Formic Acid Production Via Methane Peroxide Oxidation Over Oxalic Acid Activated Fe-MFI Catalysts

Taran, Oxana P.; Yashnik, S. A.; Boltenkov, Vadim V.; Пархомчук, Е. В.; Sashkina, K. A.; Ayusheev, Artemiy B.; Babushkin, Dmitrii E.; Parmon, Valentin N.

doi:10.1007/s11244-019-01151-8

Cited by 10 publications

(8 citation statements)

References 80 publications

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“…After synthesis, Fe-ZSM-5 is ion-exchanged and calcined to remove the organic template and generate acidity. During calcination, certain Fe atoms migrate out of the zeolite framework and transform into extra-framework Fe species, taking the forms of Fe-oxo (Fe x O y ) clusters in the micropores or oxide particles on the external surface of zeolites. ,, …”

Section: Introductionmentioning

confidence: 99%

“…The conventional routes for CH 4 conversion include steam reforming, , dry reforming, , oxidative coupling, , and dehydroaromatization, , which often require harsh reaction conditions to activate the highly stable C–H bonds. Selective oxidation is another compelling route for CH 4 conversion that directly produces multiple oxygenated compounds, such as methanol, , formic acid, , and acetic acid, , under relatively mild conditions. The selective oxidation of CH 4 with molecular oxygen (O 2 ) , or other inexpensive oxidants (e.g., N 2 O and H 2 O) has been demonstrated in gas-phase reactions using zeolite-supported Cu catalysts and in liquid-phase reactions using zeolite-supported noble metals (e.g., Rh, Ir, and Au/Pd) catalysts.…”

Section: Introductionmentioning

confidence: 99%

“…Despite the coexistence of multiple Fe species in Fe-ZSM-5 and the lack of evidence for their respective roles, the extra-framework binuclear Fe species are generally considered to be the active sites for the selective oxidation of CH 4 , ,− possibly because the well-known enzyme soluble CH 4 monooxygenase (sMMO) contains a di-iron center as the active site . Combining the results of X-ray absorption spectroscopy and theoretical calculations, Hammond et al concluded that the binuclear Fe species in Fe-ZSM-5 is [Fe 2 (μ 2 -OH) 2 (OH) 2 (H 2 O) 2 ] 2+ bound to two ion-exchange (Al) sites in the zeolite framework. − They proposed that, following the addition of H 2 O 2 , the two Fe centers synergistically activate CH 4 , with Fe(IV)O extracting an H atom from CH 4 and Fe–OOH capturing the produced methyl radical .…”

Section: Introductionmentioning

confidence: 99%

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Maximizing Active Fe Species in ZSM-5 Zeolite Using Organic-Template-Free Synthesis for Efficient Selective Methane Oxidation

Cheng

Yao

et al. 2023

J. Am. Chem. Soc.

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The selective oxidation of CH4 in the aqueous phase to produce valuable chemicals has attracted considerable attention due to its mild reaction conditions and simple process. As the most widely studied catalyst for this reaction, Fe-ZSM-5 demonstrates high intrinsic activity and selectivity; however, Fe-ZSM-5 prepared using conventional methods has a limited number of active Fe sites, resulting in low CH4 conversion per unit mass of the catalyst. This study reports a facile organic-template-free synthesis strategy that enables the incorporation of more Fe into the zeolite framework with a higher dispersion degree compared to conventional synthesis methods. Because framework Fe incorporated in this way is more readily transformed into isolated extra-framework Fe species under thermal treatment, the overall effect is that Fe-ZSM-5 prepared using this method (Fe-HZ5-TF) has 3 times as many catalytically active sites as conventional Fe-ZSM-5. When used for the selective oxidation of CH4 with 0.5 M H2O2 at 75 °C, Fe-HZ5-TF produced a high C1 oxygenate yield of 109.4 mmol gcat –1 h–1 (a HCOOH selectivity of 91.1%), surpassing other catalysts reported to date. Spectroscopic characterization and density functional theory calculations revealed that the active sites in Fe-HZ5-TF are mononuclear Fe species in the form of [(H2O)3Fe(IV)O]2+ bound to Al pairs in the zeolite framework. This differs from conventional Fe-ZSM-5, where binuclear Fe acts as the active site. Analysis of the catalyst and product evolution during the reaction suggests a radical-driven pathway to explain CH4 activation at the mononuclear Fe site and subsequent conversion to C1 oxygenates.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Maximizing Active Fe Species in ZSM-5 Zeolite Using Organic-Template-Free Synthesis for Efficient Selective Methane Oxidation

Cheng

Yao

et al. 2023

J. Am. Chem. Soc.

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show abstract

“…The conventional routes for CH 4 conversion include steam reforming 2,3 , dry reforming 4,5 , oxidative coupling 6,7 , and dehydroaromatization 8,9 , which often require harsh reaction conditions to activate the highly stable C-H bonds. Selective oxidation is another compelling route for CH 4 conversion that directly produces multiple oxygenated compounds, such as methanol 10,11 , formic acid 12,13 , and acetic acid 14,15 , under relatively mild conditions. The selective oxidation of CH 4 with molecular oxygen (O 2 ) 16,17 or other inexpensive oxidants (e.g., N 2 O 16 and H 2 O 18 ) has been demonstrated in gas-phase reactions using zeolite-supported Cu catalysts and in liquid-phase reactions using zeolite-supported noble metals (e.g., Rh 14 , Ir 19 , and Au/Pd 10 ) catalysts.…”

