from first principles PP-I-1

PP-III-81Influence of the Way of Active Sites Formation in Pt/MgAlOx Catalysts ontheir Catalytic Properties. XPS StudyNizovskii A.I. 1 , Kalinkin A.V. 1 , Smirnov M.Yu. 1 , Belskaya O.B. 2 , Stepanova L.N. 2 ,Kazakov M.O. 21 Boreskov Institute of Catalysis SB RAS, Novosibirsk, Russia2 Institute of Hydrocarbons Processing SB RAS Omsk, Russiaalexniz@inbox.ruCatalysts Pt/MgAlO x synthesized with the use of layered magnesium-aluminum doublehydroxide (MgAl-LDH) as a support precursor are the object of intensive studies, since theyare important for the base catalysis and hydrocarbons conversion [1]. This relates primarily todehydrogenation of light alkanes. The growing demand for С 2 -С 4 alkenes in the production ofpolymers raises interest in catalytic dehydrogenation and initiates the development of newcatalytic systems.Investigation of the interaction of chloroplatinic acid as a platinum precursor with MgAl-LDHshowed that the amount of anionic complexes of Pt(IV) adsorbed from an aqueous solutionand their localization in the support structure are strongly determined by the nature ofinterlayer anions in LDH and ability of the anions to ionic exchange. Thus, the exchange ofinterlayer OH – anions for [PtCl 6 ] 2– was more pronounced as compared to that ofСО 2– 3 anions, with predominant localization of metal complex in the interlayer space. As aresult, platinum reduction under constrained conditions of the layered structure wasaccompanied by the formation of particles with unusual planar morphology [2]. As aconsequence, catalysts of the same chemical composition but prepared using LDH withdifferent interlayer anions OH – or CO 2- 3 differed in the activity of propane dehydrogenation.The localization of platinum in the structure of the support and its electronic state werestudied depending on the LDH nature by XPS with analysis of Pt3d 5/2 level using Ag L irradiation. It was found that the surface concentration of platinum decreased more than 3-foldwhen interlayer anion СО 2– 3 was replaced by ОН – at the same metal content. This observationagrees with data on the fixation of platinum complexes in the interlayer space of LDH.References:[1] V. Galvita, G. Siddiqi, P. Sun, A.T. Bell, J. Catal. 271 (2010) 209.[2] O.B. Belskaya, T.I. Gulyaeva, N.N. Leonteva, V.I. Zaikovskii, T.V. Larina, T.V. Kireeva,V.P. Doronin, V.A. Likholobov, Kinet. Catal. 52 (2011) 876.238