Direct oxidation of CH4 to HCOOH over extra-framework stabilized Fe@MFI catalyst at low temperature
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作者
HIGHLY SELECTIVE OXIDATION; METHANE OXIDATION; FORMIC-ACID; DIRECT CONVERSION; ZEOLITES; FE-ZSM-5; DIOXIDE; SYSTEM; OXYGEN; SITES
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刊物名称
Fuel
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年、卷、文献号
2021, 305, 121624
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关键词
HIGHLY SELECTIVE OXIDATION; METHANE OXIDATION; FORMIC-ACID; DIRECT CONVERSION; ZEOLITES; FE-ZSM-5; DIOXIDE; SYSTEM; OXYGEN; SITES
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摘要
Direct oxidation of methane to formic acid under mild conditions is an attractive and challenging topic for methane upgrade. Fe-containing MFI-type zeolite (ZSM-5) has been recognized as a potential catalyst for this reaction. Herein, we demonstrate a simple method to crack the Fe/ZSM-5 into nanosized crystals and translate the isolated Fe3+ located in or outside the framework to extra-framework Fe ensemble species (dimer, oligomer and cluster) through high energy ball milling. The resultant catalysts exhibit up to 148% times increase in activity and provide higher formic acid selectivity and reliable stability for methane direct oxidation to formic acid with H2O2 as oxidant. The turnover frequency of Cl products over a 0.03%Fe/ZSM-5 catalyst is as high as 8380 h(-1) with 96% of formic acid selectivity at 70 degrees C. Our work provides a valuable example for the design of an efficient catalyst for methane oxidation or even other light hydrocarbon carbohydrate oxidation processes.
