Ultrafast Electron Transfer at BiVO₄-VO_x Z-Scheme Interface for Enhanced Selective Oxidation of Glycerol to...

Photoelectrochemical (PEC) selective oxidation of glycerol offers a sustainable strategy to obtain dihydroxyacetone (DHA) as a value-added chemical, which remains challenging owing to the slow kinetics and low selectivity. We construct a Z-scheme heterojunction consisting of an amorphous vanadium oxide nanolayer on BiVO₄ nanoparticles (BiVO₄-VO_x) for glycerol oxidation by a spatially confined photoelectron deposition method. BiVO₄-VO_x photoanode achieves a high DHA evolution rate of 400.4 mmol m^-2 h^-1 and a selectivity of 65.6% at 1.2 V vs. RHE. Femtosecond transient absorption spectroscopy analysis demonstrates superior charge separation efficiency and ultrafast interfacial transfer kinetics, enabling long-lived photogenerated electrons and holes accumulated in BiVO₄ conduction band and VO_x valence band, respectively. Furthermore, in situ Fourier transform infrared spectroscopy and theoretical calculations reveal that the synergy between the optimized electronic structure of amorphous VO_x and Z-scheme heterojunction promotes preferential adsorption of glycerol middle hydroxyl groups and lowers the energy barrier of the rate-determining step, thus facilitating selective DHA production. We fabricated a self-powered device with a DHA productivity of 122.0 mmol m^-2 h^-1, a H₂ productivity of 1.33 mL cm^-2 h^-1 and a solar-to-H₂ conversion efficiency of 4.7%. This work highlights the potential of heterojunction engineering for PEC biomass valorization toward value-added products.