One-pot tandem catalytic conversion of furfural to γ-valerolactone over ZrPO-x bifunctional catalysts

The transition toward renewable energy has increased interest in γ-valerolactone (GVL) as a key energy conversion chemical and fuel additive. However, existing non-precious metal catalytic systems face challenges such as difficulty in controlling acidic sites, insufficient yield and selectivity, and poor stability in GVL synthesis. In this study, a series of ZrPO-x/Al₂O₃ bifunctional catalysts were prepared by regulating the P/Zr ratio on a mesoporous Al₂O₃ support. The catalytic performance for one-pot conversion of GVL to furfural (FF) were systematically investigated. The results showed that ZrPO-3/Al₂O₃ exhibited the best catalytic activity, achieving 100% FF conversion and a GVL yield of 64.93% at 180 °C after 10 h. Reaction condition optimization further increased the GVL yield to 81.75% at 220 °C after 24 h. The improved catalytic performance was attributed to the balanced distribution of Brønsted acid sites (P-OH) and Lewis acid sites (Zr4+/Al3+). Recycling tests demonstrated that after five cycles, the GVL yield dropped from 63.97% to 36.53%, while calcination regeneration restored the yield to 58.91%. This work demonstrates an effective non-precious metal bifunctional catalyst for GVL production from biomass-derived furfural and provides a practical strategy for improving catalyst performance through acid-site regulation.