothermal route followed with high-temperature pyrolysis method to construct carbon-coated NiCo2S4 multi-shelled hollow microspheres with porous structures. As an anode material for lithium-ion batteries, it exhibits a high specific capacity of 1946.7 mAh g−1 at a current density of 0.2 A g−1 and outstanding long-term cycling performances of 1242.8 and 656.4 mAh g−1 after 1000 cycles at high current densities of 2 and 5 A g−1, respectively.Graphical abstractGraphical abstract for this article
       
  • Morphology control of nanostructure using microsphere-assisted femtosecond
           laser double-pulse ablation and chemical etching
    • Abstract: Publication date: Available online 11 October 2019Source: Applied Surface ScienceAuthor(s): Jin Zhang, Sumei Wang, Lan Jiang, Mengmeng Wang, Zhuyuan Chu, Weihua Zhu, Xin Li In this study, a microsphere-assisted femtosecond (fs) laser temporal shaping fabrication method was proposed. Different from two-dimensional (2D) micro/nanohole pattern, three-dimensional (3D) hexagonal ring-like array can be obtained by microsphere-assisted fs laser double-pulse temporal pulse shaping and chemical etching. The fused silica substrate with polystyrene (PS) microsphere mask was ablated firstly by fs laser and then etched by KOH solution. During laser irradiation, PS microspheres with a diameter of 1 μm were ionized through two-photon absorption and disturbed propagation of fs laser. Concave hexagonal array was ablated because of metal-like mask screening effect of PS microspheres, whose nanowire width can be decreased to 30 nm. The ionization process inside PS microspheres can be controlled using double pulses with different pulse delays. Because of lower absorption and reflection of PS mask under double-pulse irradiation, more laser fluence can transmit into fused silica substrate. Therefore, a uniform hexagonal ring-like array was formed under double pulses after chemical etching, which cannot be obtained through traditional single pulse irradiation. The thickness of hexagonal rings can be controlled by adjusting etching time. The hexagonal ring-like array obtained under double-pulse irradiation can be applied in lubricant reservoir, drug delivery, particle trapping and surface-enhanced Raman scattering (SERS).
       
  • Facile one-step “Polymerization-Exfoliation” route to crystalline
           graphitic carbon nitride nanosheets for increased photocatalytic hydrogen
           evolution
    • Abstract: Publication date: Available online 11 October 2019Source: Applied Surface ScienceAuthor(s): Lixia Cui, Xiaojuan Hou, Haiwei Du, Yupeng Yuan Crystalline graphitic carbon nitride (g-C3N4) nanosheets have a large surface and thus show superior photocatalytic H2 generation performance upon exposure to visible light. However, producing such crystalline g-C3N4 nanosheets is highly challenge. Herein, we report a simple one-step “polymerization-exfoliation” strategy to effectively fabricate g-C3N4 nanosheets, in which the melamine precursor was heated directly to 700 °C for achieving the simultaneous polymerization and exfoliation. Thus, the prepared g-C3N4 nanosheets offer active H2 generation. The highest H2 generation is 8.3 μmol·h-1, over 14 times higher than bulk g-C3N4 under same condition (0.6 μmol·h-1). This study demonstrates a simple and effective one-step “polymerization-exfoliation” strategy towards synthesizing highly crystalline g-C3N4 for increased H2 generation.Graphical abstractGraphical abstract for this article
       
  • Evaluation of physico-chemical properties and biocompatibility of new
           surface functionalized Fe3O4 clusters of nanoparticles
    • Abstract: Publication date: Available online 11 October 2019Source: Applied Surface ScienceAuthor(s): T. Radu, A. Petran, D. Olteanu, I. Baldea, M. Potara, R. Turcu In this research, magnetic nanoclusters of Fe3O4 (MNC) were synthesized by solvothermal method using different organic acids as surfactants such malic acid, aspartic acid and sodium tartrate in order to obtain new nanostructured materials with applications in medicine. The interaction process of these acids on the surface of magnetic nanoclusters is important in understanding the change induced on the surface properties of the obtained MNC. Structural analysis and physico-chemical characterization of the new synthesized materials were performed by means o X-ray photoelectron spectroscopy (XPS), transmission electron microscopy, zeta potential and magnetic measurements to provide their spherical shape, stability and specific functional groups and the influence of the surfactants on their magnetic properties. XPS core level and valence band photoemission spectra for all investigated samples is discussed in terms of changes induced in the electronic structure linked to variation of the Fe2+ cations at the samples surface. This is of fundamental importance to better understand the electronic structure and magnetism of the obtained MNC in order to tailor their electronic properties by surface engineering for specific biomedical applications. The biological effects of MNC in rat blood were studied by hemolysis and erythrocyte antioxidant systems (superoxide dismutase and catalase) showing no negative effect on the cells.
       
  • Sensitive, selective and rapid ammonia-sensing by gold
           nanoparticle-sensitized V2O5/CuWO4 heterojunctions for exhaled breath
           analysis
    • Abstract: Publication date: Available online 11 October 2019Source: Applied Surface ScienceAuthor(s): H. Naderi, S. Hajati, M. Ghaedi, K. Dashtian, M.M. Sabzehmeidani Marigold flower-like V2O5/CuWO4 heterojunctions were synthesized and its volatile organic compound (VOC)-sensing properties were tested and significantly enhanced after sensitizing by Au nanoparticles. Detailed characterizations were carried out by SEM, XRD and XPS to determine the morphology, crystal structure, elemental and chemical composition of the sensing materials, respectively. The fabricated gold-sensitized sensor was found to be rapidly responsive (a few seconds), highly sensitive to ammonia with good selectivity as compared to various types of VOCs. The limit of detection and linear range of sensor at 150°C were 212 ppb and 5-158 ppm, respectively, which is suitable for detection of exhaled breath ammonia of patients at their last stage of chronic kidney disease. Furthermore, it was found to be of high intra-day repeatability, which is properly explained by discussing the mechanism of NH3 sensing. Very long-term stability of the sensor was investigated over 56 days, once a week.Graphical abstractGraphical abstract for this article
       
  • Temperature-dependent Photoluminescence Properties of C(carbon)-Aided ZnO
           Nanorod Arrays on (100) Si Substrate
    • Abstract: Publication date: Available online 11 October 2019Source: Applied Surface ScienceAuthor(s): Im Taek Yoon, Hak Dong Cho, Mingkai Li, Nguyen Thuy Hang, Woochul Yang We investigate the photoluminescence (PL) spectra of ZnO nanorod (NR) and C(carbon)-aided NR arrays from 10 to 300 K. The activation energy of the donor-bound exciton of the ZnO NRs was determined to be 11.3 meV ranging over 10 ∼ 300 K. The decreasing behavior of the PL intensity for the C(carbon)-aided ZnO NRs exhibited two activation energies, i.e., 3.2 and 65.8 meV at T < 70 K and T> 70 K, respectively. The activation energy for the donor-bound exciton decreased because of stronger quantum confinement in the C(carbon)-aided ZnO NRs than that of the ZnO NRs. We attribute these results to lower lattice mismatch, a larger surface-to-volume ratio, and the dense structure of the vertically orientated hexagonal pillars with flat faceted surfaces in the C(carbon)-aided ZnO NRs. A considerable exciton binding energy of 65.8 meV from the C(carbon)-aided ZnO NR arrays produced luminescence stably at 300 K. In addition, PL spectra demonstrated that the luminescence intensities of the C(carbon)-aided ZnO NRs were higher than that of the ZnO NRs because of weak exciton-phonon coupling. The higher PL intensities of the C(carbon)-aided ZnO NRs suggest that these structures might feature improved performance in optoelectronic nano-devices manufactured from ZnO NRs.Graphical abstractGraphical abstract for this article
       
  • Two-dimensional BiP3 with high carrier mobility and moderate band gap for
           hydrogen generation from water splitting
    • Abstract: Publication date: Available online 11 October 2019Source: Applied Surface ScienceAuthor(s): Hong-Yao Liu, Chuan-Lu Yang, Mei-Shan Wang, Xiao-Guang Ma The monolayered bismuth triphosphide (BiP3) with C2/m and P3m1 space groups are predicted as a new body of the 2D triphosphide structures by using the first principles calculations. The results demonstrate that the BiP3 monolayers possess indirect bandgaps of 1.36 and 2.20 eV (HSE06) or 1.34 and 2.64 eV (G0W0). The band edges of the monolayer of P3m1 BiP3 can straddle the reduction and oxidation potentials of the water splitting reaction of hydrogen production even under the uniaxial or biaxial strain from -2% to 1%. Moreover, the highest mobility of 2.49×105 cm2V −1s−1 for the hole of the P3m1 BiP3 monolayer is larger than the previously reported values of triphosphide monolayers. The obvious absorptions in the visible light range are observed for both BiP3 monolayers and that of the P3m1 structure can be improved by the tensile strain. Therefore, the P3m1 BiP3 monolayer is a promising candidate of the photocatalytic materials for the water splitting reaction to produce hydrogen under driven by the visible light.Graphical abstractGraphical abstract for this article
       
  • Ag supported Z-scheme WO2.9/g-C3N4 composite photocatalyst for
           photocatalytic degradation under visible light
    • Abstract: Publication date: Available online 11 October 2019Source: Applied Surface ScienceAuthor(s): Xin Zhao, Xiaojing Zhang, Dongxue Han, Li Niu Efficient utilization of photo-induced carriers and adsorption capacity is a promising approach to realize positive photocatalytic dye degradation. Yet the ability to reliably combine both features within one photocatalytic system, especially inorganic stuff is challenging. Here we reported the formation of WO2.9 with oxygen vacancy demonstrating better adsorption capacity promotion in comparison with traditional WO3. Besides, resorting to Ag nanoparticles as cocatalyst supported WO2.9 on g-C3N4 (Ag/WO2.9/g-C3N4) catalyst has been constructed, which has low-energy of electrons in WO2.9 neutralized with holes in g-C3N4, leaving intensive energy holes from WO2.9 for hydroxyl radical generation and electrons of g-C3N4 resulted in superoxide radical. Depending on the dual radicals existence and exploited adsorption capacity promotion, Ag/WO2.9/g-C3N4 exhibited desired photo-degradation performance for Rhodamine B, methylene blue and methyl orange under visible light irradiation (λ ˃ 420 nm), which was distinctly better than single Ag/WO2.9 and onefold g-C3N4. In the end, a possible Z-scheme photocatalytic mechanism was proposed to explain the effective separation of photogenerated carriers Ag/WO2.9/g-C3N4 heterojunctions. This work expanded our understanding between structure-property and photocatalytic activity and applied this understanding to design highly photoactive catalyst.Graphical abstractGraphical abstract for this article
       
  • Crystal symmetry breaking in thin square nanosheets of the topological
           insulator bismuth telluride
    • Abstract: Publication date: Available online 11 October 2019Source: Applied Surface ScienceAuthor(s): Yujie Liang, Yinsi Wang, Guling Zhang, Dong Zeng, Min Zhu, Junli Fu, Wenzhong Wang For potential use as a topological insulator, thin square-like Bi2Te3 nanosheets, prepared via a facile solution-based method, were subjected to detailed micro-Raman spectral measurements. The results demonstrate remarkable activation of the infrared active A1u mode in the Raman spectra despite the forbidden nature of the odd-parity A1u mode for bulk Bi2Te3 crystals. Therefore, the results unambiguously prove the crystal symmetry breaking of the thin square-like Bi2Te3 nanosheets. This study illustrates the potential applicability of micro-Raman spectroscopy as a powerful nanometrology tool for investigating the optical properties of topological insulators.Graphical abstractRemarkable crystal symmetry breaking in thin square nanosheets of topological insulator Bi2Te3.Graphical abstract for this article
       
  • The Effect and Mechanism of Alloying Elements on Al/SiC Interfacial
           Reaction in Al Melt
    • Abstract: Publication date: Available online 11 October 2019Source: Applied Surface ScienceAuthor(s): Haotian Tong, Feng Qiu, Rui Zuo, Ping Shen, Xiaoshuang Cong, Jingshen Liu, Hongyu Yang, Qichuan Jiang The control of the Al-SiC interfacial reaction is a critical process in the preparation of SiC-reinforced Al matrix composites. The brittle phase Al4C3 formed during the interfacial reaction can reduce the strength, elastic modulus and corrosion resistance of the composites. The impregnation method was used in this paper to observe the interfacial reaction between pure Al and SiC under different reaction conditions. It was revealed that an increase in temperature is beneficial to the decomposition of SiC, the increase of atomic diffusion rate and the nucleation of Al4C3. Furthermore, an extension of reaction time promoted the further nucleation and growth of Al4C3. Meanwhile, the experimental results showed that Cu, Si and Mg all can reduce the amount of Al4C3 formed on the interface to varying degrees and function through different influence mechanisms. These results provide significant guidance for the preparation of Al/SiC used in electronic packaging with good thermal conductivity.Graphical abstractGraphical abstract for this article
       
  • Probing the in-depth distribution of organic/inorganic molecular species
           within the SEI of LTO/NMC and LTO/LMO batteries: a complementary ToF-SIMS
           and XPS study
    • Abstract: Publication date: Available online 11 October 2019Source: Applied Surface ScienceAuthor(s): Nicolas Gauthier, Cécile Courrèges, Julien Demeaux, Cécile Tessier, Hervé Martinez Spinel Li4Ti5O12 (LTO) is an attractive candidate for negative electrode materials of Li-ion batteries because of its outstanding safety characteristics. In this paper, the influence of common high voltage cathodes, LiNi3/5Co1/5Mn1/5O2 (NMC) and LiMn2O4 (LMO), upon the electrochemical performances of LTO/LMO and LTO/NMC cells, in relation with the Solid Electrolyte Interphase (SEI) properties formed over the LTO surface, is studied. After cycling, the electrodes were analyzed by ToF-SIMS and XPS with two X-ray sources (Ag and Al) to investigate both the chemical composition and the in-depth distribution of specific SEI species at the electrode surface. Facing both counter-electrodes, LTO electrodes are covered by surface layers due to the degradation of electrolyte components inducing an irreversible capacity loss, more important for LTO/LMO cells. The chemical composition of both layers is similar: organic and inorganic species but the SEI formed on LTO electrode cycled facing LMO electrode is thicker and contains small amounts of manganese compounds from the positive electrode. Moreover, 3D mappings reconstructed from ToF-SIMS depth-profile experiments, display different in-depth spatial distributions of SEI species, which are in agreement with XPS results. Consequently, the impact of interactions between electrodes on the formation of surface films is discussed.Graphical abstractGraphical abstract for this article
       
