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

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.