Catalytic hydrodeoxygenation of anisole over nickel supported on plasma treated alumina–silica mixed oxides

Abstract

Hydrodeoxygenation (HDO) of anisole, a representative of lignin-derived bio oil, was investigated on SiO₂–Al₂O₃ supported Ni nano-particles at low hydrogen pressure. Plasma was used for the surface modification of the support. The supports and catalysts were characterized by N₂ physisorption, FT-IR spectroscopy, Temperature Program Desorption of ammonia (NH₃-TPD), X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM). The results showed that the plasma treatment improved both the SiO₂–Al₂O₃ surface characteristics and pore structure. The catalyst with a plasma treated support had a higher dispersion and smaller NiO particle size, leading to an improved hydrodeoxygenation activity and product selectivity. Phenol and benzene were the major products of anisole HDO. Demethylation, hydrodeoxygenation and transalkylation reactions are the main chemical reactions for anisole upgrading using the Ni/Al₂O₃–SiO₂ catalyst. Compared to the untreated catalyst, the plasma treated Ni/Al₂O₃–SiO₂ catalyst gives higher anisole conversion at atmospheric pressure by which valuable products were obtained with higher selectivity.