Degradation mechanisms and stabilization strategies of ruthenium-based catalysts for OER in the proton exchange membrane water electrolyzer

Designing economical oxygen evolution reaction (OER) electrocatalysts with high activity and long-term stability is essential to promote the scale-up applications of proton exchange membrane water electrolyzer (PEMWE) for hydrogen production. Ruthenium (Ru) -based materials with high intrinsic activity are hailed as the most promising catalysts, but still infeasible for practical application considering their long unresolved poor stability (only dozens of lifespan). Thus, tremendous efforts have been devoted to uncovering the degradation mechanisms and developing stabilization strategies for the Ru-based catalysts. In this review, starting from summarizing the fundamental understanding of deactivation mechanisms, a picture of the stability issue of Ru-based catalysts is proposed, which is followed by a detailed discussion on the recently developed strategies and progress made on enhancing durability. Finally, insights on the prospects for the future development of stable and practical Ru-based OER catalysts are provided.