In contrast, when a lower potential (URHE = -1.54 V) was applied, the Au-S bonds in [Au25(CH2CH3)18] -NC is completely broken (Figure ). Figure illustrates the dynamic information for [Au25(SCH2COOH)18] -NC at an applied potential of URHE = -0.98 V at 300 K in an acidic environment (pH = 0). The Au 1 (surface)-S 26 bond first rapidly breaks at around 0.12 ps with the spontaneous proton adsorption at the S site. The Au 8 (staple)-S bond then breaks at 4.54 ps, which oscillates, reattaches, and completely breaks again at 7.25 ps, remaining the bond dissociated state thereafter. This eventually results in the detachment of two Au-S bonds, and meantime, the -SR ligand combines with a proton to desorb and dissolve into the solution as HSCH2COOH molecule. A similar -SR detachment process occurs for [Au25(SCH2CH3)18] -at URHE = -1.54 V (Figure ). The proton attack is accompanied by the rapid breaking of the Au 4 (surface)-S 28 bond at around 0.18 ps. Afterwards, the Au 3 (staple)-S 28 bond breaks at 5.01 ps and again at 8.37 ps, after which the ligand with adsorbed H dissolves into the solution as free HSCH2CH3 molecule. Interestingly, it seems that the hydrophilic [Au25(SCH2COOH)18] -NC dictates faster etching dynamics in the process of ligand stripping. The faster dynamic process is further supported by the higher number of hydrogen bonds observed in the hydrophilic ligand-protected [Au25(SCH2COOH)18] -system. Specifically, about 113 hydrogen bonds were formed with the surrounding 192 H2O molecules, as shown in and] -, we constructed models that include both the explicit solvation with 50 water molecules and the implicit solvation effects. The HER testing was conducted under acidic condition at pH = 0, providing an optimal environment for hydrogen evolution. While thermodynamic calculations provide valuable insights into the feasibility of reaction steps, they often overlook the kinetic barriers that determine the rate at which these reactions proceed. To address this, we employed the slow-growth method within the framework of constrained kinetics to calculate the energy barriers associated with the rate-determining step of HER for both [Au25(SCH2COOH)17] -and [Au25(SCH2CH3)17] -. Figure and Figure depict the energy barriers as a function of the constrained variable (CV) (Figure ) at an applied potential of -0.66 V. As the constraint increases, the energy barrier rises until it peaks at the point where two hydrogen atoms-one adsorbed at the Au bridge site and the other from H3O + in the water environment-combine to form H2 and then desorb. The analysis of reaction pathway shows that the [Au25(SCH2COOH)17] -system reaches this maximum energy barrier earlier, with a free energy of 0.42 eV, indicating a lower energy requirement for the rate-determining step. In contrast, at a similar potential, the energy barrier for the HER rate-determining step in the [Au25(SCH2CH3)17] -system is higher, at 0.54 eV. ). These plots detail the ΔG associated with the four key steps of CO2RR. Notably, the reaction of *COOH → *CO + OH -exhibits the highest ΔG when the potential is higher than -1.0 V, indicating that it is the thermodynamically most challenging step. In contrast, the other three steps show lower ΔG values, suggesting that they are either spontaneous or more easily facilitated under the same potential conditions. Therefore, we conclude that the conversion of *COOH to *CO is the ratedetermining step for CO2RR in both the nanocluster systems.