1
|
Elhalawany N, Abdel-Karim AM, Saleeb MM. Preparation and evaluation of some nanocarbon (NC) based composites for optoelectronic applications. Sci Rep 2023; 13:8987. [PMID: 37268703 DOI: 10.1038/s41598-023-35754-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2023] [Accepted: 05/23/2023] [Indexed: 06/04/2023] Open
Abstract
Polyaniline/nanocarbon (PANI/NC) nanocomposites have been prepared by in situ polymerization of aniline monomer in the presence of a stable colloidal solution of nanocarbon NC using ammonium persulfate as an initiator and silver ions (Ag+) as oxidizing agents to produce PANI/NC and PANI/NC/Ag2O nanocomposites, respectively. The morphological studies of the formed nanocomposites have been elucidated via transmission and scanning electron microscopes (TEM and SEM). Further characterization of the prepared nanocomposites has been done via infrared spectroscopy (IR), X-ray diffractometer (XRD), X-ray photoelectron spectroscopy (XPS), particle size distribution analysis (PSD), fluorescence microscope (FM), UV-VIS spectroscopy, and finally surface analysis. XRD results confirmed the presence of silver oxide Ag2O nanoparticles, and the obtained data is well matched with the JCPDS card number 76-1393 of silver oxide. XPS analyses have shown two prevailing characteristic peaks for Ag 3d5/2 and Ag 3d3/2 at 367.1 and 373 eV, respectively, representing Ag2O nanoparticles, which are matchable with the XRD analysis. The PSD analysis revealed that the sizes of the prepared nanocomposites are in the size range from 60 to 140 nm. The FM measurements showed luminescence from the prepared nanocomposites upon irradiation with different lights. This recommends that the fluorophores present in the prepared nanocomposites have the potential to both absorb and emit light. The AC conductivity and the dielectric permittivity of the obtained nanocomposites at room temperature and at different frequency ranges have been investigated. At higher frequency ranges, the maximum ac conductivity obtained was 1.06 × 10-2 and 2.5 × 10-2 S.Cm-1 for the PANI/NC and PANI/NC/Ag2O, respectively. As far as we know, these new nanocomposites with superior optical and electrical characteristics have not been described yet in the literature.
Collapse
Affiliation(s)
- Noha Elhalawany
- Polymers and Pigments Department, National Research Centre, 33 El Bohouth St. Dokki, Giza, 12622, Egypt.
| | - Amal M Abdel-Karim
- Physical Chemistry Department, National Research Centre, 33 El Bohouth St. Dokki, Giza, 12622, Egypt
| | | |
Collapse
|
2
|
Abstract
The field of single-atom catalysis (SAC) has expanded greatly in recent years. While there has been much success developing new synthesis methods, a fundamental disconnect exists between most experiments and the theoretical computations used to model them. The real catalysts are based on powder supports, which inevitably contain a multitude of different facets, different surface sites, defects, hydroxyl groups, and other contaminants due to the environment. This makes it extremely difficult to determine the structure of the active SAC site using current techniques. To be tractable, computations aimed at modeling SAC utilize periodic boundary conditions and low-index facets of an idealized support. Thus, the reaction barriers and mechanisms determined computationally represent, at best, a plausibility argument, and there is a strong chance that some critical aspect is omitted. One way to better understand what is plausible is by experimental modeling, i.e., comparing the results of computations to experiments based on precisely defined single-crystalline supports prepared in an ultrahigh-vacuum (UHV) environment. In this review, we report the status of the surface-science literature as it pertains to SAC. We focus on experimental work on supports where the site of the metal atom are unambiguously determined from experiment, in particular, the surfaces of rutile and anatase TiO2, the iron oxides Fe2O3 and Fe3O4, as well as CeO2 and MgO. Much of this work is based on scanning probe microscopy in conjunction with spectroscopy, and we highlight the remarkably few studies in which metal atoms are stable on low-index surfaces of typical supports. In the Perspective section, we discuss the possibility for expanding such studies into other relevant supports.
Collapse
Affiliation(s)
- Florian Kraushofer
- Institute of Applied Physics, Technische Universitat Wien, 1040 Vienna, Austria
| | - Gareth S Parkinson
- Institute of Applied Physics, Technische Universitat Wien, 1040 Vienna, Austria
| |
Collapse
|
3
|
Poddar S, Zhang Y, Chen Z, Ma Z, Fu Y, Ding Y, Chan CLJ, Zhang Q, Zhang D, Song Z, Fan Z. Image processing with a multi-level ultra-fast three dimensionally integrated perovskite nanowire array. NANOSCALE HORIZONS 2022; 7:759-769. [PMID: 35638535 DOI: 10.1039/d2nh00183g] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Besides its ubiquitous applications in optoelectronics, halide-perovskites (HPs) have also carved a niche in the domain of resistive switching memories (Re-RAMs). However owing to the material and electrical instability challenges faced by HP thin-films, rarely perovskite Re-RAMs are used to experimentally demonstrate data processing which is a fundamental requirement for neuromorphic applications. Here, for the first time, lead-free, ultrahigh density HP nanowire (NW) array Re-RAM has been utilized to demonstrate image processing via design of convolutional kernels. The devices exhibited superior switching characteristics including a high endurance of 5 × 106 cycles, an ultra-fast erasing and writing speed of 900 ps and 2 ns, respectively, and a retention time >5 × 104 s for the resistances. The work is bolstered by an in-depth mechanistic study and first-principles simulations which provide evidence of electrochemical metallization triggering the switching. Employing the robust multi-level switching behaviour, image processing functions of embossing, outlining and sharpening were successfully implemented.
Collapse
Affiliation(s)
- Swapnadeep Poddar
- Department of Electronic & Computer Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong SAR, China.
| | - Yuting Zhang
- Department of Electronic & Computer Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong SAR, China.
| | - Zhesi Chen
- Department of Electronic & Computer Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong SAR, China.
| | - Zichao Ma
- Department of Electronic & Computer Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong SAR, China.
| | - Yu Fu
- Department of Electronic & Computer Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong SAR, China.
| | - Yucheng Ding
- Department of Electronic & Computer Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong SAR, China.
| | - Chak Lam Jonathan Chan
- Department of Electronic & Computer Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong SAR, China.
| | - Qianpeng Zhang
- Department of Electronic & Computer Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong SAR, China.
| | - Daquan Zhang
- Department of Electronic & Computer Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong SAR, China.
| | - Zhitang Song
- State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Micro-system and Information Technology, Chinese Academy of Sciences, Shanghai, 200050, China.
| | - Zhiyong Fan
- Department of Electronic & Computer Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong SAR, China.
| |
Collapse
|
4
|
Structure and Properties of Electrochemically Synthesized Silver Nanoparticles in Aqueous Solution by High-Resolution Techniques. MOLECULES (BASEL, SWITZERLAND) 2021; 26:molecules26175155. [PMID: 34500589 PMCID: PMC8433840 DOI: 10.3390/molecules26175155] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/14/2021] [Revised: 08/20/2021] [Accepted: 08/23/2021] [Indexed: 02/05/2023]
Abstract
The aim of this work was to deeply investigate the structure and properties of electrochemically synthesized silver nanoparticles (AgNPs) through high-resolution techniques such as transmission electron microscopy (TEM), scanning electron microscopy (SEM), Zeta Potential measurements, and matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF-MS). Strong brightness, tendency to generate nanoclusters containing an odd number of atoms, and absence of the free silver ions in solution were observed. The research also highlighted that the chemical and physical properties of the AgNPs seemed to be related to their peculiar oxidative state as suggested by X-ray photoelectron spectroscopy (XPS) and X-ray powder diffraction (XRPD) analyses. Finally, the MTT assay tested the low cytotoxicity of the investigated AgNPs.
