Identification of the Active-Layer Structures for Acidic Oxygen Evolution from 9R-BaIrO3Electrocatalyst with Enhanced Iridium Mass Activity

Na Li, Liang Cai*, Chao Wang, Yue Lin, Jinzhen Huang, Hongyuan Sheng, Haibin Pan, Wei Zhang, Qianqian Ji, Hengli Duan, Wei Hu, Wenhua Zhang, Fengchun Hu, Hao Tan, Zhihu Sun, Bo Song, Song Jin*, Wensheng Yan*, Liang Cai*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

73 Scopus citations

Abstract

Iridium-based perovskites show promising catalytic activity for oxygen evolution reaction (OER) in acid media, but the iridium mass activity remains low and the active-layer structures have not been identified. Here, we report highly active 1 nm IrOx particles anchored on 9R-BaIrO3 (IrOx/9R-BaIrO3) that are directly synthesized by solution calcination followed by strong acid treatment for the first time. The developed IrOx/9R-BaIrO3 catalyst delivers a high iridium mass activity (168 A gIr-1), about 16 times higher than that of the benchmark acidic OER electrocatalyst IrO2 (10 A gIr-1), and only requires a low overpotential of 230 mV to reach a catalytic current density of 10 mA cm-2geo. Careful scanning transmission electron microscopy, synchrotron radiation-based X-ray absorption spectroscopy, and X-ray photoelectron spectroscopy analyses reveal that, during the electrocatalytic process, the initial 1 nm IrOx nanoparticles/9R-BaIrO3 evolve into amorphous Ir4+OxHy/IrO6 octahedrons and then to amorphous Ir5+Ox/IrO6 octahedrons on the surface. Such high relative content of amorphous Ir5+Ox species derived from trimers of face-sharing IrO6 octahedrons in 9R-BaIrO3 and the enhanced metallic conductivity of the Ir5+Ox/9R-BaIrO3 catalyst are responsible for the excellent acidic OER activity. Our results provide new insights into the surface active-layer structure evolution in perovskite electrocatalysts and demonstrate new approaches for engineering highly active acidic OER nanocatalysts.

Original languageEnglish (US)
Pages (from-to)18001-18009
Number of pages9
JournalJournal of the American Chemical Society
Volume143
Issue number43
DOIs
StatePublished - Nov 3 2021

Bibliographical note

Funding Information:
This work was financially supported by the National Natural Science Foundation of China (grant nos. 11975234, 11775225, 12075243, and 12005227), users with excellence program of Hefei Science Center CAS, (no. 2019HSC-UE002, 2020HSC-UE002, 2020HSC–CIP013). H.S. and S.J. thank the support of US NSF CHE-1955074. The authors would like to thank BSRF, SSRF, and NSRL for the synchrotron beamtime. This work was partially carried out at the USTC Center for Micro and Nanoscale Research and Fabrication.

Publisher Copyright:
© 2021 American Chemical Society.

ASJC Scopus subject areas

  • Catalysis
  • General Chemistry
  • Biochemistry
  • Colloid and Surface Chemistry

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