Selective Conversion of Furfural to Furfuryl Alcohol by Heterogeneous TiO2 Photocatalysis

Abstract

Selective synthesis of furfuryl alcohol from furfural conversion via semiconductor photocatalytic route has appeared as a promising solution for transforming biomass into high-value-added products under mild temperature and pressure conditions. Titanium dioxide (TiO₂) photocatalysts were prepared by a simple sol-gel method followed by a calcination treatment ranging from 500–1000 °C, resulting in materials with distinct physicochemical properties. The photocatalytic efficiency of the TiO₂ samples was examined in the selective production of furfuryl alcohol from furfural under UV-LED irradiation. The influence of various organic solvents, including ethanol, methanol, 2-propanol, and acetonitrile, was evaluated to optimise the selectivity towards furfuryl alcohol production. Photocatalysts with larger anatase to rutile ratio and increased density of oxygen vacancies (defects) exhibited superior performance for furfuryl alcohol production. The presence of these defects on the catalyst surface leads to a significant enhancement in the photocatalytic efficiency by acting as crucial active sites. Among the TiO₂ samples, the highest conversion of furfural into furfuryl alcohol was observed with the TiO₂ sample calcined under an air atmosphere at 600 °C (TiO₂-600), achieving 85 % yield and 100 % selectivity for furfural after 30 min reaction using ethanol as solvent.