from first principles PP-I-1

OY-III-5Studying the Influence of Precursor and Promoter on the Activity andStability of Methane Combustion CatalystsKhudorozhkov A.K., Prosvirin I.P., Bukhtiyarov V.I.Boreskov Institute of Catalysis SB RAS, Novosibirsk, Russiahak@catalysis.ruCatalytic combustion of methane, the strongest greenhouse gas, is the most effective way toreduce the emission of CH 4 and thus fulfill the current restrictions on the methaneconcentrations in the exhaust of Natural Gas Vehicles (NGV). Palladium catalysts are themost perspective ones to be used as the exhaust neutralizers in NGVs. However, seriousmodifications of such catalysts are needed because despite of high initial activity they areeasily deactivated due to high susceptibility to the concentration of catalytic poisons andwater vapor in the reaction media [1-4].It is shown in literature that the stability of palladium methane combustion catalysts can beincreased via introducing of promoters, but inconsistency of literature data makes it difficultto select the optimum catalyst structure. For example, the addition of Ni, Co and Sn oxidescan improve the catalyst tolerance to water [5, 6].The aim of this work is studying the water vapor induced deactivation of the Pd-catalystactive component. To reach this goal, influence of the Pd-precursor and promoters (Ni, Co, Ptoxides) on the stability and activity of Pd/Al 2 O 3 methane combustion catalysts in the modelreaction mixture (CH 4 +O 2 +H 2 O in Ar) with variation of reaction temperature and initial waterconcentration was studied. It was shown that the addition of Ni and Co oxides improves theactivity of Pd-catalysts, and the Pt oxides addition leads to the increase of activity andstability. The precursor influence on the catalytic properties of Pd/Al 2 O 3 catalysts was alsostudied. The active component activity and stability depend on its phase composition andox-red lability. XPS technique was used to indicate that the PdO ox-red lability stronglydepends on the concentration and type of promoter [7].References:[1] P. Briot, M. Primet, Appl. Catal. 68 (1991) 301.[2] T.R. Baldwin, R. Burch, Appl. Catal. 66 (1990) 337.[3] O. Demoulin, M. Navez, P. Ruiz, Catal. Lett. 103 (2005) 149.[4] E. Garbowski, C. Feumi-Jantou, N. Mouaddib, M. Primet, Appl. Catal. A 109 (1994) 277.[5] D. Roth, P. Gélin, E. Tena, M. Primet, Top. Catal. 16/17 (2001) 77.[6] T. Ishihara, H. Shigematsu, Y. Abe, Y. Takita, Chem. Lett. (1993) 407.[7] M.A. Mashkovtsev, A.K. Khudorzhkov, I.E. Beck et al., Catal. Industry 3 (2011) 350.98