Thesis (M.Sc.)--Chulalongkorn University, 2005

Mix metal oxide catalysts of Ni/Mg/Zr were prepared by four different methods: co-precipitation (CT), citrate precursor technique (CT), modified citric acid precursor technique (MCT), modified citric acid/ethylene glycol precursor technique (MCTE). The mixed metal oxides were characterized by several techniques: X-ray diffraction (XRD), Transmission electron microscopy (TEM), Scanning electron microscopy (SEM), Energy dispersive x-ray analysis (EDX), Fourier transorm infrared spectroscopy (FTIR), Thermogravimetric analysis (TGA) and Brunauer-emmet-teller (BET). Parameters influencing the characteristics and properties of the mixed metal oxides were studied, such as Mg/Zr molar ratio, Ni content, calcinations temperature, calcinations time and additive (Sn.). It was found from the XRD results that when using Mg/Zr molar ratio at 4 and 15% wt Ni, the mixed metal oxide exists as cubic Mg-ZrO2 phase. In the CP method, calcinations was performed at lower temperature (600 ํC), it yielded oxides with surface area of 136 sq.m/g and small pore size. In the CT method in which one calcinations was performed at high temperature (800 ํC), the oxides had very low surface area and pore size. By MCT method in which two calcinations were performed, it yielded oxides with high surface area (145 sq.m/g) and large pore size. The MCTE method also yielded oxides with high surface area (144 sq.m/g). The morphology of the oxides observed by SEM showed that the oxides had spherical shape with nanosize.