CO₂hydrogenation using bifunctional catalysts based on K-promoted iron oxide and zeolite: influence of the zeolite structure and crystal size

Abstract

In the present manuscript, the influence of the zeolite structure and crystal size has been studied on bifunctional tandem catalysts combining K-promoted iron oxide (K/Fe3O4) with different zeolites for the...

Role of Catalyst Domain Size in the Hydrogenation of CO2 to Aromatics over ZnZrOx/ZSM-5 Catalysts

“…Therefore, an increased synthesis rate of alkylated BTX compounds is (C 9 +) ensued for smaller ZSM-5 crystals. A similar trend is observed for the aromatics distribution for the other two bed orientations (separate beds and mixed particles, Figures S7A,B) and in other aromatization studies. − However, the overall share of C 6 –C 8 among total aromatics in the separate bed scenario is larger than that of two other cases. The separate bed structure would provide a shorter contact time for the chemicals over the external surface area of ZSM-5, leading to an overall reduction in methylation reactions and a higher C 6 –C 8 concentration among aromatics.…”

“…While the focus of this study was not on the aromatization products, they observed a 7% reduction in C 6 + compound selectivity when using 10–15 nm crystals of ZSM-5, compared to 200–300 nm crystal sizes. They also reported an 8% reduction in BTX selectivity among aromatics when using the smaller ZSM-5 crystals . Liu et al varied the crystal size of ZSM-5 in the range of 200–560 nm for the syngas aromatization reaction and observed a 4% improvement in the aromatics selectivity upon increasing the crystal size .…”

“…They also reported an 8% reduction in BTX selectivity among aromatics when using the smaller ZSM-5 crystals. 36 Liu et al varied the crystal size of ZSM-5 in the range of 200−560 nm for the syngas aromatization reaction and observed a 4% improvement in the aromatics selectivity upon increasing the crystal size. 37 Wang et al used different amounts of organosilanes to link or chain some zeolite crystals along the b-axis.…”

A review of the recent progress on direct heterogeneous catalytic CO2 hydrogenation to gasoline-range hydrocarbons

“…The zeolite components play a crucial role in the subsequent C-C coupling reactions of active intermediates from iron-based components, while the product distribution is highly dependent on the regular channels and acid properties on the basis of a widely accepted carbonium ion intermediate mechanism 86,87 . Ramirez et al reported a zeolite topology effect on the product distribution in the direct conversion of CO 2 with composite ironbased catalysts.…”

Conversion of Methanol to Olefins over Modified OSDA-Free CHA Zeolite Catalyst

“…The chabazite (CHA) framework contains narrow eight-member ring openings and a large cage that enhances olefin selectivity with minimal aromatics. − Different modifications and synthesis methods of CHA zeolite have been studied. These modifications are either by in situ modifications , or by post-modifications .…”