Evaluation of Active Oxygen Species Derived from Water Splitting for Electrocatalytic Organic Oxidation.

Active oxygen species (OH*/O*) derived from water electrolysis are essential for the electrooxidation of organic compounds into high-value chemicals, which can determine activity and selectivity, whereas the relationship between them remains unclear. Herein, using glycerol (GLY) electrooxidation as a model reaction, we systematically investigated the relationship between GLY oxidation activity and the formation energy of OH* (ΔG). We first identified that OH* on Au demonstrates the highest activity for GLY electrooxidation among various pure metals, based on experiments and density functional theory, and revealed that ΔG on Au-based alloys is influenced by the metallic composition of OH* coordination sites. Moreover, we observed a linear correlation between the adsorption energy of GLY (E) and the d-band center of Au-based alloys. Comprehensive microkinetic analysis further reveals a volcano relationship between GLY oxidation activity, the ΔG and the adsorption free energy of GLY (ΔG). Notably, AuPd and AuAg alloys, positioned near the peak of the volcano plot, show excellent activity, attributed to their moderate ΔG and ΔG, striking a balance that is neither too high nor too low. This research provides theoretical insights into modulating active oxygen species from water electrolysis to enhance organic electrooxidation reactions.