A DFT study of the mechanism and kinetics of methane oxidation to formaldehyde occurring on silica-supported molybdena

被引：53

作者：

Chempath, Shaji ^{[1
]}

Bell, Alexis T. ^{[1
]}

机构：

[1] Univ Calif Berkeley, Dept Chem Engn, Berkeley, CA 94720 USA

来源：

JOURNAL OF CATALYSIS | 2007年 / 247卷 / 01期

关键词：

quantum chemistry; peroxide; MoOx; methane activation; CH2O; SELECTIVE OXIDATION; OXIDE CATALYSTS; SIO2; MOO3/SIO2; BEHAVIOR; MO(VI); RAMAN; MOO3;

D O I：

10.1016/j.jcat.2007.01.012

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 theoretical analysis was carried out of the mechanism and kinetics of methane oxidation to formaldehyde occurring on isolated molybdate species supported on silica. Both mono-oxo and di-oxo molybdate structures were used to represent the active centers. The energetics for each elementary reaction was determined from density functional theory calculations, and the entropy changes were determined from calculations based on statistical mechanics. The results of this analysis show that the mechanism based on di-oxo molybdate species agrees more closely with observed rates of methane oxidation than that based on mono-oxo molybdate species. It is also found that the formation of formaldehyde occurs via the reaction of methane with peroxide species formed via the adsorption of O-2 on reduced Mo-IV centers. The extent of Mo-VI reduction to Mo-IV is well under 1% under reaction conditions, in good agreement with experimental observations. (c) 2007 Elsevier Inc. All rights reserved.

引用

页码：119 / 126

页数：8

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