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Titolo:
Pd/Al2O3-La2O3 catalysts prepared by sol-gel: characterization and catalytic activity in the NO reduction by H-2
Autore:
Barrera, A; Viniegra, M; Bosch, P; Lara, VH; Fuentes, S;
Indirizzi:
Univ Autonoma Metropolitana Iztapalapa, Dept Quim, Mexico City 09340, DF, Mexico Univ Autonoma Metropolitana Iztapalapa Mexico City DF Mexico 09340 Mexico UNAM, Ctr Ciencias Mat Condensada, Ensenada 22800, Baja California, MexicoUNAM Ensenada Baja California Mexico 22800 22800, Baja California, Mexico
Titolo Testata:
APPLIED CATALYSIS B-ENVIRONMENTAL
fascicolo: 2, volume: 34, anno: 2001,
pagine: 97 - 111
SICI:
0926-3373(20011105)34:2<97:PCPBSC>2.0.ZU;2-J
Fonte:
ISI
Lingua:
ENG
Soggetto:
AUTOMOTIVE PALLADIUM CATALYSTS; METAL SUPPORT INTERACTIONS; ONLY CATALYSTS; CO; ADSORPTION; DECOMPOSITION; AL2O3-LA2O3; DESORPTION; PD/LA2O3; PD/SIO2;
Keywords:
texture; structure; particle-size distribution; reducibility; metal-support interaction; NO reduction by H-2; Pd; La2O3; Al2O3;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Physical, Chemical & Earth Sciences
Engineering, Computing & Technology
Citazioni:
37
Recensione:
Indirizzi per estratti:
Indirizzo: Viniegra, M Univ Autonoma Metropolitana Iztapalapa, Dept Quim, Postal 55-534, Mexico City 09340, DF, Mexico Univ Autonoma Metropolitana Iztapalapa Postal 55-534 Mexico City DF Mexico 09340
Citazione:
A. Barrera et al., "Pd/Al2O3-La2O3 catalysts prepared by sol-gel: characterization and catalytic activity in the NO reduction by H-2", APP CATAL B, 34(2), 2001, pp. 97-111

Abstract

The 0.3%Pd/Al2O3-La2O3 (0, 6 and 15 wt.% La2O3) catalysts prepared by the sol-gel method were studied by N-2 physisorption, X-ray diffraction (XRD), small angle X-ray scattering (SAXS), and temperature-programmed reduction (TPR). The catalysts were tested in the reduction of NO by H-2. Results indicate that the texture and structure of Pd catalysts are modified by the addition of lanthana. The TPR profiles of the catalysts show reduction peaks at 100 and 150 degreesC, suggesting that the reduction of crystalline PdO occurs in two stages: first to Pd2O, and then to Pd-0. After recalcination ofthe samples, the reducibility properties are modified. One reduction peak appears at 360 degreesC that can be assigned to the presence of a more stable surface PdO phase interacting strongly with lanthana species. The presence of metallic Pd and Pd3La alloy species in the Pd/Al2O3-La2O3 catalysts was detected after reduction at high temperature. These species present particle sizes of 77 and 130 Angstrom. Pd3La alloy species are present also as crystallites of 20 Angstrom. The modification of the reducibility properties of the catalysts influences the activity in the NO reduction by hydrogen. The selectivity depends on the extent of interaction between Pd and lanthana reduced species. For the Pd/Al2O3-La2O3 catalysts, the selectivity to N2is high at temperatures lower than 250 degreesC. The strong interaction between Pd and lanthana species, forming Pd3LaOx species, may be responsible for the increase in activity and selectivity to N-2. (C) 2001 Elsevier Science B.V. All rights reserved.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 28/11/20 alle ore 03:44:41