Selective oxygen species for the oxidative coupling of methane

Kim, Il-Ho; Lee, Gihoon; Na, Hyon Bin; Ha, Jeong‐Myeong; Jung, Ji Chul

doi:10.1016/j.mcat.2017.03.012

Cited by 85 publications

(56 citation statements)

References 49 publications

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“…224,225 The low yields for C 2+ hydrocarbons obtained so far are largely due to secondary oxidation reactions of these reactive products with oxygen weakly bound to the surface of the catalyst and with oxygen in the gas phase, forming a significant amount of CO x . 71,222,226,227 More recently, the upper yield limit for C 2+ products in the absence of gas phase reactions was estimated to be as high as 60% at elevated pressure, which could possibly be achieved via chemical looping. 225,228 Experiments with doped-Mg 6 MnO 8 and Mn/Na 2 WO 4 /SiO 2 , a catalyst previously shown to attain single pass C 2+ product yields of B25% in co-feed mode, 229,230 gave C 2+ product yields of 23.2% and 25%, respectively under a chemical looping mode.…”

Section: View Article Onlinementioning

confidence: 99%

Chemical looping beyond combustion – a perspective

Zhu

Imtiaz

Donat

et al. 2020

Energy Environ. Sci.

367

179

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Section: View Article Onlinementioning

confidence: 99%

Chemical looping beyond combustion – a perspective

Zhu

Imtiaz

Donat

et al. 2020

Energy Environ. Sci.

367

179

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“…For OCM reactions, it is suggested that O species such as O − , or O 2 2− and O 2 − play a very important role in the activation of CH 4 . Hence, O 2 in the feed is critical for these reactions.…”

Section: Resultsmentioning

confidence: 99%

Catalytic coupling of CH₄ with CHF₃ for the synthesis of VDF over LaOF catalyst

et al. 2018

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The oxidative coupling of methane (OCM) with CHF3 facilitates the synthesis of vinylidene fluoride (VDF). The aim is to utilize CHF3, which is otherwise considered a waste with a very high global warming potential. This study focuses on the effect of a LaOF catalyst on OCM occurring in the presence of CHF3, which engenders a promoting effect of O2 on CH4 activation. It examines the structural and phase changes of the lanthanum catalyst during the reaction and then speculates on the reaction mechanism. In combining OCM with CHF3, both the conversion of CH4 and the formation rate of VDF are almost tripled at 700°C. However, at higher temperatures, gas‐phase reactions play a dominating role in the conversion of CH4 and LaOF catalyst plays a very minor role in the reaction system at elevated temperatures. Irrespective of the reaction temperature, VDF is produced via the gas‐phase coupling of CH3 radicals with CF2. During pretreatment or during the reaction itself, La2O3 is fluorinated by CHF3 and HF, yielding the formation of surface LaOF and LaF3 species. LaF3 is a relatively inactive catalyst for CH4 conversion, whereas, in comparison LaOF appears to play a very important role in the activation of CH4 at low temperatures. The activation mechanism of CH4 at relatively low temperatures is similar with that postulated to occur during the OCM. © 2018 Society of Chemical Industry and John Wiley & Sons, Ltd.

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“…Finally, they proposed that the catalytic activity and selectivity towards the desired products were higher for the optimized catalyst (Sn 5 Li 5 ) than Mn-Na 2 WO 4 /SiO 2 at a lower temperature (750 • C), which is considered a state-of-the-art catalyst for OCM. Kim et al [37] carefully explored the role of oxygen species using lanthanum-based perovskite catalysts, which are prepared by a citrate sol-gel method. Their study found that the active surface lattice oxygen species and a facile filling of lattice oxygen vacancies by gas-phase oxygen are responsible for the production of C 2 hydrocarbons in OCM.…”

Section: Alkali/alkaline Earth Metal Doped/supported On Metal Oxide Catalystsmentioning

confidence: 99%

Oxidative Coupling of Methane: Perspective for High-Value C2 Chemicals

Murthy

Liu

et al. 2021

Crystals

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The oxidative coupling of methane (OCM) to C2 hydrocarbons (C2H4 and C2H6) has aroused worldwide interest over the past decade due to the rise of vast new shale gas resources. However, obtaining higher C2 selectivity can be very challenging in a typical OCM process in the presence of easily oxidized products such as C2H4 and C2H6. Regarding this, different types of catalysts have been studied to achieve desirable C2 yields. In this review, we briefly presented three typical types of catalysts such as alkali/alkaline earth metal doped/supported on metal oxide catalysts (mainly for Li doped/supported catalysts), modified transition metal oxide catalysts, and pyrochlore catalysts for OCM and highlighted the features that play key roles in the OCM reactions such as active oxygen species, the mobility of the lattice oxygen and surface alkalinity of the catalysts. In particular, we focused on the pyrochlore (A2B2O7) materials because of their promising properties such as high melting points, thermal stability, surface alkalinity and tunable M-O bonding for OCM reaction.

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Selective oxygen species for the oxidative coupling of methane

Cited by 85 publications

References 49 publications

Chemical looping beyond combustion – a perspective

Chemical looping beyond combustion – a perspective

Catalytic coupling of CH₄ with CHF₃ for the synthesis of VDF over LaOF catalyst

Oxidative Coupling of Methane: Perspective for High-Value C2 Chemicals

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Selective oxygen species for the oxidative coupling of methane

Cited by 85 publications

References 49 publications

Chemical looping beyond combustion – a perspective

Chemical looping beyond combustion – a perspective

Catalytic coupling of CH4 with CHF3 for the synthesis of VDF over LaOF catalyst

Oxidative Coupling of Methane: Perspective for High-Value C2 Chemicals

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Catalytic coupling of CH₄ with CHF₃ for the synthesis of VDF over LaOF catalyst