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Titolo:
An amorphous approach to the structure of a Pt-Fe/gamma-Al2O3 catalyst characterized by XAFS
Autore:
Lin, LW; Kou, Y; Zou, M; Yan, Z;
Indirizzi:
Peking Univ, Coll Chem & Mol Engn, Beijing 100871, Peoples R China Peking Univ Beijing Peoples R China 100871 ijing 100871, Peoples R China Chinese Acad Sci, Dalian Inst Chem Phys, State Key Lab Catalysis, Dalian 116023, Peoples R China Chinese Acad Sci Dalian Peoples R China 116023 n 116023, Peoples R China
Titolo Testata:
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
fascicolo: 9, volume: 3, anno: 2001,
pagine: 1789 - 1794
SICI:
1463-9076(2001)3:9<1789:AAATTS>2.0.ZU;2-F
Fonte:
ISI
Lingua:
ENG
Soggetto:
X-RAY-ABSORPTION; FINE-STRUCTURE EXAFS; COORDINATE GEOMETRY; WORKING CATALYSTS; METAL-CATALYSTS; IRON CATALYSTS; CO ADSORPTION; GAS-PHASE; RE-PT; DEHYDROGENATION;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Physical, Chemical & Earth Sciences
Citazioni:
27
Recensione:
Indirizzi per estratti:
Indirizzo: Lin, LW Peking Univ, Coll Chem & Mol Engn, Beijing 100871, Peoples R ChinaPeking Univ Beijing Peoples R China 100871 0871, Peoples R China
Citazione:
L.W. Lin et al., "An amorphous approach to the structure of a Pt-Fe/gamma-Al2O3 catalyst characterized by XAFS", PHYS CHEM P, 3(9), 2001, pp. 1789-1794

Abstract

A Pt-Fe/gamma -Al2O3 catalyst has been investigated by means of Pt L-III-and Fe K-edge X-ray absorption fine structure (XAFS). X-Ray absorption near-edge structure (XANES) clearly indicates the formation of highly dispersed zerovalent Pt atoms on the surface after reduction. The iron precursor Fe2O3 is reduced to well-dispersed FeO. Six Pt neighbors at 2.72, 3.14 and 3.83Angstrom, respectively, are found for each Pt atom on Pt/gamma -Al2O3. However, only one type of Pt neighbor, at 2.75 Angstrom with a low coordination number of 0.8, is detected for the Pt sites on Pt-Fe/Al2O3. An amorphous approach to rationalizing a possible structure of Pt-Fe/Al2O3 has been discussed at the atomic level by consideration of the surface coordinate geometry. The XAFS-derived parameters are highly commensurate with a sandwich model. An iron oxide phase with the stoichiometry Fe17O19 is present as an interface between Pt and gamma -Al2O3 while zerovalent Pt atoms are randomly distributed on the iron oxide surface as a mixture of monomers, dimers and trimers, well separated from each other.

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Documento generato il 27/09/20 alle ore 00:56:13