  • Electric field and strain effects on the electronic and optical properties
           of g-C3N4/WSe2 van der Waals heterostructure
    • Abstract: Publication date: Available online 11 October 2019Source: Applied Surface ScienceAuthor(s): Jiaxin Ye, Jiwen Liu, Yukai An Efficient carrier separation and regulable visible light absorption are important characteristics for eligible nanoscale photoelectric devices. In this work, tunable electronic structure and optical properties of novel g-C3N4/WSe2 van der Waals heterostructure under various electric fields and biaxial strains are systematically investigated by first principle calculations. The results show that the g-C3N4/WSe2 heterostructure is a direct band gap semiconductor (1.395 eV) with intrinsic type-I band alignment and exhibits good UV and visible light absorption compared to the isolated g-C3N4 and WSe2 monolayers. Applied external electric-field can effectively adjust the interlayer coupling and charge transfer, which can further alter the band structure and achieve the transition of type I to type II band alignment for the g-C3N4/WSe2 heterostructure. The biaxial strain causes charge redistribution in the interfacial regions and triggers an indirect-direct band gap transition in the g-C3N4/WSe2 heterostructure, which is strongly associated with the modification of band structure contributed by W dz2 and dxy orbitals near the Fermi level. Besides, the systematical red shift and blue shift of absorption peaks is also observed under the tensile and compressive strains, respectively. The tunable electronic structure and optical properties make g-C3N4/WSe2 vdW heterostructure potential candidates for application in the photoelectronic device.Graphical abstractGraphical abstract for this article
       
  • Fine platinum nanoparticles supported on polyindole-derived nitrogen-doped
           carbon nanotubes for efficiently catalyzing methanol electrooxidation
    • Abstract: Publication date: Available online 11 October 2019Source: Applied Surface ScienceAuthor(s): Kexin Huang, Jingping Zhong, Jiongrong Huang, Huaguo Tang, Youjun Fan, Muhammad Waqas, Bo Yang, Wei Chen, Jun Yang Carbon-based nanomaterials e.g. activated carbon powder, carbon nanotubes and graphene are often used as supports to sustain high performance of metal nanoparticles in electrochemical reactions. In principle, doping the carbon-based nanomaterials with hetero-atoms is an efficient approach to increase their catalytic aspects as catalyst supports. In this study, nitrogen-doped multi-walled carbon nanotubes (N-MWCNTs) are prepared for the first time by annealing the polyindole (PIn) coated acid treated MWCNTs, and then fine platinum nanoparticles (PtNPs) are deposited on them to design the Pt/N-MWCNTs catalyst for the anodic reaction of direct methanol fuel cells (DMFCs). The characterizations including Raman spectroscopy, X-ray diffraction (XRD), transmission electron microscopy (TEM), X-ray energy dispersive spectroscopy (EDX) and X-ray photoelectron spectroscopy (XPS) confirm that zero valent Pt metal is formed on the surfaces of N-MWCNTs with highly dispersion and uniformly fine sizes (ca. 2.11 nm). The Pt/N-MWCNTs exhibit the enhanced electro-catalytic efficacy, improved electrochemical stability and anti-CO poisoning capability compared to Pt/AO-MWCNTs (the precursor used to prepare Pt/N-MWCNTs) and commercially available Pt/C catalysts for methanol oxidation reaction (MOR) due to strong electronic interaction between the fine PtNPs and the N-MWCNT supports, as verified by electrochemical cyclic voltammetry and chronoamperometry methods.Graphic abstractDfdf ddfdf.Graphical abstract for this article
       
  • Effects of Low-Temperature Plasma Treatment on Wettability of Glass
           Surface: Molecular Dynamic Simulation and Experimental Study
    • Abstract: Publication date: Available online 11 October 2019Source: Applied Surface ScienceAuthor(s): Da Li, Min Xiong, Song Wang, Xi Chen, Shen Wang, Qiang Zeng The improvement of wettability of glass surface plays a vital role in the bonding between glass and other materials. Low-temperature plasma treatment can improve the wettability of glass surface, but the micro-mechanism needs further study. In this paper, the glass surface was treated by low-temperature plasma, and the wettability of the treated surface was studied by experiment and molecular dynamics (MD) simulation. The results show that the relative content of oxygen of the glass surface increases while that of carbon impurity decreases after low-temperature plasma treatment. After low-temperature plasma treatment, the wettability of glass surface is improved obviously while the surface morphology is almost unchanged. MD simulation results show that the active groups are more easily adsorbed on the glass surface in a free state and interact strongly with water. Among them, the interaction between the hydroxylated glass surface and water droplets is the strongest, so the wettability of glass surface is obviously improved. The number of chemical bonds between the glass surface and water increases after low-temperature plasma treatment and the number of chemical bonds in the hydroxylated glass system increases the most. Therefore, the interfacial bonding is enhanced, and the wettability of the glass surface is improved. The simulation results are in agreement with the experimental ones. The above research provides a theoretical basis for improving the strength of glass bonded joints.
       
  • Surface characterization of two Ce0.62Zr0.38O2 Mixed Oxides with different
           Reducibility
    • Abstract: Publication date: Available online 10 October 2019Source: Applied Surface ScienceAuthor(s): M.P. Yeste, P.A. Primus, R. Alcantara, M.A. Cauqui, J.J. Calvino, J.M. Pintado, G. Blanco This paper presents a study of the surface properties of two Ce/Zr mixed oxides with different reducibility, obtained by applying distinct thermal ageing treatments to an oxide with the composition Ce0.62Zr0.38O2. The surface composition was investigated by XPS. Chemical reactivity of the surface was studied by adsorption of the probe molecules CO2, D2 and methanol. Nanostructural characterization was carried out by XRD, Raman and high-resolution Eu3+ spectroscopy (FLNS). The characterization showed only slight variations in surface composition and bulk Ce-Zr distribution, but hardy differences concerning the type and strength of acidic surface centres, as well as strong differences in the ability to dissociate hydrogen. Structural variations between both samples were identified by comparing the optical spectra of Eu3+ in surface doped samples.Graphical abstractGraphical abstract for this article
       
  • Influence of Gd+3 Incorporation on Ethanol Sensing Properties of Barium
           Stannate Microrod Films Prepared by Coprecipitation Method
    • Abstract: Publication date: Available online 10 October 2019Source: Applied Surface ScienceAuthor(s): Anish Bhattacharya, Xiangfeng Chu, Qi Gao, Xue Li, Yongping Dong, Shiming Liang, Amit K. Chakraborty Ethanol sensing is an important area of research given its relevance to human health, traffic control and various industries. Metal oxide semiconductor nanostructures are most commonly used as gas sensors. In this study, enhanced ethanol sensing properties were obtained by incorporation of Gd3+ ions into Barium Stannate (BSO), a bimetallic oxide microrods prepared through a simple co-precipitation method. The GBSO films, when exposed to ethanol, showed that incorporation of Gd improved the sensing response till 3 wt% of Gd (3GBSO) loading while further increase in Gd content resulted in reduced response. 3GBSO sample showed response as high as 76 to 500 ppm of ethanol vapor at an operating temperature of 220 °C along with a very low detection limit of 0.1 ppm (response of 1.5). Good repeatability and moderate stability were also observed suggesting its potential as low-cost ethanol sensor. Significant increase in both specific surface area as well as oxygen content (as measured by x-ray photoelectron spectroscopy) was observed in 3GBSO sample compared to that of BSO. Thus, we showed that incorporation of Gd improved the surface area of BSO microrods and in turn the surface adsorption of oxygen which led to their enhanced response to ethanol.
       
  • Surface wettability and emission behavior tuned via solvent in a
           supramolecular self-assembly system based on a naphthalene diimides
           derivative
    • Abstract: Publication date: Available online 10 October 2019Source: Applied Surface ScienceAuthor(s): Xinhua Cao, Yiran Li, Xiaoyuan Zhang, Aiping Gao, Ruixiang Xu, Yongsheng Yu, Xiaohan Hei A new gelator (1) based on a naphthalene diimide derivative with two adamantane groups was designed and synthesized, to form stable organogels in 1,4-dioxane, DMSO, ethyl acetate, THF/H2O (1/1, v/v), acetone, toluene, methanol and ethanol under the driving force of noncovalent bonding. Gel 1 in toluene exhibited thixotropic properties. The gel could change to a sol by mechanical force, and recover in 5 seconds. The sol-gel transition process of gel 1 was thoroughly investigated via field emission scanning electron microscopy (FESEM), ultraviolet visible spectra (UV-vis), fluorescence (FL), X-ray powder diffraction (XRD), Fourier Transform Infrared Spectroscop (FTIR) and contact angles (CA). The emission properties and xerogel surface wettability properties could be modulated via the solvent. The supra-hydrophobic surface with the contact angle of 146 ° was obtained from gel 1 in DMSO and exhibited the characteristic of “lotus-effect”. The hydrophobicity of film 1 produced profound effects on the fluorescence intensity and the lifetime of the excited state. This work offers a new way to construct supra-hydrophobicity via self-assembly.Graphical abstractGraphical abstract for this article
       
  • The microstructure and oxidation behavior of the N-doped modified layers
           on uranium surface prepared by pulsed laser irradiating
    • Abstract: Publication date: Available online 9 October 2019Source: Applied Surface ScienceAuthor(s): Huoping Zhong, Yin Hu, Qifa Pan, Yongbin Zhang, Lizhu Luo, Fangfang Li, Hong Xiao, Haibo Li, Yanping Wu, Zhilei Chen, Xiaofang Wang, Kezhao Liu The N-doped modified layer on uranium surface was prepared by pulsed laser irradiating in nitrogen atmosphere. The results of microstructure characterised by XRD, AES and XPS show that it is a composite layer with a gradual transition structure from UO2-xNy and uranium oxy-nitride(UNxOy) to UN and eventually to uranium from surface to interior. Initial oxidation behavior after sputtering for different time illustrates that UNxOy with U 4f7/2 BE at 379.6 eV is inert under oxygen exposure. Further, the thermal stability study shows that the modified layer exhibits excellent ability to prevent the O atoms from diffusing into the interior at 423 K. Moreover, the corrosion protective properties of the N-doped modified layers before and after thermal treatment were evaluated through potentiodynamic polarization tests. The results show that the N-doped modified layer improved the corrosion protective properties of metallic uranium. The self-corrosive potential and self-corrosive current of the N-doped modified layer are -5.75×10-2 V vs. SCE and 1.37×10-7 A/cm2, while the values of metallic uranium were -5.67×10-1 V vs. SCE and 8.08×10-7 A/cm2. After thermal treatment, its values are -8.57×10-2 V vs. SCE and 4.83×10-8 A/cm2, indicating that the corrosion resistance of the N-doped modified layer was further improved.
       
  • Correlation between the surface chemistry, the surface free energy and the
           adhesion of metallic coatings onto plasma-treated Poly(ether ether ketone)
           
    • Abstract: Publication date: Available online 9 October 2019Source: Applied Surface ScienceAuthor(s): David Gravis, Fabienne Poncin-Epaillard, Jean-François Coulon The effects of the surface modification of poly(ether ether ketone) (PEEK) by plasma treatment have been characterized by X-ray Photoelectron Spectroscopy and wettability measurement, while the adhesion of metallic thin films grown by PVD has been assessed by the pull-off test. To investigate the role of the modified surface chemistry on the practical adhesion stress of aluminium thin films, two different plasma technologies were considered: (i) atmospheric pressure plasma and (ii) low pressure microwave plasma. Though on different scales, both of these plasmas under oxidative conditions induced a significant increase of the surface concentration of C=O (ketones) and COO (esters and acidic) functional groups, while C-O-C (ether) groups remained constant. It is shown that after plasma functionalization, when the surface concentration of C=O and COO are above a critical value, a strong correlation appears between the concentration of these polar groups, the wettability and the adhesion potential.Graphical abstractGraphical abstract for this article
       
  • Corrosion inhibition characteristics of a novel salycilidene isatin
           hydrazine sodium sulfonate on carbon steel in HCl and a synergistic nickel
           ions additive: A combined experimental and theoretical perspective
    • Abstract: Publication date: Available online 9 October 2019Source: Applied Surface ScienceAuthor(s): Hany M. Abd El-Lateef Salycilidene isatin hydrazine sodium sulfonate (SHMB) is synthesized and characterized by different spectroscopic tools. The inhibition performance of the individual SHMB, and that in a combination with various [Ni2+] ions on the carbon steel (CS) corrosion in hydrochloric acid are investigated, using electrochemical impedance spectroscopy (EIS), linear polarization resistance (LPR) corrosion rate and potentiodynamic polarization (PDP) methods. The SHMB inhibits the corrosion of CS in 1.0 M HCl up to 87.8%. The synergism of this SHMB Schiff base and Ni2+ is confirmed from the findings. Combining the SHMB with nickel ions increases the inhibition capacity of up to 99.2 %. PDP studies indicate that the individual SHMB and SHMB + nickel cations systems can act as inhibitors of the mixed-type. The best fitted Langmuir isotherm model reveals that the adsorption process occurs through both physical and chemical adsorption in the case of individual SHMB and chemisorption in the presence of a mixed system. X-ray diffraction, UV-Visible spectroscopy, Fourier transform infrared spectroscopy (FTIR) and Field-emission scanning electron microscope/energy-dispersive X-ray spectroscopy (FE-SEM/EDX) are utilized to study the surface morphology and corrosion product phases of CS specimens. The findings of density functional theory (DFT) calculations and molecular dynamic (MD) simulations suggest high adsorption feasibility of molecular and protonated SHMB.Graphical abstractGraphical abstract for this article
       
  • Enhanced Surface Layers by Laser Cladding and Ion Sulfurization Processing
           towards Improved Wear-resistance and Self-lubrication Performances
    • Abstract: Publication date: Available online 9 October 2019Source: Applied Surface ScienceAuthor(s): Meiyan Li, Bin Han, Lixin Song, Qingkun He Enhanced surface layers with improved wear-resistance and self-lubrication performances were prepared by means of laser cladding and ion sulfurization processing. The microstructure, element distribution, phase composition, valence states, microhardness and wear resistance of the composited layers were investigated. The results show that Ni-based cladding coating is composed of γ-(Fe, Ni), Cr2C3, M23C6, M3C type carbides as well as a large number of dislocations and stacking fault in the austenite grains. FeS forms form on the surface of cladding Ni-based coating by ion sulfurizing treatment. Microhardness of Ni-based cladding coating reaches to 600HV0.1 resulting from the comfined effects of ultrafine dendrites and solid solution strengthening and dislocations strengthening, whereas microhardness of the composite layer decrease slightly near the surface (about 470HV0.1). Due to the existance of FeS film both the wear mass loss and friction coefficient of the composite layers decrease dramaticly. Moreover, there is a slight scratch on the worn surface of laser cladding-ion sulfurizing composite layer, while worn mechanism of medium carbon steel is serious abrasion along with long and deep grooves and fatigue wear occurs on the surface of Ni-based cladding coating.
       
