Dynamic active-site generation of atomic iridium stabilized on nanoporous metal phosphides for water oxidation

Kang Jiang; Min Luo; Ming Peng; Yaqian Yu; Ying-Rui Lu; Ting-Shan Chan; Pan Liu; Frank M F de Groot; Yongwen Tan

doi:10.1038/s41467-020-16558-1

Dynamic active-site generation of atomic iridium stabilized on nanoporous metal phosphides for water oxidation

Nat Commun. 2020 Jun 1;11(1):2701. doi: 10.1038/s41467-020-16558-1.

Authors

Kang Jiang¹, Min Luo², Ming Peng¹, Yaqian Yu¹, Ying-Rui Lu³, Ting-Shan Chan³, Pan Liu⁴, Frank M F de Groot⁵, Yongwen Tan⁶

Affiliations

¹ College of Materials Science and Engineering, Hunan University, Changsha, Hunan, 410082, China.
² Department of Physics, Shanghai Polytechnic University, Shanghai, 201209, China.
³ National Synchrotron Radiation Research Center, Hsinchu, 300, Taiwan.
⁴ State Key Laboratory of Metal Matrix Composites, School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai, 200030, China.
⁵ Inorganic Chemistry & Catalysis, Debye Institute for Nanomaterials Science, Utrecht University, Universiteitsweg 99, 3584, CG, Utrecht, The Netherlands.
⁶ College of Materials Science and Engineering, Hunan University, Changsha, Hunan, 410082, China. tanyw@hnu.edu.cn.

Abstract

Designing efficient single-atom catalysts (SACs) for oxygen evolution reaction (OER) is critical for water-splitting. However, the self-reconstruction of isolated active sites during OER not only influences the catalytic activity, but also limits the understanding of structure-property relationships. Here, we utilize a self-reconstruction strategy to prepare a SAC with isolated iridium anchored on oxyhydroxides, which exhibits high catalytic OER performance with low overpotential and small Tafel slope, superior to the IrO₂. Operando X-ray absorption spectroscopy studies in combination with theory calculations indicate that the isolated iridium sites undergo a deprotonation process to form the multiple active sites during OER, promoting the O-O coupling. The isolated iridium sites are revealed to remain dispersed due to the support effect during OER. This work not only affords the rational design strategy of OER SACs at the atomic scale, but also provides the fundamental insights of the operando OER mechanism for highly active OER SACs.