Direct Catalytic Coupling and Selective Oxidation of Methane to Ethanol at Low Temperature

The enormous scale of methane reserves has motivated significant research activities focused on its conversion to fuels and chemicals. Since large amounts of natural gas are located in remote areas and transporting gases in pipelines is difficult, processes for converting methane into denser products are highly desirable.

To address this challenge, we developed a bi-functional catalyst that is capable of activating the C-H bond in methane to form surface methyl groups. Some of these methyl groups undergo surface reaction that lead to the formation of higher alkyl chains. In the presence of steam, methanol and ethanol are formed by hydrolysis of the surface alkyl groups. Oxygen has to be co-fed to provide a thermodynamic driving force for this reaction. In addition to alcohols, carbon dioxide and hydrogen are formed as by-products. Importantly, formation of alcohols occurs at 450 °C under steady state conditions with a turnover frequency of at least 50 h^-1. This is a significant improvement from previous studies, in which a high-temperature calcination step was required for every turnover.

The identification of promising catalysts and suitable reaction conditions will be discussed. Spectroscopic studies are performed to identify the active sites and the synergistic way in which they enable the reaction.