Collapse
|
5
|
Li R, Xu X, Zhu B, Li XY, Ning Y, Mu R, Du P, Li M, Wang H, Liang J, Chen Y, Gao Y, Yang B, Fu Q, Bao X. In situ identification of the metallic state of Ag nanoclusters in oxidative dispersion. Nat Commun 2021; 12:1406. [PMID: 33658489 PMCID: PMC7930130 DOI: 10.1038/s41467-021-21552-2] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2020] [Accepted: 01/12/2021] [Indexed: 11/21/2022] Open
Abstract
Oxidative dispersion has been widely used in regeneration of sintered metal catalysts and fabrication of single atom catalysts, which is attributed to an oxidation-induced dispersion mechanism. However, the interplay of gas-metal-support interaction in the dispersion processes, especially the gas-metal interaction has not been well illustrated. Here, we show dynamic dispersion of silver nanostructures on silicon nitride surface under reducing/oxidizing conditions and during carbon monoxide oxidation reaction. Utilizing environmental scanning (transmission) electron microscopy and near-ambient pressure photoelectron spectroscopy/photoemission electron microscopy, we unravel a new adsorption-induced dispersion mechanism in such a typical oxidative dispersion process. The strong gas-metal interaction achieved by chemisorption of oxygen on nearly-metallic silver nanoclusters is the internal driving force for dispersion. In situ observations show that the dispersed nearly-metallic silver nanoclusters are oxidized upon cooling in oxygen atmosphere, which could mislead to the understanding of oxidation-induced dispersion. We further understand the oxidative dispersion mechanism from the view of dynamic equilibrium taking temperature and gas pressure into account, which should be applied to many other metals such as gold, copper, palladium, etc. and other reaction conditions. Designing ultra small metal nanoclusters or single atoms with metallic state is a challenge. Here, the authors demonstrate the stabilization of ultra small silver clusters in the nearly-metallic state by oxygen adsorption at high temperature, using in situ spectroscopy and microscope technologies.
Collapse
Affiliation(s)
- Rongtan Li
- State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, The Chinese Academy of Sciences, Dalian, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Xiaoyan Xu
- CAS Key Laboratory of Science and Technology on Applied Catalysis, Dalian Institute of Chemical Physics, The Chinese Academy of Sciences, Dalian, China.,Dalian National Laboratory for Clean Energy, Dalian Institute of Chemical Physics, The Chinese Academy of Sciences, Dalian, China
| | - Beien Zhu
- Interdisciplinary Research Center, Shanghai Advanced Research Institute, The Chinese Academy of Sciences, Shanghai, China.,Key Laboratory of Interfacial Physics and Technology, Shanghai Institute of Applied Physics, The Chinese Academy of Sciences, Shanghai, China
| | - Xiao-Yan Li
- University of Chinese Academy of Sciences, Beijing, China.,Key Laboratory of Interfacial Physics and Technology, Shanghai Institute of Applied Physics, The Chinese Academy of Sciences, Shanghai, China
| | - Yanxiao Ning
- State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, The Chinese Academy of Sciences, Dalian, China
| | - Rentao Mu
- State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, The Chinese Academy of Sciences, Dalian, China
| | - Pengfei Du
- University of Chinese Academy of Sciences, Beijing, China.,Dalian National Laboratory for Clean Energy, Dalian Institute of Chemical Physics, The Chinese Academy of Sciences, Dalian, China
| | - Mengwei Li
- Dalian National Laboratory for Clean Energy, Dalian Institute of Chemical Physics, The Chinese Academy of Sciences, Dalian, China
| | - Huike Wang
- School of Materials Science and Engineering, National Institute for Advanced Materials, Nankai University, Tianjin, China
| | - Jiajie Liang
- School of Materials Science and Engineering, National Institute for Advanced Materials, Nankai University, Tianjin, China
| | - Yongsheng Chen
- Key Laboratory of Functional Polymer Materials of Ministry of Education, College of Chemistry, Nankai University, Tianjin, China
| | - Yi Gao
- Interdisciplinary Research Center, Shanghai Advanced Research Institute, The Chinese Academy of Sciences, Shanghai, China. .,Key Laboratory of Interfacial Physics and Technology, Shanghai Institute of Applied Physics, The Chinese Academy of Sciences, Shanghai, China.
| | - Bing Yang
- CAS Key Laboratory of Science and Technology on Applied Catalysis, Dalian Institute of Chemical Physics, The Chinese Academy of Sciences, Dalian, China. .,Dalian National Laboratory for Clean Energy, Dalian Institute of Chemical Physics, The Chinese Academy of Sciences, Dalian, China.
| | - Qiang Fu
- State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, The Chinese Academy of Sciences, Dalian, China. .,Dalian National Laboratory for Clean Energy, Dalian Institute of Chemical Physics, The Chinese Academy of Sciences, Dalian, China.
| | - Xinhe Bao
- State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, The Chinese Academy of Sciences, Dalian, China. .,Dalian National Laboratory for Clean Energy, Dalian Institute of Chemical Physics, The Chinese Academy of Sciences, Dalian, China.
| |
Collapse
|
6
|
Jakob R, Nilius N. A fiber scanning tunneling microscope for optical analysis at the nanoscale. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2020; 91:073110. [PMID: 32752868 DOI: 10.1063/5.0009182] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/28/2020] [Accepted: 07/05/2020] [Indexed: 06/11/2023]
Abstract
A hybrid scanning tunneling/optical near-field microscope is presented, in which an optical fiber tip coated with 100 nm thick Ag/Cr films scans the surface. The tip metallization enables operating the instrument via a current-based distance control and guarantees sub-nanometer spatial resolution in the topographic channel. The fiber tip simultaneously serves as nanoscale light source, given the optical transparency of the metal coating. The emission response of the tip-sample junction is collected with two parabolic mirrors and probed with a far-field detector. To test the capabilities of the new setup, the evolution of the optical signal is monitored when the tip approaches a gold surface. The intensity rise and frequency shift of the emission provide evidence for the development of coupled plasmon modes in the tip-sample cavity. Photon mapping is employed to probe the optical inhomogeneity of Ru(0001) and TiO2(110) surfaces covered with silver deposits. While the 2D Ag flakes on Ru give rise to a near-field enhancement, the 3D particles on titania locally damp the gap plasmons and lower the emitted intensity. The lateral resolution in the optical channel has been estimated to be ∼1 nm, and optical and topographic signals are well correlated. Our fiber microscope thus appears to be suitable for probing optical surface properties at the nanoscale.
Collapse
Affiliation(s)
- René Jakob
- Carl von Ossietzky Universität, Institut für Physik, D-26111 Oldenburg, Germany
| | - Niklas Nilius
- Carl von Ossietzky Universität, Institut für Physik, D-26111 Oldenburg, Germany
| |
Collapse
|
7
|
Morphology, Photocatalytic and Antimicrobial Properties of TiO 2 Modified with Mono- and Bimetallic Copper, Platinum and Silver Nanoparticles. NANOMATERIALS 2019; 9:nano9081129. [PMID: 31390754 PMCID: PMC6722503 DOI: 10.3390/nano9081129] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/11/2019] [Revised: 08/01/2019] [Accepted: 08/03/2019] [Indexed: 11/30/2022]
Abstract
Noble metal nanoparticles (NMNPs) enhanced TiO2 response and extended its activity under visible light. Photocatalytic activity of TiO2 modified with noble metal nanoparticles strongly depends on the physicochemical properties of NMNPs. Among others, the differences in the size of NMNPs seems to be one of the most important factors. In this view, the effect of the metal’s nanoparticles size, type and amount on TiO2 photocatalytic and biocidal activity was investigated. TiO2 modified with mono- and bimetallic nanoparticles of Pt, Cu and Ag were prepared using chemical and thermal reduction methods. Obtained nanocomposites were characterized using transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD) and diffuse-reflectance spectroscopy (DR/UV-Vis) techniques. The photocatalytic activity was examined in 2-propanol oxidation and hydrogen generation processes. The mechanism of modified TiO2 excitation was evaluated in action spectrum measurements during phenol oxidation. A possibility of using less energy-consuming light sources as a set of light-emitting diodes (LEDs) selected based on action spectrum results was examined. It was found that the differences in NMNPs size were the result of the reduction method. Moreover, coupling with a second metal strongly affected and differentiated the photocatalytic and biocidal activity of the obtained TiO2-based photocatalysts.
