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Cai M, Sun S, Bao J. Synchrotron Radiation Based X-ray Absorption Spectroscopy: Fundamentals and Applications in Photocatalysis. Chemphyschem 2024; 25:e202300939. [PMID: 38374799 DOI: 10.1002/cphc.202300939] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2023] [Accepted: 02/19/2024] [Indexed: 02/21/2024]
Abstract
Photocatalysis is one of the most promising green technologies to utilize solar energy for clean energy achievement and environmental governance. There is a knotty problem to rational designing high-performance photocatalyst, which largely depends on an in-depth insight into their structure-activity relationships and complex photocatalytic reaction mechanisms. Synchrotron radiation based X-ray absorption spectroscopy (XAS) is an important characterization method for photocatlayst to offer the element-specific key geometric and electronic structural information at the atomic level, on this basis, time-resolved XAS technique has a huge impact on mechanistic understanding of photochemical reaction owing to their powerful ability to probe, in real-time, the electronic and geometric structures evolution within photocatalysis reactions. This review will focus on the fundamentals of XAS and their applications in photocatalysis. The detailed applications obtained from XAS is described through the following aspects: 1) identifying local structure of photocatalyst; 2) uncovering in situ structure and chemical state evolution during photocatalysis; 3) revealing the photoexcited process. We will provide an in depth understanding on how the XAS method can guide the rational design of highly efficient photocatalyst. Finally, a systematic summary of XAS and related significance is made and the research perspectives are suggested.
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Affiliation(s)
- Mengdie Cai
- School of Chemistry and Chemical Engineering, Anhui University, Hefei, 230601, China
| | - Song Sun
- School of Chemistry and Chemical Engineering, Anhui University, Hefei, 230601, China
| | - Jun Bao
- National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei, 230029, China
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Wang J, Hsu CS, Wu TS, Chan TS, Suen NT, Lee JF, Chen HM. In situ X-ray spectroscopies beyond conventional X-ray absorption spectroscopy on deciphering dynamic configuration of electrocatalysts. Nat Commun 2023; 14:6576. [PMID: 37852958 PMCID: PMC10584842 DOI: 10.1038/s41467-023-42370-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2023] [Accepted: 10/04/2023] [Indexed: 10/20/2023] Open
Abstract
Realizing viable electrocatalytic processes for energy conversion/storage strongly relies on an atomic-level understanding of dynamic configurations on catalyst-electrolyte interface. X-ray absorption spectroscopy (XAS) has become an indispensable tool to in situ investigate dynamic natures of electrocatalysts but still suffers from limited energy resolution, leading to significant electronic transitions poorly resolved. Herein, we highlight advanced X-ray spectroscopies beyond conventional XAS, with emphasis on their unprecedented capabilities of deciphering key configurations of electrocatalysts. The profound complementarities of X-ray spectroscopies from various aspects are established in a probing energy-dependent "in situ spectroscopy map" for comprehensively understanding the solid-liquid interface. This perspective establishes an indispensable in situ research model for future studies and offers exciting research prospects for scientists and spectroscopists.
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Affiliation(s)
- Jiali Wang
- Department of Chemistry and Center for Emerging Materials and Advanced Devices, National Taiwan University, Taipei, 10617, Taiwan
| | - Chia-Shuo Hsu
- Department of Chemistry and Center for Emerging Materials and Advanced Devices, National Taiwan University, Taipei, 10617, Taiwan
| | - Tai-Sing Wu
- National Synchrotron Radiation Research Center, Hsinchu, 30076, Taiwan
| | - Ting-Shan Chan
- National Synchrotron Radiation Research Center, Hsinchu, 30076, Taiwan.
| | - Nian-Tzu Suen
- College of Chemistry & Chemical Engineering, Yangzhou University, 225002, Yangzhou, China
| | - Jyh-Fu Lee
- National Synchrotron Radiation Research Center, Hsinchu, 30076, Taiwan
| | - Hao Ming Chen
- Department of Chemistry and Center for Emerging Materials and Advanced Devices, National Taiwan University, Taipei, 10617, Taiwan.
- National Synchrotron Radiation Research Center, Hsinchu, 30076, Taiwan.
- Graduate Institute of Nanomedicine and Medical Engineering, College of Biomedical Engineering, Taipei Medical University, Taipei, 11031, Taiwan.
