Abstract

The co-aromatization of methane and organic compounds using metal-modified zeolite catalysts represents a promising approach for the direct conversion of natural gas into valuable aromatics. In this work, we employ solid-state nuclear magnetic resonance (NMR) spectroscopy to systematically examine the reaction mechanism and evaluate the impact of co-feeding furan on methane aromatization over Mo/ZSM-5 zeolite. The results reveal a dual role of furan in promoting methane to aromatics and stabilizing the Mo/ZSM-5 zeolite catalyst in the co-aromatization. It is found that co-feeding a moderate amount of furan enhances methane conversion and boosts the selectivity to benzene, toluene, and xylene (BTX). The 12C/13C isotope switching experiments coupled with 1H and 13C MAS NMR spectroscopy reveal that furan actively participates in the methane aromatization reaction by forming an olefin pool, which promotes methane activation and contributes to the following aromatics formation. Two-dimensional 1H–95Mo heteronuclear correlation NMR spectroscopy indicates that furan facilitates the activation of Mo oxides into MoOxCy species, which serve as the active sites for methane aromatization. The co-feeding furan also helps to enhance catalyst stability by limiting the agglomeration of Mo and the deposition of coking species.

Link:https://pubs.acs.org/doi/10.1021/acscatal.4c01827?utm_source=SendGrid_ealert&utm_medium=ealert&utm_campaign=ASAP_accacs_v0_i0