Collapse
|
8
|
Wang B, Zhu X, Li S, Chen M, Lu H, Yang Y. Ag@SiO₂ Core-shell Nanoparticles Embedded in a TiO₂ Mesoporous Layer Substantially Improve the Performance of Perovskite Solar Cells. NANOMATERIALS 2018; 8:nano8090701. [PMID: 30205547 PMCID: PMC6165042 DOI: 10.3390/nano8090701] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/10/2018] [Revised: 09/04/2018] [Accepted: 09/06/2018] [Indexed: 11/16/2022]
Abstract
In this study, Ag@SiO2 nanoparticles were synthesized by a modified Stöber method for preparing the TiO2 mesoporous layer of carbon counter electrode-based perovskite solar cells (PSCs) without a hole transporting layer. Compared with normal PSCs (without Ag@SiO2 incorporated in the TiO2 mesoporous layer), PSCs with an optimal content of Ag@SiO2 (0.3 wt. % Ag@SiO2-TiO2) show a 19.46% increase in their power conversion efficiency, from 12.23% to 14.61%, which is mainly attributed to the 13.89% enhancement of the short-circuit current density, from 20.23 mA/cm2 to 23.04 mA/cm2. These enhancements mainly contributed to the localized surface Plasmon resonance effect and the strong scattering effect of Ag@SiO2 nanoparticles. However, increasing the Ag@SiO2 concentration in the mesoporous layer past the optimum level cannot further increase the short-circuit current density and incident photon-to-electron conversion efficiency of the devices, which is primarily ascribed to the electron transport pathways being impeded by the insulating silica shells inside the TiO2 network.
Collapse
Affiliation(s)
- Bao Wang
- School of Science, Wuhan University of Technology, Wuhan 430070, China.
| | - Xiangyu Zhu
- School of Science, Wuhan University of Technology, Wuhan 430070, China.
| | - Shuhan Li
- School of Science, Wuhan University of Technology, Wuhan 430070, China.
| | - Mengwei Chen
- School of Science, Wuhan University of Technology, Wuhan 430070, China.
| | - Haifei Lu
- School of Science, Wuhan University of Technology, Wuhan 430070, China.
| | - Yingping Yang
- School of Science, Wuhan University of Technology, Wuhan 430070, China.
| |
Collapse
|
9
|
Gao R, Yang Z, Zheng L, Gu L, Liu L, Lee Y, Hu Z, Liu X. Enhancing the Catalytic Activity of Co3O4 for Li–O2 Batteries through the Synergy of Surface/Interface/Doping Engineering. ACS Catal 2018. [DOI: 10.1021/acscatal.7b03566] [Citation(s) in RCA: 82] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Rui Gao
- College
of Materials Science and Optoelectronic Technology, University of Chinese Academy of Sciences, Beijing 100049, People’s Republic of China
| | - Zhenzhong Yang
- Beijing
National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, People’s Republic of China
| | - Lirong Zheng
- Beijing
Synchrotron Radiation Facility, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049, People’s Republic of China
| | - Lin Gu
- Beijing
National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, People’s Republic of China
| | - Lei Liu
- College
of Materials Science and Optoelectronic Technology, University of Chinese Academy of Sciences, Beijing 100049, People’s Republic of China
| | - Yulin Lee
- Department
of Materials, Imperial College London, Royal School of Mines, Exhibition
Road, London SW7 2AZ, U.K
| | - Zhongbo Hu
- College
of Materials Science and Optoelectronic Technology, University of Chinese Academy of Sciences, Beijing 100049, People’s Republic of China
| | - Xiangfeng Liu
- College
of Materials Science and Optoelectronic Technology, University of Chinese Academy of Sciences, Beijing 100049, People’s Republic of China
| |
Collapse
|
10
|
Duan Y, Rani S, Newberg JT, Teplyakov AV. Investigation of the influence of oxygen plasma on supported silver nanoparticles. JOURNAL OF VACUUM SCIENCE & TECHNOLOGY. A, VACUUM, SURFACES, AND FILMS : AN OFFICIAL JOURNAL OF THE AMERICAN VACUUM SOCIETY 2018; 36:01B101. [PMID: 28867872 PMCID: PMC5565488 DOI: 10.1116/1.4986208] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/02/2017] [Revised: 08/02/2017] [Accepted: 08/02/2017] [Indexed: 06/04/2023]
Abstract
Silver deposition precursor molecule trimethylphosphine(hexafluoroacetylacetonato)silver(I) [(hfac)AgP(CH3)3] was used to deposit silver onto water-modified (hydroxyl-terminated) solid substrates. A silicon wafer was used as a model flat surface, and water-predosed ZnO nanopowder was investigated to expand the findings to a common substrate material for possible practical applications. Following the deposition, oxygen plasma was used to remove the remaining organic ligands on a surface and to investigate its effect on the morphology of chemically deposited silver nanoparticles and films. A combination of microscopic and spectroscopic techniques including electron microscopy and x-ray photoelectron spectroscopy was used to confirm the change in the morphology of the deposited material consistent with Ostwald ripening as a result of plasma treatment. Particle agglomeration was observed on the surfaces, and the deposited metallic silver was oxidized to Ag2O following plasma treatment. The fluorine-containing ligands were completely removed. This result suggests that chemical vapor deposition can be used to deposit silver in a very controlled manner onto a variety of substrates using different topography methods and that the post-treatment with oxygen plasma is effective in preparing materials deposited for potential practical applications.
Collapse
Affiliation(s)
- Yichen Duan
- Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware 19716
| | - Sana Rani
- Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware 19716
| | - John T Newberg
- Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware 19716
| | - Andrew V Teplyakov
- Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware 19716
| |
Collapse
|
11
|
Kjærvik M, Hermanns A, Dietrich P, Thissen A, Bahr S, Ritter B, Kemnitz E, Unger WES. Detection of suspended nanoparticles with near-ambient pressure x-ray photoelectron spectroscopy. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2017; 29:474002. [PMID: 28891804 DOI: 10.1088/1361-648x/aa8b9d] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Two systems of suspended nanoparticles have been studied with near-ambient pressure x-ray photoelectron spectroscopy: silver nanoparticles in water and strontium fluoride-calcium fluoride core-shell nanoparticles in ethylene glycol. The corresponding dry samples were measured under ultra high vacuum for comparison. The results obtained under near-ambient pressure were overall comparable to those obtained under ultra high vacuum, although measuring silver nanoparticles in water requires a high pass energy and a long acquisition time. A shift towards higher binding energies was found for the silver nanoparticles in aqueous suspension compared to the corresponding dry sample, which can be assigned to a change of surface potential at the water-nanoparticle interface. The shell-thickness of the core-shell nanoparticles was estimated based on simulated spectra from the National Institute of Standards and Technology database for simulation of electron spectra for surface analysis. With the instrumental set-up presented in this paper, nanoparticle suspensions in a suitable container can be directly inserted into the analysis chamber and measured without prior sample preparation.
