Understanding CeO₂-modified porous carbon catalyst as an efficient electrocatalyst for reduction of CO₂ reaction

Electrochemical CO₂ reduction is a promising way to synthesize value-added fuels and feedstocks from renewable energy sources. Rare earth elements is very useful in catalysis, because it has unique redox properties, special orbital structure, large ionic radius, rich electron configuration and other properties. In addition, the doping of rare earth elements can effectively improve the adsorption strength of the intermediates and provide abundant active sites for CO₂RR. In this study, Ce-ZIF nanoparticles containing cerium zeolite-imidazole skeleton (Ce-ZIF) were synthesized by growing Ce-ZIF in the space of polystyrene spherical template. Then direct pyrolysis carbonization of ordered macroporous Ce-ZIF was performed at high temperature. Thus, CeO₂(CeO₂-NC) dispersed in macroporous carbon was successfully prepared. The optimized CeO₂-NC-1100 showed excellent catalytic performance for CO products. When the potential was −0.9 V, the current density can reach 9.7 mA cm⁻², and the Faraday efficiency of CO products can reach 94.92%. Density functional theory (DFT) calculations further reveal that CeO₂-NC-1100 has no band gap for high electron conductivity, with Ce 3d orbitals serving as the core active sites for CO₂RR; the catalyst realizes synergistic adsorption of CO₂ by CeO₂ and defective carbon, reduces the energy barrier of CO₂ reduction to CO, and elevates the desorption energy barrier of H₂ to effectively inhibit the hydrogen evolution reaction (HER).These findings provide new possibilities for the preparation of rare earth modified MOF-derived ordered macroporous carbon electrocatalysts.