Fe/Cu diatomic catalysts for electrochemical nitrate reduction to ammonia
Shuo Zhang, Jianghua Wu, Mengting Zheng, Xin Jin, Zihan Shen, Zhonghua Li, Yanjun Wang, Quan Wang, Xuebin Wang, Hui Wei, Jiangwei Zhang, Peng Wang, Shanqing Zhang, Liyan Yu, Dong Lifeng, Qingshan Zhu, Huigang Zhang, Jun Lü
Abstract
Abstract Electrochemical conversion of nitrate to ammonia offers an efficient approach to reducing nitrate pollutants and a potential technology for low-temperature and low-pressure ammonia synthesis. However, the process is limited by multiple competing reactions and NO 3 − adsorption on cathode surfaces. Here, we report a Fe/Cu diatomic catalyst on holey nitrogen-doped graphene which exhibits high catalytic activities and selectivity for ammonia production. The catalyst enables a maximum ammonia Faradaic efficiency of 92.51% (−0.3 V(RHE)) and a high NH 3 yield rate of 1.08 mmol h −1 mg −1 (at − 0.5 V(RHE)). Computational and theoretical analysis reveals that a relatively strong interaction between NO 3 − and Fe/Cu promotes the adsorption and discharge of NO 3 − anions. Nitrogen-oxygen bonds are also shown to be weakened due to the existence of hetero-atomic dual sites which lowers the overall reaction barriers. The dual-site and hetero-atom strategy in this work provides a flexible design for further catalyst development and expands the electrocatalytic techniques for nitrate reduction and ammonia synthesis.