Collapse
Affiliation(s)
- Marit Kjærvik
- Division 6.1 Surface Analysis and Interfacial Chemistry, Bundesanstalt für Materialforschung und -prüfung, Unter den Eichen 44-46, 12203 Berlin, Germany
| | | | | | | | | | | | | | | |
Collapse
|
12
|
Peláez RJ, Espinós JP, Afonso CN. Formation of nitrile species on Ag nanostructures supported on a-Al 2O 3: a new corrosion route for silver exposed to the atmosphere. NANOTECHNOLOGY 2017; 28:175709. [PMID: 28278132 DOI: 10.1088/1361-6528/aa65c0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
The aging of supported Ag nanostructures upon storage in ambient conditions (air and room temperature) for 20 months has been studied. The samples are produced on glass substrates by pulsed laser deposition (PLD); first a 15 nm thick buffer layer of amorphous aluminum oxide (a-Al2O3) is deposited, followed by PLD of Ag. The amount of deposited Ag ranges from that leading to a discontinuous layer up to an almost-percolated layer with a thickness of <6 nm. Some regions of the as-grown silver layers are converted, by laser induced dewetting, into round isolated nanoparticles (NPs) with diameters of up to ∼25 nm. The plasmonic, structural and chemical properties of both as-grown and laser exposed regions upon aging have been followed using extinction spectroscopy, scanning electron microscopy and x-ray photoelectron spectroscopy, respectively. The results show that the discontinuous as-grown regions are optically and chemically unstable and that the metal becomes oxidized faster, the smaller the amount of Ag. The corrosion leads to the formation of nitrile species due to the reaction between NO x species from the atmosphere adsorbed at the surface of Ag, and hydrocarbons adsorbed in defects at the surface of the a-Al2O3 layer during the deposition of the Ag nanostructures by PLD that migrate to the surface of the metal with time. The nitrile formation thus results in the main oxidation mechanism and inhibits almost completely the formation of sulphate/sulphide. Finally, the optical changes upon aging offer an easy-to-use tool for following the aging process. They are dominated by an enhanced absorption in the UV side of the spectrum and a blue-shift of the surface plasmon resonance that are, respectively, related to the formation of a dielectric overlayer on the Ag nanostructure and changes in the dimensions/features of the nanostructures, both due to the oxidation process.
Collapse
Affiliation(s)
- R J Peláez
- Laser Processing Group, Instituto de Optica, CSIC, Serrano 121, E-28006, Madrid, Spain
| | | | | |
Collapse
|
13
|
Duan Y, Rani S, Zhang Y, Ni C, Newberg JT, Teplyakov AV. Silver Deposition onto Modified Silicon Substrates. THE JOURNAL OF PHYSICAL CHEMISTRY. C, NANOMATERIALS AND INTERFACES 2017; 121:7240-7247. [PMID: 28652890 PMCID: PMC5482543 DOI: 10.1021/acs.jpcc.6b12896] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Trimethylphosphine(hexafluoroacetylacetonato)silver(I) was used as a precursor to deposit silver onto silicon surfaces. The deposition was performed on silicon-based substrates including silica, H-terminated Si(100), and OH-terminated (oxidized) Si(100). The deposition processes at room temperature and elevated temperature (350 °C) were compared. The successful deposition resulted in nanostructures or nanostructured films as confirmed by atomic force microscopy (AFM) and scanning electron microscopy (SEM) with metallic silver being the majority deposited species as confirmed by X-ray photoelectron spectroscopy (XPS). The reactivity of the precursor depends drastically not only on the temperature of the process but also on the type of substrate. Density functional theory (DFT) was used to explain these differences and to propose the mechanisms for the initial deposition steps.
Collapse
Affiliation(s)
- Yichen Duan
- Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware 19716, United States
| | - Sana Rani
- Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware 19716, United States
| | - Yuying Zhang
- Department of Materials Science and Engineering, University of Delaware, Newark, Delaware 19716, United States
| | - Chaoying Ni
- Department of Materials Science and Engineering, University of Delaware, Newark, Delaware 19716, United States
| | - John T. Newberg
- Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware 19716, United States
| | - Andrew V. Teplyakov
- Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware 19716, United States
| |
Collapse
|
14
|
Kong L, Ma G, Liu W, Zhu P, Xue Q, Ling X. Protein-Directed Synthesis of Lead(II) and Temperature Dual-Responsive Red Fluorescent Gold Nanoclusters and Their Applications in Cellular and Bacterial Imaging. ChemistrySelect 2016. [DOI: 10.1002/slct.201600099] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Lingcan Kong
- Wuxi Center for Disease Control and Prevention; Wuxi Jincheng Rd. 499 214023 P.R. China
- Wuxi Center for Disease Control and Prevention; Wuxi Jincheng Rd. 499 214023 P.R. China
| | - Guangyuan Ma
- Wuxi Center for Disease Control and Prevention; Wuxi Jincheng Rd. 499 214023 P.R. China
| | - Wenwei Liu
- Wuxi Center for Disease Control and Prevention; Wuxi Jincheng Rd. 499 214023 P.R. China
| | - Pengfei Zhu
- Wuxi Center for Disease Control and Prevention; Wuxi Jincheng Rd. 499 214023 P.R. China
| | - Qiang Xue
- Wuxi Center for Disease Control and Prevention; Wuxi Jincheng Rd. 499 214023 P.R. China
| | - Xia Ling
- Wuxi Center for Disease Control and Prevention; Wuxi Jincheng Rd. 499 214023 P.R. China
| |
Collapse
|
15
|
Liu X, Zhang X, Bo M, Li L, Tian H, Nie Y, Sun Y, Xu S, Wang Y, Zheng W, Sun CQ. Coordination-resolved electron spectrometrics. Chem Rev 2015; 115:6746-810. [PMID: 26110615 DOI: 10.1021/cr500651m] [Citation(s) in RCA: 111] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Xinjuan Liu
- †Institute of Coordination Bond Metrology and Engineering, College of Materials Science and Engineering, China Jiliang University, Hangzhou 310018, China
| | - Xi Zhang
- ‡Institute of Nanosurface Science and Engineering, Shenzhen University, Shenzhen 518060, China
| | - Maolin Bo
- §Key Laboratory of Low-Dimensional Materials and Application Technologies (Ministry of Education) and School of Materials Science and Engineering, Xiangtan University, Hunan 411105, China
| | - Lei Li
- ∥School of Materials Science, Jilin University, Changchun 130012, China
| | - Hongwei Tian
- ∥School of Materials Science, Jilin University, Changchun 130012, China
| | - Yanguang Nie
- ⊥School of Science, Jiangnan University, Wuxi 214122, China
| | - Yi Sun
- #Harris School of Public Policy, University of Chicago, Chicago, Illinois 60637, United States
| | - Shiqing Xu
- †Institute of Coordination Bond Metrology and Engineering, College of Materials Science and Engineering, China Jiliang University, Hangzhou 310018, China
| | - Yan Wang
- ∇School of Information Technology, Hunan University of Science and Technology, Xiangtan 411201, China
| | - Weitao Zheng
- ∥School of Materials Science, Jilin University, Changchun 130012, China
| | - Chang Q Sun
- ○NOVITAS, School of Electrical and Electronic Engineering, Nanyang Technological University, Singapore 639798, Singapore
| |
Collapse
|
16
|
Okyay TO, Bala RK, Nguyen HN, Atalay R, Bayam Y, Rodrigues DF. Antibacterial properties and mechanisms of toxicity of sonochemically grown ZnO nanorods. RSC Adv 2015. [DOI: 10.1039/c4ra12539h] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
ZnO nanorods produced sonochemically prevented microbial growth, biofilm formation and were non-toxic to mammalian cells.
