Electrocatalysis of the ammonia oxidation reaction

Ammonia stands out as a promising carbon-free carrier for the ever-expanding renewable electricity landscape, due to its ease of storage and distribution as well as compatibility with existing infrastructure. Further implementing ammonia as an energy vector in a scalable and economic manner demands multiscale advancements in the electrocatalysis of the ammonia oxidation reaction (AOR), a field that has seen notable progress in recent years. In this review, we present a comprehensive overview on AOR electrocatalysis from the viewpoints of fundamental understanding, electrochemical testing, and material advancements. After outlining the milestone discoveries and discussing prevalent AOR mechanisms, we scrutinize and propose electrochemical protocols that enable proper and fair comparisons of AOR performance. We then summarize recent advances in Pt-based and non-Pt-based electrocatalysts, along with the respective structure-performance discussion. The remaining challenges and perspectives regarding sustainable ammonia energy are provided.