Catalytic systems based on fiberglass woven matrices doped with metals in reaction of nitrogen oxide reduction
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Catalytic Systems Based on Fiberglass Woven Matrices Doped with Metals in Reaction of Nitrogen Oxide Reduction V. V. Barelko*, A. P. Khrushch*, A. F. Cherashev*, I. A. Yuranov*, V. A. Matyshak**, O. N. Sil'chenkova**, T. I. Khomenko**, and 0. V. Krylov** * Institute of Problems of Chemical Physics, Russian Academy of Sciences, Chernogolovka, Moscow oblast, 142432 Russia ** Semenov Institute of Chemical Physics, Russian A cademy of Sciences, Moscow, 117977 Russia ReceivedDecember23, 1998
Abstract--The results of a study of the reactions catalyzed by nontraditional fiberglass woven catalysts activated by metals or oxides, are presented. The catalytic activity of such catalysts, activated by implanting Pt, Pd, Co, or Cr, in NO reduction with carbon monoxide and propane is studied. Fiberglass catalysts containing Pt and Pd are more active than traditional catalysts. The catalysts are studied by temperature-programmed reduction (TPR), IR spectroscopy, and diffuse-reflectance electronic spectroscopy. Active sites of two kinds act on the platinum catalysts. One of them is platinum encapsulated in the glass matrix of the support. Active sites are assumed to be at the metal-support interface. INTRODUCTION The application of monolithic silicate glasses as catalyst supports has been known for a long time [1, 2]. In particular, upon further treatment, complexes or adducts of transition metals immobilized on porous glasses form clusters of metals or oxides that have catalytic properties. Porous monolithic glasses are interesting materials for catalysis. Thus, acidic treatment leads to saturation of the surface layer of the silicate component with OH groups. This makes it possible to perform "two-dimensional" syntheses on purpose and to implant necessary fragments of transition metal compounds onto the surface, with their further transformation into catalytic systems. Note that, among mineral supports, silicon dioxide glasses cause the least change in the cluster structure during heterogenization. It is also important for catalysis that silicate glass materials are more corrosion-proof in the reaction gases than the majority of traditional supports. Fiberglass is a special structural type of silicate glass. It is possible to produce fiberglass catalysts (FGC) from this material. It so happens, however, that the production of fiberglass materials (traditionally used as thermal and electric insulators and fillers in glass-reinforced plastics) has not attracted the attention of catalyst designers and manufacturers, although this technology offers advantages over classical techniques of catalyst deposition on oxide supports and traditional schemes of catalyst synthesis. The information on systematic studies of catalysis on amorphous fiberglass matrices (that is, systems similar to FGC) is scarce. In the 1970s and 1980s, a few attempts were made to apply silicon dioxide fiberglass fabric to the production of car exhaust catalysts. Three characteristic patents [3-5] published in these years
contained technological solutions concerni
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