Catalytic Acetalization and Hydrogenation of Furfural over the Light‐Tunable Phosphated TiO2 Catalyst

Selective conversion of furfural (FUR) into value‐added chemical commodities are of significance for biomass utilization and sustainable economy. The surface solid acid active sites usually play a crucial role in the valorization of the bio‐renewable substrates. However, the co‐presence of Brønsted and Lewis acid sites on the catalyst would result in the formation of the by‐products of acetalization and hydrogenation of FUR. Herein, acetalization of FUR was realized by virtue of the Brønsted acid sites over phosphate modified amorphous TiO2 (P‐TiO2), while the Lewis acid sites take over under the light irradiation, furfuryl alcohols (FFA) received as the product of transfer hydrogenation. Thus, the by‐products were avoided by the novel strategy of light‐tunable acidity. The feature of reversible, light‐tunable acidity provides the possibility to control the reactivity and insights for the blueprint of a one‐pot tandem catalytic system. Thermocatalytic acetalization of furfural with high selectivity was realized over the phosphate modified amorphous TiO2 dominated by its Brønsted acid sites. Differently, under UV irradiation, the capability of the Brønsted acid site was restrained by the transferred proton and photo‐induced electrons. As a result, photocatalytic hydrogenation of furfural to furfuryl alcohol was achieved over the Lewis acid sites on the catalyst.