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Murata N, Suzuki T, Lin Y, Nitani H, Niwa Y, Wada T, Uo M, Asakura K. Structure of Atomically Dispersed Pt in a SnO 2 Thin Film under Reaction Conditions: Origin of Its High Performance in Micro Electromechanical System Gas Sensor Catalysis. ACS APPLIED MATERIALS & INTERFACES 2022; 14:39507-39514. [PMID: 35994375 DOI: 10.1021/acsami.2c09535] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
A battery-driven micro electromechanical system (MEMS) gas sensor has been developed for household safety when using natural gas. The heart of the MEMS gas sensor is a 7.5 at % Pt-SnO2 thin film catalyst deposited on the SnO2 sensor layer. The catalyst enhances the sensitivity to methane, though its structure under working conditions is unclear. In this study, in situ XAFS was applied to a 7.5 at % Pt-SnO2 catalyst layer deposited on a Si substrate, and we demonstrated that atomically dispersed Pt maintains its lattice position in SnO2 with a small loss of surrounding lattice oxygen in the presence of 1% CH4 and a more reducing gas of 1% H2 at the reaction temperature (703 K), i.e., no Pt aggregation is observed. The lost oxygen is easily recovered by re-oxidation by air. This work has revealed that the atomically dispersed Pt in the SnO2 lattice is the active structure and it is stable even under reaction conditions, which guarantees a long lifetime for the gas sensor.
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Affiliation(s)
- Naoyoshi Murata
- Corporate R & D Headquarters, Fuji Electric Co., Ltd., Tokyo 191-8502, Japan
| | - Takuya Suzuki
- Corporate R & D Headquarters, Fuji Electric Co., Ltd., Tokyo 191-8502, Japan
| | - Yunli Lin
- Institute for Catalysis, Hokkaido University, Sapporo 001-0021, Japan
| | - Hiroaki Nitani
- Photon Factory, Institute of Structure Materials Science, High Energy Accelerator Research Organization (KEK-PF), Oho 1-1, Tsukuba 305-0811, Japan
| | - Yasuhiro Niwa
- Photon Factory, Institute of Structure Materials Science, High Energy Accelerator Research Organization (KEK-PF), Oho 1-1, Tsukuba 305-0811, Japan
| | - Takahiro Wada
- Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Yushima 1-5-45, Bunkyo-ku, Tokyo 113-8549, Japan
| | - Motohiro Uo
- Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Yushima 1-5-45, Bunkyo-ku, Tokyo 113-8549, Japan
| | - Kiyotaka Asakura
- Institute for Catalysis, Hokkaido University, Sapporo 001-0021, Japan
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Takakusagi S, Iwasawa Y, Asakura K. Premodified Surface Method to Obtain Ultra-Highly Dispersed Metals and their 3D Structure Control on an Oxide Single-Crystal Surface. CHEM REC 2018; 19:1244-1255. [PMID: 30203911 DOI: 10.1002/tcr.201800088] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2018] [Accepted: 08/20/2018] [Indexed: 01/23/2023]
Abstract
Precise control of the three-dimensional (3D) structure of highly dispersed metal species such as metal complexes and clusters attached to an oxide surface has been important for the development of next-generation high-performance heterogeneous catalysts. However, this is not easily achieved for the following reasons. (1) Metal species are easily aggregated on an oxide surface, which makes it difficult to control their size and orientation definitely. (2) Determination of the 3D structure of the metal species on an oxide powder surface is hardly possible. To overcome these difficulties, we have developed the premodified surface method, where prior to metal deposition, the oxide surface is premodified with a functional organic molecule that can strongly coordinate to a metal atom. This method has successfully provided a single metal dispersion on an oxide single-crystal surface with the 3D structure precisely determined by polarization-dependent total reflection fluorescence X-ray absorption fine structure (PTRF-XAFS). Here we describe our recent results on ultra-high dispersions of various metal atoms on TiO2 (110) surfaces premodified with mercapto compounds, and show the possibility of fine tuning and orientation control of the surface metal 3D structures.
