Engineering Trimetallic Core-shell Nanoclusters for CO₂Electro-reduction at Low Overpotentials

Storing energy in chemical bonds and finding an electrochemical catalyst to reduce CO₂ to hydrocarbon fuels such as CH₄ would provide an ideal solution for discontinuous renewable energy sources. Commercially used pure copper catalysts are know to possess the best Faradaic yield capacity (upyo 50%) for CO₂ conversion to CH₄, however these require large overpotentials to perform this transformation. Using density functional theory (DFT), we tailor TM_xNi_13−x@Cu₄₂(TM = 3d transitionmetals; x = 3, 6, and9) nanoclusters to catalyze CO₂ electro-reduction to CH₄ with lower overpotentials than commercial catalysts. Among these, Sc₅₍₆₎Ni₈₍₇₎@Cu₄₂ possess unprecedented low overpotentials, ∼0.17 V below standard potential value (SPV). The given core compositions ensure the optimal position of d-band center of Cu, which is required for better interaction with π orbital of CHO than with CO. This results in better stabilization of CHO, giving exergonic CO reduction. Estimated statistical coverage of CHO exceeds CO by 60% at ambient conditions on Sc₅Ni₈@Cu₄₂, ensuring CO₂ conversion to high end fuel CH₄ without CO poisoning. The energetics of the reaction pathway and the overpotential values are relatively unchanged with the inclusion of implicit aqueous solvent.