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Timoshenko J, Roldan Cuenya B. In Situ/ Operando Electrocatalyst Characterization by X-ray Absorption Spectroscopy. Chem Rev 2021; 121:882-961. [PMID: 32986414 PMCID: PMC7844833 DOI: 10.1021/acs.chemrev.0c00396] [Citation(s) in RCA: 189] [Impact Index Per Article: 63.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Indexed: 12/18/2022]
Abstract
During the last decades, X-ray absorption spectroscopy (XAS) has become an indispensable method for probing the structure and composition of heterogeneous catalysts, revealing the nature of the active sites and establishing links between structural motifs in a catalyst, local electronic structure, and catalytic properties. Here we discuss the fundamental principles of the XAS method and describe the progress in the instrumentation and data analysis approaches undertaken for deciphering X-ray absorption near edge structure (XANES) and extended X-ray absorption fine structure (EXAFS) spectra. Recent usages of XAS in the field of heterogeneous catalysis, with emphasis on examples concerning electrocatalysis, will be presented. The latter is a rapidly developing field with immense industrial applications but also unique challenges in terms of the experimental characterization restrictions and advanced modeling approaches required. This review will highlight the new insight that can be gained with XAS on complex real-world electrocatalysts including their working mechanisms and the dynamic processes taking place in the course of a chemical reaction. More specifically, we will discuss applications of in situ and operando XAS to probe the catalyst's interactions with the environment (support, electrolyte, ligands, adsorbates, reaction products, and intermediates) and its structural, chemical, and electronic transformations as it adapts to the reaction conditions.
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Affiliation(s)
- Janis Timoshenko
- Department of Interface Science, Fritz-Haber Institute of the Max-Planck Society, 14195 Berlin, Germany
| | - Beatriz Roldan Cuenya
- Department of Interface Science, Fritz-Haber Institute of the Max-Planck Society, 14195 Berlin, Germany
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Takao S, Sekizawa O, Higashi K, Samjeské G, Kaneko T, Sakata T, Yamamoto T, Uruga T, Iwasawa Y. Visualization Analysis of Pt and Co Species in Degraded Pt 3Co/C Electrocatalyst Layers of a Polymer Electrolyte Fuel Cell Using a Same-View Nano-XAFS/STEM-EDS Combination Technique. ACS APPLIED MATERIALS & INTERFACES 2020; 12:2299-2312. [PMID: 31841306 DOI: 10.1021/acsami.9b16393] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
In order to obtain a suitable design policy for the development of a next-generation polymer electrolyte fuel cell, we performed a visualization analysis of Pt and Co species following aging and degradation processes in membrane-electrode assembly (MEA), using a same-view. Nano-X-ray absorption fine structure (XAFS)/Scanning transmission electron microscope (STEM)-energy dispersive X-ray spectroscopy (EDS) technique that we developed to elucidate durability factors and degradation mechanisms of a MEA Pt3Co/C cathode electrocatalyst with higher activity and durability than a MEA Pt/C. In the MEA Pt3Co/C, after 5000 ADT-rec (rectangle accelerated durability test) cycles, unlike the MEA Pt/C, there was no oxidation of Pt. In contrast, Co oxidized and dissolved over a wide range of the cathode layer (∼70% of the initial Co amount). The larger the size of the cracks and pores in the MEA Pt/C and the smaller the ratio of Pt/ionomer of cracks and pores, the faster the rate of catalyst degradation. In contrast, there was no correlation between the size or Co/ionomer ratio of the cracks and pores and the Co dissolution of the MEA Pt3Co/C. It was shown that Co dissolved in the electrolyte region had an octahedral Co2+-O6 structure, based on a 150 nm × 150 nm nano-XAFS analysis. It was also shown that its existence suppressed the oxidation and dissolution of Pt. The MEA Pt3Co/C after 10,000 ADT-rec cycles had many cracks and pores in the cathode electrocatalyst layer, and about 90% of Co had been dissolved and removed from the cathode layer. We discovered a metallic Pt-Co alloy band in the electrolyte region of 300-400 nm from the cathode edge and square planar Pt2+-O4 species and octahedral Co2+-O6 species in the area between the cathode edge and the Pt-Co band. The transition of Pt and Co chemical species in the Pt3Co/C cathode electrocatalyst in the MEA during the degradation process, as well as a fuel cell deterioration suppression process by Co were visualized for the first time at the nano scale using the same-view nano-XAFS/STEM-EDS combination technique that can measure the MEA under a humid N2 atmosphere while maintaining the working environment for a fuel cell.
