Synergistic effect of metal-doped TiO2 for glucose dehydration

Abstract

Nine metal-doped titanium dioxide (TiO₂) catalysts (Ti, V, Cr, Zr, Nb, Mo, Hf, Ta and W) were synthesized via a gel precipitation method, and their catalytic performance for the dehydration of glucose to 5-hydroxymethylfurfural (5-HMF) in a biphasic system was systematically investigated. Using characterization techniques such as XRD, BET, NH₃-TPD, TGA and XPS, the regulatory mechanisms of metal doping on the crystal structure, surface acidity and oxygen species distribution of TiO₂ were elucidated. Experimental results demonstrated that niobium-doped TiO₂ (Nb–TiO₂) exhibited the highest 5-HMF yield (25.1%), attributed to the synergistic exposure of the {101}, {210} and {201} crystal facets, an optimized ratio of Lewis to Brønsted acid sites and a high concentration of active oxygen species. Furthermore, by comparing the catalytic performance of different metal-doped systems, it was confirmed that the synergistic effect between the electronic structure of the metal and TiO₂ was the key factor in enhancing catalytic efficiency.