Metán aktiválás új módszere: nemes fémmel promoveált Ga-HZSM-5 katalizátor alkalmazása N2O jelenlétében
Title in English
Novel method in methane activation: noble metal modified Ga-HZSM-5 in the presence of N2O
Panel
Chemistry 2
Department or equivalent
Institute of Isotopes, Hungarian Academy of Sciences
Participants
Guczi, László Horváth, Anita Koppány, Zsuzsanna
Starting date
2003-01-01
Closing date
2007-12-31
Funding (in million HUF)
7.996
FTE (full time equivalent)
0.00
state
closed project
Final report
Results in Hungarian
H-ZSM-5 zeolitból kiindulva gallium ioncserével Ga/H-ZSM-5, valamint második fém
(M- Fe, Co, Mo, Ag, Au) vegyületéből impregnálással egyfémes M/H-ZSM-5 és kétfémes M/Ga/H-ZSM-5 katalizátor sorozatot állítottunk elő. A mintákat XRF, XRD, XPS, TPR, TPD, TPSR, TPReact, NH3 lépcsőzetes termo-deszorpció (STD-NH3), Mössbauer spektroszkópia (Fe tartalmú minták esetén), TEM, valamint kinetikus módszerekkel vizsgáltuk.
A Ga bevitel növeli a H-ZSM-5 savas centrumainak erejét és számát, a második fém hatására pedig a Ga/H-ZSM-5 erős savas centrumai pedig a M/Ga/H-ZSM-5 minták oxidációs centrumaivá generálódnak. A M/Ga/H-ZSM-5 katalizátorcsalád legjobb mintáin az N2O bontás, valamint a CH4+N2O reakció reaktánsainak 50 %-os konverziójának hőmérséklete 70-160 K-nel csökken a folyamat közismerten legjobb katalizátorához viszonyítva. N2O bomlásakor az erős redox centrumokon nitrogén és oxigén keletkezik. Az oxigén atomok kisebb hányada beépül a zeolit felületbe (Oa), nagyobbik része pedig rövid életű köztes állapotú atomi oxigén (nascent oxygen) formájában reagál a metánnal. Az N2O és CH4 közötti reakció összetett oxigén átviteli mechanizmus alapján megy végbe, amely szerint a N2O nem közvetlenül reoxidálja a katalitikusan aktív centrumokat, hanem MGa-OCH3 összetételű szpecieszekkel reagálva. A katalizátor szerkezetbe beépült Oa oxigén biztosítja a M/Ga/H-ZSM-5 minták kis hőmérsékletű (323-373 K) extra aktivitásának alapját.
Results in English
Monometallic M/H-ZSM-5 and bimetallic M/Ga/H-ZSM-5 (M- Fe, Mo, Co, Ag, Au) catalysts were prepared by impregnation of H-ZSM-5 and H-ZSM-5 modified by Ga ion exchange, respectively, with M-precursor. The samples were investigated by XRF, XRD, XPS, TPR, TPD, TPSR, TPReact, stepped NH3 desorption (STD-NH3), Mössbauer spectroscopy (in case of Fe containing samples), TEM and kinetic methods.
Introduction of Ga increases the strength and number of acidic sites in H-ZSM-5, on the effect of the second metal addition the strong acid centres of Ga/H-ZSM-5 transform into the strong redox sites of M/Ga/H-ZSM-5. On the best performing samples of the M/Ga/H-ZSM-5 catalyst family the temperature of the 50% conversion (T50) in N2O decomposition and CH4+N2O reaction is lower by 70 and 160 K, respectively, than that on the catalysts regarded recently as the most active in these processes. N2O decomposition on the strong redox sites produces nitrogen and oxygen. A smaller part of atomic oxygen is accommodated on the zeolite surface, the larger part of short life time transient atomic oxygen reacts with methane producing MGa-OCH3 species. The reaction between N2O and CH4 takes place via complex oxygen transfer mechanism. N2O does not reoxidize the reduced active sites directly, but reacting with the MGa-OCH3 species. The oxygen accommodated on the catalyst surface plays key role in the low-temperature (323-373 K) extra activity of M/Ga/H-ZSM-5.
