Effect of Cation and Anion Vacancies in Ruthenium Oxide on the Activity and Stability of Acidic Oxygen Evolution
Jiao Yang, Keyu An, Zhichao Yu, Lulu Qiao, Youpeng Cao, Yujuan Zhuang, Chunfa Liu, Lun Li, Lishan Peng, Hui Pan
Abstract
Electrocatalysts capable of working efficiently in acidic media for the oxygen evolution reaction (OER) are highly demanded for the large-scale utilization of proton exchange membrane (PEM) water electrolysis. This study focuses on the design and fabrication of cation/oxygen vacancy-enriched RuO 2 catalysts to investigate the impact of defect types on the OER activity and stability of RuO 2 . The comprehensive blend of experimental and theoretical approaches elucidates that the presence of Ru vacancies in Ru 1– x O 2 modulates the d-band center and optimizes the adsorption energy of the OER intermediates, thereby augmenting the intrinsic OER activity. Conversely, the presence of oxygen vacancies in RuO 2-x diminishes the strength of Ru–O bonds, suppressing the involvement of the lattice oxygen oxidation mechanism (LOM) and Ru dissolution, consequently enhancing long-term stability. Notably, Ru 1– x O 2 exhibits the lowest overpotential of 212 mV at 10 mA cm geo –2, while RuO 2– x demonstrates superior stability, enduring 400 h under 10 mA cm geo –2, surpassing many catalysts for acidic OER in the literature. Our findings demonstrate that defect engineering is a promising strategy to achieve electrocatalysts with super catalytic performance in acid media for water electrolysis.