Oxidative Coupling of Methane over Lithium Doped （Mn+W）/SiO Catalysts

被引：0

作者：

A Malekzadeh ^{[1
]}

A Khodadadi ^{[2
]}

A K Dalai ^{[3
]}

M Abedini ^{[4
]}

机构：

[1] School of Chemistry,Damghan University of Basic Sciences,Damghan,Iran

[2] College of Chemical Engineering,University of Tehran,Tehran,Iran

[3] Department of Chemical Engineering,University of Saskatchewan,Research Annex, Maintenance Road,Saskatoon,SK SN C,Canada

[4] College of Chemistry,University of Tehran,Tehran,Iran

来源：

Journal of Natural Gas Chemistry | 2007年 / 02期

关键词：

oxidative coupling of methane; silica phase transition; lithium; intermetallic interaction; redox properties;

D O I：

暂无

中图分类号：

O643.32 [催化反应];

学科分类号：

081705 ;

摘要：

<正>Modification and performance of Li induced silica phase transition of (Mn+W)/SiO2 catalyst, under reaction conditions of oxidative coupling of methane (OCM), have been investigated employing textural characterizations and redox studies. Stability and precrystalline form of fresh Li induced silica phase transition catalyst depend on the Li loading. A catalyst, with high lithium loading, destabilizes on OCM stream. This destabilization is not due to Li evaporation at OCM reaction conditions.α-cristobalite is proposed to be an intermediate in the crystallization of amorphous silica into quartz in the Li-induced silica phase transition process. However, the type of crystalline structure was found to be unimportant with regard to the formation of a selective catalyst. Metal-metal interactions of Li-Mn, Li-W and Mn-W, which are affected during silica phase crystallization, are found to be critical parameters of the trimetallic catalyst and were studied by TPR. Role of lithium in Li doped (Mn+W)/SiO2 catalyst is described as a moderator of the Mn-W interaction by involving W in silica phase transition. These interactions help in the improvement of transition metal redox properties, especially that of Mn, in favor of OCM selectivity.

引用

页码：121 / 129

页数：9