Next, we simulated the constant potential kinetics of this rate-determining step for both nanoclusters at similar applied potentials. As depicted in Figure and In the HER rate-determining step, the RDF considers both Au(staple) and Au(surface) sites because the *H adsorption occurs at both the active Au sites. The first RDF peak corresponds to the closest interactions between the Au atoms and the hydrogen atoms of surrounding water molecules, occurring around 1.7 Å. For [Au25(SCH2COOH)17] -, the g(r) value at this peak is 3.25, whereas for [Au25(SCH2CH3)17] -, it is significantly lower at 0.98. The higher g(r) value for [Au25(SCH2COOH)17] -indicates stronger and more frequent interactions between the Au active sites and the hydrogen atoms. This can be attributed to the hydrophilic nature of the -SCH2COOH ligands, which draw water molecules closer to the Au surface, enhancing proton transfer and interaction with active sites, thereby improving the HER performance. In contrast, the lower g(r) value for [Au25(SCH2CH3)17] -reflects weaker interactions due to the hydrophobic nature of the -SCH2CH3 ligands, which repel water molecules and limit hydrogen bonding near the Au surface, thereby reducing the HER efficiency. The second RDF peak, occurring around 2.9 Å, reflects the next shell of water molecules interacting with the Au active sites. Here, the g(r) value is 5.66 for [Au25(SCH2COOH)17] -and 4.08 for [Au25(SCH2CH3)17] -. The higher and sharper peak for hydrophilic cluster indicates a more ordered and denser water structure around the Au atoms, which facilitates proton transfer and H2 formation during HER, further explaining its superior HER performance. Conversely, the less structured water network around the hydrophobic cluster hinders efficient proton transfer, limiting its HER activity.