Abstract
NiO, CeO2 and NiO/CeO2 catalysts were prepared using ceramic and wet impregnation routes followed by calcination at 400 degrees C, respectively. The crystalline phases produced due to the calcination at the mentioned temperature were characterized by XRD measurement. The microstructure, surface and catalytic properties of the calcined products of various solids were determined by transmission electron microscope, nitrogen adsorption at -196 degrees C and catalytic conversion of isopropanol at different temperatures. The results revealed that the crystallite sizes, specific surface areas and catalytic activity of individual oxides were greater than those of binary system. The binary oxides calcined at 400 C constituted of well crystalline Ni and Ce oxides. A portion of NiO dissolved in CeO2 lattice in the binary oxides system by heating at 400 degrees C and the other portion remained as a separate phase. The dissolution process resulted in the formation of Ni-Ce-O compound with subsequent decrease in the degree of crystallinity of NiO and CeO2 phases. NiO and also CeO2 acted as dehydrogenation catalysts whereas its mixture acted as dehydrogenation and dehydration catalyst for isopropanol conversion. The activation energy of the catalytic reaction was determined for various investigated solids and was found to be dependent on the nature of the as-prepared system. (C) 2010 Elsevier Ltd. All rights reserved.