Bimetallic doped C2N catalyzed CO2 reduction to ethylene: A first–principles study

In the paper, the stability, adsorption configuration and activated electronic properties of CO2 on the surfaces of C2N, single–atom–doped C2N (M/C2N), bi–atomic–metal–doped C2N (M2/C2N) were investigated by density functional theory (DFT). Calculations show that both M/C2N and M2/C2N exhibit high stability, in which NiCo/C2N has the highest stability. Based on the comparison of bond lengths and bond angles for adsorbed CO2, it indicates that M/C2N shows poor CO2 adsorption properties, while NiCo/C2N has good CO2 adsorption properties. Further studies on the generation of C1 products from CO2RR and C–C coupling reactions on M/C2N and M2/C2N materials were carried out. It was found that the outermost electron distribution and density of states of the transition metals lead to different pathways for C1 generation from CO2RR on the surfaces of Cu/C2N, Ni/C2N and Co/C2N. In particular, M2/C2N is more prone to CO2RR than M/C2N. Meanwhile, the energy barriers of C–C coupling reaction show that NiCo/C2N is favorable to CO2RR. In addition, the mechanism study of CO2RR generation of ethylene (C2H4) on the surface of NiCo/C2N material is further discussed, which provides some support for the application of bimetallic atomic catalysts in CO2RR.