OP-II-3

OP-I-8Results and discussion. It was revealed that for oxidized catalysts DRM occursgenerally via the associative route including interaction of activated CH x fragmentswith carbonates stabilized by cationic Pt forms at Pt-support interface. This iscertified by concomitant appearance of H 2 and CO in 1:1 ratio at the reactor outletafter switch from He stream to CH 4 +CO 2 for the first 20-30 s of transients.Progressive reduction of these cationic species by reaction feed decreases activity inCH 4 reforming while accelerating reverse water gas shift reaction catalyzed only byPt o , thus progressively decreasing H 2 /CO ratio in products. This process iscounteracted by the surface oxygen mobility supplying oxygen atoms to reduced Ptcenters thus providing their reoxidation, while generating surface oxygen vacanciesfor CO 2 dissociation.Modeling of the experimental transients with a due regard for the reaction stepsoccurring on the cationic forms of Pt, surface carbonates formation/consumption, Ptsupportoxygen spillover, and oxygen bulk diffusion was carried out. The keycharacteristics of the catalyst (the number of oxide surface active sites, Pt surfaceconcentration, characteristic length of oxygen diffusion) determined on the base ofcomputational results agree with values independently estimated by XPS, FTIRS ofadsorbed CO methods, and oxygen isotope exchange. The kinetic parameters ofbasic reaction steps occurring on this catalyst and the rates of surface/near surfaceoxygen mobility were evaluated by fitting the kinetic transients.Conclusion. Combination of experimental research and computational analysisallowed to determine important role of the cationic forms of Pt and oxygen latticemobility in catalytic properties of Pr-doped catalyst in DRM and to obtain thequantitative estimation of catalyst structure characteristics and the rates both of thelattice oxygen diffusion and main stages of the catalytic reaction.References[1]. A.M. O’Connor, Y. Schuurman, J.R.H. Ross, C. Mirodatos, Cat. Today 2006, 115, 191-198[2]. M. Garcia-Diegues, I.S.Pieta, M.C. Herrera, M.A.Larrubia, I.Malpartida, L.J. Alemany, Cat. Today2010, 149, 387[3]. N.N. Sazonova, V.A. Sadykov, A.S. Bobin, S.A. Pokrovskaya, E.L. Gubanova, C. Mirodatos,React. Kinet. Catal. Lett. 2009, 98, 35-41.[4]. E.L. Gubanova, A.C. Van Veen, C. Mirodatos, V.A. Sadykov, N.N. Sazonova, Russ. J. GeneralChem. 2008, 78, 2191.AcknowledgementsThis work was financially supported by RFBR–CNRS Project 09-03-93112, OCMOL FP7Project and SB RAS Interdisciplinary Integration Project 107.52