Recent progress on electrocatalysts in ammonia electrooxidation reaction for clean hydrogen production

Abstract

Hydrogen (H₂) is considered one of the most promising alternative energy resources, serving as a clean energy carrier, replacing fossil fuels. Ammonia (NH₃) is recognized as a high-potential H₂ carrier and is utilized as a primary material for H₂ production. The NH₃ electro-oxidation reaction (AOR) is crucial for both direct NH₃ fuel cells and NH₃ electrolysis. Nevertheless, AOR frequently encounters difficulties including a high overpotential, sluggish reaction rates, and catalyst deactivation as a result of its slow kinetics, even though it is thermodynamically advantageous. In order to overcome these obstacles, numerous approaches have been suggested for the creation of electrocatalysts that can sustain a strong reaction rate even when exposed to low overpotential. The kinetics, mechanisms, and experimental methods of AOR are the primary focus of this overview. It also examines recent advancements in electrocatalyst modifications, with a particular emphasis on single-atom electrocatalysts and transition metal-based catalysts. Additionally, the paper discusses the techno-economic assessment of the AOR reaction for H₂ production. Furthermore, future perspectives and recommendations for electrocatalyst development in AOR are provided. Proposing and designing new, resilient electrocatalysts will be significantly aided by the fundamentals and efforts detailed in this review; this, in turn, will propel advancements in AOR for practical applications.