Identifying and tailoring C-N coupling sites for efficient urea synthesis on diatomic Fe-Ni catalyst

Abstract Electrocatalytic urea synthesis emerged as the promising alternative of Haber-Bosch process and industrial urea synthetic protocol. Here, we report that a diatomic catalyst with bonded Fe-Ni pairs can significantly improve the efficiency of electrochemical urea synthesis. Compared with isolated diatomic and single-atom catalysts, the bonded Fe-Ni pairs act as the efficient sites for coordinated adsorption and activation of multiple reactants, enhancing the crucial C-N coupling thermodynamically and kinetically. The performance for urea synthesis is up to an order of magnitude higher than those of single-atom and isolated diatomic electrocatalysts, successfully achieving a high urea yield rate of 20.2 mmol h-1 g-1 with corresponding Faradaic efficiency of 17.8%. The competing hydrogen evolution is in-situ suppressed by C-N coupling with a total Faradaic efficiency of about 100% for the value-added products. This work presents new insights into synergistic catalysis towards sustainable urea synthesis via identifying and tailoring the atomic site configurations.