However, due to the distortion at the cationic shell and the surface ligand vacancy they showed different catalytic properties as it shapes their reactivities based on the presence of preferable catalytic sites. We observed at a potential range -0.7 to -0.9 V (vs. RHE) H2, CO and CH3OH are the primary products for Cu58-I NC (Figure and Figure ) whereas H2, CO and HCOOH for Cu58-II NC (Figure and Figure ). According to the Faradic Efficiency analysis, we observed that hydrogen evolution reaction (HER) is dominant (FEH2 > 50%) in the case of Cu58-II NC. This dominance is attributed to the higher number of defect sites with more exposed edges and vertices, making the cluster surface easily accessible for the HER reaction. In contrast, Cu58-I NC, which features a single ligand vacancy with limited distortions and exposed sites, selectively produced CH3OH with a maximum FECH3OH of ~54% at -0.7 V (vs. RHE). Comparing this with Cu58 NC, which produce only CO as the CO2RR products due to its fewer reactive sites, highlights the significant impact of structural architecture on product selectivity and efficiency in CO2RR processes (Figure and Figure ). It becomes evident that the structural configuration of Cu58-I NC exhibits a favorable propensity for CH3OH selectivity, demonstrating variability across a broad potential range. Notably, as increasingly negative potentials were applied, the selectivity for CH3OH in CO2RR gradually decreased to ~44% at -0.9 V, while the production of associated H2 and CO increased. According to the theoretical redox potentials, the formation of CO (-0.10 V vs. RHE) and H2 (0.00 V vs. RHE) requires slightly higher over potentials compared to methanol formation (0.03 V vs. RHE). These overvoltage differences likely contributed to the decrease in the formation efficiency of methanol (FECH3OH) at higher applied potentials. In addition to the NMR detection process, we further confirm the selective production of CH3OH, through a GC-MS measurement. The electrolyte after CO2RR exhibited only a peak at the same retention time (r. t. = 5.9 min) as the CH3OH introduced as the standard sample, without other CO2RR products. This peak showed a pattern with a m/z of 31, and the simulated fragment pattern based on electron ionization was consistent with that of CH3OH. (Figure ). By achieving selectivity of CO2RR products through precise control of defect-induced structural architecture, we demonstrated the exceptional catalytic activity of Cu58-I NCs. Notably, Cu58-I NCs are among a limited number of electrocatalysts capable of producing CH3OH without concurrent HCOOH generation, underscoring their unique effectiveness. To further elucidate the catalytic properties of these NCs, we investigated them through theoretical calculations in the subsequent section. In our quest to pinpoint the origin of carbon-based products, we conducted experiments by altering the feedstock source to argon (Ar) gas. Remarkably, under this condition, the detection of only H2 as a product suggests that the carbon-based products originate from the flowed CO2 feedstock rather than from impurities or contaminants in the system (Figure ).