Selective Dehydroaromatization of Methane toward Benzene on Re/HZSM-5 Catalysts and Effects of CO/CO2 Addition

The novel rhenium catalyst Re/HZSM-5 was studied for the catalytic performance of methane dehydrocondensation at 3 atm and 873–1023 K. It was found that C2 hydrocarbons and aromatic compounds such as benzene and naphthalene were catalytically obtained with a considerable evolution of hydrogen. High methane conversion (8–12%) and rates of benzene formation obtained on the Re/HZSM-5 catalyst were similar, under the experimental conditions used, to that on Mo/HZSM-5, which has been thought to be a unique catalyst for the reaction. In contrast to the molybdenum carbide (Mo2C) as the active phase for the reaction on Mo/HZSM-5, EXAFS and TG/DTA/mass studies suggest that the metallic Re on HZSM-5 is responsible for the catalytic dehydrocondensation of methane toward C2 hydrocarbons, benzene, and naphthalene. High and stable conversion of methane and high selectivities (70–87% based on carbon) of C2 hydrocarbons and benzene have been attained in the catalytic dehydrocondensation of methane on Re/HZSM-5 with CO/CO2 added in methane feed.