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Maximizing Active Fe Species in ZSM-5 Zeolite Using Organic-Template-Free Synthesis for Efficient Selective Methane Oxidation

Cheng

Yao

et al. 2022

Preprint

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The selective oxidation of CH4 in the aqueous phase to produce valuable chemicals has attracted considerable research attention due to its mild reaction conditions and simple process. As the most widely studied catalyst for this reaction, Fe-containing ZSM-5 zeolite (Fe-ZSM-5) demonstrates high intrinsic activity and selectivity; however, Fe-ZSM-5 prepared using conventional methods has a limited number of active Fe sites, resulting in low CH4 conversion per unit mass of the catalyst. To address this issue, this study reports a facile organic-template-free synthesis strategy that enables the incorporation of more Fe into the zeolite framework with a higher dispersion degree compared to conventional synthesis methods. Because framework Fe incorporated in this way is more readily to transform into isolated extra-framework Fe species under thermal treatment, the overall effect is that Fe-ZSM-5 prepared using this method (Fe-HZ5-TF) has three times as many catalytically active sites as conventional Fe-ZSM-5. When used for the selective oxidation of CH4 (30.5 bar) with 0.5 M H2O2 at 75°C, Fe-HZ5-TF produced a record high C1 oxygenate yield of 106.3 mmol gcat−1 h− 1 (a HCOOH selectivity of 91.3%), surpassing other catalysts reported to date. Spectroscopic characterization and density functional theory calculations revealed that the active sites in Fe-HZ5-TF are mononuclear Fe species in the form of [(H2O)3Fe(IV) = O]2+ bound to Al pairs in the zeolite framework. This differs from conventional Fe-ZSM-5, where binuclear Fe acts as the active site. Analysis of the catalyst and product evolution during the reaction suggests a radical-driven pathway to explain CH4 activation at the mononuclear Fe site and subsequent conversion to C1 oxygenates.

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Zeolite Synthesis in the Presence of Metallosiloxanes for the Quantitative Encapsulation of Metal Species for the Selective Catalytic Reduction (SCR) of NO_x

et al. 2023

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Metal encapsulation in zeolitic materials through one‐pot hydrothermal synthesis (HTS) is an attractive technique to prepare zeolites with a high metal dispersion. Due to its simplicity and the excellent catalytic performance observed for several catalytic systems, this method has gained a great deal of attention over the last few years. While most studies apply synthetic methods involving different organic ligands to stabilize the metal under synthesis conditions, here we report the use of metallosiloxanes as an alternative metal precursor. Metallosiloxanes can be synthesized from simple and cost‐affordable chemicals and, when used in combination with zeolite building blocks under standard synthesis conditions, lead to quantitative metal loading and high dispersion. Thanks to the structural analogy of siloxane with TEOS, the synthesis gel stabilizes by forming siloxane bridges that prevent metal precipitation and clustering. When focusing on Fe‐encapsulation, we demonstrate that Fe‐MFI zeolites obtained by this method exhibit high catalytic activity in the NH3‐mediated selective catalytic reduction (SCR) of NOx along with a good H2O/SO2 tolerance. This synthetic approach opens a new synthetic route for the encapsulation of transition metals within zeolite structures.

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Formic Acid Production Via Methane Peroxide Oxidation Over Oxalic Acid Activated Fe-MFI Catalysts

Cited by 10 publications

References 80 publications

Maximizing Active Fe Species in ZSM-5 Zeolite Using Organic-Template-Free Synthesis for Efficient Selective Methane Oxidation

Maximizing Active Fe Species in ZSM-5 Zeolite Using Organic-Template-Free Synthesis for Efficient Selective Methane Oxidation

Maximizing Active Fe Species in ZSM-5 Zeolite Using Organic-Template-Free Synthesis for Efficient Selective Methane Oxidation

Zeolite Synthesis in the Presence of Metallosiloxanes for the Quantitative Encapsulation of Metal Species for the Selective Catalytic Reduction (SCR) of NO_x

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Formic Acid Production Via Methane Peroxide Oxidation Over Oxalic Acid Activated Fe-MFI Catalysts

Cited by 10 publications

References 80 publications

Maximizing Active Fe Species in ZSM-5 Zeolite Using Organic-Template-Free Synthesis for Efficient Selective Methane Oxidation

Maximizing Active Fe Species in ZSM-5 Zeolite Using Organic-Template-Free Synthesis for Efficient Selective Methane Oxidation

Maximizing Active Fe Species in ZSM-5 Zeolite Using Organic-Template-Free Synthesis for Efficient Selective Methane Oxidation

Zeolite Synthesis in the Presence of Metallosiloxanes for the Quantitative Encapsulation of Metal Species for the Selective Catalytic Reduction (SCR) of NOx

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About

Zeolite Synthesis in the Presence of Metallosiloxanes for the Quantitative Encapsulation of Metal Species for the Selective Catalytic Reduction (SCR) of NO_x