Nanocluster Surface Microenvironment Modulates Electrocatalytic CO 2 Reduction

Abstract The catalytic activity and product selectivity of the electrochemical CO 2 reduction reaction (eCO 2 RR) depend strongly on the local microenvironment of mass diffusion at the nanostructured catalyst and electrolyte interface. Achieving a molecular‐level understanding of the electrocatalytic reaction requires the development of tunable metal‐ligand interfacial structures with atomic precision, which is highly challenging. Here, the synthesis and molecular structure of a 25‐atom silver nanocluster interfaced with an organic shell comprising 18 thiolate ligands are presented. The locally induced hydrophobicity by bulky alkyl functionality near the surface of the Ag 25 cluster dramatically enhances the eCO 2 RR activity (CO Faradaic efficiency, FE CO : 90.3%) with higher CO partial current density ( j CO ) in an H‐cell compared to Ag 25 cluster (FE CO : 66.6%) with confined hydroph…