Effect of the method of preparation of Ni/SiO2-MgO catalysts on decomposition of methanol.

Abstract

Since we observed in our previous work that Ni/SiO2-MgO was an efficient catalyst for decomposition of methanol to carbon monoxide and hydrogen, we have here studied the various methods of preparing the catalyst in detail. The following features have been observed. 1) The optimum SiO2 content in SiO2-MgO is about 60mol%; 2) Coprecipitation method is more effective than kneading method for preparation of SiO2-MgO; 3) Sodium silicate and magnesium nitrate are better precursors than ethyl orthosilicate and other magnesium salts; 4) Xerogel of SiO2-MgO is superior to its hydrogel; and 5) Impregnation method is more effective than precipitation, kneading, and tightly homogeneous coprecipitation methods for supporting Ni on SiO2-MgO. Effects of the method of preparation on the catalytic activity and selectivity are discussed in terms of catalyst surface area, acidity, sodium content, the amount of adsorbed hydrogen, and the diameter of Ni particles.