Collapse
Affiliation(s)
- Tugba O. Okyay
- Department of Civil and Environmental Engineering
- University of Houston
- Houston
- USA
| | - Rukayya K. Bala
- Department of Electrical and Electronics Engineering
- Gediz University
- 35665 Izmir
- Turkey
| | - Hang N. Nguyen
- Department of Civil and Environmental Engineering
- University of Houston
- Houston
- USA
| | - Ramazan Atalay
- Department of Biomedical Engineering
- Gediz University
- 35665 Izmir
- Turkey
| | - Yavuz Bayam
- Department of Electrical and Electronics Engineering
- Gediz University
- 35665 Izmir
- Turkey
| | - Debora F. Rodrigues
- Department of Civil and Environmental Engineering
- University of Houston
- Houston
- USA
| |
Collapse
|
17
|
Mao BH, Chang R, Shi L, Zhuo QQ, Rani S, Liu XS, Tyo EC, Vajda S, Wang SD, Liu Z. A near ambient pressure XPS study of subnanometer silver clusters on Al2O3and TiO2ultrathin film supports. Phys Chem Chem Phys 2014; 16:26645-52. [DOI: 10.1039/c4cp02325k] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
|
18
|
Liu M, Wang Q, Geng Y, Wang C, Lee YI, Hao J, Liu HG. Liquid/Liquid interfacial fabrication of thermosensitive and catalytically active Ag nanoparticle-doped block copolymer composite foam films. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2014; 30:10503-10512. [PMID: 25110832 DOI: 10.1021/la502738j] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
An aqueous solution of AgNO3 (upper phase) and a DMF/CHCl3 solution of polystyrene-b-poly(acryl acid)-b-polystyrene (PS-b-PAA-b-PS) or PS-b-PAA-b-PS/1,6-diaminohexane (DAH) (lower phase) constituted a planar liquid/liquid interface. The lower phase gradually transformed to a water-in-oil (W/O) emulsion via spontaneous emulsification due to the "ouzo effect". Polymer molecules, DAH molecules, and Ag(+) ions assembled into microcapsules around emulsion droplets that adsorbed at the planar liquid/liquid interface, resulting in formation of a foam film. DAH acted as a cross-linker during this process. Transmission electron microscopic observations indicated that Ag nanoclusters that were generated through reduction of Ag(+) ions by DMF were homogeneously dispersed in the walls of the foam structure. X-ray photoelectron spectroscopic investigations revealed that Ag(I) and Ag(0) coexisted in the film, and Ag(I) transformed to Ag(0) after further treatment. The film formed without DAH was not stable, while the film formed with DAH was very stable due to intermolecular attraction between PAA and DAH and formation of amides, as revealed by FTIR spectra. The film formed with DAH exhibited high and durable catalytic activity for hydrogenation of nitro compounds and, very interestingly, exhibited thermoresponsive catalytic behavior.
Collapse
Affiliation(s)
- Mei Liu
- Key Laboratory for Colloid and Interface Chemistry of Education Ministry, Shandong University , Jinan 250100, P. R. China
| | | | | | | | | | | | | |
Collapse
|
19
|
Ambrogi V, Donnadio A, Pietrella D, Latterini L, Proietti FA, Marmottini F, Padeletti G, Kaciulis S, Giovagnoli S, Ricci M. Chitosan films containing mesoporous SBA-15 supported silver nanoparticles for wound dressing. J Mater Chem B 2014; 2:6054-6063. [DOI: 10.1039/c4tb00927d] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|
20
|
The Adsorption, Thermal Desorption and Photochemistry of Methyl Iodide on an Ag-Covered TiO2(110) Surface. J CHIN CHEM SOC-TAIP 2013. [DOI: 10.1002/jccs.200600106] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
|
21
|
Gottesman R, Tirosh S, Barad HN, Zaban A. Direct Imaging of the Recombination/Reduction Sites in Porous TiO2 Electrodes. J Phys Chem Lett 2013; 4:2822-8. [PMID: 26706647 DOI: 10.1021/jz401549e] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
In photoelectrochemical cells, one major recombination pathway involves a reaction between the photogenerated electrons that diffuse inside the semiconductor electrode and holes, in the form of oxidized ions, which travel in the electrolyte to the counter electrode. Here we present direct imaging of the recombination/reduction sites in two types of porous TiO2 electrodes, P25 and submicrometer particles, chosen for studying the influence of the TiO2 particles' sizes and shapes on the recombination sites. The sites were labeled with 2-5 nm silver particles, electrodeposited on the TiO2 surface using chronoamperometry. The model assumes that reduction and recombination are similar with respect to the electron transfer from the TiO2 surface to an ionic electron acceptor in the electrolyte redox mediator/Ag(+) ion. Consequently the metal deposit marks the reaction locations. This first high-resolution view clearly identifies the connecting points between TiO2 particles and then the {101} facets as the sites of recombination.
Collapse
Affiliation(s)
- Ronen Gottesman
- Department of Chemistry, Center for Nanotechnology & Advanced Materials, Bar Ilan University , Ramat Gan 52900, Israel
| | - Shay Tirosh
- Department of Chemistry, Center for Nanotechnology & Advanced Materials, Bar Ilan University , Ramat Gan 52900, Israel
| | - Hannah-Noa Barad
- Department of Chemistry, Center for Nanotechnology & Advanced Materials, Bar Ilan University , Ramat Gan 52900, Israel
| | - Arie Zaban
- Department of Chemistry, Center for Nanotechnology & Advanced Materials, Bar Ilan University , Ramat Gan 52900, Israel
| |
Collapse
|
22
|
Takakusagi S, Chun WJ, Uehara H, Asakura K, Iwasawa Y. Polarization-Dependent Total-Reflection Fluorescence X-ray Absorption Fine Structure for 3D Structural Determination and Surface Fine Tuning. Top Catal 2013. [DOI: 10.1007/s11244-013-0134-y] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
|
23
|
Lira E, Hansen JØ, Merte LR, Sprunger PT, Li Z, Besenbacher F, Wendt S. Growth of Ag and Au Nanoparticles on Reduced and Oxidized Rutile TiO2(110) Surfaces. Top Catal 2013. [DOI: 10.1007/s11244-013-0141-z] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
|
24
|
Pang CL, Lindsay R, Thornton G. Structure of clean and adsorbate-covered single-crystal rutile TiO2 surfaces. Chem Rev 2013; 113:3887-948. [PMID: 23676004 DOI: 10.1021/cr300409r] [Citation(s) in RCA: 264] [Impact Index Per Article: 24.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Affiliation(s)
- Chi Lun Pang
- London Centre for Nanotechnology and Department of Chemistry, University College London, London WC1H 0AJ, United Kingdom
| | | | | |
Collapse
|
25
|
Henderson MA, Lyubinetsky I. Molecular-Level Insights into Photocatalysis from Scanning Probe Microscopy Studies on TiO2(110). Chem Rev 2013; 113:4428-55. [DOI: 10.1021/cr300315m] [Citation(s) in RCA: 204] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Michael A. Henderson
- Physical Sciences Division, Pacific Northwest National Laboratory, P.O. Box 999,
MS K8-87 Richland, Washington 99352, United States
| | - Igor Lyubinetsky
- Environmental Molecular Sciences
Laboratory, Pacific Northwest National Laboratory, P.O. Box 999, MS K8-93 Richland, Washington 99352, United States
| |
Collapse
|
26
|
Analysis on Binding Energy and Auger Parameter for Estimating Size and Stoichiometry of ZnO Nanorods. ACTA ACUST UNITED AC 2012. [DOI: 10.1155/2012/371092] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
ZnO nanorods prepared through chemical vapor deposition technique are characterized by microscopic and X-ray photoelectron spectroscopy (XPS) techniques to correlate the effects of size on the binding energy of Zn 2p3/2 photoelectrons. A positive shift in Zn 2p3/2-binding energy as compared to that in bulk ZnO is assumed to be the effect of size of ZnO tips. The shift in binding energy has been explained in terms of relaxation energy in the photoemission process. Simultaneously, Auger parameter of the nanorods is evaluated for stoichiometric composition. The extra peak in O1s spectrum of nanorods is explained as adsorbed O-bearing species or surface contaminants.
