Resistance against Carbon Deposition via Controlling Spatial Distance of Catalytic Components in Methane Dehydroaromatization

Yan Zeng,Jiaqi Fan,Peipei Zhang,Chengwei Wang,Guohui Yang,Jiaming Liang,Noritatsu Tsubaki,Xiaobo Peng,Liwei Xiao,Ayano Kimura

doi:10.3390/catal11020148

Yan Zeng, Jiaqi Fan + Show 8 more

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https://doi.org/10.3390/catal11020148

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Abstract

Molybdenum-zeolite catalysts always suffer from severe carbon deposition and rapid deactivation in the methane dehydroaromatization (MDA) process. Herein, we present a strategy that controls spatial distance between Mo species and HMCM-22 zeolite over Mo/HMCM-22 catalysts, to inhibit the severe carbon deposition. Our characterization analyses demonstrate that the Mo/HMCM-22 catalysts possess the same active components, but the spatial distance plays a key role in determining product selectivity in the MDA process. The MDA performance reveals that Mo/HMCM-22-MM (mechanical milling) catalyst, with a medium spatial distance between Mo species and HMCM-22 zeolite, significantly inhibits carbon deposition and produces high selectivity to benzene. This work shows that spatial distance between molybdenum and zeolite is an important property for suppressing carbon deposition and improving benzene selectivity in MDA process.

Highlights

Accepted: 18 January 2021Methane is the main component of natural gas, shale gas, flammable ice, etc
Mo/HMCM-22-hydrothermal synthesis (HS), Mo/HMCM-22-wet impregnation (WI), diagrams from left to right correspond to the Mo/HMCM-22-HS, Mo/HMCM-22-WI, Mo/HMCM-22-mechanical milling (MM), Mo/HMCM-22-physical mixing (PM)
A series of Mo/HMCM-22 catalysts with different spatial distances between the Mo species and HMCM-22 zeolite were designed for the methane dehydroaromatization (MDA) process

Summary

Introduction

Accepted: 18 January 2021Methane is the main component of natural gas, shale gas, flammable ice, etc. Conversion of methane into high value-added chemicals has attracted widespread attention [1,2]. Direct and indirect syntheses have been extensively explored in methane conversion. The direct synthesis usually utilizes a reaction process (such as oxidation, chlorination, or dehydroaromatization) to directly convert methane into desired products [3,4,5,6,7,8,9]. Production from methane, and conversion of the syngas into methanol, dimethyl ether, liquid fuels, and so on [10,11,12,13]. There is a great need to further develop and optimize the direct synthesis for enhancing the efficiency of methane utilization

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