L Borkó; L Guczi: Non-oxidative methane transformations into higher hydrocarbons over bimetallic Pt-Co catalysts supported on Al2O3 and NaY, Top. Catal 39: 35-43, 2006
L Borkó; L Guczi: Non-oxidative methane transformations: effect of catalyst and pressure, In: 6th European Congress on Catalysis: Abstract on CD-ROM, Innsbruck: 2003, A3.077. 2pp, 2003
L Borkó; L Guczi: Middle pressure methane conversion into C2 hydrocarbons on supported Pt-Co catalysts, In: 7th Natural Gas Conversion Symposium, Dalian: 2004. pp. 287-288, 2004
L Borkó; L. Guczi: Middle pressure methane conversion into C2 hydrocarbons on supported Pt-Co catalysts: role of platinum, Stud. Surf. Sci. Catal.(X.Bao and Y. Yu Eds.) 147: 601-606, 2004
L Borkó; L Guczi: Non-oxidative methane transformations on supported Pt-Co catalysts: role of platinum, In: 13th International Congress on Catalysis, Programme and Abstracts on CD-ROM, Paris: 2004, 2pp., 2004
L Borkó; Zs. Koppány; Z. Schay; L Guczi: Novel method in methane activation: oxidative transformations on Mo/Ga/HZSM-5 catalyst in presence of N2O, In: 7th European Congress on Catalysis, "Catalysis: a Key to Richer and Cleaner Society", Extended abstracts and programme on CD-ROM, Sofia: 2005, P-10-31, 2pp., 2005
L Borkó; Zs. Koppány; Z. Schay; L Guczi: Oxidative transformation of methane on Mo/Ga/HZSM-5 catalyst in presence of N2O, In: 5th World Congress on Oxidation Catalysis, ''Innovations in Oxidation Catalysis Leading to a Sustainable Society'', Sapporo: 2005, p. 394-395, 2005
L. Guczi; G. Stefler; L. Borkó; Zs. Koppány; F. Mizukami; M. Toba; S. Niwa: Re-Co bimetallic catalysts prepared by sol/gel technique: characterization and catalytic properties, Appl. catal. 246: 79-86, 2003
L. Borkó; Z.E. Horvath; Z Schay; L. Guczi;: The role of carbon nanospecies in deactivation of cobalt based catalysts in CH4 and CO transformations, Stud, Surf. Sci. Catal. (M. Schmal, F. B. Noronha and E. Falaballa) 167: 231-236, 2007
L. Borkó; N.V. Vlasenko; Zs. Koppány; Z. Schay; P.E. Strizhak; L. Guczi: Acid-redox transformation in Fe/Ga/H-ZSM-5 catalyst generating highly active sites in reaction between the nitrous oxide and methane, In: 8th European Congress on Catalysis,'' From theory to industrial praktice'', Extended abstracts and programme on CD-ROM, Turku/Abo: 2007, P-2-149, 2pp., 2007
L. Borkó; N.V. Vlasenko; Zs. Koppány; Z. Schay; P.E. Strizhak; L. Guczi: Generating of highly active redox sites in reaction between N2O and CH4 from acidic centers of Me/H-ZSM-5 and Me/Ga/H-ZSM-5 (Me-Fe, Co, Mo) catalysts, In: 14th International Congress on Catalysis '' Catalysis as the Pivotal Technology for the Future Society'', Book of Abstracts, 2pp., közlésre elküldve., 2008
L. Borkó; Z.E. Horvath; Z Schay; L. Guczi;: The role of carbon nanospecies in deactivation of cobalt based catalysts in CH4 and CO transformations, 8th NGCS, Book of abstracts, IBP, Natal, 2007, O 036, 159-160, 2007
L Borkó; Zs. Koppány; Z. Schay; L Guczi: Novel Mo/Ga/HZSM-5 catalyst in environmentally important reductive transformation of N2O in the presence of CH4, Top. Catal., közlésre elküldve, 2008