Collapse
|
27
|
Qin W, Wang Y, Huang Y, Zhou Z, Yang C, Sun CQ. Bond order resolved 3d5/2 and valence band chemical shifts of ag surfaces and nanoclusters. J Phys Chem A 2012; 116:7892-7. [PMID: 22716312 DOI: 10.1021/jp304366z] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Incorporating the tight-binding theory and the bond order-length-strength (BOLS) correlation into the X-ray photoelectron spectra of Ag(111) and (100) surfaces and the Auger electron spectra of Ag nanoparticles deposited on Al2O3 and CeO2 substrates has led to quantitative information of the 3d5/2 and the valence binding energies of an isolated Ag atom and their shifts upon bulk, defect, surface, and nanocrystal formation. It is clarified that the globally positive energy shifts originate from the undercoordination-induced Goldschmidt-Pauling bond contraction and the associated local quantum entrapment and the heterocoordination-induced bond nature alteration at the particle-substrate interfaces. Perturbation to the Hamiltonian by atomic ill-coordination dictates the energy shift that is proportional to the bond energy at equilibrium. Theoretical reproduction of the measured spectroscopic data derived that the 3d5/2 energy of an isolated Ag atom shifts from 363.02 to 367.65 eV and the valence band center from 0.36 to 8.32 eV upon bulk formation. The extended Wagner plots revealed the coefficients of valence recharging and potential screening to be 1.21 and 1.56 for Ag interacting with Al2O3 substrate and 1.15 and 1.50 for Ag with CeO2, respectively. Exercises exemplify the enhanced capabilities of XPS and AES in determining quantitative information regarding the evolution of the local bond length, bond energy, binding energy density, and atomic cohesive energy, with the coordination and chemical environment.
Collapse
Affiliation(s)
- Wei Qin
- Institute for Quantum Engineering and Micro-Nano Energy Technology, Key Laboratory of Low-Dimensional Materials and Application Technologies, and Faculty of Materials, Optoelectronics, and Physics, Xiangtan University , Hunan 411105, China
| | | | | | | | | | | |
Collapse
|
28
|
Pan Y, Gao Y, Kong D, Wang G, Hou J, Hu S, Pan H, Zhu J. Interaction of Au with thin ZrO2 films: influence of ZrO2 morphology on the adsorption and thermal stability of Au nanoparticles. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2012; 28:6045-6051. [PMID: 22424149 DOI: 10.1021/la205104q] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
The model catalysts of ZrO(2)-supported Au nanoparticles have been prepared by deposition of Au atoms onto the surfaces of thin ZrO(2) films with different morphologies. The adsorption and thermal stability of Au nanoparticles on thin ZrO(2) films have been investigated using synchrotron radiation photoemission spectroscopy (SRPES) and X-ray photoelectron spectroscopy (XPS). The thin ZrO(2) films were prepared by two different methods, giving rise to different morphologies. The first method utilized wet chemical impregnation to synthesize the thin ZrO(2) film through the procedure of first spin-coating a zirconium ethoxide (Zr(OC(2)H(5))(4)) precursor onto a SiO(2)/Si(100) substrate at room temperature followed by calcination at 773 K for 12 h. Scanning electron microscopy (SEM) investigations indicate that highly porous "sponge-like nanostructures" were obtained in this case. The second method was epitaxial growth of a ZrO(2)(111) film through vacuum evaporation of Zr metal onto Pt(111) in 1 × 10(-6) Torr of oxygen at 550 K followed by annealing at 1000 K. The structural analysis with low energy electron diffraction (LEED) of this film exhibits good long-range ordering. It has been found that Au forms smaller particles on the porous ZrO(2) film as compared to those on the ordered ZrO(2)(111) film at a given coverage. Thermal annealing experiments demonstrate that Au particles are more thermally stable on the porous ZrO(2) surface than on the ZrO(2)(111) surface, although on both surfaces, Au particles experience significant sintering at elevated temperatures. In addition, by annealing the surfaces to 1100 K, Au particles desorb completely from ZrO(2)(111) but not from porous ZrO(2). The enhanced thermal stability for Au on porous ZrO(2) can be attributed to the stronger interaction of the adsorbed Au with the defects and the hindered migration or coalescence resulting from the porous structures.
Collapse
Affiliation(s)
- Yonghe Pan
- National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei, Anhui 230029, China
| | | | | | | | | | | | | | | |
Collapse
|
29
|
Lin L, Shang K, Xu X, Chu C, Ma H, Lee YI, Hao J, Liu HG. Formation of Ag Nanoparticle-Doped Foam-like Polymer Films at the Liquid–Liquid Interface. J Phys Chem B 2011; 115:11113-8. [DOI: 10.1021/jp2059722] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Affiliation(s)
- Li Lin
- Key Laboratory for Colloid and Interface Chemistry of Education Ministry, Shandong University, Jinan 250100, P. R. China
| | - Ke Shang
- Key Laboratory for Colloid and Interface Chemistry of Education Ministry, Shandong University, Jinan 250100, P. R. China
| | - Xingtao Xu
- Key Laboratory for Colloid and Interface Chemistry of Education Ministry, Shandong University, Jinan 250100, P. R. China
| | - Chunxiao Chu
- Key Laboratory for Colloid and Interface Chemistry of Education Ministry, Shandong University, Jinan 250100, P. R. China
| | - Huihui Ma
- Key Laboratory for Colloid and Interface Chemistry of Education Ministry, Shandong University, Jinan 250100, P. R. China
| | - Yong-Ill Lee
- Anastro Laboratory, Department of Chemistry, Changwon National University, Changwon 641-773, Republic of Korea
| | - Jingcheng Hao
- Key Laboratory for Colloid and Interface Chemistry of Education Ministry, Shandong University, Jinan 250100, P. R. China
| | - Hong-Guo Liu
- Key Laboratory for Colloid and Interface Chemistry of Education Ministry, Shandong University, Jinan 250100, P. R. China
| |
Collapse
|
30
|
Synthesis and assembly of catalytically active platinum-doped polymer nanocomposites at the liquid/liquid interface. Colloids Surf A Physicochem Eng Asp 2011. [DOI: 10.1016/j.colsurfa.2011.07.017] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
|
31
|
Zhou C, Sun C, Yu M, Qin Y, Wang J, Kim M, Zheng J. Luminescent Gold Nanoparticles with Mixed Valence States Generated from Dissociation of Polymeric Au (I) Thiolates. THE JOURNAL OF PHYSICAL CHEMISTRY. C, NANOMATERIALS AND INTERFACES 2010; 114:7727-7732. [PMID: 20440379 PMCID: PMC2861835 DOI: 10.1021/jp9122584] [Citation(s) in RCA: 153] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
Dissociation process of glutathione-gold(I) polymers in aqueous solution resulted in the formation of a class of ~2 nm gold nanoparticles. Different from the same sized but NaBH(4) reduced gold nanoparticles, these nanoparticles exhibit strong luminescence but no surface plasmon absorption. Luminescence lifetimes of the nanoparticles were found strongly dependent on excitation wavelengths, and singlet and triplet excited states involving the emission were found degenerate in energy. X-ray photoelectron spectroscopic studies showed that nearly 40~50% gold atoms in the luminescent nanoparticles were in gold(I) state, which are responsible for the unique optical properties of the luminescent gold nanoparticles. These luminescent nanoparticles can be considered an intermediate state between luminescent gold(I) complexes and reduced nonluminescent gold nanoparticles.