  • The adsorption of phosphate on hydroxylated alpha-SiO2 (001) surface and
           influence of typical anions: A theoretical study
    • Abstract: Publication date: Available online 9 October 2019Source: Applied Surface ScienceAuthor(s): Wenchao Ji, Qingli Tang, Zhemin Shen, Maohong Fan, Feiyue Li Silica, an abundance natural geologic minerals material, has a great potential for phosphate removal. The adsorption mechanism of phosphate on hydroxylated alpha-SiO2 surface, as well as the influence of typical coexisting anions (Cl-, F-, SO42- and NO3-) towards phosphate removal were investigated by density function theory (DFT) calculations. The results showed that phosphate preferred to adsorb on the R-hollow O1-O2 site with significant surface structure change. This process was exothermic with adsorption energy of 317.657 kJ/mol. About 0.480e was transferred from H2PO4- to hydroxylated alpha-SiO2 (0 0 1) surface. The partial density of states (PDOS) analysis indicated that H2PO4- electrons distribution shifted to lower energy area with small peak values after adsorption. All typical anions considered were readily adsorbed on hydroxylated alpha-SiO2 (0 0 1) surface with chemical adsorption higher than 237.778 kJ/mol. Coadsorption results showed that Cl-, F-, SO42- can weaken the adsorption of H2PO4- except for NO3-. The interaction between Cl-/H2PO4-, F-/H2PO4-, SO42-/H2PO4-, NO3-/H2PO4- and surface was chemical adsorption. The hydroxylated alpha-SiO2 had high selectivity towards H2PO4- adsorption among other coexisting anions. The reactivity of adsorption was identified accurately by Fukui functions analysis. These findings will broaden and deepen the understanding of phosphate removal by natural minerals.Graphical abstractGraphical abstract for this article
       
  • Rational design of magnetic semiconductors of longitudinal silicene/III-V
           compound heteronanoribbons
    • Abstract: Publication date: Available online 9 October 2019Source: Applied Surface ScienceAuthor(s): Heming Li, Yuan Li, Xiaoteng Li, Changfeng Fang, Xi Zuo, Li Han, Dongmei Li, Bin Cui, De-Sheng Liu The generation and transportation of spin-polarized current in silicon-based materials represent one of the most attractive topics in spintronics. Here, we present a strategy of designing magnetic semiconductors based on zigzag silicene covalently bonded with honeycomb III-V compound nanoribbons (i.e., ZSi/AlPNR and ZSi/GaAsNR). By tuning the edge states of the heteronanoribbons, high spin-filtering efficiencies can be achieved as a result of the opposite transverse electric fields induced by the III (Al, Ga) or V (P, As) atoms connected to the Si atoms at the interfaces. Importantly, the Si-III interfaced heteronanoribbons are found to be more suitable for spin-filtering applications. It is also demonstrated that the spin polarization and spin-filtering efficiency are robust and independent of the width of the heteronanoribbons.Graphical abstractSilicene become magnetic semiconductor because of an equivalent electric field caused by the electronegativity of the adjacent P(Al) atomsGraphical abstract for this article
       
  • Synergistic photoelectrochemical performance of La-doped RuO2-TiO2/Ti
           electrodes
    • Abstract: Publication date: Available online 9 October 2019Source: Applied Surface ScienceAuthor(s): Juan Zuo, Junqiu Zhu, Mingzhou Zhang, Qiming Hong, Jie Han, Jianfu Liu RuO2-TiO2/Ti electrodes with low-content La-doping are prepared by thermal decomposition method. The effect of La doping on their electrochemical performance upon UV illumination are investigated. The doped electrodes show higher density of cracks and rugosity in microscale on the surface than the undoped ones. They also have a negative shift of the onset potential of oxygen evolution from 1.1 V to 1.0 V and higher current intensity under UV irradiation as well. Electrochemical impedence spectroscopy analysis demonstrates a better electrical conductivity of the doped film. Electron paramagnetic resonance results show that the obtained La-doped TiO2 surface provides a higher density of oxygen vacancies. This anode also has 7.5% higher degradation rate of the methylene blue than La-undoped ones under UV irradiation. This is probably due to the increased surface rugosity and better electric conductivity, higher density of oxygen vacancies under UV irradiation by the doping of La ions.
       
  • Tribological performance of surface with different wettability under
           ball-on-disc test
    • Abstract: Publication date: Available online 9 October 2019Source: Applied Surface ScienceAuthor(s): Xiuqing Hao, Pengcheng Sun, Sinong Xiao, Yinfei Yang, Liang Li This paper proposes an innovative and reliable method to reduce friction and wear using a robust lyophobic surface with microstructures. The tribological performance of four kinds of surfaces, including a microstructured surface (MS) without low surface energy treatment, a lyophobic microstructured surface (LMS), a robust lyophobic microstructured surface (RLMS), and an untextured surface (US), were investigated using ball-on-disc testing with lubrication. The experimental results indicate that compared to the US sample, the RLMS sample fabricated with the proposed method reduced the friction coefficient by approximately 21.6%. In addition, the wear mass loss of the RLMS was reduced by 36.42% under specific conditions compared to the US sample. Furthermore, the antifriction mechanism of the robust lyophobic microstructured surface is analyzed and discussed in detail.Graphical abstractThe surface wettability of friction pairs influences the tribological performance significantly. According to the results in this paper, under the ball-on-disc configuration, the lyophobic bottom surface is an effect way to reduce friction and wear compared to lyophilic surfaces. The robust lyophobic layer fabricated using laser under the fluorinated solution (i.e., RLMS sample in the figure) effectively reduces the friction and wear compared to the lyophobic surface fabricated using the traditional method (i.e., LMS sample in the figure).Graphical abstract for this article
       
  • Bimodal Size Distribution of Dewetted Gold Nanoparticles with Regrown
           Oxide Bases
    • Abstract: Publication date: Available online 9 October 2019Source: Applied Surface ScienceAuthor(s): Siyu Yao, Mao Wen, Guo-zhen Zhu Gold nanoparticles, supported on oxides, have received considerable attention for their wide range of applications. Using dewetted gold particles on single-crystal oxide substrates as model systems, the unusual particle size distribution and relevant mechanism are investigated. Gold particles usually exhibit unimodal size distributions; however, when the growth of oxide bases is detected underneath these gold particles, particles have an unusual bimodal size distributions. A simple model, considering the effect of growing oxide bases on gold adatom migration, is proposed to explain this bimodal distribution. These results demonstrate the possibility of controlling the migration of surface adatoms and subsequent particle size at high temperatures.Graphical abstractGraphical abstract for this article
       
  • Enhanced dielectric and energy storage properties of BaTiO3
           nanofiber/polyimide composites by controlling surface defects of BaTiO3
           nanofibers
    • Abstract: Publication date: Available online 9 October 2019Source: Applied Surface ScienceAuthor(s): Baoquan Wan, Haiyu Li, Yunhui Xiao, Shuangshuang Yue, Yunying Liu, Qiwei Zhang BaTiO3 (BT) nanofibers with different surface defects were prepared by electrospinning process through controlling the sintering atmospheres (Air, N2 and H2), and introduced into polyimide (PI) matrix to form composite films. The effects of different surface defects on dielectric and energy storage properties of PI composites were systematically investigated. The results showed that the fabricated composite films under a reducing (H2) atmosphere exhibited excellent dielectric properties, compared with that under Air and O2. The dielectric constant (εr) of PI composite films with 20 wt% BT-fibers reached up to 17.6, while maintaining lower loss (tgδ = 0.006@100 kHz), which was about four times greater than that of pure PI (εr = 4.1). When the content of BT-fiber was up to 15 wt%, the composite film exhibited a maximum energy storage density of Ue = 6.12 J/cm3. These results provide an effective method to tune the dielectric and energy storage properties of ferroelectric/polymer composites.Graphical abstractGraphical abstract for this article
       
  • The role of Na+ in Al surface corrosion studied by single-shot
           laser-induced breakdown spectroscopy
    • Abstract: Publication date: Available online 9 October 2019Source: Applied Surface ScienceAuthor(s): Xingchen Chen, Jie Wang, Xuewei Ju, Xiangfeng Wang Almost all previous studies on atmospheric corrosion of metals focused on anions such as Cl- and CO32-, ignoring the effects of cations such as Na+ in the atmosphere. Recent studies have shown that Na+ corrosion products such as NaAlCO3(OH)2 play an important role in the corrosion process of metals. However, detecting Na or its corrosion products remains a challenging task. In this work, Na depth profiling in Al corrosion samples was studied using single-shot laser-induced breakdown spectroscopy and 3D topography measurements. We found that the concentration of Na+ satisfies a power law, and it originates from atmospheric corrosion. An electrochemical corrosion model was established to interpret the invasion of Na+ into the Al matrix, and we employed COMSOL to simulate the corrosion process, by considering the controlling role of NaAlCO3(OH)2 on the atmospheric corrosion rate. Simulation results are consistent with the experimental data in different atmospheric environments.
       
  • First-principles study on structural stability and electronic properties
           of GaAs nanowire undergoing surface oxidization
    • Abstract: Publication date: Available online 9 October 2019Source: Applied Surface ScienceAuthor(s): Yu Diao, Lei Liu, Sihao Xia In this study, the structural stability and electronic properties for oxidized GaAs nanowire surfaces are systematically investigated through first-principles calculations based on density functional theory. Various oxidized nanowire surface models with two interaction types (adsorption and substitution) and different coverages of O atoms (one O, two O, three O and four O atoms) are built. The formation energy, atomic structure, Mulliken charge distribution, work function and dipole moment for each oxidized model are calculated and analyzed. The calculations indicate that the structural stability of oxidized nanowire surfaces is gradually enhanced with increasing O coverage, where O adsorption models are more energetically favorable than O substitution cases. In addition, O atoms interacting with GaAs nanowire surfaces have an obvious influence on the atomic structures near surface layer region, especially the thickness of the first bilayer. Moreover, the incorporation of O atoms leads to the redistribution of surface charge, which is further aggravated with higher coverage of O atoms. Overall, the dipole moment induced by O adsorption or substitution will increase surface work function and thus weaken the surface emission ability.Graphical abstractGraphical abstract for this article
       
  • Study of the stability of α-Fe/MnS interfaces from first principles
           and experiment
    • Abstract: Publication date: Available online 1 October 2019Source: Applied Surface ScienceAuthor(s): Wenting Lv, Luchun Yan, Xiaolu Pang, Huisheng Yang, Lijie Qiao, Yanjing Su, Kewei Gao First-principles calculations based on density functional theory and TEM experiments were employed to investigate the interfaces between α-Fe and the precipitated MnS inclusions. Interfacial properties such as the interface energy (γint), the work of adhesion (Wad), and the electronic structures were theoretically calculated. The results show that the interfacial Fe bonds more strongly to the S atom than to the Mn atom. Fe (110)/MnS (110) was found to be the most stable interfacial structure among the candidate interfaces. TEM examination revealed the orientation relationship of α-Fe and MnS as Fe (110)∥MnS (110), which is in good accordance with the calculated results. These fundamental data will be useful for understanding various behaviors of the α-Fe/MnS interfaces.Graphical abstractGraphical abstract for this article
       
  • Thin films of Au-Al2O3 for plasmonic sensing
    • Abstract: Publication date: 15 January 2020Source: Applied Surface Science, Volume 500Author(s): Diana I. Meira, Rui P. Domingues, Marco S. Rodrigues, Eduardo Alves, Nuno P. Barradas, Joel Borges, Filipe Vaz This works reports on the development of nanoplasmonic thin films, composed of Au nanoparticles embedded in an Al2O3 matrix. The Au-Al2O3 thin films were deposited by magnetron sputtering, and then subjected to thermal treatments (in-air) to promote the growth of the Au nanoparticles. The change of the number of gold pellets placed in the erosion zone of the aluminium target, originated Au concentrations in the films from 8.9 at.% to 20.7 at.%. While the Al2O3 matrix remained roughly stoichiometric and amorphous after the thermal treatment, a progressive crystallization of the Au nanoparticles was observed when the annealing temperature increased from 400 °C to 700 °C. Nonetheless, the amorphous matrix limited the growth of Au nanoparticles up to 20 nm. Moreover, the application of an argon plasma treatment enabled the removal of superficial layers, increasing the density of Au nanoparticles partially exposed at the films’ surface. Envisaging the application in localized surface plasmon resonance sensors, the thin films were tested using two dielectric (liquid) environments, showing a consistent response under different H2O/DMSO cycles, yet with low sensitivities (few nm/RIU). To enhance the sensitivity of these thin film system other strategies are discussed.
       
