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Titolo:
COPPER-ZINC OXIDE CATALYSTS .4. THERMAL-TREATMENT IN AIR, ARGON AND HYDROGEN AND XRD STUDY OF NEW BIMETALLIC PRECURSORS-DIRECT FORMATION OFALLOYS
Autore:
KAPPENSTEIN C; CERNAK J; BRAHMI R; DUPREZ D; CHOMIC J;
Indirizzi:
UNIV POITIERS,URA CNRS 350,EQUIPE CHIM MINERALE,40 AVE RECTEUR PINEAUF-86022 POITIERS FRANCE SAFARIK UNIV,DEPT INORGAN CHEM KOSICE 04154 SLOVAKIA
Titolo Testata:
Thermochimica acta
, volume: 279, anno: 1996,
pagine: 65 - 76
SICI:
0040-6031(1996)279:<65:COC.TI>2.0.ZU;2-O
Fonte:
ISI
Lingua:
ENG
Soggetto:
POWDER DIFFRACTION PATTERNS;
Keywords:
ARGON; BIMETALLIC COMPOUNDS; CATALYST PRECURSORS; COPPER-ZINC; CYANO COMPLEXES; HYDROGEN; THERMAL TREATMENT;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Citazioni:
21
Recensione:
Indirizzi per estratti:
Citazione:
C. Kappenstein et al., "COPPER-ZINC OXIDE CATALYSTS .4. THERMAL-TREATMENT IN AIR, ARGON AND HYDROGEN AND XRD STUDY OF NEW BIMETALLIC PRECURSORS-DIRECT FORMATION OFALLOYS", Thermochimica acta, 279, 1996, pp. 65-76

Abstract

Four new Cu-Zn bimetallic precursors of model catalysts for methanolization of syngas, Zn(NH3)(2)Cu(CN)(3) (ZCA), [Zn(en)(3)](6)[Cu-5(CN)(17)]. nH(2)O (n = 8.4) (ZCE3), [Zn(en)] [CCu(CN)(3)] (ZCE1) and [Zn1-xCux(en)] [CCu(CN)(3)] (ZCCE1), were thermally treated in air, hydrogen and argon atmosphere between 200 and 900 degrees C. The calcinations in air yield firstly a mixture of cyano-ligand-containing compounds which transform at temperatures above 300 degrees C to CuO and ZnO; the crystallite size of both oxides increases with temperature. The reduction in hydrogen at 300 degrees C gives zinc cyanide and metallic copperwhich are converted at 450 degrees C mainly to beta'-brass including some alpha- and gamma-alloys. The thermal treatment in argon displays the very high thermal stability of zinc cyanide to 900 degrees C and formation of copper or alpha-CuZn alloy. Only the hydrogen treatment avoids the segregation of both metallic elements. The results are discussed on the basis of thermodynamic data.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 05/12/20 alle ore 10:36:15