Electrocatalytic conversion of CO₂ to CH₄ over Cu-based cluster via atomically precise local environment modulation

The development of low-cost, high-performance catalysts at the atomic scale has become a challenging issue for the large-scale applications of renewable clean energy technologies. Herein, on the basis of density functional theory calculation, we systematically investigate the effect of the local environment on the activity and selectivity of electrochemical carbon dioxide reduction reaction over single/multi-atom alloy clusters formed by the transition metal (Fe, Co, and Ni)-doped Cu13/55 clusters. Our findings reveal that the catalytic performance of multi-atom alloy clusters far exceeds that of Cu (211) surface. Notably, the Co666 configuration exhibits exceptional performance with a remarkably low free energy barrier of just 0.33 eV. Furthermore, our investigations demonstrate that catalytic performance is predominantly determined by the relative proportion of modifying metallic dopant species that generate a coordination number of 6. This ratio principally influences the adsorption strength of key intermediates (HCOO* and H₂COO*). Bader charge analyses and free energy calculations elucidate a new mechanistic pathway, wherein the hydrogenation of CO₂ at C-sites catalyzes the reduction of CO₂ to CH₄. This theoretical research provides valuable insights into the fundamental processes and energy landscapes involved in converting CO₂ to CH₄ on the studied catalytic structure, potentially paving the way for more efficient and sustainable carbon dioxide utilization strategies.