Characteristics and Catalytic Properties of Ni/Ti-Si Composite Oxide Catalysts via CO<sub>2</sub> Hydrogenation
In the present work, the effects of Ti addition on the characteristics and catalytic properties of the different silica-based supported nickel (Ni) catalysts were investigated. The different supports, such as the spherical silica particle (SSP), MCM41, TiSSP, and TiMCM were synthesized and used to prepare the Ni catalysts having 20 wt% of Ni loading for CO2 hydrogenation under methanation. The different supports and catalysts were characterized by means of N2 physorption, XRD, SEM/EDX, XPS, TPR, and CO chemisorption. The TiO2 was present in the anatase form after catalyst calcination. The addition of Ti can play important roles on the characteristics and catalytic properties of Ni catalysts by: (i) facilitating the reduction of Ni oxides species strongly interacted with support, (ii) preventing the formation of silicate compounds, and (iii) promoting the CO and CO2 dissociation resulting in complete inhibition of the reverse water-gas shift (RWGS) reaction, especially at high temperature. Based on CO2 hydrogenation, the NiTiMCM exhibited the highest activity and stability.