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Affiliation(s)
- Satoru Takakusagi
- Institute for Catalysis, Hokkaido University, N21 W10, Kita-ku, Sapporo, Hokkaido, Japan
| | - Yasuhiro Iwasawa
- Innovation Research Center for Fuel Cells and Graduate School of Informatics and Engineering, The University of Electro-Communications, 1-5-1 Chofugaoka, Chofu, Tokyo, Japan
| | - Kiyotaka Asakura
- Institute for Catalysis, Hokkaido University, N21 W10, Kita-ku, Sapporo, Hokkaido, Japan
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Wakisaka Y, Kido D, Uehara H, Yuan Q, Feiten FE, Mukai S, Takakusagi S, Uemura Y, Yokoyama T, Wada T, Uo M, Sekizawa O, Uruga T, Iwasawa Y, Asakura K. Development of Surface Fluorescence X-Ray Absorption Fine Structure Spectroscopy Using a Laue-Type Monochromator. CHEM REC 2018; 19:1157-1165. [PMID: 30088337 DOI: 10.1002/tcr.201800020] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2018] [Accepted: 07/16/2018] [Indexed: 11/11/2022]
Abstract
Surface fluorescence X-ray absorption fine structure (XAFS) spectroscopy using a Laue-type monochromator has been developed to acquire structural information about metals with a very low concentrate on a flat highly oriented pyrolytic graphite (HOPG) surface in the presence of electrolytes. Generally, surface fluorescence XAFS spectroscopy is hindered by strong scattering from the bulk, which often chokes the pulse counting detector. In this work, we show that a bent crystal Laue analyzer (BCLA) can efficiently remove the scattered X-rays from the bulk even in the presence of solution. We applied the technique to submonolayer (∼1014 atoms cm-2 ) Pt on HOPG and successfully obtained high signal/noise in situ XAFS data in combination with back-illuminated fluorescence XAFS (BI-FXAFS) spectroscopy. This technique allows in situ XAFS measurements of flat electrode surfaces to be performed in the presence of electrolytes.
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Affiliation(s)
- Yuki Wakisaka
- Institute for Catalysis, Hokkaido University, Kita-ku, Sapporo, Hokkaido, 001-0021, Japan
| | - Daiki Kido
- Institute for Catalysis, Hokkaido University, Kita-ku, Sapporo, Hokkaido, 001-0021, Japan
| | - Hiromitsu Uehara
- Institute for Catalysis, Hokkaido University, Kita-ku, Sapporo, Hokkaido, 001-0021, Japan
| | - Qiuyi Yuan
- Institute for Catalysis, Hokkaido University, Kita-ku, Sapporo, Hokkaido, 001-0021, Japan
| | - Felix E Feiten
- Institute for Catalysis, Hokkaido University, Kita-ku, Sapporo, Hokkaido, 001-0021, Japan
| | - Shingo Mukai
- Institute for Catalysis, Hokkaido University, Kita-ku, Sapporo, Hokkaido, 001-0021, Japan
| | - Satoru Takakusagi
- Institute for Catalysis, Hokkaido University, Kita-ku, Sapporo, Hokkaido, 001-0021, Japan
| | - Yohei Uemura
- Institute for Molecular Science, Myodaiji-cho, Okazaki, Aichi, 444-8585, Japan
| | - Toshihiko Yokoyama
- Institute for Molecular Science, Myodaiji-cho, Okazaki, Aichi, 444-8585, Japan
| | - Takahiro Wada
- Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Yushima, Bunkyo-ku, Tokyo, 113-8549, Japan
| | - Motohiro Uo
- Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Yushima, Bunkyo-ku, Tokyo, 113-8549, Japan
| | - Oki Sekizawa
- Department of Applied Physics and Chemistry, The University of Electro-Communications, Chofugaoka, Chofu, Tokyo, 182-8585, Japan.,Japan Synchrotron Radiation Research (JASRI), Sayo-cho, Sayo-gun, Hyogo, 679-5148, Japan
| | - Tomoya Uruga
- Department of Applied Physics and Chemistry, The University of Electro-Communications, Chofugaoka, Chofu, Tokyo, 182-8585, Japan.,Japan Synchrotron Radiation Research (JASRI), Sayo-cho, Sayo-gun, Hyogo, 679-5148, Japan
| | - Yasuhiro Iwasawa
- Department of Applied Physics and Chemistry, The University of Electro-Communications, Chofugaoka, Chofu, Tokyo, 182-8585, Japan
| | - Kiyotaka Asakura
- Institute for Catalysis, Hokkaido University, Kita-ku, Sapporo, Hokkaido, 001-0021, Japan
