Identifying and tailoring C-N coupling site for efficient urea synthesis over diatomic Fe-Ni catalyst.

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 up to an order of magnitude higher than those of single-atom and isolated diatomic electrocatalysts, a high urea yield rate of 20.2 mmol h g with corresponding Faradaic efficiency of 17.8% has been successfully achieved. A total Faradaic efficiency of about 100% for the formation of value-added urea, CO, and NH was realized. This work presents an insight into synergistic catalysis towards sustainable urea synthesis via identifying and tailoring the atomic site configurations.