Recent Advances in Designing Efficient Electrocatalysts for Electrochemical Nitrate Reduction to Ammonia

Abstract

As a raw material for producing chemical fertilizers, ammonia plays an essential role in human production and life. Due to the severe energy consumption and pollution caused by the industrial Haber–Bosch process of NH3 synthesis, developing the NH3 synthesis reaction under ambient conditions is vital. Electrochemical nitrogen reduction reaction (NRR) has recently emerged as a potential method. However, its limited NH3 yield and selectivity are unsatisfactory. NO3 −, as an oxidized form of nitrogen, universally exists in drinking water (<50 mg L−1) and industrial wastewater (2000‐4000 mg L−1). Electrochemical nitrate reduction reaction (NO3 −RR), with higher production and Faradaic efficiency, is a promising strategy for water treatment and NH3 production. In this review, a detailed overview of the recent progress in NO3 −RR for NH3 production with precious group metal (PGM) electrocatalysts, PGM‐free electrocatalysts, and nonmetal electrocatalysts is summarized. In addition, effective design strategies for efficient electrocatalysts, existing challenges, and research prospects for the next stage are also discussed. This review may provide some directions for improving efficient electrocatalysts in electrocatalytic NO3 −RR and offer inspiration for the electrochemical ammonia synthesis process.

Keywords

• ammonia synthesis
• electrocatalysis
• nitrate reduction reactions
• nitrogen cycles