CO2 Reduction Performance of Cu/Er Supported on N-doped Graphene: A First Principles Study

A high atomic utilization and excellent catalytic activity distinguish atomic dispersion catalysts from the others, which are frequently utilized in CO2 reduction. Compared with single-atom catalysts (SACs), diatomic catalysts (DACs) have more dispersed active sites and different electronic structures, which could show different catalytic properties. Here, the CO2 reduction reaction (CO2RR) to C1 products process was systematically investigated for five different graphene-supported catalysts, including monatomic CuNC and ErNC, diatomic CuNC-ErNC, CuErNC-I, and CuErNC-II, using first principles calculations. Their free-energy diagrams were created, and the limit-potential /overpotential of different products were determined. It was shown that the minimum overpotential for CO2RR to CO/CH4 was 0.28/0.91 V on CuErNC-I(Er), to HCOOH was 1.01 V on CuErNC-I(Cu/Er), and to CH3OH was 0.81 V on CuErNC-I(Cu), respectively. At the same time, CuErNC-I displayed better electrochemical activity than others, and CuNC-ErNC had high selectivity comparing CO2RR with hydrogen evolution reaction (HER). This work provided a successful example to design high performance and selectivity catalysts by anchoring metal dimers to N-doped graphene substrates.