Characterization and reactivity of vanadium oxide catalysts supported on niobia

Chary, Komandur V. R.; Kishan, Gurram; Kumar, Chinthala Praveen; Sagar, Guggilla Vidya; Niemantsverdriet, J.W.

doi:10.1016/s0926-860x(02)00654-3

Cited by 41 publications

(22 citation statements)

References 42 publications

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“…A new V 2p 3/2 peak at 516.4-516.5 eV appears in the reaction mixture pointing to the partial reduction of V 5+ to V 4+ even at room temperature. It should be noted that in the highly cited studies [57][58][59][60][61] [20,[62][63][64][65][66][67][68]. These numbers are in good agreement with our data.…”

Section: In Situ Nap Xps Xanes and Tpr Studysupporting

confidence: 93%

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: In Situ Nap Xps Xanes and Tpr Studysupporting

confidence: 93%

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

View full text Add to dashboard Cite

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“…Many authors have also used the XPS intensity ratio to predict the trend in vanadia dispersion on the support, particularly when V 2 O 5 is supported on metal oxides. In a recent work [32] it has also been proved that similar trend in dispersion behaviour can be obtained by both gas adsorption and XPS intensity ratio techniques. Though the XPS intensity ratio may not provide an absolute value for dispersion, it can be safely considered to understand the general dispersion pattern of vanadia on the support surface.…”

Section: Vanadia Dispersion By Xps Studiessupporting

confidence: 52%

Studies on Preparation, Characterization and Ammoxidation Functionality of Zirconium Phosphate-Supported V2O5 Catalysts

et al. 2006

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Zirconium pyrophosphate (ZrP 2 O 7 ) was synthesized from zirconyl chloride and phosphoric acid. A series of ZrP 2 O 7 -supported V 2 O 5 catalysts, with the oxide loading ranging from 2 to 8 wt.%, was prepared by wet impregnation method. These catalysts were characterized by various techniques like X-ray diffraction, BET surface area, pore size distribution, FT-IR spectroscopy, acidity measurements and X-ray photoelectron spectroscopy. Their catalytic functionality was evaluated in the ammoxidation of 2-methyl pyrazine (MP) to 2-cyano pyrazine (CP). The V 2 O 5 /ZrP 2 O 7 catalysts are found to be highly active and selective. FT-IR profiles of used catalysts indicate the interaction of ammonia with vanadia. The physico-chemical properties of the catalysts are correlated with their activity and nitrile selectivity.KEY WORDS: vanadia catalysts; zirconium pyrophosphate; ammoxidation of 2-methyl pyrazine; vanadium ammonium complex.

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“…This finding indicated that the MFI structure of TS-1 is not collapsed after impregnation of V 2 O 5 . The peak at 2θ, 20.2 corresponding to V 2 O 5 is not observed even for higher loadings which suggests that an amorphous or a highly dispersed state of V 2 O 5 on the surface of the support or the crystallites formed are less than 4 nm in size that is beyond the detection capability of the XRD technique [14,17]. Thus, the absence of any V 2 O 5 or orthovanadate peaks at lower loadings, is a clear indication that vanadia exists in a highly dispersed state on the support surface.…”

Section: A Structural Characterization Of V 2 O 5 /Ts-1 Materialsmentioning

confidence: 97%

Vanadium Contribution to the Surface Modification of Titanium Silicalite for Conversion of Benzene to Phenol

Mulyatun¹,

Prasetyoko²

2011

JTS

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AbstractVanadium oxide supported on the surface of titanium silicalite was investigated in benzene hydroxylation to determine its activity as heterogeneous catalyst. Effect of vanadium loading on structure and activity of titanium silicalite was investigated. On the basis of X-ray diffraction and infrared spectroscopy techniques, it was found that the titanium structure was remained on the modified catalyst. The catalytic activity of the modified catalyst was observed to be higher than that of parent catalyst.Keywordstitanium silicalite, vanadium oxide, hydroxylation, benzene AbstrakAktivitas vanadium oksida yang berada pada permukaan titanium silikalit sebagai katalis heterogen telah diteliti pada hidroksilasi benzena. Pengaruh loading vanadium terhadap struktur dan aktivitas titanium silikalit telah dipelajari. Berdasarkan teknik difraksi sinar-X dan spektroskopi inframerah, ditemukan bahwa titanium pada katalis yang telah dimodifikasi tidak mengalami perubahan struktur. Aktivitas katalitik dari katalis yang telah dimodifikasi diamati lebih tinggi dibandingkan dengan katalis induk.Kata Kuncititanium silikalit, vanadium oksida, hidroksilasi, benzenahenol is an important intermediate compound for the synthesis of petrochemicals, agrochemicals, and plastics. Nowadays approximately 95 % of phenol production was produced by cumene process consisting of three main reaction steps (alkylation of benzene with propylene to cumene, oxidation of cumene to cumene hydroperoxide and decomposition to phenol and acetone) [1]. The advantage of the cumene process is that it takes two inexpensive starting materials, benzene and propylene and converts them into two high value useful products, phenol and acetone, using air. Despite its great success, the cumene process has some disadvantages such as the production of an explosive intermediate (cumene hydroperoxide), it has a high environmental impact, and it uses a corrosive catalyst. It is multi-step process, which makes it difficult to achieve high phenol yields in relation to benzene used and which leads to a high capital investment. It requires the uses of aggressive media (dilute sulphuric acid at 60-70 o C) and has a high acetone production as a co-product which results in an over supply in the market [2]. This situation encouraged scientists to develop other methods for producing phenol from benzene, preferably via a single-step and free of coproducts reaction, which thus would be economically favorable.The direct hydroxylation of benzene to phenol is an attractive alternative to phenol production for economically and environmentally reason [3]. One of the alternative routes to produce phenol which has more Mulyatun is with Department of Chemical Education, Faculty of Education, Institut Agama Islam Negeri Walisongo, Semarang, Indonesia.Didik Prasetyoko is with Department of Chemistry, FMIPA, Institut Teknologi Sepuluh Nopember, Surabaya, 60111, Indonesia. E-mail: didikp@chem.its.ac.id. advantages is through benzene hydroxylation reaction using H 2 O 2 as oxidant agent a...

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Characterization and reactivity of vanadium oxide catalysts supported on niobia

Cited by 41 publications

References 42 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

Studies on Preparation, Characterization and Ammoxidation Functionality of Zirconium Phosphate-Supported V2O5 Catalysts

Vanadium Contribution to the Surface Modification of Titanium Silicalite for Conversion of Benzene to Phenol

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