Formation of active sites of metal catalysts; effect of additives  Page description

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Details of project

  
Identifier
37241
Type K
Principal investigator Paál, Zoltán
Title in Hungarian Fémkatalizátorok aktív helyeinek kialakulása; hozzáadott komponensek hatása
Title in English Formation of active sites of metal catalysts; effect of additives
Panel Chemistry 1
Department or equivalent Izotópkutató Intézet (MTA Kémiai Kutatóközpont)
Participants Bakos, István
Teschner, Detre
Wootsch, Attila
Starting date 2002-01-01
Closing date 2005-12-31
Funding (in million HUF) 7.896
FTE (full time equivalent) 0.00
state closed project





 

Final report

  
Results in Hungarian
Kétkomponensű katalizátor-rendszereket vizsgáltunk. Egyik esetben a (tipikusan platinához) hozzáadott komponens nemfémes, katalitikusan inaktív. Ilyen komponensek a szén, a kén és a germánium. A szén a reakció során, a szénhidrogén-reagensekből marad a felületen, helye és kémiai állapota tudatosan nem szabályozható, de XPS-sel jól követhető. Kimutattunk a hőmérséklet, a hidrogénnyomás és a reagens telített jellegének a hatását. Germániumot célzott mennyiségben vittünk be, ez ahordozós katalizátor fémkomponenséhez kötődött. Kevés Ge az aktivitást és annak stabilitását megnövelte, kisebb szigetekre osztva a felületet, ezzel akadályozva a szénlerakódást. Ugyanez érvényesült kevés kén jelenlétében is. Több Ge esetén tömbi kölcsönhatás lépett fel, ami a katalitikus tulajdonságokat rontotta. több kén pedig tömbi PtS fázist képez. A másik esetben a második, fémes komponens is aktív volt. A platina és a palládium hasonló katalitikus tulajdonságú fémek. Megfelelő reagens esetében mégis észlelni lehetett az aktivitás és a szelektivitás változását, ami az XPS-sel megfigyelt összetétellel korrelációt mutatott. A Pt-hez képest a ródium aktívabb a C–C kötés felhasításában. Kevés Rh is mutatott Rh jellegű katalitikus tulajdonságokat, ugyanakkor a Pt-ra jellemző termékösszetétel is megmaradt.
Results in English
Two-component catalytic systems were studied. First, adding a nonmetallic, catalytically inactive component was added to the parent catalyst (typically platinum). Carbon, sulfur and germanium represented these additives. Carbon was formed as a residue during catalytic reactions of hydrocarbons. Its position and chemical state on the surface cannot be controlled, but it was monitored by XPS. The effect of exposition temperature, hydrogen pressure and the saturated character of the reagent have been shown. Germanium, in turn, was introduced in controlled amounts. It was bound to the metallic component of supported catalysts. Small amounts of Ge increased the activity and catalyst stability by dividing the active surface into smaller islands, preventing this way the formation of carbonaceous overlayers. The same phenomenon appeared when small amounts of sulfur was present. Bulk interactions appeared with more Ge, this state was harmful for the catalytic properties. More sulfur formed bulk PtS phase. Another case represented adding a second catalytically active metallic component. Platinum and palladium have similar catalytic properties. Selecting an appropriate reagent permitted us to observe activity and selectivity changes, correlating with the composition monitored by XPS. Rhodium is more active in C–C bond splitting than platinum. Rh-like catalytic properties appeared even in the presence of small amounts of Rh; but products characteristic of Pt were also observed.
Full text http://real.mtak.hu/125/
Decision
Yes





 