  • 3D hierarchical layered double hydroxide/carbon spheres composite with
           hollow structure for high adsorption of dye
    • Abstract: Publication date: 15 January 2020Source: Applied Surface Science, Volume 500Author(s): Haixia Lyu, Kai Hu, Jingshuang Fan, Yunxiafei Ling, Zenghong Xie, Jinxia Li In this paper, a 3D hierarchical layered double hydroxide (LDH)/carbon sphere (CS) composite was prepared via self-assembly method. After calcination, the hollow structure with high surface area was formed due to removing the carbon core, meanwhile, LDH turned into layered double oxide (LDO) which exhibited superior anion adsorption capacity. The formation of the prepared material was confirmed and characterized, and the adsorption mechanism of the obtained material for different charge anionic dyes was further discussed in detail. Under the optimal conditions, the maximum adsorption capacities of the prepared materials for amaranth and Orange II were 638.634 and 849.674 mg/g, separately, which revealed that the materials can be applied into the effective adsorption of anionic dyes, especially those with less charges.Graphical abstractGraphical abstract for this article
       
  • In situ nitrogen doping of lithium cobalt oxide via rhodamine B
           degradation offers the reused material a better activity
    • Abstract: Publication date: 15 January 2020Source: Applied Surface Science, Volume 500Author(s): Wei Gao, Yang Liu, Hao Zhou, Yongming Bao, Jingjing Zhan Recycling the wasted lithium-ion batteries for environmental catalysis is promising to control pollution since the electrode materials usually contain metal oxides showing good catalytic activities. Herein, the LiCoO2 was synthesized and used to treat the simulated dye wastewater. In order to cope with the practical water pollution, the effects of rhodamine B (RhB) concentration, concomitant ions, solution pH, air blowing and reaction temperature were systematically investigated. The most important finding of this study is the in situ nitrogenization of the LiCoO2 via RhB degradation, which offered the reused material a much better activity than the fresh one due to the formation of more defect oxygen species, and the activity of the reused LiCoO2 became better and better with cycling runs. At the third time of usage, ~90% of RhB could be removed under the conditions of 0.2 g of catalyst, 50 mL of 5 mg·L−1 RhB solution and 30 °C whereas only ~60% of RhB was degraded over the fresh sample. The results of this study will also have scientific significance for the development of nitrogen-doped LiCoO2 in other application fields.Graphical abstractGraphical abstract for this article
       
  • Samarium doping boosts catalytic oxidation of airborne benzene over
           todorokite-type MnO2
    • Abstract: Publication date: 15 January 2020Source: Applied Surface Science, Volume 500Author(s): Yang Liu, Lei Yan, Wei Gao, Si-Rui Zhu, Jingjing Zhan, Ranran Cao, Hao Zhou Catalytic VOCs oxidation is primarily developed towards the synthesis of active, stable and economical materials that work efficiently at low temperatures. Herein, an active todorokite-type MnO2 (T-MnO2) was prepared for the catalytic oxidation of gaseous benzene for the first time and the effect of samarium (Sm) modification was investigated. The T-MnO2 was much more active than the reported transition metal oxide counterparts, complete removal of 237 ppm of benzene achieved at a low reaction temperature of 175 °C and a very high space velocity of 120 L·g−1·h−1. According to ICP-OES, XRD and ATR, Sm existed as amorphous Sm2O3 in SmMnO. Of all tested samples, Sm0.01MnO (atomic ratio of Sm/Mn was 0.01) performed the best, exhibiting 100% conversion for 229 ppm of benzene at 150 °C and above under 120 L·g−1·h−1, and almost no residual benzene was detected at 200 °C and above even under 240 L·g−1·h−1. According to C6H6-TPD, XPS, H2-TPR and O2-TPD, the origin of the excellent performance of the Sm0.01MnO came from it having a high benzene adsorption capacity, strong binding with benzene molecules and plenty of active surface oxygen. Moreover, the effect of concomitant water on catalyst activity was elucidated.Graphical abstractGraphical abstract for this article
       
  • A DFT study of dissolved gas (C2H2, H2, CH4) detection in oil on
           CuO-modified BNNT
    • Abstract: Publication date: 15 January 2020Source: Applied Surface Science, Volume 500Author(s): Xin He, Yingang Gui, Jufang Xie, Xiong Liu, Qian Wang, Chao Tang In this work, CuO modified BNNT surface was investigated by DFT calculation. We suppose that BNNT is a potential gas sensitive material. The modified model is present, and the combination between CuO and BNNT proved to be stable by DFT. Besides, CuO-modified BNNT shows high reactivity and sensitivity toward dissolved gas in oil. After the adsorption of dissolved gas in oil, and the adsorption capacity occurred in the following order: C2H2 > H2 > CH4. CuO-BNNT has a chemical adsorption effect on C2H2 only. Meanwhile, band gap of the system increased by 72.0% after the adsorption of C2H2, which leading to a significant decrease in conductivity. Importantly, the recovery time at room temperature (298 K) is significantly shorter than other recently proposed materials. The CuO-BNNT system shows excellent gas-sensitive response to C2H2, but low sensitivity to CH4 and H2. This allows detection of C2H2 in certain gas environments without interference.
       
  • One-step simultaneously heteroatom doping and phosphating to construct 3D
           FeP/C nanocomposite for lithium storage
    • Abstract: Publication date: 15 January 2020Source: Applied Surface Science, Volume 500Author(s): Kefu Zhang, Zhaoqiang Zhu, Jiahao Lin, Ruizhi Zhang, Chongjun Zhao FeP in-situ anchored on nitrogen and phosphorous dual-doping carbon nanosheets (FeP/NPCS) with unique 3D structure was synthesized through a one-step facile approach as a promising anode for lithium ion batteries. Benefiting from its remarkable architecture, as-prepared FeP/NPCS delivered a superb reversible rate capacity of 764 and 385 mAh g−1 at 0.1 A g−1 and 2.0 A g−1, respectively. Moreover, the intimate relationship of FeP and carbon nanosheets also endowed it an excellent long-term activity and durable cycling stability of over 134% retention (831.2 mAh g−1) at a current density of 0.5 A g−1.Graphical abstractGraphical abstract for this article
       
  • Tip-based nanomanufacturing process of single crystal SiC: Ductile
           deformation mechanism and process optimization
    • Abstract: Publication date: 15 January 2020Source: Applied Surface Science, Volume 500Author(s): Binbin Meng, Dandan Yuan, Jian Zheng, Pei Qiu, Shaolin Xu Nanoscale structures have attracted a lot of attention in various fields in recent years. Tip-based nanomanufacturing (TBN) process has proven to be a promising technique for fabrication of nanostructures on single crystal SiC. This study investigates the deformation and removal mechanism of SiC under different scratching directions in TBN process by molecular dynamics (MD) simulations. By analyzing the dislocation glide motion and the phase transformation mechanism of SiC, the deformation type that occurs during TBN process was found to be principally the sliding motion of the primary slip system (recoverable elastic slip motion and dislocation glide motion) and the phase transformation (amorphization and sp3→sp2-like structure transition). This study also shows that the deformation mechanism of SiC during processing is controllable and can be achieved by simply changing the feed direction. The results in this paper can provide direct guidance for the processing of nanogrooves in SiC materials.Graphical abstractGraphical abstract for this article
       
  • Influence of surface dissolution on sodium oleate adsorption on ilmenite
           and its gangue minerals by ultrasonic treatment
    • Abstract: Publication date: 15 January 2020Source: Applied Surface Science, Volume 500Author(s): Shuai Fang, Longhua Xu, Houqin Wu, Yanbo Xu, Zhoujie Wang, Kaiqian Shu, Yuehua Hu Selective separation of ilmenite from gangue minerals after ultrasonic preconditioning was studied in terms of surface dissolution. After preconditioning, ilmenite exhibited better single-mineral flotation capacity while titanaugite and olivine had lower recoveries. Significant separation could be obtained at pH 6.0 after ultrasonic treatment (500 W, 5 min). Zeta potentials of preconditioned titanaugite and olivine shifted positively compared to those of raw titanaugite and olivine treated with sodium oleate (NaOL), respectively. Meanwhile, the zeta potential of ilmenite was similar before and after NaOL adsorption. Mineral dissolution results indicate that ultrasonic preconditioning promotes the dissolution of Mg and Fe species but not the Ca species. The dissolution of Ca and Mg is much higher than that of Fe. According to solution chemistry calculation, Fe(OH)3 precipitate is dominant at pH greater than 2.5, and Ca2+, Mg2+, Fe2+, and Fe(OH)+ are dominant under acidic conditions. Microcalorimetric measurements demonstrate that the preconditioned ilmenite releases more heat during NaOL adsorption than titanaugite and olivine do. XPS results reveal that ultrasonic treatment facilitates the conversion of Fe2+ to Fe3+. After preconditioning, Fe species interacted with NaOL to promote the latter’s chemisorption on ilmenite and olivine, while Ca2+ was more likely to interact with NaOL on titanaugite.Graphical abstractGraphical abstract for this article
       
  • Ti:Sapphire laser irradiation of graphene oxide film in order to tune its
           structural, chemical and electrical properties: Patterning and
           characterizations
    • Abstract: Publication date: 15 January 2020Source: Applied Surface Science, Volume 500Author(s): Somayeh Mortazavi, Mahmoud Mollabashi, Rasoul Barri, Lars Gundlach, Kevin Jones, John Q. Xiao, Robert L. Opila, S. Ismat Shah Femtosecond laser processing was employed in order to tune various properties of graphene oxide (GO) films. Raman spectroscopy showed the effects of laser irradiation on decreasing the defects in the GO films. Structural and chemical properties of the irradiated GO films were investigated by XRD and XPS as a function of laser fluences. Conductive patterns were produced on insulating surfaces of GO films as a result of the removal of oxygen functional groups. Laser fluences dependent sheet resistances and current-voltage measurements were studied using four probe method. Investigation of the correlation between property changes in the GO films and the laser fluences used for irradiating the films can be useful for many applications, such as microelectronics, which requires control of various characteristics of the films. In addition to tuning various properties of the GO films, AFM and SEM studies were performed on different regions of the irradiated GO films, including films on silicon and gold electrodes, which showed regular ripples on gold electrodes. These investigations were also followed by optical contrast calculations of the films that can be used to recognize different regions of the films.
       
  • Interconnected structure Si@TiO2-B/CNTs composite anode applied for
           high-energy lithium-ion batteries
    • Abstract: Publication date: 15 January 2020Source: Applied Surface Science, Volume 500Author(s): Nan Zhou, Yufan Wu, Yiran Li, Jiankui Yang, Qing Zhou, Yuwei Guo, Mao Xia, Zhi Zhou As an anode with ultrahigh capacity (4200 mAh g−1), silicon (Si) has inherent defects, such as drastic volume change (~300%) and poor conductivity. To cope with these problems, constructing a rigid shell (e.g. TiO2) on the surface of Si particles is an effective method. Typically, monoclinic titanium dioxide (TiO2-B) has the more excellent electrochemical performance among the various crystalline of TiO2 (anatase, rutile, etc.) for its open channel and characteristic pseudocapacitive effect. In addition, carbon nanotubes (CNTs) are good conductor of electricity. It is hopeful to increase the conductivity of the Si anode by adding CNTs. In this work, therefore, a Si@TiO2-B/CNTs composite is prepared by hydrothermal method. The composite exhibits superior electrochemical properties during the half-cell test (1184 mAh g−1 under 0.1 A g−1 at 200th cycles). Furthermore, the electrochemical kinetics of the materials were studied by cyclic voltammetry, which demonstrated that coating TiO2-B could increase the capacitive effects of the composite (68.75%).Graphical abstractGraphical abstract for this article
       
  • Carrier dynamics in monolayer WS2/GaAs heterostructures
    • Abstract: Publication date: 15 January 2020Source: Applied Surface Science, Volume 500Author(s): Kuilong Li, Wenjia Wang, Jiancai Leng, Benxiao Sun, Dengke Li, He Yang, Tengfei Jiang, Yang He We investigate the carrier dynamics in monolayer-WS2/SiO2 and WS2/GaAs heterojunctions using time-resolved photoluminescence in this study. The exciton lifetime and radiative lifetime for WS2/GaAs sample were determined to be 497 ps and 46 ns, respectively, which are much larger than those of the WS2/SiO2 sample. Then the energy band structure at the WS2/GaAs heterojunction was explored using x-ray photoelectron spectroscopy. A type-Ⅱ band alignment was confirmed at the interface with the conduction band offset about 1.415 eV and valence band offset 0.55 eV, which was further proved by ultraviolet photoelectron spectroscopy. As a result, the WS2/GaAs junction facilitated electron and hole separation by the aid of built-in field, and in turn enlarged the carrier lifetime. This work provided a promising integration of 2D materials with traditional bulk semiconductors for future high efficiency, highly reliable applications in photonic and optoelectronic devices.
       
