Electrocatalytic nitrate reduction: The synthesis, recovery and upgradation of ammonia

Abstract

The nitrogen cycle has been disrupted by human activities, and a large amount of nitrate pollutants was discharged into the environment. This has resulted in an increase in nitrate levels in groundwater, posing threats to aquatic ecosystems and human health. Electrocatalytic nitrate reduction to ammonia (NRA), as an eco-friendly technology with the potential for pollution removal and resource recycling, has been widely studied. Here, focusing on the pathway of electrocatalytic nitrate reduction to achieve turning waste into valuable resources, we provide an overview of NRA from a broader perspective. The mechanisms of NRA, various electrocatalyst design strategies, and the control of reaction conditions have all been discussed in depth. Special attention is dedicated to summarizing the process of simultaneous ammonia recovery. Meanwhile, we discussed some emerging technologies developed based on NRA, such as C-N coupling and nitrate batteries. Finally, we discussed the challenges of NRA for industrial applications. This review provides a broader and comprehensive perspective on NRA, aiming to offer guidance for the catalyst design and practical application of NRA and promote the development of sustainable chemistry.