Carrier-Dynamics-Regulated BiOI/Au/TiO₂ Z-Scheme Photoanode for Selective Glycerol Photoelectrooxidation and...

Selective conversion of biomass-derived glycerol into high-value chemicals is challenged by poor selectivity and mass-transfer limitations. Here, a BiOI/Au/TiO₂ photoanode is developed, where plasmonic Au mediators facilitate a transition from Type-II to Z-scheme charge transfer. This heterojunction preserves strongly oxidative holes on the TiO₂ surface, as confirmed by femtosecond transient absorption spectroscopy and spatially resolved MnO_x photodeposition. In situ characterizations and density functional theory (DFT) reveal that this hole-rich interface strengthens specific primary hydroxyl (pri-OH) adsorption, lowering the rate-determining dehydrogenation barrier to ∼0.6 eV. It also promotes rapid glyceraldehyde (GLAD) desorption, suppressing over-oxidation. In a static H-cell, the photoanode achieves 87% GLAD selectivity with a glycerol conversion rate of 341.25 mmol·m^-2·h^-1. To overcome diffusion limitations, computational fluid dynamics (CFD) simulations were employed to design a continuous-flow reactor for the 100 cm² large-area photoanode. The flow system prevents product accumulation, boosting GLAD selectivity from 48% (H-cell) to 77% for the large-area electrode, with enhanced glycerol conversion (60.34%) and stable 120 h operation. This work provides a laboratory scale-up by integrating nanoscale reprogramming with macroscale reactor engineering.