Rational design of iron single-atom catalysts for electrochemical nitrate reduction to produce ammonia

Ammonia (NH3) is the second-most produced chemical with broad applications and vital for the chemical industry. However, the current Haber–Bosch synthesis is problematic with high energy consumption and carbon footprints. Electrochemical nitrate reduction (NO3RR) to produce NH3 is a green, low-carbon and efficient alternative route to simultaneously benefit wastewater treatment, mild NH3 production and global warming mitigation. Compared to noble metal catalysts or the nanosized counterparts, iron single-atom catalysts (Fe SACs) boast unique advantages to promote the NO3RR because of the exceptional selectivity, inexpensiveness, high efficiency and good durability. Due to the rapid development of the emerging field, a timely Perspective with an emphasis on the recent advances in Fe SACs-catalyzed NO3RR is currently lacking. The Perspective aims to give an account of the up-to-date progresses on Fe SACs-promoted NO3RR for NH3 production. The catalyst design, characterizations, mechanism studies, etc. will be illustrated, and lastly the challenges and outlook will be discussed to provide insights for future studies.