SOL-GEL PREPARATION OF PT AL2O3 CATALYSTS FOR CATALYTIC COMBUSTION/

Pt/Al2O3 catalyst was synthesized by the sol-gel method starting from a mixture of aluminum sec butoxyde and platinum acetylacetonate in sec butanol. Hydrolysis and condensation processes of the precursors are induced by acetic acid addition. Thermal stability of supported platin um particles and their catalytic activity in ethane combustion were st udied. The results show that previous calcination of catalyst between 500 and 800 degrees C favours metallic dispersion likely by migration of occluded platinum in alumina matrix to the surface. Then the improv ement of dispersion and the simultaneous increase of platinum particul e size observed with samples calcined at high temperature favour the b reaking of C-C bond exalting their catalytic properties in ethane comb ustion.