E, CO2 adsorption energy against surface iron's d-band center. F, Surface oxygen vacancy formation energies for SFM, FNR@FeO, and FeO. Reaction models for G, SFM, H, FNR@FeO, and I, FeO, incorporating CO2 adsorbate on their slab surfaces. J, Gibbs free energies for CO2 reduction on SFM, FNR@FeOx, and FeO. The inserted image shows the schematic representation of the CO2 reduction reaction over the FNR@FeOx-SFMNR catalyst.