Collapse
Affiliation(s)
- Chen Zhou
- Department of Chemistry, University of Texas at Dallas, Richardson, TX 75080
| | - Ce Sun
- Department of Materials Science and Engineering, The University of Texas at Dallas, Richardson, TX 75080
| | - Mengxiao Yu
- Department of Chemistry, University of Texas at Dallas, Richardson, TX 75080
| | - Yanping Qin
- Department of Chemistry, University of Texas at Dallas, Richardson, TX 75080
| | - Jinguo Wang
- Department of Materials Science and Engineering, The University of Texas at Dallas, Richardson, TX 75080
| | - Moon Kim
- Department of Materials Science and Engineering, The University of Texas at Dallas, Richardson, TX 75080
| | - Jie Zheng
- Department of Chemistry, University of Texas at Dallas, Richardson, TX 75080
- Advanced Imaging Research Center, The University of Texas Southwestern Medical Center, Dallas, TX 75235
| |
Collapse
|
32
|
Shifu C, Wei Z, Wei L, Huaye Z, Xiaoling Y, Yinghao C. Preparation, characterization and activity evaluation of p-n junction photocatalyst p-CaFe2O4/n-Ag3VO4 under visible light irradiation. JOURNAL OF HAZARDOUS MATERIALS 2009; 172:1415-1423. [PMID: 19709814 DOI: 10.1016/j.jhazmat.2009.08.007] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/26/2009] [Revised: 08/01/2009] [Accepted: 08/04/2009] [Indexed: 05/28/2023]
Abstract
p-n junction photocatalyst p-CaFe(2)O(4)/n-Ag(3)VO(4) was prepared by ball milling Ag(3)VO(4) in H(2)O doped with p-type CaFe(2)O(4). The structural and optical properties of the photocatalyst were characterized by X-ray powder diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and UV-vis diffuse reflection spectrum (DRS). The photocatalytic activity was evaluated by photocatalytic degradation of methylene blue (MB) under visible light irradiation. The results showed that the photocatalytic activity of the p-CaFe(2)O(4)/n-Ag(3)VO(4) was higher than that of Ag(3)VO(4). When the amount of doped p-CaFe(2)O(4) was 2.0 wt.% and the p-CaFe(2)O(4)/n-Ag(3)VO(4) was ball milled for 12h, the photocatalytic degradation efficiency was 85.4%. Effect of ball milling time on the photocatalytic activity of the photocatalyst was also investigated. The mechanisms of the increase in the photocatalytic activity were discussed by the p-n junction principle.
Collapse
Affiliation(s)
- Chen Shifu
- Department of Chemistry, Huaibei Coal Normal College, Anhui, Huaibei 235000, People's Republic of China.
| | | | | | | | | | | |
Collapse
|
33
|
Štofik M, Strýhal Z, Malý J. Dendrimer-encapsulated silver nanoparticles as a novel electrochemical label for sensitive immunosensors. Biosens Bioelectron 2009; 24:1918-23. [DOI: 10.1016/j.bios.2008.09.028] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2008] [Revised: 09/08/2008] [Accepted: 09/24/2008] [Indexed: 12/21/2022]
|
34
|
Ren L, Zeng YP, Jiang D. Preparation, characterization and photocatalytic activities of Ag-deposited porous TiO2 sheets. CATAL COMMUN 2009. [DOI: 10.1016/j.catcom.2008.11.016] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
|
35
|
Zhou Y, Li M, Su B, Lu Q. Superhydrophobic surface created by the silver mirror reaction and its drag-reduction effect on water. ACTA ACUST UNITED AC 2009. [DOI: 10.1039/b819251k] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|
36
|
Formation and Characterization of Two-Dimensional Arrays of Silver Oxide Nanoparticles under Langmuir Monolayers of n-Hexadecyl Dihydrogen Phosphate. B KOREAN CHEM SOC 2008. [DOI: 10.5012/bkcs.2008.29.12.2368] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
|
37
|
Lv W, Zhang X, Lu J, Zhang Y, Li X, Jiang J. Synthesis and Hollow-Sphere Nanostructures of Optically Active Metal-Free Phthalocyanine. Eur J Inorg Chem 2008. [DOI: 10.1002/ejic.200800546] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
|
38
|
Xue M, Guo Q, Wu K, Guo J. Initial oxidation and interfacial diffusion of Zn on faceted MgO(111) films. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2008; 24:8760-8764. [PMID: 18624420 DOI: 10.1021/la801314s] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
The interaction of zinc and faceted MgO(111) thin films prepared on a Mo(110) substrate was investigated in situ by using various surface analysis techniques, including X-ray photoelectron spectroscopy, ultraviolet photoelectron spectroscopy, Auger electron spectroscopy, high-resolution electron energy loss spectroscopy, and low-energy electron diffraction. The results revealed that three-dimensional Zn islands exist on the faceted MgO(111) films and that no chemical interaction takes place at the interface at room temperature. Initially, deposited Zn is stable at temperatures below 400 K and diffuses into MgO at temperatures above 425 K. A portion of Zn is oxidized at approximately 10 (-6) mbar O 2 at room temperature. An interfacial phase of Zn x Mg 1- x O was formed after Zn was exposed to approximately 10 (-6) mbar O 2 at temperatures >or=500 K. The faceted structure on the MgO(111) surface is of a disadvantage for the epitaxial growth of ZnO films.
Collapse
Affiliation(s)
- Mingshan Xue
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, PO Box 603, Beijing, China
| | | | | | | |
Collapse
|
39
|
Li Y, Zhang H, Guo Z, Han J, Zhao X, Zhao Q, Kim SJ. Highly efficient visible-light-induced photocatalytic activity of nanostructured AgI/TiO2 photocatalyst. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2008; 24:8351-8357. [PMID: 18605746 DOI: 10.1021/la801046u] [Citation(s) in RCA: 87] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Nanostructured AgI/TiO(2) photocatalyst was synthesized by a feasible approach with AgNO(3), LiI, and Ti(OBu)(4) and characterized by X-ray diffraction, transmission electron microscopy, angle-dependent X-ray photoelectron spectroscopy, diffusive reflectance UV-vis spectroscopy, Raman spectroscopy, photoluminescence, and the Brunauer-Emmett-Teller technique. The results of characterization reveal that the nanostructured AgI/TiO(2) has a novel core/shell/shell nanostructure of AgI/Ag-I(2)/TiO(2). Compared with TiO(2) (P25) supported AgI, the formation of the nanostructure results in substantial shifting of the absorption edge of AgI to red, enhancement of the absorption intensity, and the appearance of a strong tail absorption above 490 nm, which is assigned to the absorption of I(2) and Ag. Photocatalytic tests show that the nanostructured AgI/TiO(2) photocatalyst exhibited very high visible-light-induced photocatalytic activity for the photodegradation of crystal violet and 4-chlorophenol, which is 4 and 6 times higher than that of P25 titania supported AgI, respectively. The highly efficient visible-light-induced photocatalytic activity of the nanostructured AgI/TiO(2) is attributed to its strong absorption in the visible region and low recombination rate of the electron-hole pair due to the synergetic effect among the components of AgI, Ag, I(20, and TiO(2) in the nanostructured AgI/TiO(2).
Collapse
Affiliation(s)
- Yuanzhi Li
- Key Laboratory of Silicate Materials Science and Engineering (Wuhan University of Technology), Ministry of Education, 122 Luoshi Road, Wuhan 430070, People's Republic of China
| | | | | | | | | | | | | |
Collapse
|
40
|
Zheng J, Ding Y, Tian B, Wang ZL, Zhuang X. Luminescent and Raman active silver nanoparticles with polycrystalline structure. J Am Chem Soc 2008; 130:10472-3. [PMID: 18636722 DOI: 10.1021/ja803302p] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We report the synthesis of silver nanoparticles with grain sizes down to electron Fermi wavelength. These nanoparticles exhibit bright luminescence and large Raman enhancement effect. The number of photons emitted from these nanoparticles exceeded that from quantum dots or dye molecules by approximately 2 or 5 orders of magnitude, respectively.