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Affiliation(s)
- Shinobu Takao
- Innovation Research Center for Fuel Cells , The University of Electro-Communications , Chofugaoka, Chofu , Tokyo 182-8585 , Japan
| | - Oki Sekizawa
- Innovation Research Center for Fuel Cells , The University of Electro-Communications , Chofugaoka, Chofu , Tokyo 182-8585 , Japan
- Japan Synchrotron Radiation Research Institute , Spring-8 , Sayo , Hyogo 679-5198 , Japan
| | - Kotaro Higashi
- Innovation Research Center for Fuel Cells , The University of Electro-Communications , Chofugaoka, Chofu , Tokyo 182-8585 , Japan
| | - Gabor Samjeské
- Department of Chemistry, Graduate School of Science , Nagoya University , Chikusa, Nagoya , Aichi 464-8602 , Japan
| | - Takuma Kaneko
- Innovation Research Center for Fuel Cells , The University of Electro-Communications , Chofugaoka, Chofu , Tokyo 182-8585 , Japan
| | - Tomohiro Sakata
- Innovation Research Center for Fuel Cells , The University of Electro-Communications , Chofugaoka, Chofu , Tokyo 182-8585 , Japan
| | - Takashi Yamamoto
- Department of Mathematical and Material Sciences, Faculty of Integrated Arts and Sciences , The University of Tokushima , Minamijosanjima, Tokushima 770-8502 , Japan
| | - Tomoya Uruga
- Innovation Research Center for Fuel Cells , The University of Electro-Communications , Chofugaoka, Chofu , Tokyo 182-8585 , Japan
- Japan Synchrotron Radiation Research Institute , Spring-8 , Sayo , Hyogo 679-5198 , Japan
| | - Yasuhiro Iwasawa
- Innovation Research Center for Fuel Cells , The University of Electro-Communications , Chofugaoka, Chofu , Tokyo 182-8585 , Japan
- Department of Engineering Science, Graduate School of Informatics and Engineering , The University of Electro-Communications , Chofugaoka, Chofu , Tokyo 182-8585 , Japan
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Matsui H, Maejima N, Ishiguro N, Tan Y, Uruga T, Sekizawa O, Sakata T, Tada M. Operando XAFS Imaging of Distribution of Pt Cathode Catalysts in PEFC MEA. CHEM REC 2018; 19:1380-1392. [PMID: 30375154 DOI: 10.1002/tcr.201800123] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2018] [Accepted: 09/28/2018] [Indexed: 11/10/2022]
Abstract
Three-dimensional imaging using X-ray as a probe is state-of-the-art for the characterization of heterogeneous materials. In addition to simple imaging of sample morphology, imaging of elemental distribution and chemical states provides advanced maps of key structural parameters of functional materials. The combination of X-ray absorption fine structure (XAFS) spectroscopy and three-dimensional imaging such as computed tomography (CT) can visualize the three-dimensional distribution of target elements, their valence states, and local structures in a non-destructive manner. In this personal account, our recent results on the three-dimensional XAFS imaging for Pt cathode catalysts in the membrane electrode assembly (MEA) of polymer electrolyte fuel cell (PEFC) are introduced. The distribution and chemical states of Pt cathode catalysts in MEAs remarkably change under PEFC operating conditions, and the 3D XAFS imaging revealed essential events in PEFC MEAs.
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Affiliation(s)
- Hirosuke Matsui
- Department of Chemistry, Graduate School of Science & Research Center for Materials Science & Integrated Research Consortium on Chemical Science, Nagoya University Furo, Chikusa, Nagoya, Aichi, 464-8602, Japan.,RIKEN SPring-8 Center Koto, Sayo Hyogo, 679-5198, Japan
| | - Naoyuki Maejima
- Department of Chemistry, Graduate School of Science & Research Center for Materials Science & Integrated Research Consortium on Chemical Science, Nagoya University Furo, Chikusa, Nagoya, Aichi, 464-8602, Japan
| | | | - Yuanyuan Tan
- Department of Chemistry, Graduate School of Science & Research Center for Materials Science & Integrated Research Consortium on Chemical Science, Nagoya University Furo, Chikusa, Nagoya, Aichi, 464-8602, Japan
| | - Tomoya Uruga
- Innovation Research Center for Fuel Cells, The University of Electro-Communications Chofu, Tokyo, 182-8585, Japan.,Japan Synchrotron Radiation Research Center, SPring-8 Koto, Sayo, Hyogo, 679-5198, Japan
| | - Oki Sekizawa
- Innovation Research Center for Fuel Cells, The University of Electro-Communications Chofu, Tokyo, 182-8585, Japan.,Japan Synchrotron Radiation Research Center, SPring-8 Koto, Sayo, Hyogo, 679-5198, Japan
| | - Tomohiro Sakata
- Innovation Research Center for Fuel Cells, The University of Electro-Communications Chofu, Tokyo, 182-8585, Japan
| | - Mizuki Tada
- Department of Chemistry, Graduate School of Science & Research Center for Materials Science & Integrated Research Consortium on Chemical Science, Nagoya University Furo, Chikusa, Nagoya, Aichi, 464-8602, Japan.,RIKEN SPring-8 Center Koto, Sayo Hyogo, 679-5198, Japan
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