Photoelectrolysis of glucose and fructose containing solution in PGM-free cells for hydrogen and valuable chemicals production

This study investigates the reforming of glucose and fructose by photoelectrolyis, employing TiO2 NTs photoanodes for the selective oxidation of the carbohydrates and Ni foam as cathode. TiO2 NTs with different structural features were grown on Ti felt via anodizing and annealing to promote their crystallization. These electrodes were tested in aqueous solutions at three different pH values (i.e., 2, 7, and 12) both without and with the addition of biomass. When biomass was present, the hydrogen production rate increased, reaching faradic efficiencies (FEs) ∼ 100% in spite of the use of undivided cell, allowing the simultaneous production of valuable partial oxidation compounds, such as gluconic acid (GA) and formic acid (FA), with FEs of 24% and 55% respectively, and overall quantum yields of 5.67% and 4.36% respectively. The photoanodes used demonstrated high mechanical and chemical stability under all the tested conditions, with electrode performance remaining consistent over time, allowing the reuse of the same electrode for a not limited number of runs after a mild cleaning step.The results demonstrated that this photoelectrocatalytic (PEC) process is promising for both biomass valorization and H2 production.