Super Durable Acidic Oxygen Evolution Catalyst of Ruthenium Oxide for Proton Exchange Membrane Electrocatalytic Water Splitting
Dongdong Zhang, Qilong Wu, Yun Han, Liyun Wu, Hongliang Dong, Rongrong Zhang, Nan Song, Fangfang Zhu, Yiqing Fang, Haodong Liu, J. Chen, Aijun Du, Keke Huang, Pei Yuan, Xiangdong Yao
Abstract
Ruthenium oxide (RuO 2 ) is a promising candidate for proton exchange membrane water electrolyzers (PEMWEs) due to its high activity and relatively low cost. However, its limited stability remains a critical challenge. Although substantial efforts have been made to improve the stability, the advance is insufficient for requirement of practical PEMWEs. In this study, the intrinsic structure of RuO 2−δ, specifically oxygen vacancies (O Vs ), was precisely manipulated to quantitatively investigate the underlying principles governing its activity–stability balance. Combining theoretical calculations and experimental results, it is revealed that the spatial distance between O Vs controlled by the density of O V dictates the catalytic performance, e. g. activity decays exponentially as intervacancy distance decreases while stability exhibits Gaussian-like fluctuations. Electrochemical analysis demonstrates that the as-synthesized h-RuO 2−δ nanosheet, with an O V density of 33%, achieves an optimal activity–stability synergy, exhibiting exceptional activity (1 A cm –2 @1.63 V) and stability (over 120 h) in a PEMWE, far surpassing the performance of commercial RuO 2 catalyst. In situ FTIR and DFT calculations demonstrate that RuO 2−δ with an optimal spatial arrangement of O Vs ( Meta -O Vs configuration) weakens the hydrogen-bonding network of interfacial water, facilitating water dissociation, and exhibits enhanced structural stability during the oxygen evolution reaction. The findings of this study establish a quantitative structure–property relationship for defect engineering in Ru-based catalysts.