In conclusion, we reported an atomically precise Cu23 NC uniquely formed by the integration of two similar Cu(I) subunits through a central Cu(0) atom. This distinct structural architecture, along with the specific arrangement of the protecting ligands, ensures the electronic and geometric stability of the NC despite the presence of a highly reactive Cu(0) center. We leveraged this remarkable stability to evaluate the electrocatalytic properties of the Cu23 NC in the CO2RR when supported on the CB surface. Our results demonstrate that the Cu23 NC exhibits selective production of HCOOH, achieving a maximum FEHCOOH of ~26% at an applied potential of -1.2 V (vs. RHE). The theoretical study identified the selectivity of this specific product through stronger intermediate adsorption and lower limiting potential values than the counterparts. Although we experienced some loss of neutral ligands during the prolonged electrochemical process, the overall stable electronic environment of the metallic architecture underscores the importance of this structural arrangement. This study not only opens new synthetic avenues for Cu NC synthesis but also directs further research towards utilizing Cu(0)-containing NC systems in practical applications.