Efficient Photoelectrocatalytic glycerol to dihydroxyacetone synergistic hydrogen production on Co-LDH nanowires modified TiO2 nanorod arrays

The highly selective conversion of glycerol into high value-added products, accompanied by hydrogen generation, through photoelectrocatalytic technology represents an upcycling process that enhances resource utilization and sustainability. In this study, we designed a composite photoanode with a Type II heterojunction structure, Co-LDH(6 h)/TiO2, achieving a high glycerol conversion rate (1083.22 mmol·m−2·h−1) and hydrogen production rate (20.35 mmol·m−2·h−1) while maintaining a high level of DHA selectivity (48 %). Characterization revealed that the engineered Type II heterojunction significantly enhanced visible light absorption and charge separation, thereby reducing electron-hole recombination and improving the efficiency of glycerol conversion and hydrogen production. Furthermore, it was confirmed by in-situ Fourier transform infrared that the Co-LDH(6 h)/TiO2 composites exhibited significant affinity for adsorption intermediate hydroxyl group in glycerol and rapid desorption of DHA, which is a critical factor in achieving high selectivity for the oxidation pathway to DHA. Mechanistic analyses and isotopic labelling indicate that the photogenerated holes in the Co-LDH(6 h)/TiO2 photoanode are the primary active species responsible for the oxidation of glycerol, yielding a spectrum of valuable products. This research provides a novel strategy and in-depth understanding for developing efficient photoanodes for selective oxidation in organic reactions.