Fundamental understanding on electrocatalytic ammonia oxidation to nitrogen reaction and the designing for non-noble metal based electrocatalysts and devices

Abstract

The conversion and utilization of ammonia-hydrogen energy have garnered significant attention in recent years, offering a feasible approach to optimizing the energy structure. Ammonia serves as an energy carrier for hydrogen or directly drive fuel cells, with the ammonia oxidation reaction (AOR) being a crucial half-reaction for both applications, especially the ammonia oxidation to produce nitrogen, which shows significantly lower theoretical potential than the ammonia oxidation to nitrite/nitrate. Consequently, developing low-cost and high-performance materials to catalyze the AOR is of great significance, necessitating a deep investigation into non-noble metal-based AOR electrocatalysts. In this review, the underlying mechanisms for AOR, as well as the scientific research methods for AOR over non-noble metal-based materials, are extensively discussed to provide a fundamental understanding of the reaction. Furthermore, the modification strategies and electrochemical performance are summarized, along with the applications of AOR in hydrogen production through ammonia decomposition and fuel cells. This review provides instructive guidance for the design and application of non-noble metal-based AOR electrocatalysts.