Synergistic Effect of Metal-doped TiO2 for Glucose dehydration

Nine metal-doped titanium dioxide (TiO2) catalysts (Ti, V, Cr, Zr, Nb, Mo, Hf, Ta, 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 {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 the lattice oxygen activity of TiO2 was the key factor in enhancing catalytic efficiency.