Electrochemically converting nitrate, a widespread water pollutant, back to valuable ammonia is a green and delocalized route for ammonia synthesis, and can be an appealing and supplementary alternative to the Haber-Bosch process. This study reports a selective and active nitrate reduction to ammonia on an Fe single atom catalyst, achieving a maximal ammonia Faradaic efficiency of ~75% and a yield rate of up to ~20,000 µg h⁻¹ mgcat⁻¹. The Fe single atom catalyst prevents the N-N coupling step required for N2 formation, promoting ammonia selectivity. Density functional theory calculations reveal the reaction mechanisms and potential limiting steps.

Zhen-Yu Wu, Mohammadreza Karamad, Xue Yong, Qizheng Huang, David A. Cullen, Peng Zhu, Chuan Xia, Qunfeng Xiao, Mohsen Shakouri, Feng-Yang Chen, Jung Yoon (Timothy) Kim, Yang Xia, Kimberly Heck, Yongfeng Hu, Michael S. Wong, Qilin Li, Ian Gates, Samira Siahrostami, Haotian Wang