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

摘要

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 LIII-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.