Oxidant Activation Over Structural Defects of Oxide Catalysts in Oxidative Methane Coupling

Abstract

Different aspects concerning the process of direct methane conversion to oxygen-containing products developed during more than half a century have been considered in previous reviews [1–3]. In particular, Gesser et al. [13 paid most attention to the homogeneous stages in methane conversion, while Foster [2] and Pitchai and Klier [3] examined the effect of different catalysts on methanol and formaldehyde formation. At present the main product of the homogeneous methane oxidation process with oxygen is shown to be methanol formed according to a chain-branching mechanism. In the presence of homogeneous initiators [4] (benzene, 2,2,4- trimethylpentane, etc.) or heterogeneous catalysts [2,3,5,6], formaldehyde is formed together with CH30H. However, the yield of the desirable products is low and does not exceed 8–10%. Charged atomic oxygen forms are considered to take part in the process of catalytic methane oxidation.

Key Words:

• Methane oxidative coupling
• Oxidant activation
• Oxygen defects
• p-Type semiconductivity.