To gain deeper insight into the ligand effect, the difference in HER activity between the two Cu11 NCs is analyzed using LSV measurements in a phosphate buffer medium at pH 7.4. Interestingly, the Cu11ABT NC exhibited a higher current density compared to Cu11PTT NC, indicating greater efficiency of Cu11ABT NC towards the HER (Figure ). Moreover, at any fixed overpotentials, the mass-based H2 evolution activity of Cu11ABT NC was significantly superior to that of Cu₁₁PTT NC (Figure ). To understand the underlying reason for this observation, we hypothesized that the variation in HER activity might be attributed to differences in hydrophilicity stemming from the distinct ligand systems of the NCs. A drop test was conducted using carbon paper coated with the respective catalysts (Figure ). The results showed that a water droplet collapsed rapidly on the Cu11ABT NC-coated sample, indicating its higher hydrophilicity, while the droplet remained intact for an extended period on the Cu11PTT NC-coated sample, suggesting a more hydrophobic surface.