Fig. 5: DFT calculations on the Fe−N catalyzed CO2RR.

a The electronic density of states and d-band centers of Fe in the FeN, Fe3N, and FeN/Fe3N structures. The electrostatic potential for adsorption of COOH b and CO c on the FeN/Fe3N interface. 3D electron density difference distributions for adsorption of COOH d and CO e on the FeN/Fe3N interface. The electron localization for adsorption of COOH f and CO g on the FeN/Fe3N interface. h Schematic reaction CO2RR to CO pathway projected on the FeN/Fe3N surface. i The calculated Gibbs free energy diagrams for CO2RR on the FeN, Fe3N, and FeN/Fe3N surfaces.