(500f) Catalytic Aromatization of Methane: Strategies for Improving Active Chemistry and Stability of the Catalysts

Intensifying the use of CH₄ as a chemical feedstock for its conversion to liquid fuels and other added value chemicals is of increasing interest since CH₄ is the main constituent of natural gas, of which vast natural reserves are being exploited. Paradoxically, a significant amount of natural gas is wasted in flaring, due to the expensive handling and transportation of natural gas. Among the different processes that exist to convert CH₄ to added-value liquids, there has been an emerging interest in the heterogeneous catalytic conversion of methane, CH₄, to a mixture of benzene and hydrogen, by the non-oxidative methane aromatization reaction (6 CH₄(g) → C₆H₆(g) + 9H₂(g)), which happens in one step. Our group is carrying out a fundamental and systematic study of this catalytic process with the goal to answer some fundamental questions, which can mitigate the technological challenges of this process.

Zeolite-supported molybdenum catalysts have so far been the most widely studied catalysts for the CH₄ aromatization reaction. Rapid catalyst deactivation and low conversions are disadvantages that impede commercialization of the methane aromatization process. It is agreed that Mo carbide species, originated by exposure of the Mo oxide species to the reactant methane, are responsible for methane activation, however, the nature and amount of carbide phases formed in the induction period of the reaction are not controlled.

We will present out results related to the exploration of the pretreatment conditions that are necessary to purposefully prepare zeolite-supported metal carbide phases with the best catalytic properties and relate the reaction and deactivation pathways to the structure of a specific carbide phase.