Electroreduction of CO_(2) to C_(2)H_(4) Regulated by Spacing Effect:Mechanistic Insights from DFT Studies

It is crucial to construct an efficient catalyst with high activity and excellent selectivity for realizing CO_(2) electroreduction reaction(CO_(2)ER)to high-value-added chemicals,especially the C2 products.Density functional theory(DFT)provides a powerful tool for investigating the promotional effect on C2 selectivity of finely tuned catalyst structures,which is currently difficult to control using experimental techniques,such as interatomic distances.In the work,5 Cu_(2)O catalyst models are constructed with different Cu-Cu atomic spacing(d_(Cu-Cu)).The results of DFT calculations show that adjusting the d_(Cu-Cu) can effectively tailor the electronic structures of active sites,enhance catalytic activity,and improve product selectivity.Specifically,the Cu atom pair spaced at d_(Cu-Cu)=2.5Åcould optimize the adsorption configuration of*CO and enhance the binding strength of*CO,thus improving*CO adsorption energy and reducing the energy barrier of C-C coupling.The work proves the feasibility of spacing effect in enhancing the C_(2)H_(4) selectivity of CO_(2) ER and provides a new idea for the catalyst modification for other reactions of polyprotons-coupled electrons.