  • A poly(ionic liquid)-pillar[5]arene honeycombed isoporous membrane for
           high performance Cu2+ sensors
    • Abstract: Publication date: 15 January 2020Source: Applied Surface Science, Volume 500Author(s): Yunxia Ni, Mingjie Yin, Shengyi Dong, Feihe Huang, Qiang Zhao Honeycombed isoporous membranes (HIPMs) represent enabling roles in environment and energy applications, but their preparation by block copolymer self-assembly and transferable breath figure methods involves synthetic complexity and labor intensiveness. Here we report the straightforward preparation of HIPMs through the combinational self-assembly and electrostatic complexation between a poly(ionic liquid) homopolymer and pillar[5]arene molecules. Free-standing HIPMs with defined surface pores and interconnected cross-sectional pores were prepared, embedded with beneficial properties of poly(ionic liquid) and pillar[5]arene supramolecular entities. The polymer synthesis and membrane preparation are facile, and the strategy is applicable to both planar and curved surfaces such as glass plates, particles and fibers. The synergy of surface pores with underlying structures facilitates functionalities beyond separation, such as a HIPMs coating on fiber-optic sensors that feature good responsiveness and limit (0.075 nM) for detecting Cu2+ heavy ions. This work renders the facile preparation of isoporous membranes from ionic liquid homopolymers and their surface coatings for sensors with environmental application potentials.Graphical abstractThe facile preparation of honeycombed poly(ionic liquid)-pillar[5]arene isoporous membranes was exploited, which applies to both the planar and curved surfaces for fiber-optic sensors detecting a very small amount (0.075 nM) of Cu2+ in water.Graphical abstract for this article
       
  • A Simple Method of Growing Endotaxial Silver Nanostructures on Silicon for
           Applications in Surface Enhanced Raman Scattering (SERS)
    • Abstract: Publication date: Available online 8 October 2019Source: Applied Surface ScienceAuthor(s): Abhijit Roy, Tapas Kumar Chini, Biswarup Satpati Endotaxial structures are related to the growth of precipitate phases in the bulk matrix having a coherent interface with the surrounding. In general, sophisticated physical vapor deposition techniques, like molecular beam epitaxy (MBE) in ultra-high vacuum (UHV) or ion implantation followed by high-temperature annealing are used to grow endotaxial structures. Here, we have shown that a simple electroless deposition followed by rapid thermal annealing process can generate triangular-shaped endotaxial Ag nanostructures along with spherical Ag nanoparticles on the planar silicon surface. Remarkably, compared to only Ag spherical particles, a silicon surface covered with spherical plus triangular-shaped nanoparticles shows significant SERS enhancement revealing the crucial role of the endotaxial triangular Ag nanostructures in SERS. By studying the aging effect, we have demonstrated that embedded triangular endotaxial particles are structurally more stable than the spherical nanoparticles residing on the surface revealing a robust route of fabricating SERS substrate where stability is an important issue. We presume that the nanogaps between the spherical and triangular endotaxial particles act as one of the major sources of “hot spots” where the sharp edges of the triangular geometry pose favorable situation for SERS enhancement observed in the present case.Graphical abstractGraphical abstract for this article
       
  • Plasmon-enhanced and controllable synthesis of azobenzene and
           hydrazobenzene using Au/TiO2 composite
    • Abstract: Publication date: Available online 8 October 2019Source: Applied Surface ScienceAuthor(s): Qiuwen Liu, Jingwen Zhang, Fangshu Xing, ChuChu Cheng, Yawei Wu, Caijin Huang The selective reduction of nitroaromatics has long been the focus of fundamental and practical interest. The challenging issue lies in how to finely control the product selectivity. Herein, we report a light-assisted thermocatalytical process to convert nitrobenzene into azobenzene and hydrazobenzene with high selectivity and high yields by simply controlling the reaction time. The light-enhanced efficiency of Au/TiO2 catalyst is up to 14.8% at 90°C due to the localized surface plasmon resonance (LSPR) effect of Au nanoparticles. Moreover, the hydrogen-delivery rate here is much faster than that of current reported systems. The reaction mechanism was also investigated by EPR technique, where Au–H intermediate species is found to account for the high efficiency in this reduction process. The favorable results demonstrated that plasmon-enhanced catalytic reaction might be more attractive and applicable in industrial organic synthesis.Graphical abstractGraphical abstract for this article
       
  • Synthesis and characterization of F-doped MgZnO films prepared by RF
           magnetron co-sputtering
    • Abstract: Publication date: Available online 8 October 2019Source: Applied Surface ScienceAuthor(s): Huiqin Wang, Ailing Wang, Yaoming Sun, Lili Wu, Wei li, Wenwu Wang, Jingquan Zhang, Lianghuan Feng Fluorine-doped Mg0.21Zn0.79O (MZO:F) thin films were successfully deposited on glass substrates at room temperature by radio frequency (RF) magnetron co-sputtering method with Mg0.21Zn0.79O, MgF2, and ZnF2 targets. Low resistivity (1.26×10-1 Ω⋅cm), high Hall mobility (3.55 cm2/Vs) and high carrier concentration (1.39×1019 cm-3) were simultaneously realized in the annealed MZO:F film. The effects of doping concentration and annealing temperature on the structural, morphological, electronic, electrical and optical properties of MZO:F films were systematically investigated in this study. XRD and XPS analysis confirmed that F atoms have entered into crystal lattices of MZO and acted as donors when they occupied O sites in the hexagonal lattice. Moreover, it was observed that both doping concentration and annealing temperature greatly affected the crystallinity, grain size, growth orientation and surface morphology of the MZO:F thin films. In addition, the optical gap changed dramatically with the F content and annealing temperature, which could be attribute to the Burstein-Moss effect accompanied by the effects of fluctuating potential arising from the randomly situated impurities.Graphical abstractGraphical abstract for this article
       
  • Evolution of lattice defects upon Bi-doping of epitaxial Si overlayers on
           Si(100)
    • Abstract: Publication date: Available online 8 October 2019Source: Applied Surface ScienceAuthor(s): Jiaming Song, Bethany M. Hudak, Andrew R. Lupini Single Bi dopants in Si exhibit promising properties for quantum information science. Here we study, as a function of Bi-doped Si film thickness, the evolution and ultimate removal of lattice defects that are associated with a recently demonstrated viable route to precisely incorporate Bi dopants in homoepitaxial Si thin films. Scanning tunneling microscopy imaging reveals how the elongated defect structures in the Si lattice, originating from prefabricated Bi nanolines on the substrate surface that are the source of the Bi dopants, evolve with increasing Si overlayer thickness. Moreover, we demonstrate that a prolonged low-temperature annealing is able to annihilate these defect structures while leaving a significant Bi dopant concentration in the Si films.Graphical abstractGraphical abstract for this article
       
  • DFT studies of adsorption properties and bond strengths of H2S, HCN and
           NH3 on Fe(1 0 0)
    • Abstract: Publication date: Available online 8 October 2019Source: Applied Surface ScienceAuthor(s): Lu Ren, Yanhai Cheng, Rui Shao, Xianliang Meng, Jinyong Yang, Qingqing Wang Based on the first principle method of density functional theory (DFT), the adsorption properties, bond strengths of three molecules (H2S, HCN and NH3) in coke oven gas on the Fe-based surface were analyzed using the adsorption energy and the partial densities of states (PDOS). Consequently, the adsorption energy of H2S, NH3 and HCN molecules were the lowest respectively at h-H-down-p, t-H-up and Fourfold adsorption sites on Fe(1 0 0) surface. The adsorption energy of them is -2.298eV, -0.984eV and -1.920eV individually. Furthermore, the consequence of densities of states evidences that there are hybrid peaks when the three molecules act on Fe-based surface, and new bonds are constituted between surface molecules and the substrate. The interaction energy between those molecules and the Fe(1 0 0) surface in turn is H2S>HCN>NH3, which also demonstrates that in coke oven gas H2S has the maximum sedimentation on the heat transfer surface.Graphical abstractGraphical abstract for this article
       
  • Mechanism of atomic and close-to-atomic scale cutting of monocrystalline
           copper
    • Abstract: Publication date: Available online 8 October 2019Source: Applied Surface ScienceAuthor(s): Wenkun Xie, Fengzhou Fang Mechanical cutting is one of promising subtractive machining processes to enable the atomic and close-to-atomic scale (ACS) manufacturing of the processed surface with atomic scale form accuracy or functional feature size. When cutting depth is decreased to ACS, minimum chip thickness could be decreased to several atomic layers and even single atomic layer. Consequently, there arises one disruptive cutting technology towards atomic and close-to-atomic scale manufacturing, i.e. ACS cutting, the next-generation cutting technology different from conventional cutting, microcutting and nanocutting. In this paper, one ACS cutting model is proposed to study the material removal mechanism at close-to-atomic scale and even atomic scale. It is postulated that chip formation in ACS cutting is conducted by shear stress-driven dislocation movement, significantly different from the shearing-dominated chip formation in conventional cutting and the extrusion-dominated chip formation in micro/nano cutting. Moreover, two kinds of sizing effects, namely, cutting edge radius effect and atomic sizing effect, would greatly influence the surface generation and material removal in ACS cutting.
       
  • Facile synthesis of freestanding cellulose/RGO/silver/Fe2O3 hybrid film
           for ultrahigh-areal-energy-density flexible solid-state supercapacitor
    • Abstract: Publication date: Available online 8 October 2019Source: Applied Surface ScienceAuthor(s): Zhanghua Zou, Wei Xiao, Yanhua Zhang, Hong Yu, Wenjie Zhou We report the design of a freestanding cellulose/RGO/silver/Fe2O3 hybrid film for direct use as electrodes for construction of high-performance flexible solid-state supercapacitor (FSS). It is well characterized and found to feature noticeable capacitive properties due to the unique structure, high conductivity and dual electroactive species (i.e., RGO and Fe2O3) for charge storage. As demonstrated in a three-electrode system, such film electrode achieves the maximum areal and volumetric capacitance of 2044 mF cm−2 and 75.7 F cm−3, respectively, with prominent rate performance and long-term cyclic durability. Later, a symmetric FSS device is constructed by employing this film as both anode and cathode electrodes. The as-assembled device offers the highest areal and volumetric capacitance of 1132 mF cm−2 and 18.2 F cm−3, respectively, displays inconspicuous performance degradation under different curved states, and possesses the largest areal energy density of 226.4 μWh cm−2, which is far better than that of many advanced symmetric and asymmetric flexible supercapacitors. The attractive capacitive behaviors and easy fabrication processes could render cellulose/RGO/silver/Fe2O3 hybrid film a promising material for the applications in next-generation flexible and wearable electronics in the future.Graphical abstractGraphical abstract for this article
       
  • Atomic Engineering of Metastable BeO6 Octahedra in a Rocksalt
           Framework
    • Abstract: Publication date: Available online 8 October 2019Source: Applied Surface ScienceAuthor(s): Woo Chul Lee, Sangtae Kim, Eric S. Larsen, Jung-Hae Choi, Seung-Hyub Baek, Minji Lee, Deok-Yong Cho, Han-Koo Lee, Cheol Seong Hwang, Christopher W. Bielawski, Seong Keun Kim An atomic structure is widely recognized as the key that determines the physical properties of a material. A critical challenge to engineer the atomic structure is that many useful crystals are metastable under ambient conditions and difficult to realize. Here, it is demonstrated that highly metastable atomic arrangements can be synthesized in the isostructural matrix via atomic layer deposition. Studying highly metastable BeO6 octahedra in rocksalt MgO as a model system, it is experimentally and theoretically shown that the single-phase BexMg1-xO thin films adopt rocksalt structure over wurtzite for the composition range x < 0.21. The single-phase rocksalt films exhibit almost doubled dielectric constants with the presence of BeO6 octahedra. Such atomic environment engineering may create intriguing properties that have not been realized in the constituent materials. This work provides excellent opportunities to explore unprecedented materials properties via engineering metastable atomic arrangements using the isostructural matrix approach.Graphical abstractGraphical abstract for this article
       
  • Chalcogenated-Ti3C2X2 MXene (X = O, S, Se and Te) as a high-performance
           anode material for Li-ion batteries
    • Abstract: Publication date: Available online 8 October 2019Source: Applied Surface ScienceAuthor(s): Deqiao Li, Xianfei Chen, Pan Xiang, Haiying Du, Beibei Xiao Limited interlayer spacing and undesired surface functional group on Ti3C2 MXene surface impede the Li-ion accessibility and mobility, leading to inferior Li-storage capacity. Fine-tuning of the surface chemistry is considered as an effective approach to modulate the properties of solid surface and interface, which is extremely important for the two-dimensional (2D) electrode materials, where Li-ions residing on the surface. Herein, based on first-principle calculations, surface chalcogenation of Ti3C2 MXene, resulting in the formation of Ti3C2X2 (X= O, S, Se and Te), has been proposed to improve the electrochemical performance of Ti3C2 anode in Li-ion batteries. The results reveal that Ti3C2X2 exhibits metallic conductivity with improved mechanical strength, which renders enhanced rate performance and endures repeated lattice expansion and contraction during charge/discharge process, respectively. As compared to Ti3C2O2, Ti3C2S2 and Ti3C2Se2 render enhanced Li-ion storage and mobility with a theoretical Li storage capacity of 462.6 and 329.3 mAh/g and diffusion energy barrier of 0.25and 0.15 eV, respectively. Moreover, chalcogenation yields expanded interlayer spacing, which improves the Li-ion accessibility in Ti3C2X2. The present study demonstrates that S- and Se- terminated Ti3C2 MXenes are promising anode materials with high capacity, low diffusion barrier and lower open circuit voltage (OCV) for next-generation Li-ion batteries.Graphical abstractGraphical abstract for this article
       
  • The interfacial surface of an electrode for a supercapacitor as a factor
           affecting the capacitance and energy density
    • Abstract: Publication date: Available online 8 October 2019Source: Applied Surface ScienceAuthor(s): D.S. Dmitriev, A.V. Nashchekin, V.I. Popkov The present paper proposes a criterion-based approach for selecting carbon material for supercapacitors, which is based on the type of surface functional groups and the micro/mesopore ratio. The activated carbons DLC Supra 30, W35, SX1G and CAP Super WJ (Cabot Corp.) with different porous structure and surface composition have been used as model objects. The BJH, DFT and t-plot methods have been used to calculate the specific surface area and the porosity of activated carbons, characterizing them as micro- and mesoporous materials with a surface area from 845 to 1855 m2∙g-1. The SEM micrographs of electrodes allowed estimating the size and agglomeration degree of carbon particles and width of pores on surface. The combined results of FTIR spectroscopy and Boehm titration showed the presence of phenolic, carbonyl and carboxyl functional groups on the surface, the concentration of which depended on the activated carbon grade. By comparing these results with the data of cyclic voltammetry, the influence of the micro/mesopore surface area ratio on the specific capacitance was established. Also, a correlation between the ionic character of the functional groups and the value of energy density has been noted. The results obtained by these methods can serve as a criterion for choosing the activated carbon as an electrode material for supercapacitors.Graphical abstractGraphical abstract for this article
       
  • Vacuum treatment to stabilize oxidation at low temperature region in
           porous silicon
    • Abstract: Publication date: Available online 8 October 2019Source: Applied Surface ScienceAuthor(s): Kevin Allen, Juan S. Pereira-Cubillo, Arturo Ramírez-Porras Oxidation in porous silicon is studied for as-etched samples and samples subjected to high vacuum at room temperature. Attenuated Total Reflectance (ATR) measurements in infrared spectroscopy for temperatures ranging from 21°C to 201°C show two behaviors concerning oxide evolution: at temperatures below 100 – 130°C, oxidation proceeds very slowly, and slower in the case of vacuum treated samples. It is believed that moisture extraction from the pores in vacuum medium is responsible for this enhanced behavior. Optical measurements show that nanostructures resident in the samples are not affected morphologically, although their surfaces exhibit a relatively low oxidation increase, lower for the vacuum treated samples, in accordance with the infrared results.
       
