Fig. 5: DFT calculations of the water oxidation reaction cycle.
From: Metal-hydroxyls mediate intramolecular proton transfer in heterogeneous O–O bond formation
a, The calculated Gibbs free energy profile of the WNA pathway with optimized structures of Aza-CMP–Ni. The distances at the transition states are given in Ångstroms. b, Proposed catalytic cycle for Ni sites under strong alkaline conditions, with the O–O bond formation governed by a decoupled PT–ET process. c, The calculated Gibbs free energy profile of the nucleophilic attack pathway with optimized structures of Aza-CMP–NiFe. d, Comparison of transition state configurations and corresponding activation energy; the bottom axial ligands are omitted for clarity. The pKa values of commonly used buffer components are listed at the bottom. e, Proposed catalytic cycle for Ni–Fe sites under strong alkaline conditions, with the O–O bond formation governed by the IPT-assisted APT mechanism.
