Fig. 1. Computational results of CO₂RR process on different catalysts. (a) Free energy diagram for the CO₂RR to CO at U = −0.7 V vs. RHE on the Fe site in CoP/Fe–N–C, Fe site in Fe–N–C, Co site in CoP/N–C, and Zn site in CoP/Zn–N–C, respectively. (b) The differences in limiting potentials for CO₂RR (U_L (CO₂)) and HER (U_L (H₂)) on the active sites. (c) Schematic atomic structure of CO₂RR process on the Fe site in CoPc/Fe–N–C with the free energies at U = −0.7 V versus RHE. DFT calculations (copyright 2019 Wiley-VCH).⁶⁵ (d) Free energy diagrams solvation effect corrections for the CO₂RR and the HER. (e and f) Optimized atomic structures of different Ni–N structures with Ni atoms coordinated with 4 N atoms (NiN₄), 3 N atoms (NiN₃ and NiN₃V), 2 N atoms (NiN₂V₂) (copyright 2012 Science).⁶⁷.