Pd/SiC Exhaust Gas Catalyst for Heavy-Duty Engines: Improvement of Catalytic Performances by Controlling the Location of the Active Phase on the Support

Abstract

Medium surface area β-SiC was successfully used as support for palladium particles for the total oxidation of methane. A two-step impregnation procedure, using the dual character of the β-SiC support surface, being partly hydrophobic and partly hydrophilic in nature, led to propose that the active phase was located outside the pores of the support, compared to a conventional one step incipient wetness impregnation technique leading to palladium particles inside the porous network of the support. The specific location of the palladium active phase outside the pores improved catalytic performance when compared to the catalyst with palladium particles located inside the β-SiC porous network. The low-temperature shift observed for the light-off temperature was attributed to the higher accessibility to the active sites for methane when the palladium particles were located outside the pores of the support.