Structural reversibility of a ternary CuO-ZnO-Al2O3 ex hydrotalcite-containing material during wet Pd impregnation

被引：16

作者：

Melián-Cabrera, I ^{[1
]}

Granados, ML ^{[1
]}

Fierro, JLG ^{[1
]}

机构：

[1] CSIC, Inst Catalisis & Petroleoquim, E-28049 Madrid, Spain

来源：

CATALYSIS LETTERS | 2002年 / 84卷 / 3-4期

关键词：

rehydration; hydrotalcite reconstruction; Pd-modifed materials; methanol synthesis catalysts;

D O I：

10.1023/A:1021467617700

中图分类号：

O64 [物理化学（理论化学）、化学物理学];

学科分类号：

070304 ; 081704 ;

摘要：

A Cu-Zn-Al precursor was synthesized by coprecipitation of the corresponding cations with sodium carbonate at constant pH and temperature. CuO-ZnO-Al(2)O(3) composite oxide support was obtained by calcination (673 K) of the Cu-Zn-Al precursor. Two palladium-modified CuO-ZnO-Al(2)O(3) samples were prepared by impregnation of the mixed-oxide support and further calcination (673 K). The presence of remaining CO(3)(2-) anions in the CuO-ZnO-Al(2)O(3) mixed oxide, as a result of incomplete Cu-Zn hydrotalcite phase decomposition, and the hydrothermal-like treatment during the Pd impregnation step, allow the partial reconstruction of the Cu-Zn hydrotalcite-type structure (memory effect). In addition, an enhancement in the CuO crystallinity was obtained for the Pd-modified oxides. A detailed characterization revealed that the hydrotalcite restoration enhances the crystallinity of the copper oxide as a consequence of a crystalline rearrangement of this oxidic phase.

引用

页码：153 / 161

页数：9

共 34 条

[1] Partial oxidation of methanol to produce hydrogen over Cu-Zn-based catalysts [J].

Alejo, L ;

Lago, R ;

Pena, MA ;

Fierro, JLG .

APPLIED CATALYSIS A-GENERAL, 1997, 162 (1-2) :281-297

[2]

[Anonymous], 801268 JCPDS

[3]

Bart J. C., 1987, CATAL TODAY, V2, P1

[4] Hydrotalcite decomposition mechanism: A clue to the structure and reactivity of spinel-like mixed oxides [J].

Bellotto, M ;

Rebours, B ;

Clause, O ;

Lynch, J ;

Bazin, D ;

Elkaim, E .

JOURNAL OF PHYSICAL CHEMISTRY, 1996, 100 (20) :8535-8542

[5] A reexamination of hydrotalcite crystal chemistry [J].

Bellotto, M ;

Rebours, B ;

Clause, O ;

Lynch, J ;

Bazin, D ;

Elkaim, E .

JOURNAL OF PHYSICAL CHEMISTRY, 1996, 100 (20) :8527-8534

[6] HYDROTALCITE-TYPE ANIONIC CLAYS: PREPARATION, PROPERTIES AND APPLICATIONS [J].

Cavani, F. ;

Trifiro, F. ;

Vaccari, A. .

CATALYSIS TODAY, 1991, 11 (02) :173-301

[7] SYNTHESIS OF METHANOL .1. CATALYSTS AND KINETICS [J].

CHINCHEN, GC ;

DENNY, PJ ;

JENNINGS, JR ;

SPENCER, MS ;

WAUGH, KC .

APPLIED CATALYSIS, 1988, 36 (1-2) :1-65

[8] Synthesis and characterization of hydrotalcites containing Ni(II) and Fe(III) and their calcination products [J].

del Arco, M ;

Malet, P ;

Trujillano, R ;

Rives, V .

CHEMISTRY OF MATERIALS, 1999, 11 (03) :624-633

[9] Spectroscopic evidence of Cu-Al interactions in Cu-Zn-Al mixed oxide catalysts used in CO hydrogenation [J].

Figueiredo, RT ;

Martinez-Arias, A ;

Granados, ML ;

Fierro, JLG .

JOURNAL OF CATALYSIS, 1998, 178 (01) :146-152

[10]

FUJIMOTO K, 1993, STUD SURF SCI CATAL, V77, P393

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