Effect of thermal treatment on various characteristics of nickel/aluminum phosphate catalysts Original Research Article

Five Ni/AlPO4 samples containing 5–50 wt.% nickel were prepared by impregnation method, calcined at 400–1000°C and reduced at 400°C. The structural properties of the samples were determined by thermal analysis and X-ray diffraction (XRD) techniques, while the adsorption of nitrogen at –196°C was used to elucidate their textural parameters. The catalytic conversion of cyclohexane on the prepThe thermal analysis of pure AlPO4 and 35 wt.% Ni/AlPO4 samples demonstrated the presence of crystalline aluminum phosphate phase. The presence of nickel greatly affected the position of exothermic peak of AlPO4 phase. The X-ray diffraction lines of the investigated samples suggest the role of both nickel content and calcination temperature on the crystallization of AlPO4 and nickel metal phases. The results of N2-adsorption indicated that the surface areas evaluated for various Ni/AlPO4 samples studied were found to decrease on increasing their nickel content and calcination temperatures. The selectivity of cyclohexane was found to depend on the nickel content and thermal treatment of the solids employed. The dehydrogenation and hydrogenolysis of cyclohexane are parallel reactions and proceed on active sites of different natures.ared solids was investigated using a pulse microcatalytic technique.