III International Conference

PP-II-161PALLADIUM CATALYSTS SUPPORTED ON SILICON NITRIDE FOR THETOTAL OXIDATION OF METHANEKurzina I.A., Cadete Santos Aires F.J. 1 , Bertolini J.C. 1Tomsk State University of Civil Engineering, Tomsk, Russia1 Institut de Recherches sur la Catalyse, 2 Av. A. Einstein, 69626 Villeurbanne cedex, FranceE-mail: ikurzina@tsuab.ruPalladium catalysts were prepared by impregnation of Pd(II) acetylacetonate in toluenesolution of silicon nitride powder and were tested in the methane total oxidation reaction. Astrong influence of the phase composition and the crystalline states of supports on thecatalytic properties of Pd catalysts was found. Pd supported on α-Si 3 N 4 is found to be themost active and stable under reaction conditions.Transition metals catalysts, especially Pd, are very active and widely used inhydrogenation processes and total oxidation of methane. Catalysts that are used for thisreaction are generally supported on different refractory materials. The high thermalconductivity of silicon nitride, especially at high temperatures, could be useful to createthermostable catalysts. The objective of this work is to study the influence of the Si 3 N 4support nature and of the chemical compounds used for preparations on the physicalchemistryand catalytic properties of the palladium systems in the total oxidation of methane.In order to investigate the influence of the phase-structural state of silicon nitride on thecatalytic properties of Pd, three kinds of silicon nitride were used as supports in this work:amorphous silicon nitride (SiN-am); amorphous silicon nitride annealed at 1450 o C for 2hunder nitrogen flow (SiN-annl) and α-Si 3 N 4 . The Pd catalysts were prepared by impregnationof the silicon nitride supports with adequate amounts of Pd(II) bis acetylacetonate dissolvedin toluene [1]. In order to determine the influence of the used solvents on the physical –chemical properties of the Pd deposited on α-Si 3 N 4 , two samples were prepared byimpregnation of the supports using Pd (II) acetate dissolved in water and toluene (Pd/α-Si 3 N 4 –wat; Pd/α-Si 3 N 4 –tol). All catalysts had about the same amount of the loaded Pd (near0.5 wt %).It was established that the preparation of Pd catalysts by impregnation Pd(AcAc) 2 onsilicon nitride supports (SiN-am, SiN-annl, α-Si 3 N 4 ) leads to the formation of nanosized metalparticles (3 – 6 nm). Palladium catalysts show different catalytic activity for the totaloxidation of methane. For the as-prepared catalysts it increases with the α-Si 3 N 4 content and462