Electrochemical C-N Coupling on Tri-metallic Mo-embedded Graphdiyne towards Efficient Urea Synthesis

Synthesis of urea by electrochemical C-N coupling is a promising alternative to the conventional approaches. A metal-cluster catalyst generally possesses multi-atomic active sites and can achieve co-adsorption and activation of several species. As a two-dimensional porous material, graphdiyne (GDY) is predicated to be a good substrate for loading a metal cluster. In this study, tri-metallic Mo-embedded graphdiyne (Mo-3@GDY) stands out for efficient urea synthesis among several TM3@GDY (TM=Mo, Fe, Co, Ni and Cu), based on density functional theory (DFT) computations. The co-adsorption of side-on N-2 and end-on CO on Mo-3@GDY is benefit to the formation of the urea precursor *NCON with a negative free energy change (-0.66 eV). The final hydrogenation step is the potential-determining step (PDS) with a medium onset potential (-0.71 V). This work extends the application of GDY and first provides a new approach for the electrochemical synthesis of urea by loading tri-metallic atoms on GDY.