Pt-Nb2O5-TiO2 based semiconductors for photo-reforming of glucose and fructose aqueous solutions
Muhammad Umair, Giovanni Palmisano, Reem Al Sakkaf, Samar Al Jitan, Albin Pintar, Gregor Žerjav, Leonardo Palmisano, Vittorio Loddo, Marianna Bellardita
Abstract
The conversion of biomass derivatives into fuels and valuable compounds under green conditions is increasingly attracting the attention of the scientific community. In this study, the photo-reforming of aqueous glucose and fructose solutions in the presence of 0.5 wt% Pt-loaded homemade bare and Nb2O5-TiO2 catalysts was investigated to maximize the activity of titania for both hydrogen production and valuable chemical production. The most efficient sample was the home-prepared Pt-4%Nb2O5-HP, for both glucose and fructose conversion, with the highest H2 productivity and the highest selectivity towards partially oxidized compounds. The behaviour of the Pt-4%Nb2O5-HP derives from a favourable compromise of some surface and intrinsic electronic properties as, for instance, photoluminescence, zeta potential and surface acidity. The presence of Nb2O5 decreased the recombination rate of photoproduced charges. Photo-deposition of Pt was essential for H2 production and, surprisingly, also increased the basicity of the TiO2 surface; an increase in surface acidity was measured when only niobium oxide was added, whereas stronger basic sites were observed in the simultaneous presence of Pt and niobium oxide.