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Bromine-mediated conversion of methane to C1 oxygenates over Zn-MCM-41 supported mercuric oxide

Paper ID Volume ID Publish Year Pages File Format Full-Text
43810 45989 2008 6 PDF Available
Title
Bromine-mediated conversion of methane to C1 oxygenates over Zn-MCM-41 supported mercuric oxide
Abstract

The structure mobility of the zigzag mercuric oxide chains and the strong preference of mercuric (II) cation sites for bromine lead to a novel bromine-mediated partial methane oxidation at relatively low reaction temperature (220 °C). Zn-MCM-41 supported mercuric oxide nanophases were used as the model catalyst to investigate the role of bromine in the catalytic cycle. The introduction of bromine to feed gas consisting of CH4/O2/Ar (3:1:6) leads to a sharp increase in the methane conversion. Meanwhile, a transient high product selectivity to C1 oxygenates was observed. Two bromine-mediated routes can be identified: MeHgBrn as the intermediate species and mercuric hypobromite as the active agent for methane oxidation, which occur simultaneously in the methane conversion. The controlling mechanism transfers from the former to the latter with the gradual fixation of bromine into mercuric oxide lattice. The catalyst was characterized detailedly by XRD, XPS, and N2 sorption. The chemical composite changes of active species were detected by XPS, which provide some direct information about the mediator role of bromine in the catalytic cycle.

Graphical abstractThe structure mobility of the zigzag mercuric oxide chains and the strong preference of mercuric (II) cation sites for bromine lead to a novel bromine-mediated partial methane oxidation at relatively low reaction temperature (220 °C). Two bromine-mediated routes can be identified: MeHgBrn as the intermediate species and mercuric hypobromite as the active agent for methane oxidation, which occur simultaneously in the methane conversion. The controlling mechanism transfers from the former to the latter with the gradual fixation of bromine into mercuric oxide lattice.Figure optionsDownload full-size imageDownload as PowerPoint slide

Keywords
Bromine; Methane; Selective oxidation; C1 oxygenates; Mercuric oxide
First Page Preview
Bromine-mediated conversion of methane to C1 oxygenates over Zn-MCM-41 supported mercuric oxide
Publisher
Database: Elsevier - ScienceDirect
Journal: Applied Catalysis A: General - Volume 335, Issue 1, 1 February 2008, Pages 82–87
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Catalysis