Methanol oxidation over vanadia-based catalysts

Forzatti, Pio; Tronconi, Enrico; Elmi, Ahmed S.; Busca, Guido

doi:10.1016/s0926-860x(97)00026-4

Cited by 110 publications

(79 citation statements)

References 43 publications

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“…On the one hand, this is the excellent example of a relatively simple reaction of selective oxidation, which can produce a wide range of various compounds such as formaldehyde (F), dimethyl ether (DE), methyl formate (MF), dimethoxymethane (DMM), and formic acid (FA) with the selectivities that depend on a catalyst, reaction temperature, conversion, and partial pressures of reactants [1][2][3][4]. For instance, unsupported and silica-supported crystallites of vanadium pentoxide show high selectivity towards formaldehyde with the yield of 96-98 % in the temperature range of 300-400 °С [5][6][7][8].…”

Section: Introductionmentioning

confidence: 99%

Selective oxidation of methanol to form dimethoxymethane and methyl formate over a monolayer V2O5/TiO2 catalyst

Каичев

Popova

Chesalov

et al. 2014

Journal of Catalysis

130

150

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address: vvk@catalysis.ru (V.V. Kaichev). A B S T R A C TThe methanol oxidation over highly dispersed vanadium oxide supported on TiO 2 (anatase) has been investigated by in situ Fourier transform infrared spectroscopy (FTIR), near ambient pressure X-ray photoelectron spectroscopy (NAP XPS), X-ray absorption near edge structure (XANES), and temperature-programmed reaction spectroscopy. The data were complimented with kinetics measurements in a flow reactor. It was found that at low temperatures dimethoxymethane competes with methyl formate, whereas the production of formaldehyde is greatly inhibited. FTIR shows the presence of non-dissociatively adsorbed molecules of methanol, as well as adsorbed methoxy, dioximethylene, and formate species under reaction conditions. According to the NAP XPS and XANES data, the reaction involves the reversible reduction of V 5+ cations, pointing that the vanadia lattice oxygen participates in the methanol oxidation through the classical Mars-van Krevelen mechanism. The detailed mechanism of the methanol oxidation on vanadia catalysts is discussed.

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Section: Introductionmentioning

confidence: 99%

Selective oxidation of methanol to form dimethoxymethane and methyl formate over a monolayer V2O5/TiO2 catalyst

Каичев

Popova

Chesalov

et al. 2014

Journal of Catalysis

130

150

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“…Transition metal oxides are also used to support other oxides in the socalled monolayer catalysts. For example, V 2 O 5 /TiO 2 systems are used for the partial oxidation of methanol, and have been extensively studied in single crystal as well as in powder form [2][3][4][5]. …”

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confidence: 99%

Synthesis of TiO2 nanoparticles on the Au(111) surface

Biener

Farfan-Arribas

Biener

et al. 2005

The Journal of Chemical Physics

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The growth of titanium oxide nanoparticles on reconstructed Au(111) surfaces was investigated by scanning tunneling microscopy and X-ray photoelectron spectroscopy. Ti was deposited by physical vapor deposition at 300 K. Regular arrays of titanium nanoparticles form by preferential nucleation of Ti at the elbow sites of the herringbone reconstruction. Titanium oxide clusters were synthesized by subsequent exposure to O 2 at 300 K. Two-and three-dimensional titanium oxide nanocrystallites form during annealing in the temperature range from 600 to 900 K. At the same time, the Au(111) surface assumes a serrated, <110> oriented step-edge morphology, suggesting step-edge pinning by titanium oxide nanoparticles. The oxidation state of these titanium oxide nanoparticles varies with annealing temperature. Specifically, annealing to 900 K results in the formation of stoichiometric TiO 2 nanocrystals as judged by the observed XPS binding energies. Nano-dispersed TiO 2 on Au(111) is an ideal system to test the various models explaining the enhanced catalytic reactivity of supported Au nanoparticles. IntroductionMetal oxides are of considerable interest because of their technological importance, e.g. in the field of heterogeneous catalysis, where they are used as catalyst supports for a wide variety of metals. The interaction of the adsorbed metal particles with the oxide support is complex and gives rise to interesting phenomena such as the strong metal support interaction (SMSI). This term describes the change in catalytic activity (favoring hydrogenation) observed when group VIII B metals supported on reducible oxides (TiO 2 , TaO 5 , CeO 2 , NbO) are annealed in a reducing atmosphere [1]. Transition metal oxides are also used to support other oxides in the socalled monolayer catalysts. For example, V 2 O 5 /TiO 2 systems are used for the partial oxidation of methanol, and have been extensively studied in single crystal as well as in powder form [2][3][4][5].

