Unraveling the activity of iron carbide clusters embedded in silica for thermocatalytic conversion of methane

2021 ◽  
Author(s):  
Gopal Krishna Dixit ◽  
Manish Kumar ◽  
Ankita Katiyar ◽  
Antonius P.J. Jansen ◽  
Sander van Bavel ◽  
...  
Keyword(s):  
High Selectivity ◽  
Iron Carbide ◽  
Silica Substrate ◽  
Conversion Of Methane ◽  
Fe Sites ◽  
Thermocatalytic Conversion

Isolated Fe-sites on silica substrate have recently been reported for direct and non-oxidative conversionof gaseous methane with high selectivity. The activated catalyst was proposed to be FeC2 clusterembedded in silica....

scholarly journals Unraveling the Activity of Iron Carbide Clusters Embedded in Silica for Thermocatalytic Conversion of Methane

2020 ◽  
Author(s):  
Gopal K. Dixit ◽  
Manish Kumar ◽  
Ankita Katiyar ◽  
Antonius P. J. Jansen ◽  
Alexander van Bavel ◽  
...  
Keyword(s):  
Partial Pressure ◽  
Density Functional ◽  
High Selectivity ◽  
Iron Carbide ◽  
Methyl Radical ◽  
Reaction Conditions ◽  
Silica Substrate ◽  
Rate Determining Step ◽  
Conversion Of Methane ◽  
Thermocatalytic Conversion

<p>Isolated Fe-sites on silica substrate have recently been reported for direct and non-oxidative</p> <p>conversion of gaseous methane with high selectivity. The activated catalyst was proposed to be</p> <p>FeC2 cluster embedded in silica. Using a combination of density-functional theoretic methods</p> <p>and micro-kinetic modeling, we show that under the same reaction conditions (1223 K , 1 atm)</p> <p>FeC2 sites convert to FeC3 and the latter is instead responsible for the observed activity. We</p> <p>investigate the detailed mechanism of conversion of methane to methyl radical and hydrogen</p> <p>on FeC3@SiO2 under different conditions of methane partial pressure. We find that methyl</p> <p>radical evolution is the rate-determining step for the overall conversion. Our calculations also</p> <p>indicate that the conversion of embedded FeC3 to FeC4 competes with methyl radical evolution</p> <p>from the active catalyst. However, due to the higher stability of FeC3 sites, we anticipate that</p> <p>formation of higher carbides can be inhibited by controlling the hydrogen partial pressure.</p>

scholarly journals Unraveling the Activity of Iron Carbide Clusters Embedded in Silica for Thermocatalytic Conversion of Methane

2020 ◽  
Author(s):  
Gopal K. Dixit ◽  
Manish Kumar ◽  
Ankita Katiyar ◽  
Antonius P. J. Jansen ◽  
Alexander van Bavel ◽  
...  
Keyword(s):  
Partial Pressure ◽  
Density Functional ◽  
High Selectivity ◽  
Iron Carbide ◽  
Methyl Radical ◽  
Reaction Conditions ◽  
Silica Substrate ◽  
Rate Determining Step ◽  
Conversion Of Methane ◽  
Thermocatalytic Conversion

<p>Isolated Fe-sites on silica substrate have recently been reported for direct and non-oxidative</p> <p>conversion of gaseous methane with high selectivity. The activated catalyst was proposed to be</p> <p>FeC2 cluster embedded in silica. Using a combination of density-functional theoretic methods</p> <p>and micro-kinetic modeling, we show that under the same reaction conditions (1223 K , 1 atm)</p> <p>FeC2 sites convert to FeC3 and the latter is instead responsible for the observed activity. We</p> <p>investigate the detailed mechanism of conversion of methane to methyl radical and hydrogen</p> <p>on FeC3@SiO2 under different conditions of methane partial pressure. We find that methyl</p> <p>radical evolution is the rate-determining step for the overall conversion. Our calculations also</p> <p>indicate that the conversion of embedded FeC3 to FeC4 competes with methyl radical evolution</p> <p>from the active catalyst. However, due to the higher stability of FeC3 sites, we anticipate that</p> <p>formation of higher carbides can be inhibited by controlling the hydrogen partial pressure.</p>

Research Progress on Photocatalytic Activation of Methane to Methanol

2021 ◽  
Author(s):  
Yu dong Tian ◽  
Lingyu Piao ◽  
Xiaobo Chen
Keyword(s):  
Thermodynamic Equilibrium ◽  
Research Progress ◽  
Conversion Of Methane ◽  
Thermocatalytic Conversion

The conversion of methane (CH4) to methanol (CH3OH) has attracted much attention in catalysis. However, the traditional thermocatalytic conversion of CH4 to CH3OH is largely restricted by the thermodynamic equilibrium...

