Investigation of the Effect of Alumina Phase on Adsorption and Distribution of Nano Pd Catalyst in Combustible Gas Detection

Alumina is the most widely used as a remarkable choice for noble metal catalyst support applications in combustion of hydrocarbon gases due to its high thermal stability and Lewis acid sites on its surface. Variable features of ceramic support influence on adsorption, distribution and also formation of appropriate phase of catalyst which result in sufficient gas detection. To prepare Pd/Al2O3, acidic solution includes 5% mole Pd was impregnated in aqueous suspension of alumina powder. This composition was calcined in air in 500 ℃. The as-prepared materials was characterized by scanning electron microscopy (SEM), nitrogen adsorption (BET) and X-ray diffraction (XRD). Dynamic gas test also was done to observe the catalyst performance followed by noble metal components reduction. According to the gas test results, catalytic characteristics of metal components promoted as alumina surface area increased. Alumina particle size under 50 nm was found to be efficient in order to ensure suitable sensitivity of catalyst to oxidize combustible gases.