Highly selective aerobic oxidation of biomass alcohol to benzaldehyde by an in situ doped Au/TiO2 nanotube photonic crystal photoanode for simultaneous hydrogen production promotion

Abstract

Photoelectrocatalytic conversion of biomass and its derivatives is a very significant and promising strategy for energy production. The selective oxidation of biomass alcohol to the corresponding aldehydes is an important class of biomass conversion reactions. In this study, a Z-scheme type solar-driven dual photoelectrode photoelectrochemical cell was used for the simultaneous selective oxidation of benzyl alcohol, which was a model biomass alcohol to benzaldehyde reaction, for hydrogen production promotion using Au/TiO₂ nanotube photonic crystals (Au/TiO₂ NTPC) as the photoanode. The results show that the Au/TiO₂ NTPC photoanode exhibits excellent photoelectrochemical performance and can efficiently conduct charge transport. The conversion of benzyl alcohol is as high 84.68%, whereas selectivity can reach more than 99%. The high conversion rate is attributed to the improvement in the photoelectrocatalytic performance due to the in situ doping of Au nanoparticles. In addition to the Au nanoparticles, O₂ is an indispensable factor for the high selectivity. The simultaneous hydrogen production at the cathode can reach 143.83 μmol cm⁻². The results show that the anodic oxidation reaction can promote hydrogen production and the hydrogen production efficiency increases with the oxidation rate. This model reaction can also be applied to a series of biomass alcohol selective oxidations. This study achieves simultaneous efficient selective access to hydrocarbon fuels and hydrogen and reveals a novel, sustainable and green energy production idea and direction for development.