Investigation of catalytic hydrodeoxygenation of anisole as bio-oil model compound over Ni-Mo/TiO2 and Ni-V/TiO2 catalysts: Synthesis, kinetic, and reaction pathways studies

This work investigates the catalytic hydrodeoxygenation (HDO) of a model component (anisole) of lignocellulose biomass over Mo- and V-promoted Ni deposited on titania support. The physico-chemical properties of each material were elucidated, and reactions were studied over a wide range of temperatures to enable examination of kinetic parameters. Crystallite sizes were estimated and were corroborated strongly by the transmission electron microscopy results. The presence of Ni, Ti, Mo, and V species was confirmed through X-ray photoelectron spectroscopy (XPS). Significant HDO activity for both the catalysts could be attributed to high dispersions of metals and acidic sites, which were affected by the interaction between Ni metal and the titania support. The higher activity of Ni-Mo/TiO2 may have resulted from the high Ni/Ti surface atomic ratio, which was confirmed by XPS. The major product of the anisole HDO reactions was phenol. Interestingly, a considerable amount of benzene and cyclohexane was also noticed in the anisole HDO reaction. The overall activation energy values for anisole reactions over Ni-Mo/TiO2 and Ni-V/TiO2 were 80.9 kJ/mol and 53.9 kJ/mol, respectively.