Conversion of methane to ethylene

1997 ◽  
Vol 75 (4) ◽  
pp. 465-468
Author(s):  
B.K. Miremadi ◽  
K. Colbow ◽  
S. Roy Morrison
Keyword(s):  
Ethylene Production ◽  
Active Sites ◽  
High Selectivity ◽  
Oxidation Catalyst ◽  
Ethylene Oxidation ◽  
Lithium Aluminate ◽  
Co Catalyst ◽  
Conversion Of Methane ◽  
Ethylene Selectivity ◽  
Intermediate Value

A lithium aluminate – MgO catalyst has been found to convert methane to ethylene with a high selectivity. The rate of conversion increased when a MoO3 co-catalyst was used to remove the poisoning products. It is shown that for optimum conversion and selectivity to ethylene, the oxygen pressure should be at an intermediate value, high enough to provide active sites but low enough to avoid ethylene oxidation. Thus the oxygen should be "bled-in" along the catalyst bed. In demonstration of these concepts we have shown a 28.6% CH4 conversion with 63.2% ethylene selectivity and 9.8% ethane, producing a C2 yield of about 21.4%. Keywords: methane oxidation, methane conversion, ethylene production, oxidation catalyst, aluminate catalyst.

scholarly journals Isolated Fe Sites in Metal Organic Frameworks Catalyze the Direct Conversion of Methane to Methanol

ACS Catalysis ◽  
2018 ◽  
Vol 8 (6) ◽  
pp. 5542-5548 ◽  
Author(s):  
Dmitrii Y. Osadchii ◽  
Alma I. Olivos-Suarez ◽  
Ágnes Szécsényi ◽  
Guanna Li ◽  
Maxim A. Nasalevich ◽  
...  
Keyword(s):  
Metal Organic Frameworks ◽  
Direct Conversion ◽  
Conversion Of Methane ◽  
Metal Organic ◽  
Fe Sites

Highly efficient conversion of methane to formic acid under mild conditions at ZSM-5-confined Fe-sites

Nano Energy ◽  
2021 ◽  
Vol 82 ◽  
pp. 105718
Author(s):  
Kaixin Zhu ◽  
Suxia Liang ◽  
Xiaoju Cui ◽  
Rui Huang ◽  
Ningbo Wan ◽  
...  
Keyword(s):  
Formic Acid ◽  
Mild Conditions ◽  
Efficient Conversion ◽  
Highly Efficient ◽  
Conversion Of Methane ◽  
Fe Sites

scholarly journals Postbiosynthetic modification of a precursor to the nitrogenase iron–molybdenum cofactor

2021 ◽  
Vol 118 (11) ◽  
pp. e2015361118
Author(s):  
Suppachai Srisantitham ◽  
Edward D. Badding ◽  
Daniel L. M. Suess
Keyword(s):  
Electronic Structures ◽  
Spectroscopic Analysis ◽  
High Selectivity ◽  
Azotobacter Vinelandii ◽  
Molecular Level ◽  
High Yield ◽  
Promising Strategy ◽  
Fe Sites ◽  
Site Selective ◽  
Iron Molybdenum Cofactor

Nitrogenases utilize Fe–S clusters to reduce N2 to NH3. The large number of Fe sites in their catalytic cofactors has hampered spectroscopic investigations into their electronic structures, mechanisms, and biosyntheses. To facilitate their spectroscopic analysis, we are developing methods for incorporating 57Fe into specific sites of nitrogenase cofactors, and we report herein site-selective 57Fe labeling of the L-cluster—a carbide-containing, [Fe8S9C] precursor to the Mo nitrogenase catalytic cofactor. Treatment of the isolated L-cluster with the chelator ethylenediaminetetraacetate followed by reconstitution with 57Fe2+ results in 57Fe labeling of the terminal Fe sites in high yield and with high selectivity. This protocol enables the generation of L-cluster samples in which either the two terminal or the six belt Fe sites are selectively labeled with 57Fe. Mössbauer spectroscopic analysis of these samples bound to the nitrogenase maturase Azotobacter vinelandii NifX reveals differences in the primary coordination sphere of the terminal Fe sites and that one of the terminal sites of the L-cluster binds to H35 of Av NifX. This work provides molecular-level insights into the electronic structure and biosynthesis of the L-cluster and introduces postbiosynthetic modification as a promising strategy for studies of nitrogenase cofactors.

Photocatalytic and Thermocatalytic Conversion of Methane

Solar RRL ◽  
2021 ◽  
pp. 2000596
Author(s):  
Zhonghua Li ◽  
Zhiguo Yi ◽  
Zhaosheng Li ◽  
Zhigang Zou
Keyword(s):  
Conversion Of Methane ◽  
Thermocatalytic Conversion
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