Unveiling coke formation mechanism in MFI zeolites during methanol-to-hydrocarbons conversion

Recent advances in hydrogenation of CO2 into hydrocarbons via methanol intermediate over heterogeneous catalysts

“…The position of coke could be on the internal surface of the micropores (called soft/internal coke) blocking the accessibility to the active sites or as a coating on the outer surface of the zeolite crystal (called external coke) blocking the entrance to the internal pores. 190,191 The growth of coke species inside the internal pore is limited by the size and shape of the pore. No such spatial limitation is anticipated for the external coke.…”

“…No such spatial limitation is anticipated for the external coke. The role (chemical nature, amount, and composition) of internal and external coke in deactivation was studied by Lee et al 190 They chose MFI zeolites with different crystallite sizes. Regardless of the crystallite size and the reaction time, the…”

Effect of the Post‐Treatment of HZSM‐5 on Catalytic Performance for Methanol to Aromatics

“…However, the high amount of weak acid led to a sharp increase of C 9+ selectivity, while the selectivity of BTX was not significantly improved. Rich C 9+ content significantly increased the amount of carbon deposition, which accelerated the deactivation of the catalyst because the acidic site was covered by a large amount carbon deposition . Significant increase of BTX selectivity after acid‐treatment of HZSM‐5‐0.09 M, and the C 9+ only was 6.3 %, meanwhile, the selectivity of BTX accounted for 89.1 % in aromatics as shown in Figure e.…”

Disentangling Reaction Processes of Zeolites within Single‐Oriented Channels

“…[7][8][9][10][11][12] ZSM-5 coking in the MTH process has long been studied, [13] and it is known that the deactivation is caused by the coking of aromatic species, and that the deactivation heavily depends on the location of the coke. [13,[19][20][21][22][23][24] To fully elucidate the key descriptor for zeolite deactivation, it is of utmost importance to study the reaction behaviors at the level of single-oriented zeolite-channels. Previous studies on zeolite ZSM-5 in the MTH reaction have concentrated on either designing materials/reactors for kinetic studies [11,16,20,22,[24][25] or gaining spatial insights by using advanced characterization techniques.…”

“…[13,[19][20][21][22][23][24] To fully elucidate the key descriptor for zeolite deactivation, it is of utmost importance to study the reaction behaviors at the level of single-oriented zeolite-channels. Previous studies on zeolite ZSM-5 in the MTH reaction have concentrated on either designing materials/reactors for kinetic studies [11,16,20,22,[24][25] or gaining spatial insights by using advanced characterization techniques. [17,18,[26][27][28][29][30][31] However, none of these studies have been capable of disentangling the structure-reactivity relationships for specific zeolite-channel orientations under operando conditions.…”