Oxygen vacancy induced oxide pathway mechanism of hollow RuO2 to improve the stability of acidic oxygen evolution reaction

Adjusting the content of oxygen vacancies (O v s) in RuO 2 can effectively improve its stability in the acidic oxygen evolution reaction (OER). However, the internal relationship among the O v s contents, spatial configuration and reaction mechanism still lacks a clear understanding. In this work, we construct a RuO 2 catalyst with a suitable O v s content, exhibiting a highly OER stability. The effects of O v s on catalytic properties were investigated by theoretical and experimental methods. Density functional theory (DFT) analyses found that the introduction of O v s shortens the interatomic distance of Ru-Ru, which activates the oxide pathway mechanism (OPM). The Ru dissolution energy barrier first rises and then decreases when enhancing the O v s contents, thus achieving optimal stability of the catalyst with a suitable number of O v s. More importantly, porous hollow RuO 2 spheres with the different O v s contents were synthesized under the guidance of DFT calculations. Among them, RuO 2 calcined at 220°C shows the best OER activity and stability (165 mV @10 mA cm −2 , 2000 h @10 mA cm −2 ) due to possessing a moderate O v s amount. In short, this work provides an effective strategy for developing Ru-based OER catalysts by using DFT calculations to reveal the relationship between O v s contents and the performances.