Operando Direct Observation of Stable Water-Oxidation Intermediates on Ca2-xIrO4 Nanocrystals for Efficient Acidic Oxygen Evolution.

Li, Na; Cai, Liang; Gao, Guoping; Lin, Yue; Wang, Chao; Liu, Hengjie; Liu, Yuying; Duan, Hengli; Ji, Qianqian; Hu, Wei; Tan, Hao; Qi, Zeming; Wang, Lin-Wang; Yan, Wensheng

Operando Direct Observation of Stable Water-Oxidation Intermediates on Ca_2-xIrO₄ Nanocrystals for Efficient Acidic Oxygen Evolution.

Li, Na; Cai, Liang; Gao, Guoping; Lin, Yue; Wang, Chao; Liu, Hengjie; Liu, Yuying; Duan, Hengli; Ji, Qianqian; Hu, Wei; Tan, Hao; Qi, Zeming; Wang, Lin-Wang; Yan, Wensheng.

Afiliação

Li N; National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei, Anhui 230029, China.
Cai L; Department of Materials Science and Engineering, National University of Singapore, 117575 Singapore.
Gao G; Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States.
Lin Y; Department of Materials Science and Engineering, National University of Singapore, 117575 Singapore.
Wang C; Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States.
Liu H; MOE Key Laboratory for Non-equilibrium Synthesis and Modulation of Condensed Matter, Shaanxi Province Key Laboratory of Advanced Functional Materials and Mesoscopic Physics, School of Physics, Xi'an Jiaotong University, Xi'an, Shaanxi 710049, China.
Liu Y; Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei, Anhui 230029, China.
Duan H; National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei, Anhui 230029, China.
Ji Q; National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei, Anhui 230029, China.
Hu W; National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei, Anhui 230029, China.
Tan H; National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei, Anhui 230029, China.
Qi Z; National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei, Anhui 230029, China.
Wang LW; National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei, Anhui 230029, China.
Yan W; National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei, Anhui 230029, China.

Nano Lett ; 22(17): 6988-6996, 2022 Sep 14.

Article em En | MEDLINE | ID: mdl-36005477

ABSTRACT

ABSTRACT

We report Ca2-xIrO4 nanocrystals exhibit record stability of 300 h continuous operation and high iridium mass activity (248 A gIr-1 at 1.5 VRHE) that is about 62 times that of benchmark IrO2. Lattice-resolution images and surface-sensitive spectroscopies demonstrate the Ir-rich surface layer (evolved from one-dimensional connected edge-sharing [IrO6] octahedrons) with high relative content of Ir5+ sites, which is responsible for the high activity and long-term stability. Combining operando infrared spectroscopy with X-ray absorption spectroscopy, we report the first direct observation of key intermediates absorbing at 946 cm-1 (Ir6+âO site) and absorbing at 870 cm-1 (Ir6+OO- site) on iridium-based oxides electrocatalysts, and further discover the Ir6+âO and Ir6+OO- intermediates are stable even just from 1.3 VRHE. Density functional theory calculations indicate the catalytic activity of Ca2IrO4 is enhanced remarkably after surface Ca leaching, and suggest IrOO- and IrâO intermediates can be stabilized on positive charged active sites of Ir-rich surface layer.

Palavras-chave

acidic oxygen evolution reaction; electrocatalysis; iridium-based oxides; iridium-rich surface layer; key intermediates

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Texto completo: 1 Bases de dados: MEDLINE Idioma: En Revista: Nano Lett Ano de publicação: 2022 Tipo de documento: Article País de afiliação: China