The variation in Gibbs free energy (ΔG) with respect to pressure, as indicated by the provided data, highlights the interplay between temperature and entropy (equation 10, 11) in determining the thermodynamic favorability of the oxygen evolution reaction (OER). At each pressure (0, 0.1333, 0.26667, and 0.4 Pa), the ΔG values reveal how the system's energy changes during the reaction, with more negative values indicating higher thermodynamic driving forces. The results suggest that the pressure of 0.26667 Pa achieves an optimal balance, as the ΔGO2 and ΔGO values at this pressure (-0.25369 and -0.25883, respectively) are closest to zero without being overly negative, signifying an environment conducive to the fastest reaction rate for OER. Temperature and entropy effects (equation 9) play a critical role in this behavior. The Gibbs free energy equation, (Z), demonstrates that the system's spontaneity depends not only on the enthalpy change (ΔH) but also on the entropy change (ΔS), modulated by temperature (T). At elevated pressures, the system's entropy changes as the reaction involves gases like O2, which are sensitive to pressureinduced constraints on molecular motion. While higher pressures tend to favor negative enthalpy changes by increasing molecular interactions, they can also reduce entropy contributions, making ΔG less negative. This dynamic explains why, despite the generally favorable ΔG values at higher pressures, the reaction rate peaks at 0.26667 Pa, where entropy loss is minimized relative to the energy gained from enhanced interactions.