Impact of Ni doping on the catalytic activity and stability of RuO2 electrocatalyst for the oxygen evolution reaction in acidic media

Doping with transition metals (TMs) has been recognized as an effective strategy to improve the material stability of RuO₂ electrocatalysts for the oxygen evolution reaction (OER). However, the detailed mechanisms of material degradation and the impact of TM doping remain unclear. In this work, using density functional theory (DFT) calculations, we demonstrate that the experimental conditions under which OER proceeds can also trigger the degradation of RuO₂ through Ru dissolution, and that Ni doping can suppress this dissolution process. Specifically, the formation of RuO₄(aq), a product of the dissolution reaction, becomes thermodynamically favorable at a bias comparable to OER overpotentials. Ni doping makes RuO₄ formation less favorable without significantly altering the OER pathway. Furthermore, the Ru-O bond near a Ni dopant becomes stronger, making the reaction pathway for Ru dissolution more difficult to proceed. By expanding the atomistic understanding of the role of Ni doping on OER and material stability, this work paves the way for the development of high-performance and sustainable electrocatalysts for water splitting.