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The Catalyzed Conversion of Methane to Value‐Added Products
Author(s) -
Zhao Guangyu,
Drewery Matthew,
Mackie John,
Oliver Tim,
Kennedy Eric Miles,
Stockenhuber Michael
Publication year - 2020
Publication title -
energy technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.91
H-Index - 44
eISSN - 2194-4296
pISSN - 2194-4288
DOI - 10.1002/ente.201900665
Subject(s) - catalysis , oxygenate , methane , chemistry , methanol , oxide , methane monooxygenase , anaerobic oxidation of methane , yield (engineering) , oxygen , redox , partial oxidation , inorganic chemistry , organic chemistry , materials science , metallurgy
The progress of direct, selective conversion of methane (CH 4 ) to organic oxygenates utilizing heterogeneous and homogeneous processes conducted in the gaseous or liquid phase is reviewed. The most active catalytic systems are examined in terms of rates, longevity, and reaction mechanisms. Despite significant effort, the successful heterogeneous mimicking of selective CH 4 oxidation performed in an enzymatic system (methane monooxygenase) is still elusive. Under mild reaction conditions, the reaction is too slow, and under harsh conditions, total oxidation prevails. Thus, of particular interest herein is the assessment of oxidation at intermediate temperatures to 1) reduce total oxidation and 2) obtain sufficient concentration of activated oxygen and CH 4 species. Important operational parameters such as reaction conditions, catalyst preparation methods, and cofeeding of chemicals, which significantly affect the yield of desired products, are discussed. One particular system that is successful is the catalytic conversion of CH 4 to methanol under mild conditions using nitrous oxide (N 2 O) with Fe‐based catalysts or oxygen (O 2 ) with Cu‐based catalysts. Special attention is paid to the controversy related to the identification of active sites, where the oxygen species suitable for CH 4 oxidation are purportedly formed.