Facilely Synthesized H-Mordenite Nanosheet Assembly for Carbonylation of Dimethyl Ether

Abstract

Hard coke blockage of micropores of acidic zeolites generally causes serious catalytic deactivation for many chemical processes. Herein, we report a facile method to synthesize H-mordenite nanosheet assemblies without using any template agent. The assemblies exhibit the high catalytic activity for carbonylation of dimethyl ether because of their large quantity of framework Brønsted acids. The specific morphology of the nanosheet unites improves mass diffusion for both reactants and products. Consequently, the coke precursor species can readily migrate from the micropores to the external surface of the assemblies, inducing the improved catalytic stability through inhibiting hard coke formation in frameworks.

Catalytic Properties of Hierarchical Mordenite Nanosheets Synthesized by Self-Assembly Between Subnanocrystals and Organic Templates

“…Notably, although two the kinds of zeolites had similar acid strength, Hi-MOR had higher acid density than conventional mordenite because of the mesoporous structure (Supporting Information, Fig. S6 and Table S1) [21,22,27]. Constraint indexes (CI) could effectively characterize the pore structure of zeolites [28].…”

“…To overcome these disadvantages, Hi-MOR had been prepared by both top-down and bottomup methods [17][18][19][20][21][22]. Li et al prepared mesoporous mordenite by three methods (i.e.…”

“…Owing to the low decomposition temperature of organosilane, 4 days were still needed to crystallization though the bulk zeolite seeds could accelerate the crystallization process. More recently, it is reported that H-mordenite nanosheets assemblies were prepared without using any template agent and acted as a high efficient catalyst for carbonylation of dimethyl ether [22]. Nevertheless, the resultant zeolites did not have larger external surface areas because of the larger assemble size of nanosheets.…”

Restraining deactivation of hierarchical zeolite supported NiW catalysts in the HDS of thiophene

“…[20][21][22] One explanation is that external active sites outside micropores were able to perform the catalytic function even aer active sites inside micropores were deactivated. 21 Thus, from the viewpoint of deactivation the use of hierarchical zeolites as the support of TMS catalysts might inhibit deactivation of catalysts to some extent.…”

“…[20][21][22]37 Indeed coke formation is known to preferably occur inside the micropores that can block or cover active sites. 41 In this case external active sites outside micropores are available to perform the catalytic function even when active sites inside micropores are deactivated.…”