Library
local_library Home Repository

Revealing Active Sites and Reaction Pathways in Methane Non-Oxidative Coupling over Iron-Containing Zeolites

Journal Article (2023)
Author(s)

Hao Zhang (Eindhoven University of Technology)

Aleksei Bolshakov (Eindhoven University of Technology)

Raghavendra Meena (Wageningen University & Research)

Gustavo A. Garcia (L'Orme les Merisiers Saint-Aubin)

A. Iulian Dugulan (TU Delft - RST/Fundamental Aspects of Materials and Energy, TU Delft - RID/TS/Instrumenten groep)

Alexander Parastaev (Eindhoven University of Technology)

Guanna Li (Wageningen University & Research)

Emiel J.M. Hensen (Eindhoven University of Technology)

Nikolay Kosinov (Eindhoven University of Technology)

Research Group
RST/Fundamental Aspects of Materials and Energy
DOI related publication
https://doi.org/10.1002/anie.202306196
More Info
expand_more
Publication Year
2023
Language
English
Research Group
RST/Fundamental Aspects of Materials and Energy
Issue number
32
Volume number
62
Reuse Rights

Other than for strictly personal use, it is not permitted to download, forward or distribute the text or part of it, without the consent of the author(s) and/or copyright holder(s), unless the work is under an open content license such as Creative Commons.

Abstract

Non-oxidative coupling of methane is a promising route to obtain ethylene directly from natural gas. We synthesized siliceous [Fe]zeolites with MFI and CHA topologies and found that they display high selectivity (>90 % for MFI and >99 % for CHA) to ethylene and ethane among gas-phase products. Deactivated [Fe]zeolites can be regenerated by burning coke in air. In situ X-ray absorption spectroscopy demonstrates that the isolated Fe3+ centers in zeolite framework of fresh catalysts are reduced during the reaction to the active sites, including Fe2+ species and Fe (oxy)carbides dispersed in zeolite pores. Photoelectron photoion coincidence spectroscopy results show that methyl radicals are the reaction intermediates formed upon methane activation. Ethane is formed by methyl radical coupling, followed by its dehydrogenation to ethylene. Based on the observation of intermediates including allene, vinylacetylene, 1,3-butadiene, 2-butyne, and cyclopentadiene over [Fe]MFI, a reaction network is proposed leading to polyaromatic species. Such reaction intermediates are not observed over the small-pore [Fe]CHA, where ethylene and ethane are the only gas-phase products.