Development of active oxide catalysts for the direct oxidation of methane to formaldehyde

Herman, R.G.; Sun, Qun; Shi, Chunlei; Klier, K.; Wang, Chuan-Bao; Hu, Hangchun; Wachs, Israel E.; Bhasin, Madan M.

doi:10.1016/s0920-5861(96)00256-8

Cited by 80 publications

(49 citation statements)

References 38 publications

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“…Supported vanadium oxides exhibit a large potential as heterogeneous catalysts in a variety of oxidation reactions such as the selective oxidation of methane [1][2][3][4][5][6] and methanol [7][8][9] to formaldehyde or the oxidative dehydrogenation of ethane and propane. [10][11][12][13] Regarding technical applications, catalytic processes based on the oxidative transformation of alkanes to olefins or oxygenates are still scarce.…”

Section: Introductionmentioning

confidence: 99%

Nature of dispersed vanadium oxide: influence of the silica support structure and synthesis methods

Chlosta

Tzolova-Müller

Schlögl

et al. 2011

Catal. Sci. Technol.

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Dispersed vanadium oxide samples were prepared on the basis of two differently structured high surface area silica materials (Aerosil 300, SBA-15). For each support material incipient wetness impregnation and a grafting/ion exchange procedure were applied to prepare catalyst samples with comparable vanadium density. The influence of the silica support material and preparation method on the vanadium oxide structure and dispersion has been studied using diffuse reflectance UV-Vis spectroscopy, visible Raman spectroscopy and X-ray photoelectron spectroscopy (XPS). By independent spectroscopic characterization a fully consistent picture regarding the relation of the structure (UV-Vis, Raman) and dispersion (XPS) is developed. Based on the present structural data and recent findings the dispersed vanadium oxide is proposed to consist of monomers and oligomers with a distorted tetrahedral (VO 4 ) structure containing one short VQO bond. A different degree of hydroxylation of vanadium gives rise to two VQO stretching bands at 1027 and 1040 cm À1. The structure and dispersion of vanadium oxide are more strongly influenced by the support material than by the synthesis method. In this regard the Aerosil 300 samples show a higher degree of oligomerization, i.e. less dispersion of the surface vanadium oxide species, than the SBA-15 samples. Likewise incipient wetness impregnation leads to more oligomerized species than grafting/ion-exchange.

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Section: Introductionmentioning

confidence: 99%

Nature of dispersed vanadium oxide: influence of the silica support structure and synthesis methods

Chlosta

Tzolova-Müller

Schlögl

et al. 2011

Catal. Sci. Technol.

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“…Therefore, silica seems to be the material of choice considering its weak interaction with vanadium oxides as well as with other transition metal oxides. [10][11][12] Supported vanadium oxide catalysts have great potential for a variety of oxidation reactions such as selective oxidation of o-xylene to phthalic anhydride, [13][14][15][16] selective oxidation of methane [17][18][19][20][21][22] and methanol [23][24][25] to formaldehyde, and oxidative dehydrogenation of ethane and propane. [26][27][28][29] The properties of supported vanadium oxide catalysts have been the subject of recent reviews.…”

Section: Introductionmentioning

confidence: 99%

Nanostructured Vanadium Oxide Model Catalysts for Selective Oxidation Reactions

Heß

2009

ChemPhysChem

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Controlled synthesis based on spectroscopic characterization, structure, and catalytic performance of mesoporous silica SBA-15-supported vanadium oxide model catalysts (see TEM image) are reviewed. The effect of water on the structure and dispersion of highly dispersed vanadium oxide is discussed in the light of recent results in multiple in situ spectroscopy.Characterization of the synthesis, structure, and catalytic performance of vanadium oxide catalysts supported on mesoporous silica SBA-15 for selective oxidation reactions are reviewed. Controlled synthesis on the basis of surface functionalization and ion exchange allows homogeneous deposition of vanadium oxide within the pores of SBA-15. Catalytic tests on the selective oxidation of methanol and propane demonstrate the full catalytic function of these model powder catalysts. Characterization of the dehydrated state by vibrational spectroscopy provides insight into the structure of SBA-15-supported vanadium oxide at low loadings. The effect of water on the structure and dispersion of highly dispersed vanadium oxide is discussed in light of recent results from multiple in situ spectroscopy.

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“…Several supported oxide catalysts have been employed for this reaction at atmospheric pressure, among them are the supported MoO 3 catalysts, which have been reported to be one of the most active and selective ones for oxygenate production [4][5][6][7][8][9][10][11][12][13]. Silica as a support has been widely used in metal oxide catalysts for methane partial oxidation, and a number of papers have illustrated that silica itself shows discernible activity for formaldehyde formation [14][15][16].…”

Section: Introductionmentioning

confidence: 99%

On the Reactivity of Mo Species for Methane Partial Oxidation on Mo/HMCM-22 Catalysts

et al. 2004

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By characterizing fresh and used Mo/HMCM-22 catalysts with ICP-AES, XRD, NH 3 -TPD technique, UV-Vis DRS and UV Raman spectroscopy, the reactivity of Mo species for methane partial oxidation into formaldehyde were directly studied with a new point of view. By comparing the fresh and used catalysts, it was found that the tetrahedral Mo species bonding chemically to the support surface were practically unchanged after the reaction, while the polymolybdate octahedral Mo species, which had a rather weak interaction with the MCM-22 zeolite, leached out during the reaction, especially when the Mo loading was high. Correspondingly, it was found from the time-on-stream reaction data that the HCHO yield remained unchanged, while CO x decreased with the reaction time during the reaction. By combining the characterization results and the reaction data, it can be drawn that the isolated tetrahedral molybdenum oxo-species (T d ) is responsible for HCHO formation, while the octahedral polyoxomolybdate species (O h ) will lead to the total oxidation of methane.

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Development of active oxide catalysts for the direct oxidation of methane to formaldehyde

Cited by 80 publications

References 38 publications

Nature of dispersed vanadium oxide: influence of the silica support structure and synthesis methods

Nature of dispersed vanadium oxide: influence of the silica support structure and synthesis methods

Nanostructured Vanadium Oxide Model Catalysts for Selective Oxidation Reactions

On the Reactivity of Mo Species for Methane Partial Oxidation on Mo/HMCM-22 Catalysts

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