Catalytic hydrodeoxygenation of lignin pyrolytic-oil over Ni catalysts supported on spherical Al-MCM-41 nanoparticles: Effect of Si/Al ratio and Ni loading

Nickel modified Al-containing MCM-41 nanoparticles with Si/Al molar ratio ranging from 10 to 60 were synthesized by direct insertion of aluminum at room temperature followed by wet impregnation. The obtained materials were characterized by low and high angle X-ray diffraction (XRD), N2 adsorption/desorption isotherms, Field Emission Scanning Electron Microscopy (FESEM), energy-dispersive X-ray spectrometer (EDS), transmission electron microscopy (TEM), and NH3-TPD. Structural analyses confirmed that all the samples present a highly ordered mesoporous structure with hexagonal pore array. Acidity and pore diameter of the synthesized catalyst can be tuned by the insertion of aluminum into the framework of MCM-41 material. The synthesized catalysts were used for hydrodeoxygenation (HDO) of anisole at atmospheric hydrogen pressure. The catalyst acidity contributed the hydrogenolysis of anisole and transalkylation reaction, whereas metallic nickel sites may further hydrodeoxygenate the intermediate compounds, indicating the importance of both Ni and Al for high catalytic activity. Phenol and benzene were the major products of anisole HDO using the Ni-Al-MCM-41 catalyst. The highest anisole conversion and deoxygenation degree of 74.1 % and 43 % were obtained, respectively. The time on stream experiments showed that the catalyst is stable during 600 min reaction time.