Fig. 4. Schematic diagrams of the proposed OER and EOOR pathways and Gibbs free energy steps under two conditions.

The proposed OER and EOOR pathways with shared initial steps (a) and schematic illustration of the electrochemical generation of Co^3+δ/Ni^3+δ−OH* species during OER and EOOR, and the Gibbs free energy steps under the two conditions. b The vital fast-kinetic electron transfer step (marked in red) and free energy steps during OER. c The vital fast-kinetic electron transfer step and altered free energy steps (marked in red arrow) during EOOR, under the influence of organics oxidation. The dark blue, red, and white balls represent the metal site, oxygen, and hydrogen atoms, respectively. “R” represents the organic substance, “P” represents the oxidation product and superscript “*” indicates the adsorbed species.