Characterization of rice husk ash-supported nickel catalysts prepared by ion exchange Original Research Article

The rice husk ash-supported nickel catalysts prepared by ion exchange technique and the support itself have been characterized by transmission electron microscopy (TEM) and X-ray diffraction (XRD). In addition to BET surface area, total pore volume and average pore diameter were also measured. The metal surface area and the crystal size of nickel were measured by the selective chemisorption of hydrogen. The effect of calcination temperature on the catalyst reduction was investigated by the temperature-programmed reduction (TPR) technique. The results show that nickel silicate with a layer structure formed after drying step. The BET surface area increases with the nickel loading of the catalyst. The nickel surface area increases with nickel loading up to 16.7 wt.% Ni and then decreases with further increase in nickel loading. The dispersion of nickel gradually decreases with nickel loading. Furthermore, the mean size of nickel crystallites increases with nickel loading. The reduction temperature increases with the increase of calcination temperature. Reduction of NiO from the thermal decomposition of the layered nickel silicates is found to be unusually difficult.