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

Direct conversion of methane under nonoxidative conditions

“…The dissociated oxygen species [O] from CO might react with the surface inert carbon species to regenerate CO, resulting in the suppression of coke formation on the catalyst. This type of effect on catalyst stability, due to the addition of CO and CO 2 , can be extended to the Co-Mo/HZSM-5, Fe-Mo/HZSM-5, and Re/HZSM-5 catalysts [58,59].…”

Study of the carbonaceous deposits formed on a Mo/HZSM-5 catalyst in methane dehydro-aromatization by using TG and temperature-programmed techniques

“…Ichikawa and co-workers reported that, the formation of carbonaceous deposits in the reaction was greatly suppressed if a small amount of CO and/or CO 2 (less than 3%) was added to the feed, as compared with that when pure CH 4 was used as the feed [20][21][22][23][24]. It is suggested that, the role of the CO addition will cause the Bouduard reaction, leading to the formation of minute amounts of CO 2 and C. The formed C is hydrogenated to a common active carbon species (CH x ) involving methane conversion towards aromatics products.…”

The synergic effect between Mo species and acid sites in Mo/HMCM-22 catalysts for methane aromatization

“…34 Iglesia et al studied Mo/ HZSM-5 catalysts prepared by using mechanical mixtures of MoO 3 and HZSM-5 via solid exchange reaction. [13][14][15][16] The authors also presented evidence that most of the Mo species migrate into the channels and are properly reduced by CH 4 into MoO x C y . Recently, in our proton MAS NMR study on HZSM-5 zeolite modified with perfluorotributyl amine we clearly distinguish the external and internal Brønsted sites.…”

“…Nevertheless, more anchored Mo species results in less free Brønsted sites remaining inside the channels, and less consecutive channels. Therefore, for the best bi-functional catalyst, the amount of active Mo species, either in the form of Mo 2 C or MoO x C y , [13][14][15][16] and the amount of free Brønsted acid sites should be well balanced. One may put forward a question on what is the suitable balance between the free Brønsted acid sites and the anchored Mo species and thus to give the best catalytic performance.…”