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Yuan Q, Takakusagi S, Wakisaka Y, Uemura Y, Wada T, Ariga H, Asakura K. Polarization-dependent Total Reflection Fluorescence X-ray Absorption Fine Structure (PTRF-XAFS) Studies on the Structure of a Pt Monolayer on Au(111) Prepared by the Surface-limited Redox Replacement Reaction. CHEM LETT 2017. [DOI: 10.1246/cl.170423] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Affiliation(s)
- Qiuyi Yuan
- ICAT, Hokkaido University, Kita 21 Nishi 10, Kita-ku, Sapporo, Hokkaido 001-0021
| | - Satoru Takakusagi
- ICAT, Hokkaido University, Kita 21 Nishi 10, Kita-ku, Sapporo, Hokkaido 001-0021
| | - Yuki Wakisaka
- ICAT, Hokkaido University, Kita 21 Nishi 10, Kita-ku, Sapporo, Hokkaido 001-0021
| | - Yohei Uemura
- Institute for Molecular Science, Okazaki, Aichi 444-0867
| | | | - Hiroko Ariga
- ICAT, Hokkaido University, Kita 21 Nishi 10, Kita-ku, Sapporo, Hokkaido 001-0021
| | - Kiyotaka Asakura
- ICAT, Hokkaido University, Kita 21 Nishi 10, Kita-ku, Sapporo, Hokkaido 001-0021
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van Veelen A, Bargar JR, Law GTW, Brown GE, Wogelius RA. Uranium Immobilization and Nanofilm Formation on Magnesium-Rich Minerals. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2016; 50:3435-3443. [PMID: 26990311 DOI: 10.1021/acs.est.5b06041] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Polarization-dependent grazing incidence X-ray absorption spectroscopy (XAS) measurements were completed on oriented single crystals of magnesite [MgCO3] and brucite [Mg(OH)2] reacted with aqueous uranyl chloride above and below the solubility boundaries of schoepite (500, 50, and 5 ppm) at pH 8.3 and at ambient (PCO2 = 10(-3.5)) or reduced partial pressures of carbon dioxide (PCO2 = 10(-4.5)). X-ray absorption near edge structure (XANES) spectra show a striking polarization dependence (χ = 0° and 90° relative to the polarization plane of the incident beam) and consistently demonstrated that the uranyl molecule was preferentially oriented with its Oaxial═U(VI)═Oaxial linkage at high angles (60-80°) to both magnesite (101̅4) and brucite (0001). Extended X-ray absorption fine structure (EXAFS) analysis shows that the "effective" number of U(VI) axial oxygens is the most strongly affected fitting parameter as a function of polarization. Furthermore, axial tilt in the surface thin films (thickness ∼ 21 Å) is correlated with surface roughness [σ]. Our results show that hydrated uranyl(-carbonate) complexes polymerize on all of our experimental surfaces and that this process is controlled by surface hydroxylation. These results provide new insights into the bonding configuration expected for uranyl complexes on the environmentally significant carbonate and hydroxide mineral surfaces.
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Affiliation(s)
| | - John R Bargar
- Department of Photon Science and Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory , 2575 Sand Hill Road, Menlo Park, California 94025, United States
| | | | - Gordon E Brown
- Department of Photon Science and Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory , 2575 Sand Hill Road, Menlo Park, California 94025, United States
- Surface and Aqueous Geochemistry Group, Department of Geological Sciences, School of Earth, Energy, and Environmental Sciences, Stanford University , Stanford, California 94305-2115, United States
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Mochizuki I, Ariga H, Fukaya Y, Wada K, Maekawa M, Kawasuso A, Shidara T, Asakura K, Hyodo T. Structure determination of the rutile-TiO2(110)-(1 × 2) surface using total-reflection high-energy positron diffraction (TRHEPD). Phys Chem Chem Phys 2016; 18:7085-92. [DOI: 10.1039/c5cp07892j] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Detailed structure of the rutile-TiO2(110)-(1 × 2) has been determined using the newly developed technique of total-reflection high-energy positron diffraction (TRHEPD).
