Despite their promise, studies on Cu NCs for CO₂RR remain limited. The pioneering work in this field, initiated by Tang et al., demonstrated that Cu NCs exhibit formic acid (HCOOH) selectively at lower overpotentials. However, as the applied potential increases, the selectivity shifts towards the hydrogen evolution reaction (HER). They further identified that the presence of lattice hydrides in Cu NCs plays a crucial role in promoting product selectivity. However, Li et al. identified another Cu NC containing the highest metal-to-hydride ratio that predominately produces HCOOH. On the other side, Liu et al. synthesized three distinct hydrides free Cu8 NCs by systematically varying the surface-protecting ligands. These variations in ligands altered the arrangement of the metal ions, resulting in two distinct geometric structures. They discovered that twisted-cubic Cu8 NCs favored the HER, whereas ditetrahedron-shaped Cu8 NCs predominantly produced HCOOH. Thus, the above findings cumulatively identified the effect of various factors but there is no clear understanding of whether the presence of hydrides, the change in the structural architecture, and the alteration in surface ligand have any individual effect on the selectivity of the products. Expanding the understanding of ligand effects, Wu et al. revealed that the precise design of ligand structures enables Cu NCs to exhibit selective production of various hydrocarbons. Our previous research was focused on the role of structural defects in Cu NCs that significantly influence their selectivity in CO₂RR products, providing an additional parameter for optimizing catalytic performance. So, the utilization of new Cu NCs in electrochemical CO₂RR is rapidly expanding with diverse structural architectures and related properties. However, the ultimate goal of creating industrial-grade catalysts remains unmet. This highlights a significant knowledge gap concerning the precise structural features or functional groups necessary for the product selectivity. Addressing this requires comparing the catalytic efficacy of NCs with similar geometries but different ligands, as well as those with consistent ligands but distinct geometries. However, independently controlling NC geometry while maintaining uniform ligands, or modifying ligands without altering the geometry, remains challenging. Ligands coordinate metal atoms, often impacting the structural framework, making it difficult to isolate these variables. As a result, generating NCs with either uniform geometries and varied ligands or consistent ligands and diverse geometries is particularly complex, limiting precise comparisons of their catalytic performance.