  • Two-dimensional chromium boride MBenes with high HER catalytic activity
    • Abstract: Publication date: Available online 8 October 2019Source: Applied Surface ScienceAuthor(s): Bikun Zhang, Jian Zhou, Zhonglu Guo, Qiong Peng, Zhimei Sun Facing the increasing demands of clean energy, searching low-cost and highly active catalysts of hydrogen evolution reactions (HER) has emerged as a major task. Herein on the basis of density functional theory calculations, we reported that a series of Cr-based MBenes of different atomic-layer thickness (referring to 2D transition metal borides), Crn+1B2n (n=1-3), exhibit superior electrocatalytic performance towards HER. They are highly stable, mechanical anisotropic and intrinsic ferromagnetic conductive systems. Furthermore, we found that they show thickness-dependent mechanical properties and HER catalytic activity. Especially, Cr4B6 exhibits quite high Young’s module of 335 N/m (comparable to 342 N/m of graphene) and 247 N/m along x and y axes, respectively. More importantly, Cr4B6 is identified as a superior HER electrocatalyst with overpotential of only 0.003 V at H coverage of 1 monolayer (ML), which is a promising alternative of Pt catalyst.
       
  • DFT Study of Ethanol Adsorption on CaO(001) Surface
    • Abstract: Publication date: Available online 8 October 2019Source: Applied Surface ScienceAuthor(s): V. Orazi, A. Juan, E.A. González, Jorge M. Marchetti, P.V. Jasen Ethanol adsorption on CaO (001) surface at low coverage is studied using Density Functional Theory (DFT) calculations with van der Waals corrections. We investigated the CaO surface in its rock salt structure. The more favorable sites for C2H5OH adsorption are on one (or two) Ca cations bonding the O atom from ethanol, while H atom bond to surface oxygens with an adsorption energy of -1.12 (-1.14) eV. The distance of ethanol to surface is in the range of 2.3-2.5 Å. The molecule presents a strong elongation of the adsorbed O-H group being 53% (51%) larger that its molecular distance. Bond order analysis shows that distances and BO are similar for Ca-Omolecule and Ca-Osurface. A charge transfer occurs from O atom of the 2nd layer to Ca ions at 1st layer and the molecular O atom gain some charge, while H loses charge towards surface oxygen and from this to the rest of the surface.Graphical abstractGraphical abstract for this article
       
  • Contact-induced molecular rearrangement of acrylic acid-incorporated
           pressure sensitive adhesives
    • Abstract: Publication date: Available online 8 October 2019Source: Applied Surface ScienceAuthor(s): Ju Hak Lee, Dong Woog Lee Although recent literatures have pointed out that viscoelastic dissipation is the main mechanism affecting the adhesion of pressure sensitive adhesives (PSAs), the controversial issue found previously has spurred us to be interested in the contribution of surface chemistry and physics. Herein, it was found that changes in the surface energy of PSAs caused a significant increase in the adhesion energy via rearrangement of the polymer chains, inducing reorientation of the polar group toward the metallic adherend. The adhesion energy increased with increasing contact time on the adherend, where the adhesion performance of acrylic acid-incorporated PSA increased by more than 300% after 24 h contact with stainless steel. The surface energy of the adhesives were calculated as a function of contact time via contact angle measurements and using the Fowkes theory in order to substantiate the changes in the surface properties influencing the adhesion. The surface chemistry of the PSAs was analyzed by Fourier-transform infrared analysis and time-of-flight secondary ion mass spectrometry, which suggest that the enhanced adhesion of acrylic acid-incorporated PSA is due to the contact time-dependent mechanism, in which induces the polymer chains rearranged and polar groups exposed at the interface.Graphical abstractGraphical abstract for this article
       
  • Surface roughness evolution induced low secondary electron yield in carbon
           coated Ag/Al substrates for space microwave devices
    • Abstract: Publication date: Available online 8 October 2019Source: Applied Surface ScienceAuthor(s): Qi Lu, Bin Yu, Zhongqiang Hu, Yun He, Tiancun Hu, Yanan Zhao, Zhiguang Wang, Ziyao Zhou, Wanzhao Cui, Ming Liu High power microwave devices have been suffering from secondary electron yield (SEY), which occurs at the surface and leads to increases in energy dissipate and noise level in microwave cavities. The suppression of SEY in microwave materials is significant for space applications. In this work, we report a surface roughness evolution mechanism induced by carbon coating on a widely-used microwave cavity material Ag/Al. The competition between the preferred growth and the island growth modes leads to the roughness enhancement in the 60 nm carbon coated Ag/Al substrates. By extracting the smooth factor Ks in Vaughan model from the angular dependent SEY measurement, we attribute the suppression of SEY to the intrinsic low SEY of the carbon film and the high surface roughness. Our work demonstrates a low-cost, easy-to-scale coating process to effectively prevent the formation of secondary electron avalanche in space borne microwave devices.
       
  • Texturing of Metallic Surfaces for Superhydrophobicity by Water Jet Guided
           Laser Micro-Machining
    • Abstract: Publication date: Available online 8 October 2019Source: Applied Surface ScienceAuthor(s): Yi Shi, Zilin Jiang, Jian Cao, Kornel F. Ehmann This experimental work demonstrates a new cost-effective way of achieving superhydrophobicity on metallic surfaces by micro-texturing with a novel water jet guided laser process. Compared to conventional pure laser texturing by nanosecond, picosecond and femtosecond lasers, water jet guided laser processing yields textures with an almost zero heat affected zone while the debris on the textured surface is simultaneously cleaned by the jet during the process. The effects of grid spacing, laser power coupled into the jet and water jet diameter are examined and processing conditions for achieving superhydrophobicity are provided. Changes in the wetting of the surface over time under ambient conditions from hydrophilic to superhydrophobic, due to changes in surface chemistry, were explored. It has been shown that the surface contact angle dramatically increases within the first couple of days after texturing when exposed to air. After around 20 days, the contact angle stabilized at 150°, 130° and 129° on textured 304 stainless steel, titanium and 6061 aluminum surfaces, respectively.Graphical abstractGraphical abstract for this article
       
  • The effect of thermal annealing on the magnetic properties of graphene
           oxide quantum dots
    • Abstract: Publication date: Available online 8 October 2019Source: Applied Surface ScienceAuthor(s): Yuanyuan Sun, Hongzhe Pan, Yongping Zheng, Kaiyu Zhang, Lin Fu, Jie Chen, Weili Zhang, Nujiang Tang The magnetism of graphene oxide quantum dots (GOQDs) has attracted much attention for the prospective applications in spintronics, which is relevant to the oxidation degree. Although the oxidation degree of GOQDs can be tuned by altering the annealing temperature, the specific effect of thermal annealing on the magnetic properties of GOQDs have not been identified. In this study, we report the effect of thermal annealing on the magnetic properties of GOQDs. All the annealed GOQDs samples show paramagnetism. Hydroxyl groups and vacancies on the basal-plane, and the phenolic hydroxyl passivated zigzag edges give various contribution to the magnetism determined by the annealing temperature. Our studies clarified the effect of thermal annealing on the magnetic properties of GOQDs, that would give benefits to their prospective applications in spintronics.Graphical abstractGraphical abstract for this article
       
  • Antibacterial activity of a porous silver doped TiO2 coating on titanium
           substrates synthesized by plasma electrolytic oxidation
    • Abstract: Publication date: Available online 8 October 2019Source: Applied Surface ScienceAuthor(s): Monica Thukkaram, Pieter Cools, Anton Nikiforov, Petra Rigole, Tom Coenye, Pascal Van Der Voort, Gijs Du Laing, Chris Vercruysse, Heidi Declercq, Rino Morent, Lieven De Wilde, Patrick De Baets, Kim Verbeken, Nathalie De Geyter The objective of this study was the development of Ag-rich antibacterial coatings on titanium to prevent post-operative infections. A series of Ag-doped TiO2 coatings were synthesized on Ti discs by plasma electrolytic oxidation in an electrolyte containing AgNPs. The incorporation, distribution and chemical composition of the AgNPs on Ti were determined using scanning electron microscopy-energy dispersive spectroscopy. The crystalline structure and wettability of the coating was characterized by X-ray diffraction and water contact angle analysis respectively. Surface roughness and hardness of the coating were examined using surface profilometry and Knoop indentation test respectively, while silver ion release was quantified using inductively coupled plasma-mass spectroscopy.Following PEO, the surface of the Ti substrate was converted to TiO2 composed of anatase and rutile phases. The SEM micrographs showed that the AgNPs were distributed throughout the oxide layer, without changing the morphology of the coating. The coatings also revealed an increased surface roughness, microhardness and improved surface wettability relative to untreated Ti substrates. Furthermore, the incorporation of Ag into the coating did not alter the phase component, roughness, microhardness and wettability. A series of in-vitro antibacterial assays indicated that increasing the number of AgNPs in the electrolyte led to excellent antibacterial activities.Graphical abstractGraphical abstract for this article
       
  • Cr2O3-Modified NiFe Nanoparticles as A Noble-Metal-Free Catalyst for
           Complete Dehydrogenation of Hydrazine in Aqueous Solution
    • Abstract: Publication date: Available online 8 October 2019Source: Applied Surface ScienceAuthor(s): Jianmin Chen, Hongtao Zou, Qilu Yao, Minghong Luo, Xiugang Li, Zhang-Hui Lu The development of highly active, stable, and inexpensive catalysts for efficient and complete dehydrogenation of hydrazine is highly attractive but still very challenging. Herein, Cr2O3-modified NiFe (NiFe-Cr2O3) nanopartciles (NPs) have been designed as the heterogeneous catalyst. Both the catalytic activity and hydrogen selectivity of Ni0.9Fe0.1-Cr2O3 NPs were improved remarkably as compared with those of their mono-metallic counterparts. The prepared Ni0.9Fe0.1-Cr2O3 catalyst exhibited an outstanding catalytic activity to release 3.0 equiv. (H2 + N2) from hydrazine in only 8.5 min at 70 oC, providing a turnover frequency (TOF) value of 893.5 h-1 based on surface metal atoms. Systematic studies indicated that the small size and high surface area of Ni0.9Fe0.1-Cr2O3 as well as the strong synergistic electronic effect between Cr2O3 and NiFe NPs resulted in the excellent activity of Ni0.9Fe0.1-Cr2O3 catalyst. Such a highly rapid, long term durability, and low cost catalyst may encourage greatly the practical application of hydrous hydrazine as a chemical hydrogen storage material.Graphical abstractA simple and facile co-reduction route was developed to fabricate NiFe-Cr2O3 NPs, which exhibited high catalytic activity and 100% H2 selectivity for hydrogen generation from hydrazine.Graphical abstract for this article
       
  • Adsorption properties of dopamine derivatives using carbon nanotubes: a
           first-principles study
    • Abstract: Publication date: Available online 8 October 2019Source: Applied Surface ScienceAuthor(s): Heeju Kim, Gunn Kim Detecting dopamine is of great biological importance because the molecule plays many roles in the human body. For instance, lack of dopamine release is the cause of Parkinson’s disease. Although many researchers have carried out experiments on dopamine detection using carbon nanotubes (CNTs), there are only a few theoretical studies on this topic. We study the adsorption properties of dopamine and its derivatives, L-DOPA and dopamine o-quinone, adsorbed on a semiconducting (10, 0) CNT, using density functional theory calculations. Our computational simulations reveal that localized states originating from dopamine o-quinone appear in the bandgap of the (10, 0) CNT, but those originating from dopamine and L-DOPA do not appear in the gap. Therefore, dopamine o-quinone is expected to be detectable using an external electric field but dopamine and L-DOPA should be difficult to detect.Graphical abstractGraphical abstract for this article
       
  • Hydrogen sensing and adsorption kinetics on ordered mesoporous anatase
           TiO2 surface
    • Abstract: Publication date: Available online 5 October 2019Source: Applied Surface ScienceAuthor(s): Azhar Ali Haidry, Lijuan Xie, Zhe Wang, Zhong Li Employing TiO2 as a gas sensing material is advantageous owing to its excellent hydrogen surface receptiveness and stability under extreme conditions. However, their commercial applications are constrained by limited operating temperature range (150 – 400 ℃) and poor selectivity. In this work, we demonstrate that the ordered mesoporous structured TiO2 is highly favourable for room temperature hydrogen sensing. The sensors prepared with evaporation induced self-assembly (EISA) showed best response ∼2.98×102 toward 1,000 ppm H2 at room temperature with a sensitivity of ∼4.6±1.5×106 ohm/ppm. Moreover, the sensor showed a response time of ∼85 s (recovery time of ∼198 s) with full baseline recovery and a selectivity factor of ∼290 to 1,000 ppm of interfering reducing gases CO and CH4 at room temperature. With a power consumption of ∼1×10-9 watts the sensors are incredibly suitable for practical applications. We performed XRD, SEM, TEM, XPS, BET and PL characterization not only to confirm the crystal structure, morphology at nanoscale, surface chemical identification, specific surface area, pore size and photo-generated charge species that contribute to the electronic transport properties but sensing mechanism also.Graphical abstractGraphical abstract for this article
       
  • Intrinsic Properties of Nitrogen-Rich Carbon Nitride for Oxygen Reduction
           Reaction
    • Abstract: Publication date: Available online 5 October 2019Source: Applied Surface ScienceAuthor(s): Jiayi Xu, Bin Liu The intrinsic electronic and catalytic properties of two-dimensional (2D) graphitic carbon nitride (g-C3N4) and its heterostructures were investigated to evaluate its potential as an oxygen reduction reaction (ORR) electrocatalyst. While rich in native pyridinic N and showing favorably interactions toward ORR intermediates, g-C3N4 lacks the ability to enable efficient charge transfer for practical electrochemical processes. The electronic structures of freestanding g-C3N4 and hetero-bilayers derived from additional graphene (GN) and hexagonal boron nitride (hBN) were evaluated using Density Functional Theory (DFT). The energy band gap, calculated from the HSE06 hybrid functional, for the g-C3N4/GN bilayer is found to be significantly narrowed, and could become suitable for ORR. Moreover, a 4-coordinated single Fe atom Fe-N-C site, with Fe being anchored by the pyridinic N to resemble the GN-based FeN4 motif, exists. The bindings of ORR intermediates at these Fe sites were found to be tunable as well, suggesting opportunities to fine-tune g-C3N4-based materials to achieve superior performance as Pt-free electrocatalysts.
       
