Acid-stable oxygen-evolving catalysts: progress in non-precious material engineering and scalability barriers

As the cornerstone of proton exchange membrane water electrolyzers (PEMWE) systems, oxygen-evolving electrocatalysts play a decisive role in governing both energy conversion efficiency and cost-effectiveness. In recent years, non-precious metal-based oxygen-evolving catalysts have garnered significant attention as promising alternatives to noble metal counterparts. This review comprehensively explores the fundamental principles of acidic oxygen evolution reaction (OER) catalysis mediated by non-precious metal systems, with particular emphasis on the dynamic interplay between their activity and stability. Furthermore, it systematically analyzes degradation mechanisms within key components of PEMWE and outlines corresponding mitigation strategies. Specific advancements in diverse categories of non-precious metal catalysts and their associated design strategies are elaborated in detail. Finally, an in-depth discussion addresses the remaining barriers hindering the industrialization of non-precious catalysts. By integrating fundamental insights with practical engineering considerations, this work aims to guide the development of cost-effective yet robust catalysts for next-generation green hydrogen technologies.