Rational Design and Characterization on RuO2-Based Catalysts for Acidic Oxygen Evolution Reaction Guided by Reaction Pathway Regulation

Abstract

Ruthenium dioxide (RuO2) is regarded as a promising alternative to iridium-based catalysts for the oxygen evolution reaction (OER) in proton exchange membrane water electrolyzers (PEMWE), owing to its high intrinsic activity and relatively lower cost. Nevertheless, the activity-stability trade-off induced by competing reaction pathways under harsh acidic conditions severely restricts the large-scale industrial application of RuO2 catalysts. In-depth understanding of these reaction pathways is therefore critical for the precise structural design and performance optimization of RuO2-based catalysts. This review systematically summarizes three mainstream OER mechanisms of RuO2 catalysts in acidic environments, namely the adsorbate evolution mechanism (AEM), lattice oxygen-mediated mechanism (LOM), and oxide path mechanism (OPM). Subsequently, recent advances in reaction pathways regulation strategies, such as element doping, heterostructure engineering, defect engineering, are highlighted with the aim to break the activity-stability limitation. Furthermore, the critical role of in situ characterization technologies during the OER process in identifying reaction intermediates and dynamic structural evolution is discussed. Finally, the remaining challenges and future directions for achieving precise control and industrial-scale application are outlined, providing a foundation for designing high-performance, durable RuO2-based catalysts for sustainable hydrogen production.