Light-induced selectivity of photoelectrochemical glycerol oxidation using BiVO4 photoanodes

The photoelectrochemical (PEC) glycerol oxidation reaction (GOR) provides a sustainable route to convert biomass waste into value-added chemicals, but controlling product selectivity remains a key challenge. In this study, we show that light intensity influences PEC GOR selectivity on BiVO 4 photoanodes. Increasing illumination from 5 to 100 mW/cm 2 shifts the reaction from partial oxidation products—glyceraldehyde (GLAD), glycolaldehyde (GCAD), and dihydroxyacetone (DHA)—toward the deeply oxidized product formic acid (FA). Frequency-resolved measurements, including intensity-modulated photocurrent spectroscopy and PEC impedance spectroscopy, reveal that higher light intensities enhance surface hole accumulation and interfacial charge transfer, enabling multi-electron oxidation pathways. Control experiments further elucidated the reaction mechanism, identifying GLAD as the primary precursor to FA and GCAD as a secondary intermediate that is further oxidized under higher illumination. These findings provide important insights into the selective control of the PEC GOR, offering a potential strategy for optimizing product distribution in solar-driven biomass valorization and chemical synthesis.