Operando Identification of Dual Active Sites in Ca2IrO4Nanocrystals with Yttrium Substitutions Boosting Acidic Oxygen Evolution Reaction

Yuying Liu, Liang Cai*, Qianqian Ji, Chao Wang, Ziyi Liu, Liyang Lv, Bing Tang, Hengli Duan, Fengchun Hu, Huijuan Wang, Na Li*, Zhihu Sun, Wensheng Yan*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

14 Scopus citations


Non-noble metal substitutions of the iridium sites in iridium-based complex oxides while boosting acidic oxygen evolution reaction (OER) is a promising method for developing efficient electrocatalysts, but this remains a huge challenge. Herein, we report yttrium substitution of iridium in Ca2IrO4(Ca2YxIr1-xO4) nanocrystals for the first time, which is demonstrated by detailed structural characterizations using X-ray absorption spectra, X-ray diffraction patterns, and elemental mapping images. The synthesized Ca2Y0.2Ir0.8O4catalyst requires a low overpotential of only 213 mV, achieving an acidic OER current density of 10 mA cm-2, which represents an approximately 203.7-fold improvement in iridium mass activity and 204.4-fold improvement in turnover frequency in comparison to that of IrO2at 1.5 V vs RHE, respectively. Systematic characterizations of electronic structures reveal the synergistic effects between high-valence iridium sites and increased lattice oxygen concentration induced by Y3+substitutions, which greatly enhance the intrinsic OER activity of Ca2Y0.2Ir0.8O4. Operando X-ray absorption spectra and Raman spectra reveal the iridium and yttrium dual active sites during acidic OER. Our results provide a method for designing dual active sites in iridium-based complex oxides for highly active acidic OER electrocatalysts.

Original languageEnglish (US)
Pages (from-to)3798-3806
Number of pages9
JournalACS Energy Letters
Issue number11
StatePublished - Nov 11 2022

Bibliographical note

Funding Information:
This work was financially supported by the National Key Research and Development Program of China (2021YFA1600800); National Natural Science Foundation of China (Grant Nos. 11975234, 11775225, U2032150, U1932211, 12075243, 12005227, and 12105286); the Users with Excellence Program of Hefei Science Center CAS (Nos. 2020HSC-UE002, 2020HSC-CIP013, 2021HSC-UE002, and 2021HSC-UE003),; the Major Science and Technology Project of Anhui Province (202103a05020025); the Key Program of Research and Development of Hefei Science Center, CAS (2021HSC-KPRD002); the Fundamental Research Funds for the Central Universities (WK 2310000103); and the Postdoctoral Science Foundation of China (Grant Nos. 2020M682041 and 2020TQ0316) and was partially carried out at the USTC Center for Micro and Nanoscale Research and Fabrication. The authors thank Beijing Synchrotron Radiation Facility (BSRF), Shanghai Synchrotron Radiation Facility (SSRF), and Beamlines MCD-A and MCD-B (Soochow Beamline for Energy Materials) at NSRL for the synchrotron beamtime.

Publisher Copyright:
© 2022 American Chemical Society. All rights reserved.

ASJC Scopus subject areas

  • Chemistry (miscellaneous)
  • Renewable Energy, Sustainability and the Environment
  • Fuel Technology
  • Energy Engineering and Power Technology
  • Materials Chemistry


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