Oxidation of methane to formaldehyde over FeSiO2 and SnW mixed oxides

Kobayashi, Tetsuhiko; Guilhaume, N.; Miki, Jun; Kitamura, Naoyuki; Haruta, Masatake

doi:10.1016/s0920-5861(96)00173-3

Cited by 68 publications

(17 citation statements)

References 11 publications

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“…The intensity of the transitions at g $ 8.3 and g $ 4.3 increased at lower temperatures, which is typical for paramagnetic species. These signals suggest the presence of isolated Fe 3+ ions with distorted tetrahedral or octahedral coordination [24][25][26]. The broad signal at g ‡ 2.3 decreased in intensity and was shifted to lower magnetic fields at )150°C, thus it does not follow CurieÕs law.…”

Section: Characterization Of Iron Exchanged Catalystsmentioning

confidence: 99%

Investigation of HNCO adsorption and hydrolysis on Fe-ZSM5

et al. 2007

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At 150°C, HNCO adsorbs dissociatively on Fe-ZSM5 producing principally isocyanate species (-NCO) adsorbed on Al and Fe sites. In the presence of water the hydrolysis of the -NCO groups to NH 3 was observed. Comparison of the DRIFT results with measurements of the catalytic activity of coated cordierite monoliths suggests that -NCO groups are likely intermediate species in the hydrolysis of HNCO over Fe-ZSM5.

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Section: Characterization Of Iron Exchanged Catalystsmentioning

confidence: 99%

Investigation of HNCO adsorption and hydrolysis on Fe-ZSM5

et al. 2007

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“…Similarly, the cited ambivalence is also present in the mixed iron oxide from magnetite, the major component in our catalytic system. In fact, meaningful results in methane partial oxidation to formaldehyde have been reported for several catalysts containing iron oxide species [3,[8][9][10][11][12][13][14]. The most encouraging finding to keep deploying resources in CH 4 conversion technology is, indeed, nature's iron-containing active center located in the methane monooxygenase enzyme able to selectively transform CH 4 into methanol, formaldehyde, and formic acid at ambient conditions [76,77].…”

Section: Discussionmentioning

confidence: 97%

“…In any case, the direct oxidation of methane into methanol, formaldehyde, and other oxygenated products is still very far from being competitive for commercial implementation [2,3]. Among the catalysts employed for direct oxidation of methane to formaldehyde using molecular oxygen, those based on vanadium, molybdenum [4][5][6][7], and especially iron [3,[8][9][10][11][12][13][14][15][16][17] have shown the most promising performance. Nevertheless, the yield of formaldehyde reported with these catalysts does not exceed 5% [2,4,8,[18][19][20], although higher yields can be found in the literature for other catalysts.…”

Section: Introductionmentioning

confidence: 99%

(Ag)Pd-Fe3O4 Nanocomposites as Novel Catalysts for Methane Partial Oxidation at Low Temperature

et al. 2020

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Nanostructured composite materials based on noble mono-(Pd) or bi-metallic (Ag/Pd) particles supported on mixed iron oxides (II/III) with bulk magnetite structure (Fe3O4) have been developed in order to assess their potential for heterogeneous catalysis applications in methane partial oxidation. Advancing the direct transformation of methane into value-added chemicals is consensually accepted as the key to ensuring sustainable development in the forthcoming future. On the one hand, nanosized Fe3O4 particles with spherical morphology were synthesized by an aqueous-based reflux method employing different Fe (II)/Fe (III) molar ratios (2 or 4) and reflux temperatures (80, 95 or 110 °C). The solids obtained from a Fe (II)/Fe (III) nominal molar ratio of 4 showed higher specific surface areas which were also found to increase on lowering the reflux temperature. The starting 80 m2 g−1 was enhanced up to 140 m2 g−1 for the resulting optimized Fe3O4-based solid consisting of nanoparticles with a 15 nm average diameter. On the other hand, Pd or Pd-Ag were incorporated post-synthesis, by impregnation on the highest surface Fe3O4 nanostructured substrate, using 1–3 wt.% metal load range and maintaining a constant Pd:Ag ratio of 8:2 in the bimetallic sample. The prepared nanocomposite materials were investigated by different physicochemical techniques, such as X-ray diffraction, thermogravimetry (TG) in air or H2, as well as several compositions and structural aspects using field emission scanning and scanning transmission electron microscopy techniques coupled to energy-dispersive X-ray spectroscopy (EDS). Finally, the catalytic results from a preliminary reactivity study confirmed the potential of magnetite-supported (Ag)Pd catalysts for CH4 partial oxidation into formaldehyde, with low reaction rates, methane conversion starting at 200 °C, far below temperatures reported in the literature up to now; and very high selectivity to formaldehyde, above 95%, for Fe3O4 samples with 3 wt.% metal, either Pd or Pd-Ag.

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“…Kobayashi et al [120] found that highly dispersed tetrahedrally coordinated Fe 3+ species on SiO 2 could significantly boost formaldehyde yields. A study on the effects of direct hydrothermal synthesis (DHT) and template-ion exchange (TIE) methods on the catalytic performance of Fe-MCM-41 catalysts revealed that the DHT method resulted in isolated tetrahedrally coordinated Fe-O species within the support skeleton, whereas the catalysts prepared by the TIE method provided predominantly polymeric, octahedrally coordinated iron oxide clusters.…”

Section: Iron-based Catalystmentioning

confidence: 99%

Gas-Phase Selective Oxidation of Methane into Methane Oxygenates

Park

2022

Catalysts

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Methane is an abundant resource and its direct conversion into value-added chemicals has been an attractive subject for its efficient utilization. This method can be more efficient than the present energy-intensive indirect conversion of methane via syngas, a mixture of CO and H2. Among the various approaches for direct methane conversion, the selective oxidation of methane into methane oxygenates (e.g., methanol and formaldehyde) is particularly promising because it can proceed at low temperatures. Nevertheless, due to low product yields this method is challenging. Compared with the liquid-phase partial oxidation of methane, which frequently demands for strong oxidizing agents in protic solvents, gas-phase selective methane oxidation has some merits, such as the possibility of using oxygen as an oxidant and the ease of scale-up owing to the use of heterogeneous catalysts. Herein, we summarize recent advances in the gas-phase partial oxidation of methane into methane oxygenates, focusing mainly on its conversion into formaldehyde and methanol.

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Oxidation of methane to formaldehyde over FeSiO2 and SnW mixed oxides

Cited by 68 publications

References 11 publications

Investigation of HNCO adsorption and hydrolysis on Fe-ZSM5

Investigation of HNCO adsorption and hydrolysis on Fe-ZSM5

(Ag)Pd-Fe3O4 Nanocomposites as Novel Catalysts for Methane Partial Oxidation at Low Temperature

Gas-Phase Selective Oxidation of Methane into Methane Oxygenates

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