Surface Properties and Catalytic Activity of Ni/Al_2O_3-AlPO_4 Catalysts

摘要

A series of Ni/Al_2O_3-AlPO_4 catalysts has been prepared, thereby allowing the effect of nickel content and calcination temperature on the structural and catalytic activity of such solids to be investigated. The textural parameters of all the prepared samples were determined from nitrogen adsorption studies conducted at -196 ℃, while thermal analysis methods (DTA, TGA and DrTGA) and X-ray diffraction techniques were used to elucidate their structures. Their surface acidities were measured by the amine titration method, while the conversion of isopropanol on the prepared catalysts was investigated using a pulse microcatalytic reactor. Significant changes in the structure, texture, surface acidity and catalytic activity of the prepared solids were observed as a result of varying their nickel content and calcination temperatures. Thus, XRD studies demonstrated the presence of nickel metal, nickel aluminate spinel, γ-alumina and tridymite phases while both the surface areas and the porous structures were found to depend on the metal content and calcination temperatures. The catalytic selectivity for isopropanol conversion was found to depend on the number of surface acid sites present.