Fig. 6: DFT-based energetic and electronic structure analysis of CO2 electrolysis.

a Gibbs free energy diagram for CO2 electrolysis over three active sites: Fe and Ru centers at SFRuM (121) surface and Fe border at RuFe@SFRuM interface (800 °C and −1.0 V). *(\({{{{{{\rm{V}}}}}}}_{{{{{{\rm{O}}}}}}}^{{{{{{\rm{\cdot \cdot }}}}}}}\)) and *(int) denote the oxygen-defected and the intact surfaces. b Corresponding local atomic configurations (top view) from CO2* (upper) to CO* (lower). c Top (upper) and side (lower) views of electron density differences of CO2 adsorption over Fe-SFRuM surface and RuFe@SFRuM interface. Yellow and cyan areas denote the accumulation and dissipation of electrons. d PDOS of active Fe and Ru centers at SFRuM surface and RuFe@SFRuM interface before CO2 adsorption. The dashed gray line marks the Fermi level and the orange block highlights the main difference of the d-band.