Artificially steering electrocatalytic oxygen evolution reaction mechanism by regulating oxygen defect contents in perovskites

Min Lu; Yao Zheng; Yang Hu; Bolong Huang; Deguang Ji; Mingzi Sun; Jianyi Li; Yong Peng; Rui Si; Pinxian Xi; Chun-Hua Yan

doi:10.1126/sciadv.abq3563

Artificially steering electrocatalytic oxygen evolution reaction mechanism by regulating oxygen defect contents in perovskites

Sci Adv. 2022 Jul 29;8(30):eabq3563. doi: 10.1126/sciadv.abq3563. Epub 2022 Jul 29.

Authors

Min Lu¹, Yao Zheng², Yang Hu¹, Bolong Huang³, Deguang Ji¹, Mingzi Sun³, Jianyi Li¹, Yong Peng⁴, Rui Si⁵, Pinxian Xi¹, Chun-Hua Yan^{1

6}

Affiliations

¹ State Key Laboratory of Applied Organic Chemistry, Frontiers Science Center for Rare Isotopes, College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou 730000, China.
² School of Chemical Engineering and Advanced Materials, The University of Adelaide, Adelaide, South Australia 5005, Australia.
³ Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong SAR, China.
⁴ School of Materials and Energy, Electron Microscopy Centre of Lanzhou University, Lanzhou 730000, China.
⁵ Shanghai Synchrotron Radiation Facility, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201204, China.
⁶ Beijing National Laboratory for Molecular Sciences, State Key Laboratory of Rare Earth Materials Chemistry and Applications, PKU-HKU Joint Laboratory in Rare Earth Materials and Bioinorganic Chemistry, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China.

Abstract

The regulation of mechanism on the electrocatalysis process with multiple reaction pathways is more efficient and essential than conventional material engineering for the enhancement of catalyst performance. Here, by using oxygen evolution reaction (OER) as a model, which has an adsorbate evolution mechanism (AEM) and a lattice oxygen oxidation mechanism (LOM), we demonstrate a general strategy for steering the two mechanisms on various La_xSr_1-xCoO_3-δ. By delicately controlling the oxygen defect contents, the dominant OER mechanism on La_xSr_1-xCoO_3-δ can be arbitrarily transformed between AEM-LOM-AEM accompanied by a volcano-type activity variation trend. Experimental and computational evidence explicitly reveal that the phenomenon is due to the fact that the increased oxygen defects alter the lattice oxygen activity with a volcano-type trend and preserve the Co⁰ state for preferably OER. Therefore, we achieve the co-optimization between the activity and stability of catalysts by altering the mechanism rather than a specific design of catalysts.