Mediating CO2 Electroreduction Activity and Selectivity over Atomically Precise Copper Clusters

Atomically precise copper clusters are highly desirable catalysts for electrocatalytic CO₂ reduction reaction (CO₂ RR) and provide an ideal platform for elaborating structure-activity relationships. However, systematic comparative studies of Cu cluster isomers for electrocatalytic CO₂ RR are lacking because they are challenging to synthesize. A group of structurally precise Cu₈ cluster isomers with different core structures (cube- and ditetrahedron-shaped) were developed and investigated for highly active and selective CO₂ reduction. Electrocatalytic measurements showed that the ditetrahedron-shaped Cu₈ cluster exhibited a higher FE_HCOOH (≈92 %) at -1.0 V and higher selectivity than the cube-shaped cluster. Theoretical investigations revealed different levels of competitiveness with the hydrogen evolution reaction on the respective core-shaped Cu₈ clusters and decreased free energies for the adsorbed HCOO* intermediates on the ditetrahedron-shaped Cu₈ clusters.