Arc Plasma Processing of Pt and Pd Catalysts Supported on γ-Al2O3 Powders

Direct deposition of Pt and Pd nanoparticles onto gamma-Al2O3 powders was studied by using a pulsed arc plasma process under vacuum to use them as an automotive catalyst. As deposited Pt catalyst exhibited a higher metal dispersion and thus a higher catalytic activity for CO oxidation, compared to the conventional Pt/Al2O3 prepared by wet impregnation. In contrast, Pd/Al2O3 prepared by the arc plasma method was less active because of its metallic state of Pd with a lower dispersion. A weak interaction between precious metals and gamma-Al2O3 is not enough for thermal stabilization of as deposited nanoparticles during ageing in a stream of 10% H2O in air at 900 degrees C.