The efficient promoting hydrodeoxygenation of bioderived furans over Pd/HPW-SiO2 by phosphotungstic acid

Acidic promoters are significant in the hydrodeoxygenation (HDO) of bioderived furans into alkanes over metal-acid bifunctional catalysts. Here, a supported Pd/HPW-SiO2 catalyst was prepared to investigate the promotion effect of phosphotungstic acid (HPW) on the HDO of HMF-acetone adduct (H-Ac). Characterizations suggested that an intimate contact between Pd and HPW was established in Pd/HPW-SiO2. HPW promoters significantly reduced the reduction temperature of Pd oxides with enhanced hydrogenation and HDO capability. Particularly, in-situ DRIFTS confirmed that Pd-HPW sites significantly weakened the πCO η2 adsorption mode (ν3(C=O)) of C=O group on Pd surfaces. Thereby, the HDO efficiency was synergistically improved through releasing more Pd metal sites to activate hydrogen for hydrogenation and HDO with HPW promoters. Eventually, >90% yield of nonane was efficiently achieved at 160 °C. This work is applicable to explore the structure-activity relationship of bifunctional catalysts in the efficient HDO of complicated oxygenated bioderived furans.