Methane dehydroaromatization over Mo-modified H-MFI for gas to liquid catalysts.

For direct gas to liquid (GTL), a novel process producing energy sources for methane dehydroaromatization is needed. Supporting MoO3 on H-MFI zeolite shows the high catalytic capacity and a selective activity for dehydroaromatization of methane to benzene at 973 K in a fixed bed reactor. On the other hand, deactivation by coke on the active sites in all the catalysts is formed during the reaction. H2 co-feed suppressed the deactivation, which is probably due to the decrease in coking amount. Mo K-edge X-ray absorption fine structure (XAFS) results showed the formation of dispersed Mo2C species with low crystallinity after dehydroaromatization. Mo L(III)-edge XANES (X-ray absorption near-edge structure) indicated the formation of active Mo species including Mo2C and Mo-oxycarbide (MoOxCy), where the redox state should be independent in the absence/presence of H2. It is concluded that Mo-oxycarbide species act as highly active species, and their stability affected the durable activity in the presence of H2.