Nitrogen reduction reaction catalysts are broadly classified into six categories: single-atom, noble metal, metal oxide, carbide, nitride, and metal organic frameworks catalysts. Each category offers distinct advantages, alongside specific challenges and prospects for future catalyst design.

Electrochemical nitrogen reduction reaction (eNRR) is an effective way for clean electricity energy storage and production of useful chemicals such as ammonia. Hence, it has become one of the most attractive research topics in recent years. However, the catalysts with high activity, stability, and production selectivity under ambient conditions have not been fully developed. Herein, the recent progress in those novel eNRR catalysts, including single atoms, oxides, carbides, nitrides, and others, is briefly reviewed in terms of the synthesis, characterization, functional mechanism, and performance validation/optimization. Finally, to facilitate the conversion, the technical challenges are summarized and analyzed, and several directions for developing highly efficient catalysts are proposed.