Shining light on non-platinum-based electrocatalysts for efficient ammonia oxidation in low-temperature direct ammonia fuel cells: Fundamentals, progress, and perspectives

In response to growing energy and environmental concerns associated with fossil fuels, renewable energy-powered fuel cells have gained significant attention as sustainable alternatives. Especially, ammonia offers high energy density as well as superior storage and transport properties, thus attracting increasing attention as a promising alternative to hydrogen and rendering direct ammonia fuel cells (DAFCs) distinct safety advantages over hydrogen-based systems. While platinum-based catalysts currently dominate the anodic ammonia oxidation reaction (AOR) applications, their scarcity and high cost substantially hinder DAFC commercialization. In this context, developing non-platinum-based electrocatalysts for the AOR represents the efforts towards the more economical use of ammonia energy. This review comprehensively introduces recent progress in non-platinum-based AOR electrocatalysts for low-temperature DAFC applications. Beginning with introductory section highlighting historical context and catalytic breakthroughs, fundamental understanding of DAFC system and the anodic AOR are systematically presented. Subsequently, it outlines the advancements in typical non-platinum-based catalysts, highlighting material innovations and performance enhancements. The analysis concludes by identifying critical research challenges and future directions, offering strategic insights to accelerate the development of high-efficiency DAFC systems.