One-pot domino conversion of biomass-derived furfural to γ-valerolactone with an in-situ formed bifunctional catalyst

γ-Valerolactone (GVL) is widely used as a green solvent and in the generation of liquid fuels. GVL can be obtained from biomass-derived furanic compounds through a cascade reaction process, which is extremely challenging due to the need for different active sites in a single pot. Here, we reported a domino conversion process of directly upgrading furfural (FF) to GVL in isopropanol over a commercially available and budget catalyst ZrCl4 that can in-situ release Brønsted acid (HCl) and Lewis acid/base species (ZrO(OH)n·xH2O). The in-situ formed bifunctional catalyst can significantly enable twice transfer hydrogenation, etherification, the ring-opening, and cyclization reactions, giving a high GVL yield of 56.5% from FF at 180°C for 6 h. In addition, the solid residues collected after reaction could be calcined to obtain t-ZrO2-(C) nanoparticles with a rough surface, in which the insoluble humin attached to the hydrolyzed solid was demonstrated to improve the layered aggregate structure of the resulting t-ZrO2-(C). Interestingly, t-ZrO2-(C) showed good performance in catalytic conversion of FF to furfuryl alcohol (FAOL) with ca. 80% yield. The developed bifunctional and recyclable catalytic system exhibits potential for one-pot multi-step biomass valorization.