Conversion of lower hydrocarbons in the presence of carbon dioxide: The theoretic analysis and catalytic tests over active carbon supported vanadium oxide

The results of thermodynamic analysis of methane oxidative coupling and dehydrogenation of C-2-C-4 hydrocarbons in the presence of carbon dioxide were compared to the corresponding results in an inert gas atmosphere. Moreover, conversion of alkanes in some undesirable side reactions, such as decomposition of alkanes to the synthesis gas or to carbon oxide and water, as well as the gasification of coke by carbon dioxide in the Boudouard reaction, were investigated. Finally, the results of the theoretical calculations were compared with the experimental data obtained over VOx/C-act catalyst. The results are discussed in relation to the acid-base properties of the catalyst surface and the atomic charge on the hydrogen most susceptible to abstraction (i.e., the weakest C-H bond in hydrocarbons). Thus, the changes of the catalytic performance in the presence and absence of carbon dioxide are explained.