List of publications

  
Wootsch A., Paál Z.: Hexane Dehydrogenation to Hexenes: A General Indicator for Deactivation of Pt Catalysts in ''Skeletal'' Reactions, Reaction Kinetics and Catalysis Letters 77: 355-361, 2002
Paál Z, Wootsch A, Wild U, Schlögl R: Electron Spectroscopy and Catalytic Properties of Carbonized Pt Catalysts, 6th Pannonian International Symposium on Catalysis, 2002
Paál Z, Wootsch A: Catalytic Properties of the Platinum-Hydrogen-Carbon System, Catalysis in Application, The Royal Soc. Chem. p. 8-15., 2003
Pirault-Roy L; Teschner D; Paál Z:: A new approach of selective Ge deposition for RhGe/Al2O3 catalysts: characterization and testing in 2,2,3-trimethylbutane hydrogenolysis, Applied Catalysis A: General 245 (1) 15-31, 2003
Teschner D; Pirault-Roy L; Naud D; Guerin M; Paál Z: Methylcyclopentane reactions on RhGe/Al2O3 catalysts prepared by controlled surface reaction, Applied Catalysis A: General 252 (2) 421-426, 2003
Paál Z; Wootsch A; Schlögl R; Wild U: Surface spectroscopy and catalytic properties of model platinum catalysts exposed to hydrocarbons, EUROPACAT-VI Poster No. A2.046, 2003
Pirault-Roy L; Wootsch A; Boghian-Fifere I; Descorme C; Guerin M; Paál Z: Special active sites on tailor-made Pt-Ge catalysts, EUROPACAT-VI Poster No. A2.082, 2003
Appay MD; Manoli JM; Potvin C; Muhler M; Wild U; Pozdnyakova O; Paál Z: High-Resolution Electron Microscopic, Spectroscopic and Catalytic Studies of Intentionally Sulfided Pt/ZrO2–SO4 Catalysts, Journal of Catalysis 222; 419-428, 2004
Paál Z: Carbon Accumulation on Pt Black from Hydrocarbons of Different Structure, React Kinet Catal Lett 82(2) 381-386, 2004
Wootsch A; Wild U; Schlögl R; Paál Z: Effect of K on the Deactivation of Model Pt Black Catalysts: Electron Spectroscopy and Hexane Test Reaction, Catalysis Communications 5: 419-423, 2004
Baker RTK; Rodriguez NM; Mastalir Á; Wild U; Schlögl R; Wootsch A; Paál Z: Pt/Graphite Nanofiber Catalysts of Various Structure: Characterization and Catalytic Properties, J Phys Chem. B 108 (38): 14348-14355, 2004
Wootsch A; Wild U; Schlögl R; Paál Z: Carbon accumulation, deactivation and reactivation of Pt catalysts upon exposure to hydrocarbons, Applied Catalysis, A: General, 282, 135 – 145, 2005
N. Győrffy, B. Veisz, L. Tóth; Z. Paál; D. Teschner, R. Schlögl, U. Wild, M. Bartók: Preparation, Characterization of Model Pd-Pt Catalysts and their Catalytic Properties in the Opening of the Cyclopropane Ring, Poster, No. A2.124, EUROPACAT-VI Innsbruck, 2003
Z. Paál , D. Teschner, N.M. Rodriguez, R.T.K. Baker, L. Tóth, U. Wild, R. Schlögl: Rh/GNF catalysts: Characterization and catalytic performance in methylcyclopentane reactions,, Catalysis Today, 102-103 (2005) 254 – 258, 2005
B. Veisz, L. Tóth, D. Teschner, Z. Paál, N. Győrffy, U. Wild, R. Schlögl,: Palladium-platinum powder catalysts manufactured by colloidal synthesis. I. Preparation and characterization, Journal of Molecular Catalysis, A: Chemical, 238 (2005) 56-62, 2005
N. Győrffy, L. Tóth, M. Bartók, J. Ocskó, U. Wild, R. Schlögl, D. Teschner, Z. Paál ,: Palladium-platinum powder catalysts manufactured by colloidal synthesis. II. Characterization and catalytic tests after oxidizing and reducing treatment, . Molecular Catalysis, A: Chemical, 238 (2005) 102-110, 2005
M. Chamam, A. Wootsch, K. Lázár, C. Bourry, I. Boghian-Fifere, O. Pozdnyakova, L. Pirault-Roy, Z. Paál: Characterisation of Tailor-Made Rh-Sn/Al2O3 Catalysts by Mössbauer Spectroscopy and Methylcyclopentane Ring Opening Reaction, Poster No. P2-08 EUROPACAT-VII, Sofia, 2005. aug.28-szept.1, 2005
N. Győrffy, A. Wootsch, S. Szabó, I. Bakos, O. Pozdnyakova, Z. Paál: Characterisation of Rh-Pt/SiO2 Catalysts by Methylcyclopentane Ring Opening Reaction, Poster No. P2-87 EUROPACAT-VII, Sofia, 2005. aug.28-szept.1, 2005
A. Wootsch, Z. Paál, N. Győrffy, S. Ello, I. Boghian, J. Leverd, L. Pirault-Roy: Characterization and catalytic study of Pt-Ge/Al2O3 catalysts prepared by organometallic grafting, Journal of Catalysis 238 (2006) 67-78, 2006
M. Chamam, A. Wootsch, L. Pirault-Roy, I. Boghian, Z. Paál: Methylcyclopentane transformation on Rh-Ge bimetallic catalysts prepared by organometallic grafting, Catalysis Communications, submitted, 2006
Z. Paál, A. Wootsch, I. Bakos, S. Szabó, H. Sauer, U. Wild¸: Hydrogen Effects on Intentional Carbonization of Unsupported Pt Catalyst: Physical Characterization and Catalytic Properties, Applied Catalysis A: General, submitted, 2006



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