Ex Situ Reconstruction-Shaped Ir/CoO/Perovskite Heterojunction for Boosted Water Oxidation Reaction
Hongquan Guo, Yanling Yang, Guangming Yang, Xiaojuan Cao, Ning Yan, Zhishan Li, Emily Chen, Lina Tang, Meilan Peng, Lei Shi, Shunji Xie, Hua Bing Tao, Chao Xu, Yinlong Zhu, Xian‐Zhu Fu, Yuanming Pan, Ning Chen, Jinru Lin, Xin Tu, Zongping Shao, Yifei Sun
Abstract
High Resolution Image Download MS PowerPoint Slide The oxygen evolution reaction (OER) is the performance-limiting step in the process of water splitting. In situ electrochemical conditioning could induce surface reconstruction of various OER electrocatalysts, forming reactive sites dynamically but at the expense of fast cation leaching. Therefore, achieving simultaneous improvement in catalytic activity and stability remains a significant challenge. Herein, we used a scalable cation deficiency-driven exsolution approach to ex situ reconstruct a homogeneous-doped cobaltate precursor into an Ir/CoO/perovskite heterojunction (SCI-350), which served as an active and stable OER electrode. The SCI-350 catalyst exhibited a low overpotential of 240 mV at 10 mA cm –2 in 1 M KOH and superior durability in practical electrolysis for over 150 h. The outstanding activity is preliminarily attributed to the exponentially enlarged electrochemical surface area for charge accumulation, increasing from 3.3 to 175.5 mF cm –2 . Moreover, density functional theory calculations combined with advanced spectroscopy and 18 O isotope-labeling experiments evidenced the tripled oxygen exchange kinetics, strengthened metal–oxygen hybridization, and engaged lattice oxygen oxidation for O–O coupling on SCI-350. This work presents a promising and feasible strategy for constructing highly active oxide OER electrocatalysts without sacrificing durability.