Defect-rich ZrO2 anchored Pd nanoparticles for selective hydrodeoxygenation of bio-models at room temperature

The hydrodeoxygenation (HDO) of biomass-derived compounds into high-quality fuels and chemicals is an effective solution to the fossil energy shortage. However, the development and design of catalysts with high-performance HDO under mild reaction conditions is a significant challenge. In this paper, the defect-rich ZrO2 anchored Pd nanoparticles was investigated for selective HDO of bio-models at room temperature. The oxygen vacancies of Pd/ZrO2(x) catalysts can be regulated by the addition of template agent cetyltrimethylammonium bromide (CTAB), in which CTAB combines with OH on the support to form complex oxides and then promoting the formation of Zr3+-Ov-Zr4+ structure of the as-prepared Pd/ZrO2(x) catalysts. When the mass ratio of CTAB/ZrOSO4 is 0.5, the Pd/ZrO2(0.5) catalyst with the highest oxygen defect content exhibits excellent performance towards 99.9% yield of 2-methoxy-4-methylphenol (MMP) at 25 °C for one hour in vanillin HDO. The rich oxygen vacancies of Pd/ZrO2(x) catalysts can regulate the electronic structure of the catalyst surface metal palladium and zirconium, and promote the adsorption and hydrogenolysis of C-O in vanillin HDO. In addition, it is obviously that the catalysts had excellent versatility and stability, and the MMP selectivity of the Pd-ZrO2(0.5) catalyst slightly decreased after five consecutive reactions.