Rational Design of Bimetallic FeCo-MOF Electrocatalysts for Highly Selective Nitrate Reduction to Ammonia

Ammonia (NH₃), as an indispensable chemical in modern agriculture and industry, has long been produced on a large scale through the traditional Haber-Bosch process. However, this process is not only highly energy-intensive but also accompanied by substantial CO₂ emissions, necessitating the development of green alternatives. Meanwhile, nitrate (NO₃−) pollution in water bodies has become increasingly severe, posing significant threats to both ecosystems and human health. In this study, we successfully designed a bimetallic iron-cobalt organic framework (FeCo-MOF) catalyst and, for the first time, applied it to the electrocatalytic nitrate reduction reaction for ammonia synthesis. Experimental results demonstrate that at a working potential of −1.5 V (vs. SCE), the catalyst exhibits outstanding catalytic performance, achieving a current density of 52.17 mA/cm² and a remarkable NH₄⁺ Faradaic efficiency of 97.90%, significantly surpassing those of single-metal Fe-MOF and Co-MOF counterparts. Through spectroscopic characterization and electrochemical analysis, we elucidated the synergistic mechanism of the Fe-Co bimetallic active sites. The scientific significance of this work lies in its dual contributions: providing an efficient electrocatalytic strategy for nitrate pollution remediation while pioneering a low-carbon-emission approach to green ammonia synthesis, thereby holding substantial environmental and energy implications.