Ligand-Dependent Intracluster Interactions in Electrochemical CO Reduction Using Cu Nanoclusters.

The electrochemical CO reduction reaction (CORR) has been extensively studied because it can be leveraged to directly convert CO into valuable hydrocarbons. Among the various catalysts, copper nanoclusters (Cu NCs) exhibit high selectivity and efficiency for producing CORR products owing to their unique geometric/electronic structures. However, the influence of protective ligands on the CORR performance of Cu NCs remains unclear. In this study, it is shown that different thiolate ligands, despite having nearly identical geometries, can substantially affect the electrochemical stability of Cu NCs in the CORR. Notably, Cu NCs protected by 2-phenylethanethiolate exhibit greater stability and achieve a relatively higher selectivity (≈40%) for formic acid production compared with the cyclohexanethiolate-protected counterpart. These insights are crucial for designing Cu NCs that are both stable and highly selective, enhancing their efficacy for electrochemical CO reduction.