Ni/Alumina catalysts produced by combustion synthesis

Abstract

The key step in the production of supported catalysts has been the support impregnation with the precursor of the active species, even if in cases such as the Ni/alumina catalysts, they can be produced by coprecipitation of the support and active species precursors. In this case, wet-chemical methods are used, with tight control of the process variables in order to achieve well defined chemical compositions and homogeneous distribution of the elements. A calcining step must then follow, before the catalyst is activated. Combustion synthesis is a quick, straightforward preparation process to produce homogeneous, very fine, crystalline and unagglomerated multicomponent oxide ceramic powders, without the intermediate decomposition and/or calcining steps. The present work describes the combustion synthesis of a Ni/alumina catalyst oxide precursor, and compares it with that obtained with the usual technique of an independent support impregnation step. The effect of the reaction variables on the phase formation and the characteristics of the powder produced were investigated and are also discussed.