Nickel supported on titania-silica: Preparation, characterisation and activity for liquid phase hydrogenation of acetophenone

Abstract

TiO 2:SiO 2 supports were prepared by impregnation of SiO 2 with an n-hexane solution of titanium tetraethoxide and were used to prepare supported nickel (20% w/w) catalysts. The supports were characterised by X-ray fluorescence (XRF), BET surface area measurements, X-ray diffraction (XRD), UV-VIS diffuse reflectance spectroscopy, and transmission electron microscopy (TEM ). The supported nickel catalysts were further characterised by hydrogen chemisorption, XRD, TEM, temperature-programmed reduction (TPR), and degree of reduction measurements. The catalysts were tested for liquid-phase hydrogenation of acetophenone. The TiO 2 : SiO 2 supports were found to have good dispersion of TiO 2 at lower loading but showed agglomeration at higher loadings and existed exclusively as anatase phase. Ni/TiO 2:SiO 2 catalysts showed strong suppression in hydrogen chemisorption similar to a Ni/ TiO 2 catalyst indicating strong metal support interaction (SMSI). The catalysts showed good activity for liquid-phase hydrogenation of acetophenone, which was comparable to Ni/TiO 2 and greater than Ni/SiO 2. Ni/7.3%TiO 2:SiO 2 showed a maximum in both catalytic activity and in the suppression of hydrogen chemisorption.