Heterojunction-Engineered Photoelectrocatalytic Glycerol Oxidation Coupled with On-Site H2O2 Production

The selective oxidation of biomass-derived compounds is a cornerstone of sustainable chemical production, offering pathways to integrate renewable energy into industrial processes. In this work, we present the first proton exchange membrane (PEM) photoelectrochemical (PEC) flow cell for simultaneous glycerol valorization and hydrogen peroxide (H₂O₂) production. Bi₂O_2.33/TiO₂ (BO-x/TO, x = 1, 2, and 3) heterostructures were optimized as advanced photoanodes to achieve selective glycerol oxidation to dihydroxyacetone (DHA) at a low bias of 0.45 V vs. RHE. The optimized BO-2/TO photoanode demonstrated a photocurrent density of 1.2 mA cm^–2, achieving a DHA yield of 1680 mmol m^–2 h^–1 with 49% selectivity. Mechanistic insights revealed that the incorporation of BO not only selectively activates the middle hydroxyl group of glycerol but also enhances the generation of hydroxyl radicals (•OH), which are critical for promoting selective oxidation to DHA while suppressing overoxidation pathways. Simultaneously, the cathode yields H₂O₂ on-site and enhances the overall system performance. This innovative integration of PEM technology with PEC systems establishes a scalable and energy-efficient platform for biomass valorization, bridging the gap between green chemistry and renewable energy and setting a new benchmark for sustainable chemical transformation.