Exploring the potential Ru-based catalysts for commercial-scale polymer electrolyte membrane water electrolysis: A systematic review

Proton-conducting polymer electrolyte membrane water electrolysis (PEMWE) is a vital clean hydrogen generation technology that can ease the energy crisis resulting from global warming and dependence on fossil fuels. However, the long-term catalytic activity and stability of the extensively studied benchmark RuO₂ catalysts in an acidic environment is insufficient for large-scale renewable energy conversion devices. Thus, significant recent efforts have focused on identifying and exploring acid-stable Ru-based electrocatalysts with low overpotential and high stability for the oxygen evolution reaction (OER). This review offers a comprehensive analysis of recent advances in Ru-based acidic OER catalysts, starting with a detailed understanding of design principles for Ru-based catalysts, encompassing the reaction mechanisms, degradation mechanism, and activity-stability relationships. Subsequently, advanced Ru-based catalysts regulating strategy are into four categories, within each category, a critical assessment of catalyst design and synthesis, electrocatalytic performance, along with typical examples and existing challenges. Representative examples in practical PEMWE are also provided to illustrate these advancements. Finally, the challenges and prospects for future studies on the development of Ru-based acidic OER catalysts towards the ultimate application of PEMWE are also examined.