Non-quantum nanostructure-enabled hot carrier generation for enhancive photoelectrocatalytic oxidation of bio-alcohol in water coupled with hydrogen evolution

A photoelectrochemical system is a promising method for biomass valorization but is still in its infancy. Herein, a Mo–BVO–TiCoNO–CoFeOxy photoanode with a nanowire structure was prepared for the first time to efficiently convert bio-based benzyl alcohol (BA) to benzoic acid (97.7% yield) in water while coupling H2 production of 136.8 μmol cm−2. The nanowire structure enables a significant increase in the exposed active sites on the photoelectrode surface to enhance the BA oxidation capacity, whereas its large aspect ratio increases visible light absorption, and the thermal effect (resulting from the size effect) increases H2 production at the counter electrode. DFT calculations and further experiments revealed that Co species of the CoFeOxy layer functioned as stabilizers of photoelectrode properties, while Fe species acted as catalytic site providers in the BA oxidation. The analysis of steady-state photoluminescence with variable temperature showed the generation of hot carriers and conversion to photocurrent over the non-noble bimetallic material.