Comparative study of catalytic conversion of glucose over γ-alumina supported tungsten oxide catalysts with controlling acidity

Abstract

For the advancement of sustainable energy systems, biomass holds the potential to become a primary energy source worldwide. Glucose is one of the most economical and abundant carbohydrates, which can be converted to more value-added chemical feedstock. Here, a series of tungsten oxide catalysts supported on γ-alumina with varying tungsten content were synthesized using the wet impregnation method, and applied on the glucose conversion. The physicochemical properties of the prepared catalysts were investigated through powder X-ray diffraction, N2 sorption, scanning electron microscopy, UV-diffuse reflectance spectroscopy, and Raman spectroscopy. Pyridine-adsorption IR analysis was conducted to elucidate the acidic properties of the catalysts. As the loaded tungsten content increased, the concentration of Brønsted acid sites increased while the Lewis acid sites exhibited a decreasing trend. By controlling the acid concentration by the tungsten content, it was possible to adjust the optimal glucose conversion and the product selectivity in this cascade chemical reaction. When the tungsten content is too high, the Brønsted acid site is excessively present, and the resulting side reaction can be occurred. Here, we propose a catalyst design with appropriate acidity, which can obtain the target product with high yield.