Role of Dissolution Intermediates in Promoting Oxygen Evolution Reaction at RuO2(110) Surface

摘要

RuO2 is one of the most active electrocatalysts toward oxygen evolution reaction (OER), but it suffers from rapid dissolution in electrochemical environments. It is also established experimentally that corrosion of metal oxides can, in fact, promote catalytic activity for OER owing to the formation of a surface hydrous amorphous layer. However, the mechanistic interplay between corrosion and OER across metal-oxide catalysts and to what degree these two processes are correlated are still debated. Herein, we employ ab initio molecular dynamics-based blue moon ensemble approach in combination with OER thermodynamic analysis to reveal a clear mechanistic coupling between Ru dissolution and OER at the RuO2(110)/water interface. Specifically, we demonstrate that (i) dynamic transitions between metastable dissolution intermediates greatly affect catalytic activity toward OER, (ii) dissolution and OER processes share common intermediates with OER promoting Ru detachment from the surface, (iii) the lattice oxygen can be involved in the OER, and (iv) the coupling between different OER intermediates formed at the same Ru site of the metastable dissolution state can lower the theoretical overpotential of OER down to 0.2 eV. Collectively, our findings illustrate the critical role of highly reactive metastable dissolution intermediates in facilitating OER and underscore the need for the incorporation of interfacial reaction dynamics to resolve apparent conflicts between theoretically predicted and experimentally measured OER overpotentials.