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Titolo:
STRUCTURAL-PROPERTIES OF PD CATALYSTS SUPPORTED ON AL2O3-LA2O3 PREPARED BY SOL-GEL METHOD
Autore:
BOGDANCHIKOVA NE; FUENTES S; AVALOSBORJA M; FARIAS MH; BORONIN A; DIAZ G;
Indirizzi:
UNAM,CTR CIENCIAS MAT CONDENSADA,AP 2681 ENSENADA 22800 BAJA CALIFORNIA MEXICO CICESE ENSENADA BAJA CALIFORNIA MEXICO RUSSIAN ACAD SCI,INST CATALYSIS NOVOSIBIRSK 630090 RUSSIA UNAM,INST FIS MEXICO CITY DF MEXICO
Titolo Testata:
Applied catalysis. B, Environmental
fascicolo: 3, volume: 17, anno: 1998,
pagine: 221 - 231
SICI:
0926-3373(1998)17:3<221:SOPCSO>2.0.ZU;2-8
Fonte:
ISI
Lingua:
ENG
Soggetto:
PALLADIUM; ALUMINA; CLUSTERS; STATE; H-2; CO;
Keywords:
PD/AL2O3-LA2O3 CATALYSTS; SOL-GEL PREPARATION METHOD; XRD; HRTEM; XPS; NH3 PRODUCTION;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Science Citation Index Expanded
Citazioni:
23
Recensione:
Indirizzi per estratti:
Citazione:
N.E. Bogdanchikova et al., "STRUCTURAL-PROPERTIES OF PD CATALYSTS SUPPORTED ON AL2O3-LA2O3 PREPARED BY SOL-GEL METHOD", Applied catalysis. B, Environmental, 17(3), 1998, pp. 221-231

Abstract

The structure of palladium catalysts (0.3 wt% Pd), supported on sol-gel alumina-lanthana mixed oxides, was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM) and X-ray photoelectron spectroscopy (XPS), The investigation of the structure of lanthana-promoted Pd catalysts, prepared by different methods, is of great importance for the improvement of palladium-only three-way catalysts, The data obtained show the presence of a crystalline phase, different from alumina, lanthana or alumina-lanthana reported compounds, in Al2O3-La2O3 and Pd/Al2O3-La2O3. Attempts to assign this crystalline phase to a known one were unsuccessful. According to XPS data, in lanthanum-containing samples, the state of lanthanum is different from that in La2O3. After calcination in air at 1273 K for 3 h this phase vanishes and large crystals ofLaAlO3, metastable for studied composition, appear. The sol-gel preparation method, in comparison with traditional preparation methods, leads to stabilization of LaAlO3 phase under the considered conditions and the increase of the stability of gamma-Al2O3 phase at high temperature. The improvement of the catalytic activity at medium temperature and the increase of the selectivity to NH3 at high temperatures for lanthanum-promoted Pd catalyst are ascribed to a lanthanum-containing phase. The increase in NH3 production decreases its practical value for anNO reduction catalyst. (C) 1998 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 25/11/20 alle ore 04:07:02