Tailoring atomic species in electrochemical-driven catalysts for efficient ammonia oxidation toward hydrogen production and wastewater treatment

The development of clean energy technologies to address the energy crisis, the environmental issues caused by excessive fossil fuel consumption, and the resulting CO₂ emissions has become a critical and urgent task of modern society. Electrochemical (EC) and photoelectrochemical (PEC) ammonia oxidation have emerged as promising environmentally benign strategies due to its potential for hydrogen production and ammonia-containing wastewater treatment under ambient conditions. However, most ammonia splitting systems face significant challenges related to electrocatalytic ammonia oxidation reaction (AOR), including sluggish reaction kinetics, which lead to high overpotential, reduced cell efficiency, and catalyst deactivation, thereby limiting its practical industrial applications. The development of efficient, sustainable, and low-cost catalysts for the AOR is crucial for enhancing the reaction kinetics and overall efficiency. In this review, we first outlined the fundamental principles of the AOR and the key parameters influencing its performance. Second, we systematically summarized and discussed recent advances in electrochemical and photoelectrochemical approaches for achieving high AOR activity. Finally, the remaining challenges and future perspectives on the rational design and development of active, durable AOR catalysts for practical applications were proposed.