Hydrodeoxygenation of lignin-derived phenoic compounds to hydrocarbon fuel over supported Ni-based catalysts

Ni-based catalysts supported on γ-Al2O3 and SiO2 were prepared by impregnation. Catalyst characterization was performed using XRD, NH3-TPD, H2-TPR and chemisorption. Effects of supports on catalytic performance were tested using the hydrodeoxygenation (HDO) of phenolic compounds as a model reaction. Experiment result shows that single phenolic compounds can be converted via HDO reaction over Ni/SiO2 and Ni/γ-Al2O3 catalysts at 300 °C. The hydrocarbon yields are in the range of 60-90%. The effect of supports on the reaction mechanism was also explored. It is found that hydrogenation of the aromatic ring preferentially occurs over Ni/SiO2 catalyst while the cleavage of CARO bond preferentially occurs over Ni/γ-Al2O3 catalyst in the HDO of phenol. Compared to Ni/γ-Al2O3 catalyst, Ni/SiO2 catalyst exhibits better repeatability and higher catalytic activity for hydrocarbon yield when mixed phenolic compounds were used as feedstock in the HDO reaction, and the carbon deposited on the surface of Ni/SiO2 catalyst is lower.