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“…However, in addition, this reaction can be also used for determining, in "in-situ" conditions, the acid and redox nature of catalytically active sites of catalysts [3,[36][37][38]. One advantage of methanol compared to other molecules is its high sensitivity to the nature of the surface active sites.…”

Section: Introductionmentioning

confidence: 99%

“…According to Tatibouet [36], the selectivity pattern in methanol transformation and the formation rates of the reaction products can be used to characterize both structural (dispersion), as well as chemical properties (acid-base and redox) of supported oxide catalysts. Thus, methanol transformation can be summarized into three principal reactions [36][37][38][39]: (i) oxidation reactions which need oxygen (molecular or supplied by the catalyst), involving the formation of formaldehyde, formic acid and carbon oxides; (ii) dehydration reactions, which do not need oxygen, carried out by acid catalysts which are involved in the formation of DME; and (iii) both redox and acid reactions, involved in the formation of dimethoxymethane and methyl formate. Several metal oxides, including supported vanadium oxides catalysts, have been studied for methanol oxidation [4,[36][37][38][39].…”

Section: Introductionmentioning

confidence: 99%

“…Thus, methanol transformation can be summarized into three principal reactions [36][37][38][39]: (i) oxidation reactions which need oxygen (molecular or supplied by the catalyst), involving the formation of formaldehyde, formic acid and carbon oxides; (ii) dehydration reactions, which do not need oxygen, carried out by acid catalysts which are involved in the formation of DME; and (iii) both redox and acid reactions, involved in the formation of dimethoxymethane and methyl formate. Several metal oxides, including supported vanadium oxides catalysts, have been studied for methanol oxidation [4,[36][37][38][39]. In addition, a comparison between catalytic performance for oxidation of methanol [39][40][41][42][43] or ethanol [44] and propane ODH has been reported in the last years.…”

Section: Introductionmentioning

confidence: 99%

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Vanadium Supported on Alumina and/or Zirconia Catalysts for the Selective Transformation of Ethane and Methanol

et al. 2018

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Vanadium supported on pure (Al 2 O 3 , ZrO 2 ) or mixed zirconia-alumina (with Al/(Al + Zr) ratio of 0.75 or 0.25) catalysts have been prepared by wet impregnation, using homemade prepared supports. The catalysts have been characterized and tested in the oxidative dehydrogenation (ODH) of ethane and in the methanol aerobic transformation. The catalytic performance strongly depends on the nature of the metal oxide support. Thus, activity decreases in the order: VOx/ZrO 2 > VOx/(Al,Zr-oxides) > VOx/Al 2 O 3 . On the other hand, at low and medium ethane conversions, the selectivity to ethylene presents an opposite trend: VOx/Al 2 O 3 > VOx/(Al,Zr-oxides) > VOx/ZrO 2 . The different selectivity to ethylene at high conversion is due to the lower/higher initial ethylene formation and to the extent of the ethylene decomposition. Interestingly, VOx/(Al,Zr-oxides) with low Zr-loading present the lowest ethylene decomposition. The catalytic results obtained mainly depend on the nature of the supports whereas the role of the dispersion of vanadium species is unclear. In methanol oxidation, the catalysts tested present similar catalytic activity regardless of the support (Al 2 O 3 , ZrO 2 or mixed Al 2 O 3 -ZrO 2 ) but strong differences in the selectivity to the reaction products. Thus, dimethyl ether was mainly observed on alumina-supported vanadium oxide catalysts (which is associated to the presence of acidic sites on the surface of the catalyst, as determined by TPD-NH 3 ). Formaldehyde was the main reaction product on catalysts supported on Zr-containing oxides (which can be related to a low presence of acid sites). In this article, the importance of the presence of acid sites in ethane ODH, which can be estimated using the methanol transformation reaction, is also discussed.

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Methanol oxidation over vanadia-based catalysts

Cited by 110 publications

References 43 publications

Selective oxidation of methanol to form dimethoxymethane and methyl formate over a monolayer V2O5/TiO2 catalyst

Selective oxidation of methanol to form dimethoxymethane and methyl formate over a monolayer V2O5/TiO2 catalyst

Synthesis of TiO2 nanoparticles on the Au(111) surface

Vanadium Supported on Alumina and/or Zirconia Catalysts for the Selective Transformation of Ethane and Methanol

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