Theoretical study on low temperature reverse water gas shift (RWGS) mechanism on monatomic transition metal M doped C2N catalyst (M=Cu, Co, Fe)

Abstract

The reaction path of low temperature reverse water gas reaction (RWGS) on M/C2N (M=Cu, Co, Fe) was studied by density functional theory (DFT). The results show that after doping, electrons transfer from M to C2N and gather directionally on the surface of C2N, which significantly changes the catalytic behavior of C2N. Because the increase of electronic activity reduces the reaction activation energy, it effectively promotes the RWGS on C2N at low temperature. We also found that the low-temperature RWGS on Cu/C2N and Co/C2N proceed according to the redox mechanism, while Fe/C2N tend to the carboxyl mechanism. Moreover, the energy barrier of rate-determining step in redox mechanism for Cu/C2N is the lowest, indicating that the low-temperature RWGS reaction is more likely to occur on this structure.