Kinetic Properties of Oxygen Evolution Reaction Catalysis in Hematite

Water splitting is a promising method for hydrogen generation, but current catalytic reactions suffer from low efficiency. One possible reason for such inefficiency is a high kinetic barrier for water oxidation, and there is a lack of direct and efficient method to calculate the barrier for each reaction. In this paper, the inner sphere component of the reorganization energy that contributed to the activation energies is calculated. A novel algorithm is used for calculating the reorganization energy based on Marcus theory combined with the climbing image nudged elastic band method used to find transition states and activation energies of the oxygen evolution reaction steps, which allows the calculation of the activation energy at different potentials and without simulating solvation in order to obtain the inner sphere component alone arising from the reorganization of the ionic surface. The new method is tested in both acidic and basic conditions and with explicit water molecules, as well as implicit solvation. It is discovered that the reaction involving the transition of the *O intermediate into *OOH has the highest activation energy of all steps, thus explaining the high coverage of the *O intermediate found by experiments.

Automated summary

In this study, the inner sphere component of the reorganization energy that contributed to the activation energies was calculated using a novel algorithm based on Marcus theory combined with the climbing image nudged elastic band method. The new method was tested in both acidic and basic conditions with explicit and implicit solvation. It was found that the reaction involving the transition of the *O intermediate into *OOH had the highest activation energy, which explained the high coverage of the *O intermediate found in experiments.