Challenges and Breakthroughs in Single-Atom Catalysts for Electrocatalytic Nitrate Reduction to Ammonia

Single-atom catalysts (SACs) represent a novel category of catalytic materials with substantial potential for the electrocatalytic reduction of nitrate to ammonia (NO3RR). These catalysts possess multiple advantages, such as excellent atom utilization, electrocatalytic activity, and selectivity, along with tunable composition, structure, and unique electronic properties. These features endow them with great significance and wide application in the NO3RR field. Currently, extensive research is being carried out to engineer highly efficient SACs for NO3RR. This perspective elucidates the merits of SACs and their underlying catalytic mechanisms. It enumerates several common SAC preparation methods and characterization techniques, highlighting the crucial role of density functional theory calculations in guiding the design and development of efficient SACs. The recent practical applications of SACs in NO3RR and several strategies for enhancing their performance are also discussed in this perspective. Finally, some insights into future research directions in this vital area are provided.