A bifunctional Ni-HPMo/Fe3O4@Al-MCM-41 catalyst was prepared by impregnation method and used for the liquefaction of switchgrass in isobutanol/water mixed solvents. It was found that the introduction of Al species into MCM-41 could improve its catalytic performance of catalyst by enhancing the acidity and stability of mesoporous silica. The grafting of HPMo onto the Al-MCM-41 materials not only greatly increased the acidity but also enhanced the acid strength, with an optimal HPMo loading amount in the catalyst of 20 wt%. There was a clear effect of the catalyst on product yield and quality. A switchgrass conversion of 84.7% and a liquid yield of 55.0% could be obtained under the optimal conditions. Reuse of the catalyst indicated that it had a stable catalytic activity. Furthermore, the results showed that the isobutanol/water system was an efficient solvent for switchgrass liquefaction as well as the separation of higher heating value isobutanol phase products and lower heating value water phase products from the liquefaction mixture. This work thus offers an effective approach to improve the product yields and quality in biomass liquefaction by using metal-heteropolyacid bifunctional catalysts. (C) 2019 Elsevier Ltd. All rights reserved.