  • Understanding Loading, Diffusion and Releasing of Doxorubicin and
           Paclitaxel Dual Delivery in Graphene and Graphene Oxide Carriers as Highly
           Efficient Drug Delivery Systems
    • Abstract: Publication date: Available online 5 October 2019Source: Applied Surface ScienceAuthor(s): Hassan Hashemzadeh, Heidar Raissi The adsorption mechanism of Doxorubicin (DOX) and Paclitaxel (PTX) mixture (1:1) on graphene (GRA) and graphene oxide (GOX) is determined using the molecular dynamics (MD) simulation and free energy calculation. The results indicate that the drug molecules spontaneously move toward the carriers. In the GRA system, the drug molecules form strong π-π interactions with the graphene surface, while the formation of intermolecular hydrogen bonds between the drug molecules and carrier expects in the GOX system due to different surface chemistry. The range of the drug-carrier intermolecular distances is around 2.5-4 A°. It is found that the binding energy of PTX (-487.67 Kj/mol) with the graphene is higher than DOX (-373.53 Kj/mol). In the GOX system, the oxygen-containing functional groups lead to a decrease in the binding of PTX (-414.79 Kj/mol) and DOX (-121.12 Kj/mol) to the carrier. Moreover, the study of drug release in acidic pH shows that some drug molecules can be desorbed from the carrier due to strong electrostatic repulsion. Finally, the interaction of the drug delivery systems (DDSs) and membrane cell is investigated. It is found that the graphene-based DDS cannot spontaneously diffuse into the membrane cell, while the GOX-based DDS easily penetrate in the membrane cell.Graphical abstractGraphical abstract for this article
       
  • Synthesis of γ-Fe2O3-ZnO-biochar Nanocomposites
           for Rhodamine B Removal
    • Abstract: Publication date: Available online 5 October 2019Source: Applied Surface ScienceAuthor(s): Ying Zhang, Peidong Su, Daria Weathersby, Qinku Zhang, Jinju Zheng, Ruimei Fan, Junke Zhang, Qilin Dai Organic dye molecules, for example Rhodamine B (RhB), cause a serious environmental issue in industry wastewater. Magnetic biochar adsorption is one of the effective ways for water treatment. In this work, we develop a facile technique to synthesize magnetic biochar γ-Fe2O3-ZnO-biochar nanocomposites by thermal decomposition of zinc(II) acetylacetonate and iron(III) 2,4-pentanedionate in the presence of biochar in triethylene glycol solvent under the protection of nitrogen. The synthesized magnetic biochar nanocomposites are characterized using X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscope (SEM), and their adsorption performance on RhB is investigated. The adsorption capabilities of the nanocomposites are controlled by the ratios of zinc(II) acetylacetonate: iron(III) 2,4-pentanedionate: biochar, which provides an easy way to optimize the adsorption performance of the nanocomposites. The removal RhB tests indicate that magnetic γ-Fe2O3-ZnO-biochar nanocomposites exhibit improved performance than bare biochar. The improved performance is attributed to photocatalyst properties of ZnO in the composite. The developed method represents a novel strategy to prepare magnetic biochar nanocomposites with improved removal capabilities via photocatalyst nanoparticles toward wastewater treatment.
       
  • Similarity in ruthenium damage induced by photons with different energies:
           from visible light to hard X-rays
    • Abstract: Publication date: Available online 4 October 2019Source: Applied Surface ScienceAuthor(s): I. Milov, V. Lipp, D. Ilnitsky, N. Medvedev, K. Migdal, V. Zhakhovsky, V. Khokhlov, Yu. Petrov, N. Inogamov, S. Semin, A. Kimel, B. Ziaja, I.A. Makhotkin, E. Louis, F. Bijkerk We performed combined experimental and computational research on damage processes in ruthenium thin films induced by femtosecond lasers with various photon energies. We present an experiment with an optical laser at normal incidence conditions and compare it with previously reported experiments at grazing incidence conditions with XUV and hard X-ray photons, covering a large range of photon energies. Analysis of ablation craters in Ru shows very similar crater morphology and depth of about 10-20 nm for all considered irradiation conditions. Simulations of light-matter interactions are performed with our combined Monte Carlo and two-temperature hydrodynamics approach. The simulation results show that the primal cause of eventual ablation is Auger decay of core-shell holes created after absorption of XUV and hard X-ray photons in the vicinity of ruthenium surface. They lead to the creation of many low-energy electrons which consequently release the absorbed energy near the surface, resembling the optical irradiation case. Similar absorbed energy distributions in the top part of ruthenium induce a similar thermo-mechanical response and, therefore, similar ablation process. Our results suggest that such mechanism is universal in a wide range of photon energies at grazing incidence conditions, when the photon absorption depth is smaller than the photoelectrons range.Graphical abstractGraphical abstract for this article
       
  • Directional and sustainable transportation of water droplets using
           lubricated carbon fibers on a superhydrophobic substrate
    • Abstract: Publication date: Available online 4 October 2019Source: Applied Surface ScienceAuthor(s): Haibao Hu, Qiqi Dong, Liping Qin, Peng Du, Gang Cao, Luyao Bao, Xiao Huang Directional transportation of water droplets on solid surfaces has been extensively studied over the past century owing to its scientific and engineering significances. In contrast to the wettability/stiffness/structure gradient methods, we present a new approach using lubricated carbon fiber tracks. The transportation process with different widths of the fiber, the substrates and the sizes of the droplet is tested and analyzed. Two failure modes of the transportation are characterized, which allows the passage of the droplet with a certain range of sizes. These insights are possible to manipulate droplets directionally and selectively, without changing the substrate. We anticipate that this transportation technique will find an extensive range of applications.
       
  • H / Cu ( 100 ) , H / Ag ( 100 ) +and+ O / Cu ( 100 ) +systems&rft.title=Applied+Surface+Science&rft.issn=0169-4332&rft.date=&rft.volume=">Monte Carlo simulations and Cluster-exact Approximation applied to
           H / Cu ( 100 ) , H / Ag ( 100 ) and O / Cu ( 100 ) systems
    • Abstract: Publication date: Available online 4 October 2019Source: Applied Surface ScienceAuthor(s): Fabricio O. Sanchez-Varretti, Elizabeth del V. Gómez, Lucía B. Avalle, Fernando M. Bulnes, M. Cecilia Gimenez, Antonio J. Ramirez-Pastor The systems H/Cu(100),H/Ag(100) and O/Cu(100) were analyzed theoretically by means of DFT calculations, Monte Carlo (MC) simulations and a Cluster-exact (CA) Approximation. To model these real systems, a two stages procedure was used. In a first stage, DFT calculations were performed in order to determine the adsorption energies corresponding to a hydrogen or oxygen atom in different environments. The obtained values depend on the number of first neighbors present in each adsorption site. For the systems H/Cu(100) and O/Cu(100), lateral interactions between adatoms were found to be repulsive, while for the H/Ag(100) system, the interactions are attractive, except for the case of four nearest neighbours. Then, with this information, MC simulations and CA approximation were applied for different temperatures. The process was monitored by following the surface coverage as a function of the chemical potential (adsorption isotherm). Interesting behaviors were observed and discussed in terms of the low-temperature phases formed in the adsorbed layer. In addition, a good agreement was found between MC and CA results, especially at high temperatures. At low temperatures, a chessboard-like phase was observed for the systems H/Cu(100) and O/Cu(100).
       
  • Nanolayer in brush collector contact under Joule heating
    • Abstract: Publication date: Available online 4 October 2019Source: Applied Surface ScienceAuthor(s): Vera Deeva, Stepan Slobodyan There has been little research into the contact areas between electric brushes and collectors during sliding interactions due to the difficulty of observing them. A layer of nanosized wear particles forms on the brush contact due to stochastic interactions between the surfaces that give the layer a mottled/speckled structure. This causes the output signal current or voltage to fluctuate. Taking a new approach, we investigate different polyhedral nanoparticle shapes, considering each particle to be enclosed in a bounding cube. Here we focus on Joule’s first law and assume that the particles are flattened due to electric currents, leading to Joule heating and hence temperature changes. Our results show that the degree of wear particle dispersion has a significant effect on the wear rate and electrical contact durability.Graphical abstractGraphical abstract for this article
       
  • Functionalized Iron Oxide Nanoparticles Conjugate of Multi-Anchored
           Schiff’s Base Inorganic Heterocyclic Pendant Groups: Cytotoxicity
           Studies
    • Abstract: Publication date: Available online 3 October 2019Source: Applied Surface ScienceAuthor(s): Dinesh Kumar C, Ananthan Alagumalai, Joydev Acharya, Pawan Kumar, Koustav Sarkar, Senthil A. Gurusamy Thangavelu, Vadapalli Chandrasekhar It is our objective to hybridize iron oxide nanoparticles with functional inorganic substrate to afford the potential conjugate nanoparticles for cytotoxicity studies. Magnetic iron oxide nanoparticles (Fe3O4 NPs), tethered with amine functional groups on its surface has been chosen as template to condense with the inorganic heterocyclic Schiff’s base (SBCTP) as a pendant group to afford conjugate nanoparticles. SBCTP, a non-geminal heterobifunctional substrate is synthesized by the substitution of five arms of Schiff’s base and one unit of aromatic aldehyde on hexachlorocyclotriphosphazene (HCCP). Despite the above two substrates exhibiting inherent drug properties, their mutual complementary role with case of Fe3O4@SBCTP NPs is investigated upon simple condensation of Schiff’s base units of SBCTP substrate on the surface of Fe3O4 NPs. Synthesis and characterization of the originally designed conjugate nanoparticles, Fe3O4@SBCTP NPs tends to exhibit potential anti-cancer properties to treat cancerous cells. As such the prospective hybrid product, Fe3O4@SBCTP NPs and its precursors, Fe3O4 NPs and SBCTP have been investigated separately for the cytotoxic activity with normal and cancerous cells at five different concentrations, with/without addition of the drug in MTT assay. Structural characterization of the above samples was deduced by data collected from multinuclear NMR (1H, 13C and 31P), solid state NMR, ESI mass, HR MS, FT-IR, UV-vis, XRD, FESEM, HRTEM, EDX, TGA and VSM at ambient temperature.Graphical abstractIron oxide nanoparticles (Fe3O4 NPs) and functional inorganic cyclotriphosphazene Schiff’s base (SBCTP) are hybridized to afford conjugate NPs, Fe3O4@SBCTP NPs for cytotoxicity studies with normal and cancerous cells at five different concentrations, with/without addition of the drug in MTT assayGraphical abstract for this article
       
  • Insight into the effect of Pd and Pd3Pb surface structure on activation of
           reactant O2 and product H2O in direct oxidative esterification
    • Abstract: Publication date: Available online 1 October 2019Source: Applied Surface ScienceAuthor(s): Hongxia Liu, Jing Ma, Dongwei Wei, Baohe Wang, Jing Zhu Density functional theory is performed to systematically study the effect of surface structure and facet of Pd and Pd3Pb catalysts on activity for O2, H2O activation, O diffusion and stability of resistance toward deactivation induced by H2O adsorption and aggregation. Our results show that flat (111) (Pd3Pb(111), Pd(111)) and (100) (Pd(100)) facets rather than stepped (211) facet (Pd(211), Pd3Pb(211)) are active surfaces, mathing well with our previous experimental result that Pd(111) and Pd3Pb(111) planes detected in Pd-Pb alloy, further confirm that main exposed Pd3Pb(111) surface of Pd3Pb promotes O2, H2O activation, O diffusion and inhibits H2O adsorption, aggregation. Moreover, preadsorbed O coverage and numbers of H2O on Pd3Pb have little effect on H2O adsorption and cluster forming. Therefore, Pd3Pb catalysts not only present better activity and stronger stability but also decrease cost than pure Pd. Firstly finding that surface average charge through Mulliken charge analysis serves as a indicator judging minimum active region. Higher activity and stability of Pd3Pb catalysts are attributed to exposed rhomboid active unit with Pb synergistic effect. Dependence of Pd and Pd3Pb catalyst’s activity and stability on surface structure and facet revealed may provide new way for designing better, stable Pd-Pb catalysts in direct oxidative esterification.Graphical abstractGraphical abstract for this article
       
  • Reactivation of Fenton Catalytic Performance for Fe3O4 Catalyst:
           Optimizing the Cyclic Performance by Low Voltage Electric Field
    • Abstract: Publication date: Available online 1 October 2019Source: Applied Surface ScienceAuthor(s): Jing Wang, Zhan-fang Cao, Hongshan Ren, Chao Yu, Shuai Wang, Liqing Li, Hong Zhong Some Fenton Fe3O4 catalysts have the problem that the catalytic performance gradually weakens with increasing number of cycles, which brings economic losses and treatment difficulties to industrial wastewater treatment. In this work, the cyclic catalytic performance of Fenton N-rGO/Fe3O4 NPs catalysts for methylene blue (MB) has been enhanced by the reactivation process under the electric field. The effects of chemical reactions, voltage and electrolytic time on the cyclic performance of Fenton catalysts during the reactivation were discussed in detail. The first and fourth complete degradation of MB by fresh catalysts need 10 min and 20 min. After 2 h of reactivation using H2O as electrolyte at 1.0 V, the fourth complete degradation of MB only took 10 min. Zeta potential and CV curves showed that recovered catalyst has supplemented with surface electrons during the reactivation process. Characterizations demonstrated that the structure and composition of catalyst would not be influenced during the reactivation process. In short, the reactivation process under low voltage electric field is of great significance to Fenton Fe3O4 catalysts in the field of industrial water treatment.Graphical abstractGraphical abstract for this article
       
