STRUCTURE OF UNPROMOTED AND ALKALI-METAL PROMOTED MNOX-BASED CATALYSTS FOR OXIDATIVE COUPLING OF METHANE

被引:13
作者
BARONETTI, GT
SCELZA, OA
CASTRO, AA
CORBERAN, VC
FIERRO, JLG
机构
[1] CSIC, INST CATALISIS PETR QUIM, SERRANO 119, E-28006 MADRID, SPAIN
[2] INST INVEST CATALISIS PETR QUIM, RA-3000 SANTA FE, ARGENTINA
来源
APPLIED CATALYSIS | 1990年 / 61卷 / 02期
关键词
manganese oxide; manganese oxide/alumina; methane oxidative coupling; selectivity (C2 hydrocarbons). Catalyst characterization (TPR; XPS; XRD);
D O I
10.1016/S0166-9834(00)82153-3
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
Bulk manganese oxide, a catalyst for total combustion, becomes moderately selective for the oxidative coupling of methane when supported on α-alumina, its activity being dramatically reduced. Its selectivity can be further increased by doping with potassium chloride. In order to explain these effects in terms of catalyst structure, samples of manganese oxide catalysts, both supported and unsupported, with or without potassium chloride promoter, have been characterized by means of temperature-programmed reduction, X-ray diffractometry and X-ray photoelectron spectroscopy. The results revealed that supported promoted manganese oxide catalyst has a complex structure. The main effect of the support was to modify the reducibility of manganese oxide, reducing the lability of its oxygen atoms. The action of the alkali metal halide takes place in three different ways: modifying the MnOx active centers, as a source of active chlorine radical species and giving rise to new active centers through interaction of potassium with the alumina support. © 1990.
引用
收藏
页码:311 / 328
页数:18
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