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Affiliation(s)
- I. Mochizuki
- Institute of Materials Structure Science
- High Energy Accelerator Research Organization (KEK)
- Ibaraki 305-0801
- Japan
| | - H. Ariga
- Institute for Catalysis
- Hokkaido University
- Sapporo
- Japan
| | - Y. Fukaya
- Advanced Science Research Center
- Japan Atomic Energy Agency
- Naka
- Japan
| | - K. Wada
- Institute of Materials Structure Science
- High Energy Accelerator Research Organization (KEK)
- Ibaraki 305-0801
- Japan
| | - M. Maekawa
- Quantum Beam Science Directorate
- Japan Atomic Energy Agency
- Takasaki
- Japan
| | - A. Kawasuso
- Quantum Beam Science Directorate
- Japan Atomic Energy Agency
- Takasaki
- Japan
| | - T. Shidara
- Accelerator Laboratory
- High Energy Accelerator Research Organization (KEK)
- Tsukuba
- Japan
| | - K. Asakura
- Institute for Catalysis
- Hokkaido University
- Sapporo
- Japan
| | - T. Hyodo
- Institute of Materials Structure Science
- High Energy Accelerator Research Organization (KEK)
- Ibaraki 305-0801
- Japan
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Murata N, Kobayashi M, Okada Y, Suzuki T, Nitani H, Niwa Y, Abe H, Wada T, Mukai S, Uehara H, Ariga H, Takakusagi S, Asakura K. A high-temperature in situ cell with a large solid angle for fluorescence X-ray absorption fine structure measurement. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2015; 86:034102. [PMID: 25832248 DOI: 10.1063/1.4914459] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
We present the design and performance of a high-temperature in situ cell with a large solid angle for fluorescence X-ray absorption fine structure (XAFS) spectra. The cell has a large fluorescence XAFS window (116 mm(ϕ)) near the sample in the cell, realizing a large half-cone angle of 56°. We use a small heater (25 × 35 mm(2)) to heat the sample locally to 873 K. We measured a Pt-SnO2 thin layer on a Si substrate at reaction conditions having a high activity. In situ measurement enables the analysis of the difference XAFS spectra between before and during the reaction to reveal the structure change during the operation.
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Affiliation(s)
- Naoyoshi Murata
- Corporate R & D Headquarters, Fuji Electric Co., Ltd., Tokyo 191-8502, Japan
| | - Makoto Kobayashi
- Corporate R & D Headquarters, Fuji Electric Co., Ltd., Tokyo 191-8502, Japan
| | - Yukari Okada
- Corporate R & D Headquarters, Fuji Electric Co., Ltd., Tokyo 191-8502, Japan
| | - Takuya Suzuki
- Corporate R & D Headquarters, Fuji Electric Co., Ltd., Tokyo 191-8502, Japan
| | - Hiroaki Nitani
- Photon Factory, Institute of Materials Structure Science, High Energy Accelerator Research Organization (KEK-PF), Tsukuba 305-0811, Japan
| | - Yasuhiro Niwa
- Photon Factory, Institute of Materials Structure Science, High Energy Accelerator Research Organization (KEK-PF), Tsukuba 305-0811, Japan
| | - Hitoshi Abe
- Photon Factory, Institute of Materials Structure Science, High Energy Accelerator Research Organization (KEK-PF), Tsukuba 305-0811, Japan
| | - Takahiro Wada
- Department of Advanced Biomaterials, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo 113-8549, Japan
| | - Shingo Mukai
- Catalysis Research Center, Hokkaido University, Sapporo 001-0021, Japan
| | - Hiromitsu Uehara
- Catalysis Research Center, Hokkaido University, Sapporo 001-0021, Japan
| | - Hiroko Ariga
- Catalysis Research Center, Hokkaido University, Sapporo 001-0021, Japan
| | - Satoru Takakusagi
- Catalysis Research Center, Hokkaido University, Sapporo 001-0021, Japan
| | - Kiyotaka Asakura
- Catalysis Research Center, Hokkaido University, Sapporo 001-0021, Japan
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Micro Reverse Monte Carlo Approach to EXAFS Analysis. E-JOURNAL OF SURFACE SCIENCE AND NANOTECHNOLOGY 2014. [DOI: 10.1380/ejssnt.2014.322] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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9
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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]
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