At a specific external pressure, such as 0.26667 Pa, the system reaches a state where the balance between the enthalpy change (ΔH) and the entropy change (ΔS) results in a stable value for the Gibbs free energy. The enthalpy term, representing the heat released during the reaction, becomes more significant at higher pressures, causing the reaction to release more energy. As a result, the Gibbs free energy, which is defined in equation ( ), reaches a point where the exothermic nature of the system counteracts any entropy-driven changes. This leads to a steady or common value for ΔG, ensuring that the system remains thermodynamically favorable and efficient in hydrogen production at 0.26667 Pa. The exothermic reaction, therefore, stabilizes the Gibbs free energy at this pressure, optimizing the catalytic process.