Coordination Effect of Metal Centers in Electrochemical CO₂ Reduction: A First-Principles Mechanistic Study

Recent development of single-atom or few-atom catalysts have demonstrated superior catalytic performance owing to their under-coordinated structure and unique electronic properties in contrast to their bulk counterparts. The catalytic metal centers are highly sensitive to neighboring physical and chemical environment. In this study, we have adopted transition metal dimers supported on modified graphene sheets as our model catalysts and conducted first-principles calculations for electrochemical CO₂ reduction. The coordination of these metal centers is varied in a systematic way, which in turn has a profound effect on the catalytic behavior. Their catalytic reactivity and product selectivity is discussed in light of the electronic structure, the oxidation state and the bonding feature of these metal centers. The insights provide further guidance on engineering the coordination of metal centers for purpose-driven applications.