  • Modulation of the photocatalytic performance of g-C3N4 by two-sites
           co-doping using variable valence metal
    • Abstract: Publication date: Available online 1 October 2019Source: Applied Surface ScienceAuthor(s): Yanhui Dai, Yingjie Gu, Yuyu Bu Copper element was employed to achieve the interlayer doping and intralayer doping in g-C3N4 (CN). Univalent Cu single atom prefer to dope into the interlayer site of CN to form a steady bridged bond structure. Further increasing the doping amount of Cu, except for the univalent Cu at the interlayer, some divalent Cu single atoms can be doped on the intralayer site of CN to form an unstable but active-catalysis structure. Electrochemical and theoretical calculation results reveal that Cu-interlayer doping can form an energy gradient between the different CN layers to decrease the charge transfer energy barrier between them. More importantly, these interlayer photogenerated electrons will converge on the divalent Cu, a catalysis active site for the photogenerated electrons, inducing more superoxide radicals and high activity. This two-sites modified CN, can mineralize a refractory antibiotic Norfloxacin (NOR) to CO2 and H2O completely under visible light stimulation, and the two-sites co-doping method provides a reference for CN photocatalyst modification to solve the questions of insufficient redox energy and low photons quantum efficiency of CN.Graphical abstractVariable valence metal Cu with univalent and divalent conversion capacity was developed to achieve the interlayer doping and intralayer co-doping of g-C3N4. Univalent Cu atom prefer to dope into the interlayer of g-C3N4 to form a steady bridged bond structure to improve the charge transfer capacity of g-C3N4. Divalent Cu atoms can be doped on the intralayer of g-C3N4, to form an unstable but active-catalysis site.Graphical abstract for this article
       
  • Preparation of MOFs derived nitrogen self-doped porous carbon and its
           electrochemical performance in mixed electrolytes
    • Abstract: Publication date: Available online 1 October 2019Source: Applied Surface ScienceAuthor(s): Qian Wang, Shuai Li, Jianqiang Zhang, Xia Zhao, Huixia Feng, Heming Luo Owing to the versatile chemical compositions and structures of metal-organic frameworks (MOFs), design and synthesis of MOFs derived complicated nano-structures has been a key topic in chemistry and materials science. Aimed at key issues such as low energy density of supercapacitors, {[Ag3(BTC)(IM)]·H2O}n (ABI) was synthesized using the hydrothermal method and nitrogen self-doped porous carbon ABIC-T was prepared using the one-step carbonization method. The electrochemical performances of ABIC-T in KOH and ASS-4.0 mixed electrolyte were investigated and the mechanism of mixed electrolyte reaction was clarified. The results indicated that the synthesized nitrogen self-doped porous carbon ABIC-750 has a spongy porous structure with specific surface area of 602 m2/g. At current density of 1.0 A/g, the specific capacitance of ABIC-750 in KOH (6 M) was 142.2 F/g and its capacitance retention after 5000 cycles was 91.05%. At current density of 1.0 A/g, the specific capacitance of ABIC-750 was 817.1 F/g in the ASS-4.0 mixed electrolyte. In other words, the energy density of ABIC-750 in the ASS-4.0 mixed electrolyte was 5.75 times of that in KOH (6 M). This can be attributed to the Faradaic pseudocapacitance developed by redox reactions of sodium alizarinsulfonate in the mixed electrolyte.
       
  • Facile Fabrication of Cellulose Membrane Containing Polyiodides and Its
           Antibacterial Properties
    • Abstract: Publication date: Available online 1 October 2019Source: Applied Surface ScienceAuthor(s): Shengli Zhang, Chengcheng Kai, Bofang Liu, Silue Zhang, Wei Wei, Xiaoling Xu, Zuowan Zhou Iodine exhibits a broad antibacterial spectrum, low toxicity, high efficiency and no drug resistance. However, free iodine is unstable and has strong irritation on wounds if applied directly. Hence, a carrier improving the stability of iodine is required. In this study, a branched polyethylenimine (PEI) was employed as an iodine carrier. It was firstly fixed to dialdehyde cellulose membrane (DCM) via Schiff-base reaction. Then the PEI-DCM was immersed in an I2-KI aqueous solution to prepare a novel antibacterial cellulose membrane containing polyiodides (I-PEI-DCM). Its structure and properties were characterized by SEM, EDX, XPS, Raman, ATR-FTIR, XRD and antibacterial activity. Results demonstrated that the iodine loaded on the I-PEI-DCM was the mixture of I3− and I5−, whose distribution on the membrane was uniform. During the iodination treatment, the amino groups of PEI molecular chains participated in the complex reaction with polyiodide ions. The microbiological tests showed that the I-PEI-DCM had excellent antibacterial activity against both E. coli and S. aureus. It can completely inactivate all of two bacteria within 0.5 min even after 30-day storage. Meanwhile, the antibacterial membrane exhibited good stability and reusability. Based on the characteristic features, the I-PEI-DCM can be regarded as a promising wound dressing.Graphical abstractGraphical abstract for this article
       
  • Synthesis of one-dimensional magnetite hydroxyapatite nanorods on reduced
           graphene oxide sheets for selective separation and controlled delivery of
           hemoglobin
    • Abstract: Publication date: Available online 1 October 2019Source: Applied Surface ScienceAuthor(s): G. Bharath, K. Rambabu, Abdul Hai, Shoaib Anwer, Fawzi Banat, N. Ponpandian A novel magnetic sorbent, one-dimensional (1D) magnetite hydroxyapatite nanorods on two-dimensional (2D) reduced graphene oxide (MHAp/RGO) was developed for selective separation of hemoglobin (Hb). The MHAp/RGO nanocomposite was prepared through a hydrothermal method at 180 oC for 12h. Nucleation growth mechanism was analyzed for the formation of the nanocomposite. Electron microscopy analysis showed that the 1D MHAp with average diameter and length of 25 and 200 nm respectively were uniformly grown on 2D RGO sheets. Ternary phases of magnetite, HAp, and RGO in the samples were studied using various physicochemical characterization tools. The obtained MHAp/RGO nanocomposite was used as a high-performance magnetic sorbent for selective adsorption and controlled release of Hb. The as-prepared MHAp/RGO nanocomposite exhibited a maximum adsorption capacity of 1012 mg g-1 at near the isoelectric point (pI(Hb)) of Hb (pH 7.0). Hb adsorption behavior on the nanosorbent was analyzed through the adsorption mechanism, equilibrium isotherms, and kinetic models. Also, the adsorbed Hb on the nanosorbent could be effectively recovered up to 86% at pH 4.0 within 45 min. The present study revealed that the developed magnetic sorbent shows a potential scope for pH-dependent Hb protein isolation and release, thus making it suitable for biomedical applications.Graphical abstractGraphical abstract for this article
       
  • Carbide-bonded graphene-based Joule heating for embossing fine
           microstructures on optical glass
    • Abstract: Publication date: Available online 1 October 2019Source: Applied Surface ScienceAuthor(s): Lihua Li, Gao Yang, Wing Bun Lee, Man Cheung Ng, Kin Leung Chan This paper reports the fabrication of high-quality microstructures on optical glass via hot embossing using carbide-bonded graphene (CBG) based Joule heating for the first time. In this study, a tailor-made micro hot embossing tool equipped with a modified CBG-based Joule heating system was designed and developed for transferring microstructures (e.g., microlens arrays, MLAs for short) from the CBG-coated silicon mold insert into the optical glass (P-SK57). Initially, the surface topographies of a typical 3×3 MLA from a bare silicon mold to an embossed glass replica were compared for evaluating form errors brought in during different preparation stages. The feasibility of the CBG-based Joule heating technique for the non-equilibrium thermal forming of optical glass was evaluated by the surface integrity and replication fidelity of the embossed MLA features. Thermally induced residual stress and imaging performance of the embossed glass lens were assessed as well. Experimental results indicate that the proposed CBG-assisted hot embossing technique, in combination with single point diamond turning technology, has the capability of producing high-quality glass MLAs. Moreover, this technique allows notably fine replication of surface shapes at the microscale, as well as roughness information at the nanoscale. Consequently, the embossed MLA replica shows satisfactory imaging performance.Graphical abstractGraphical abstract for this article
       
  • An air-plasma enhanced low-temperature wafer bonding method using
           high-concentration water glass adhesive layer
    • Abstract: Publication date: Available online 1 October 2019Source: Applied Surface ScienceAuthor(s): Yang Xu, Shengkai Wang, Peilin Yao, Yinghui Wang, Dapeng Chen An air-plasma enhanced low-temperature wafer bonding method using high-concentration water glass adhesive layer has been demonstrated. The high-concentration water glass adhesive layer for wafer bonding has been achieved by introducing nitrogen and preventing CO2, and successfully bonded using spot pressing bonding and air-plasma enhancement for the first time. The tensile strength of the bonded pairs was about 15 MPa and maintained even after long-term storage. The influence of air-plasma treatment was investigated by comparing the contact angles of different substrates and storage time after air-plasma treatment. In addition, the influence of the carbon residue in different preparation conditions were also investigated by X-ray photoelectron spectroscopy (XPS), current-voltage (I-V) and capacitance-frequency (C-f) measurements. The samples coated in nitrogen have lower intensity of carbon, higher leakage current density and lager dielectric constant comparing to the samples coated in the air. Therefore, the bonding method is a promising method for low-temperature bonding with high-concentration adhesive.
       
  • Achieving ultralow surface roughness and high material removal rate in
           fused silica via a novel acid SiO2 slurry and its chemical-mechanical
           polishing mechanism
    • Abstract: Publication date: Available online 1 October 2019Source: Applied Surface ScienceAuthor(s): Xiao-Lei Shi, Gaopan Chen, Li Xu, Chengxi Kang, Guihai Luo, Haimei Luo, Yan Zhou, Matthew S. Dargusch, Guoshun Pan Fused silica is widely used as a substrate material in various optical precision devices, and its surface quality plays a significant role in determining the optical performance. However, it is difficult to achieve an ultra-smooth surface without obvious damage using traditional planarization techniques. In this work, we report on the simultaneous achievement of ultralow surface roughness of ∼0.193 nm and high material removal rate of ∼10.9 μm h-1 on a fused silica substrate via a novel acid SiO2 slurry. The results show an improvement of removal rate by ∼900% compared to its alkaline counterpart. Comprehensive studies based on thermogravimetric analysis, infrared X-ray photoelectron spectroscopy, and nuclear magnetic resonance spectra reveal that phenolic hydroxyl in the acid SiO2 slurry plays a critical role in achieving high material removal rate during the chemical-mechanical polishing process, by well-distributing the SiO2 abrasives with an average size of only ∼80 nm. This approach delivers the high surface quality. Evidence in support of this explanation has been obtained using advanced characterization techniques including scanning electron microscopy, atomic force microscopy, and optical interferometry profiling. This novel acid SiO2 slurry is also environmentally friendly with significantly higher durability and stability, which is especially suitable for industrial scale production.Graphical abstractWe simultaneously achieve an ultralow surface roughness of ∼0.193 nm and a high material removal rate of ∼10.9 μm h-1 in the fused silica via a novel acid SiO2 slurry.Graphical abstract for this article
       
  • Promoting effects of acid enhancing on N2 selectivity for selectivity
           catalytic oxidation of NH3 over RuO x /TiO2: The mechanism study
    • Abstract: Publication date: Available online 1 October 2019Source: Applied Surface ScienceAuthor(s): Qiulin Zhang, Tengxiang Zhang, Futing Xia, Yaqing Zhang, Huimin Wang, Ping Ning RuOx/TiO2 and RuOx/TiO2-SO42- catalysts were prepared and used for selective catalytic oxidation of ammonia (NH3-SCO). The results indicated that N2 selectivity over RuOx/TiO2 was significantly enhanced after the introduction of SO42-. The introduction of SO42- into RuOx/TiO2 observably increased the amount and strength of acid species on the surface of catalyst. Specifically, the RuOx/TiO2-SO42- sulfated treatment at 2 hour possessed the optimal surface acidic property obtaining more than 85% N2 selectivity at 300 °C, which was apparently higher than that of RuOx/TiO2 with 66% N2 selectivity. The strong interaction between sulfated support and RuOx resulted in excellent redox property at high temperature, abundant surface oxygen and more Ru4+ species. Particularly, DRIFTS and NH3-TPD illustrated that the increased N2-selectivity was put down to Brönsted and Lewis acid sites augmented via sulfating treatment of TiO2, promoting the dehydrogenation of adsorbed ammonia species on the catalyst surface, then the formation of more -NH2 species could facilitate the reduction of NO to harmless N2, meanwhile, the generation of HNO species also were reduced to N2 by NH. Therefore, the excellent acid properties of RuOx/TiO2-SO42- gave rise to the formation of few nitrate species with an iSCR mechanism, which ensured to the high N2 selectivity.Graphical abstractThe introduction of SO42- increased the amount and strength of acid species (Brönsted and Lewis acid) on the surface of RuOx/TiO2 catalyst enhancing the N2 selectivity for NH3-SCO, which was in favor of promoting the dehydrogenation of adsorbed ammonia forming more -NH2 species to facilitate the rapid reduction of NO to N2, and HNO species could be partly reduced to N2 by NH.Graphical abstract for this article
       
  • Controlled etching of silica nanospheres monolayer for template
           application: A systematic study
    • Abstract: Publication date: Available online 1 October 2019Source: Applied Surface ScienceAuthor(s): Utsav, Sakshum Khanna, Sagar Panelia, Abhijit Ray, Indrajit Mukhopadhyay, Rupak Banerjee Monolayers of silica nanospheres (SNs), via self- or guided-assembly has been extensively used for template fabrication in thin films, employed in the areas of plasmonics, photonic crystals, and solar cells. We report on a versatile, rapid, and controllable process to obtain non-close-packed structure by restructuring the SNs geometry at two-particle level. A geometrical model has been proposed to quantify parameters that control the final morphology of the monolayer. SNs of different sizes (viz. 140 nm, 170 nm, and 220 nm) were self-assembled as a close-packed monolayer on a silicon substrate using a three-step spin coating method and then sintered at 950°C before being exposed to an etchant. We investigate the dependence of particle radius, neck (formed due to sintering) parameters and distance between the SNs, on etching time and etchant concentration. The intermediate and final morphology of the restructured monolayer is used as a template to grow silicon nanowires using metal-assisted chemical etching. We provide quantitative estimates of the parameters pertaining to the restructuring of the monolayer of SNs, which can be used as tunable templates for the growth of nanowires. The optimized process can be scaled-up for industrial application because of its faster and controllable rate of production.Graphical abstractDescription: Schematic of the monolayer restructuring process from high coverage close-pack unsintered silica nanoparticles to a non-close pack structure by pre-sintering the monolayer at 950°C, and subsequent etching under controlled time and etchant concentration. This non-close pack structure is used as a template to grow silicon nanowires by metal-assisted chemical etching.Graphical abstract for this article
       
 
 
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