Influence of ageing on MoO3 formation in the preparation of alumina-supported Mo catalysts

被引：39

作者：

Carrier, X

Lambert, JF

Kuba, S

Knözinger, H

Che, M

机构：

[1] Univ Paris 06, Lab React Surface, CNRS, UMR 7609, F-75252 Paris 05, France

[2] Univ Munich, Dept Chem, D-81377 Munich, Germany

来源：

JOURNAL OF MOLECULAR STRUCTURE | 2003年 / 656卷 / 1-3期

关键词：

dissolution; Anderson-type heteropolyanion; (NH4)(3)[Al(OH)(6)Mo6O18; hexamolybdoaluminate; freeze-drying; hydrotreatment;

D O I：

10.1016/S0022-2860(03)00328-4

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：

Raman spectroscopy and XRD are used to study the preparation of alumina-supported Mo catalysts, with emphasis on the molecular level understanding of the influence of the ageing step (i.e. leaving the catalyst in contact with water after impregnation and before drying) on Mo speciation. For incipient wetness impregnation with heptamolybdate ((NH4)(6)Mo7O24), long oxide/water contact times (ageing) favor alumina dissolution and consequently increase the formation and crystallization of the resulting compound, (NH4)(3)[Al(OH)(6)Mo6O18] on Al2O3. Precipitation of this compound leads to the formation of MoO3 after calcination. On the contrary, minimizing the oxide/water contact time (and therefore alumina dissolution) by freeze-drying the system after impregnation inhibits the formation and crystallization of (NH4)(3)[Al(OH)(6)Mo6O18] and therefore drastically limits MoO3 formation after calcination. (C) 2003 Elsevier B.V. All rights reserved.

引用

页码：231 / 238

页数：8

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