Restoring the Nitrogen Cycle by Electrochemical Reduction of Nitrate: Progress and Prospects

The increasing amount of anthropogenic nitrogen has resulted in alarming levels of nitrate in bodies of water and caused a cascade of damage to the environment and human health. Electrochemical nitrate reduction is an efficient strategy ancillary to biological nitrogen cycle management, which utilizes electrons as green reductants and rebalances the N₂ cycle. In this review, the fundamental principles and implementation of electrochemical nitrate reduction are described to lay the foundation for the eventual large-scale application in the remediation of nitrate-laden wastewaters. Factors that influence the activity and selectivity of electrochemical nitrate reduction are also discussed. Moreover, electrolytic cell design and construction are discussed via a rational choice of critical components and assembly. Finally, a roadmap for the development of highly selective nitrate reduction catalysts is proposed. This review attempts to provide a practical strategy for electrochemical nitrogen cycle management and aims to stimulate future research for final implementation.