non-oxidative methane aromatization by bimetallic (la, co, pd and pt) m-zn/hzsm-5: impact of propane addition

The non-oxidative aromatization of methane was studied over m-zn/hzsm-5 (m=la, co, pd, and pt) catalysts using propane as a coreactant. the catalysts were characterized by bet, sem, nh3tpd and xrd techniques. catalytic tests were performed in a fixed-bed reactor at 823 k, using a mixture of methane, propane, and nitrogen with ratio of 6/1/1.3, respectively. propane conversion was above50% and remained stable in the first 12 hours on stream; however, the methane conversion rapidly dropped from a high of about 10% to zero within 4 hours, implying the absence of a stoichiometric reaction between the reactants. both zinc and the second metal (m) had a beneficial effect on aromatic selectivity and pt-zn/hzsm5 exhibited the highest aromatic yields and catalyst stability. the results of the present study showed that cofeeding of methane with propane cannot successfully induce methane to participate in aromatization reactions.