Collapse
Affiliation(s)
- Jie Zheng
- Department of Chemistry and Chemical Biology, Howard Hughes Medical Institute, Harvard University, Cambridge, Massachusetts 02138, USA.
| | | | | | | | | |
Collapse
|
41
|
Sá J, Fernández-García M, Anderson JA. Photoformed electron transfer from TiO2 to metal clusters. CATAL COMMUN 2008. [DOI: 10.1016/j.catcom.2008.03.041] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
|
42
|
Liu HG, Xiao F, Wang CW, Lee YI, Xue Q, Chen X, Qian DJ, Hao J, Jiang J. One-step synthesis of silver nanoparticles at the air-water interface using different methods. NANOTECHNOLOGY 2008; 19:055603. [PMID: 21817611 DOI: 10.1088/0957-4484/19/05/055603] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Silver nanoparticles were synthesized in a one-step process at the air-AgNO(3) aqueous solution interface under Langmuir monolayers of 5,10,15,20-tetra-4-oxy(2-stearic acid) phenyl porphyrin (TSPP) at room temperature by using different methods including UV-light irradiation, ambient light irradiation, and formaldehyde gas reduction. It was found that parallel aligned one-dimensional (1D) chains composed of discrete silver nanoparticles with the size of 3-5 nm were formed under UV-light irradiation for a short time, while large areas of uniform silver spherical nanoparticles were formed under natural daylight illumination for several days or by formaldehyde gas treatment for several hours. The average size of the spherical nanoparticles ranges from 6.88 ± 0.46 to 11.10 ± 1.47 nm, depending on the experimental conditions. The 1D chains formed under UV-light irradiation result from the templating effect of parallel aligned linear supramolecular arrays formed by TSPP at the air-water interface, and rapid nucleation and growth of the nanoparticles. The formation of the uniform silver nanoparticles under daylight illumination or by formaldehyde gas treatment, however, should be ascribed to a kinetically controlled growth process of the nanoparticles.
Collapse
Affiliation(s)
- Hong-Guo Liu
- Key Laboratory for Colloid and Interface Chemistry of Education Ministry, Shandong University, Jinan 250100, People's Republic of China
| | | | | | | | | | | | | | | | | |
Collapse
|
43
|
Brook L, Evans P, Foster H, Pemble M, Steele A, Sheel D, Yates H. Highly bioactive silver and silver/titania composite films grown by chemical vapour deposition. J Photochem Photobiol A Chem 2007. [DOI: 10.1016/j.jphotochem.2006.09.014] [Citation(s) in RCA: 92] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
|
44
|
Pillay D, Hwang GS. Structure of small Aun, Agn, and Cun clusters (n=2−4) on rutile TiO2(110): A density functional theory study. ACTA ACUST UNITED AC 2006. [DOI: 10.1016/j.theochem.2006.03.040] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
|
45
|
Canário AR, Esaulov VA. Electron transfer processes on Ag and Au clusters supported on TiO2(110) and cluster size effects. J Chem Phys 2006; 124:224710. [PMID: 16784304 DOI: 10.1063/1.2205849] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The results of a detailed study of Li(+) neutralization in scattering on Ag and Au clusters and thin films supported on TiO(2) are presented. A very efficient neutralization is observed on small clusters with a decrease for the smallest clusters. These results closely follow the size-effects observed in the reactivity of these systems. The energy dependence of the neutralization was studied for the larger clusters (>4 nm) and observed to be similar in trend to the one observed on films and bulk (111) crystals. A general discussion of possible reasons of the enhancement in neutralization is presented and these changes are then tentatively discussed in terms of progressive modifications in the electronic structure of clusters as a function of reduction in size and as it evolves from metallic-like to discretised states. The highest neutralization efficiency would appear to correspond to clusters sizes for which a metal to nonmetal transition occurs. The relative position of the Li level and the highest occupied molecular orbital in the molecular cluster can be expected to strongly affect the electron transfer processes, which in this case should be described in a molecular framework.
Collapse
Affiliation(s)
- Ana Rita Canário
- Laboratoire des Collisions Atomiques et Moléculaires (Unité Mixte CNRS Université UMR8625), Université Paris Sud, 91405 Orsay, France
| | | |
Collapse
|
46
|
Günster J, Kempter V, Souda R. Sodium Interacting with Amorphous Water Films at 10 and 100 K. J Phys Chem B 2005; 109:17169-73. [PMID: 16853190 DOI: 10.1021/jp044697c] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
In the present study, we compare the adsorption of Na on amorphous D(2)O ice films, held at 10 and 100 K. OH, D(2)O, and Na are easily distinguished by their characteristic signatures in metastable impact electron spectroscopy (MIES). It is found that at 10 K substrate temperature the donation of 3sNa charge to the ice film, which is regarded as a precursor for water deprotonation, is significantly reduced relative to 100 K. This observation is discussed on the basis of recent theoretical work, suggesting that a rearrangement of the water molecules at the outermost water surface is the prerequisite for hydration/solvation of the 3sNa electron in the water ice bulk. The MIES spectra, showing spectral features from both OH and D(2)O, can be interpreted as reflecting the composition of the Na-water complexes in the near surface region. The relative intensity of the OH and D(2)O features is the same for 10 and 100 K. This finding suggests that two different sites for Na adsorption exist, one on the perfect water network and the other at OH dangling bond sites whereby, at 10 K, only the latter one leads to deprotonation of D(2)O. Finally, charge exchange phenomena observed when applying electron spectroscopies to ice films are discussed.
Collapse
Affiliation(s)
- Jens Günster
- Institut für Nichtmetallische Werkstoffe, Technische Universität Clausthal, D-38678 Clausthal-Zellerfeld, Germany.
| | | | | |
Collapse
|
47
|
You X, Chen F, Zhang J, Anpo M. A novel deposition precipitation method for preparation of Ag-loaded titanium dioxide. Catal Letters 2005. [DOI: 10.1007/s10562-005-5863-5] [Citation(s) in RCA: 149] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
|
48
|
Nucleation and growth of 1B metal clusters on rutile TiO2(110): Atomic level understanding from first principles studies. Catal Today 2005. [DOI: 10.1016/j.cattod.2005.04.016] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
|
49
|
Fu Q, Wagner T. Metal/Oxide Interfacial Reactions: Oxidation of Metals on SrTiO3 (100) and TiO2 (110). J Phys Chem B 2005; 109:11697-705. [PMID: 16852436 DOI: 10.1021/jp050601i] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We studied chemical reactions between ultrathin metal films (Al, Cr, Fe, Mo) and single-crystal oxides (SrTiO3 (100), TiO2 (110)) with X-ray photoelectron spectroscopy (XPS). The work function of the metal and the electron density in the oxide strongly influence the reaction onset temperature (T(RO)), where metal oxidation is first observed, and the rate of metal oxidation at the metal/oxide interfaces. The Fermi levels of the two contacting phases affect both the space charges formed at the interfaces and the diffusion of ionic defects across the interfaces. These processes, which determine metal oxidation kinetics at relatively low temperatures, can be understood in the framework of the Cabrera-Mott theory. The results suggest that the interfacial reactivity is tunable by modifying the Fermi level (E(F)) of both contacting phases. This effect is of great technological importance for a variety of devices with heterophase boundaries.
Collapse
Affiliation(s)
- Qiang Fu
- Max-Planck-Institut für Metallforschung, Heisenbergstrasse 3, D-70569 Stuttgart, Germany
| | | |
Collapse
|
50
|
Luo K, Lai X, Yi CW, Davis KA, Gath KK, Goodman DW. The Growth of Silver on an Ordered Alumina Surface. J Phys Chem B 2005; 109:4064-8. [PMID: 16851464 DOI: 10.1021/jp045948k] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The growth of Ag on an ordered Al2O3 surface was studied by low energy ion scattering spectroscopy (LEIS), scanning tunneling microscopy (STM), X-ray photoelectron spectroscopy (XPS), and temperature programmed desorption (TPD). Three-dimensional (3D) growth of Ag clusters was observed with STM and LEIS, with the cluster size increasing with Ag coverage. The XPS core level binding energies and the Auger parameters indicate a weak interaction between the Ag clusters and the Al2O3 support. Final state effects are determined to be the primary contribution to the Ag core level binding energy shift. Nonzero order kinetics was observed for Ag desorption in TPD with the Ag sublimation energy decreasing with decreasing cluster size.
Collapse
Affiliation(s)
- K Luo
- Department of Chemistry, Texas A&M University, P.O. Box 30012, College Station, Texas 77842-3012, USA
| | | | | | | | | | | |
Collapse
|