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Titolo:
Synthesis of Ni/SiO2 catalysts through precipitation of silica-sols: effect of aging and Ca(Ba) additives
Autore:
Castillon, FF; Bodganchikova, N; Fuentes, S; Avalos-Borja, M;
Indirizzi:
UNAM, Ctr Ciencias Mat Condensada, San Ysidro, CA 92143 USA UNAM San Ysidro CA USA 92143 ias Mat Condensada, San Ysidro, CA 92143 USA CICESE, Ensenada 22800, Baja California, Mexico CICESE Ensenada Baja California Mexico 22800 800, Baja California, Mexico Univ Sonora, DIPMUS, Dept Polimeros & Mat, Hermosillo, Sonora, Mexico UnivSonora Hermosillo Sonora Mexico s & Mat, Hermosillo, Sonora, Mexico
Titolo Testata:
APPLIED CATALYSIS A-GENERAL
fascicolo: 1-2, volume: 175, anno: 1998,
pagine: 55 - 65
SICI:
0926-860X(199812)175:1-2<55:SONCTP>2.0.ZU;2-B
Fonte:
ISI
Lingua:
ENG
Soggetto:
SUPPORTED NICKEL; GEL PREPARATION; HYDROGEN; EXAFS; DESORPTION; OXIDE;
Keywords:
Ni/SiO2 catalysts; silica sols; benzene hydrogenation; alkaline earth additives; TPD;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Physical, Chemical & Earth Sciences
Engineering, Computing & Technology
Citazioni:
36
Recensione:
Indirizzi per estratti:
Indirizzo: Fuentes, S UNAM, Ctr Ciencias Mat Condensada, POB 439036, San Ysidro, CA 92143 USA UNAM POB 439036 San Ysidro CA USA 92143 an Ysidro, CA 92143 USA
Citazione:
F.F. Castillon et al., "Synthesis of Ni/SiO2 catalysts through precipitation of silica-sols: effect of aging and Ca(Ba) additives", APP CATAL A, 175(1-2), 1998, pp. 55-65

Abstract

The preparation of Ni/SiO2 catalysts by precipitation of silica sols with NH4OH is described. Nickel introduction during precipitation of silica solsdid not affect significantly the silica surface area, yielding amorphous Ni/SiO2 catalysts in both calcined and reduced forms. This method of preparation results in Ni/SiO2 catalysts showing homogenous distribution of components, surface areas ca. 255 m(2) g(1), and mean size of nickel particles between 4 and 6 nm. The effects of gel aging and the addition of Ca or Ba cations on the textural, structural and catalytic properties of Ni/SiO2 catalysts were studied. Results are interpretated according to reported processesof dissolution-precipitation of silica occurring under basic conditions [R. K. ner, The Chemistry of Silica, Chapters 3 and 4, Wiley, New York, 1979]. Alkaline earth addition to the nickel/silica catalysts decreased the surface area to 100-155 m(2) g(-1). For reduced Ni/SiO2-Ba and Ni/SiO2-Ca catalysts, the X-ray diffraction (XRD) peak of (111) planes of metal nickel crystals was identified. Several XRD peaks not corresponding to any Ni, Si and Ba/Ca containing crystalline phase reported in the ICDD database were revealed. They were assigned to new crystalline phases including Ba and Ca in thesecond coordination sphere of nickel. Hydrogen adsorption on these new phases was stronger than on metal nickel. Variation of hydrogen chemisorption properties and reaction rate for benzene hydrogenation were observed with alkaline earth addition. (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 28/11/20 alle ore 04:20:27