Hydrodeoxygenation of phenol as a bio-oil model compound over intimate contact noble metal–Ni2P/SiO2 catalysts

Abstract

This study investigates phenol hydrodeoxygenation on supported Ni₂P, prepared via the sol–gel and TPR methods, and noble metal (Pd, Pt and Ru)–Ni₂P catalysts, prepared from Ni₂P by the partial in situ reduction of a noble metal precursor. 10% Ni₂P/SiO₂ had a relatively uniform distribution of Ni₂P nanoparticles and a highly active activity for phenol hydrodeoxygenation. Phenol conversion increased with increasing reaction temperature and the main products on noble metal–Ni₂P/SiO₂ also changed from cyclohexanol at 453 K to cyclohexane at 493 K. In comparison with supported Ni₂P or noble metal catalysts and their physical mixture, Pd–Ni₂P/SiO₂ presented the highest conversion activity and cyclohexane selectivity. Physicochemical characterization showed that the number of active sites on the catalysts increased and electron transfer occurred from Ni₂P to the noble metal due to the intimate contact between Ni₂P and the noble metal. A synergistic effect of the deoxygenation and carbonyl hydrogenation from Ni₂P and the hydrodeoxygenation from Pd resulted in an improvement of the catalytic activity and differences in the selectivity of the catalysts.