Structure du vanadate d'indium: InVO<sub>4</sub>

Touboul, M.; Tolédano, P.

doi:10.1107/s0567740880003020

Cited by 72 publications

(50 citation statements)

References 14 publications

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“…The complex phase transformation and crystalline structure of InVO 4 have been reported by Touboul and co-workers [7][8][9] and Roncaglia et al [10]. A high-temperature stable orthorhombic (Cmcm) InVO 4 -III phase is formed when annealed at 800 • C for 6 h by solid-state reaction method in accordance with the scheme below [8]:…”

Section: Introductionsupporting

confidence: 51%

“…The crystal of InVO 4 is composed of two kinds of polyhedra, octahedron of InO 6 and tetrahedron of VO 4 . They possess two groups of different V-O distances, two short ones of 1.662 Å and two long ones of 1.791 Å [7]. The InO 6 octahedra are connected to each other by sharing edges that form chains along the [0 0 1] direction and are linked by the VO 4 tetrahedra based on the report of Oshikiri et al [18].…”

Section: Synthesis and Phase Analysismentioning

confidence: 97%

See 1 more Smart Citation

Characterization of nano-InVO4 powders synthesized by the hydrothermal process on various In/V molar ratio and soaking conditions

Yao

Lee

Yang

et al. 2009

Journal of Alloys and Compounds

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Section: Introductionsupporting

confidence: 51%

Section: Synthesis and Phase Analysismentioning

confidence: 97%

Characterization of nano-InVO4 powders synthesized by the hydrothermal process on various In/V molar ratio and soaking conditions

Yao

Lee

Yang

et al. 2009

Journal of Alloys and Compounds

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“…The average coordination number becomes larger in order from I to IV indicating that the atomic packing becomes denser in this order. Actually, the volume per formula unit decreases as 78. and Tolé dano (11). Table 5 lists the lattice parameters and…”

Section: Discussionmentioning

confidence: 99%

Hydrothermal Synthesis, Crystal Structure, and Magnetic Properties of FeVO4-II

Oka

Yao

Yamamoto

et al. 1996

Journal of Solid State Chemistry

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“…Numbers I and III refer to the parent InVO4 forms 28) . The orthorhombic form of CrVO4, CrVO4-III, is isostructural to the InVO4-III 27),34), 35) , and the monoclinic form, CrVO4-I, is compared with InVO4-I compound 28) . As for CrVO4-I with isostructure to α-MnMoO4, the Cr and V atoms replace Mn and Mo, respectively, forming CrO6 octahedra and VO4 tetrahdra, respectively.…”

Section: 1 Structures Of Crvo4-i and IIImentioning

confidence: 99%

Preparation of Crystalline CrVO<sub>4</sub> Catalyst by Soft Chemistry Technique and Application for Vapor-phase Oxidation of Picolines

Shishido

2011

J. Jpn. Petrol. Inst.

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A series of Cr _ V mixed oxide catalysts (CrVO4, Cr1-xAlxVO4 and CrV1-xPxO4) have been prepared by "soft chemistry" technique. By mixing the aqueous solution of the raw materials and controlling the pH value, chromium vanadates (CrVO4-I and III) were prepared as the pure orthovanadate crystalline form. Prepared chromium vanadates were employed in the vapor phase oxidation of 2-, 3-, and 4-picolines in order to investigate the relationship between the catalysis and structure of chromium vanadate. CrVO4-I (monoclinic) showed much higher activity than CrVO4-III (orthorhombic), suggesting that the bridging oxygen in the V _ O _ Cr bond is responsible for the catalytic activity. When a part of Cr or V was replaced with Al or P without changing the CrVO4-I type structure, the activities were enhanced. The acidity increased by the replacement of Cr with Al and V with P in CrVO4-I, resulting in the accelerating desorption of products. A partial replacement of V with P significantly improved activity and this is probably due to the modification of the redox properties of V _ O _ Cr site in addition to the accelerating desorption of products. An addition of large amount of steam in the reactants improved the yield of desired products. Both Lewis and Brønsted acid sites were detected on the surface of CrV0.95P0.05O4, and the number of the latter increased by the addition of steam. The enhanced activity by the addition of steam is interpreted by the fact that Brønsted acid sites are produced by the hydrolysis of V _ O _ Cr bond on the surface and activate picoline molecules by withdrawing the electrons of the pyridine ring, and at the same time, enable to accelerate the desorption of the acid products. Even in the absence of gaseous oxygen, the oxygenated products were formed, thus, a Mars and van Krevelen mechanism was suggested. KeywordsChromium vanadate catalyst, Soft chemistry, Picoline, Vapor phase oxidation, Brønsted acid site, Mars and van Krevelen mechanism viewed 21) recently. Shishido and co-workers have reported that CrVO4 prepared by "soft chemistry" technique in the pure crystalline form (CrVO4-I, monoclinic) is also active for the vapor phase oxidation of picolines 22)～26) . In this article, the characterization of Cr _ V mixed oxide catalysts by using XRD, FT-IR, TG-DTA, NH3-TPD, Raman, and TPR techniques, and their catalysis in vapor phase oxidations of 2-, 3-and 4-picolines are demonstrated. The correlation between surface structure and catalytic behavior of a series of Cr _ V mixed oxide catalysts prepared by "soft chemistry" technique are briefly reviewed. Experimental 1. Catalyst PreparationA series of CrVO4, Cr1-xAlxVO4 (x 0.25, 0.5, 0.75 and 1.0) and CrV1-xPxO4 (x 0.02-1.00) catalysts were prepared following method proposed by Touboul and co-workers 27),28) . Aqueous solutions of NH4VO3, Cr(NO3)3 9H2O, Al(NO3)3 9H2O and NH4H2PO4 were mixed and the pH value of the solution was lowered below 1.0 to form homogeneous solution by adding 3 M (1 M 1 mol ・dm -3 ) nitric acid. Then, the pH value of the solution...

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Structure du vanadate d'indium: InVO₄

Cited by 72 publications

References 14 publications

Characterization of nano-InVO4 powders synthesized by the hydrothermal process on various In/V molar ratio and soaking conditions

Characterization of nano-InVO4 powders synthesized by the hydrothermal process on various In/V molar ratio and soaking conditions

Hydrothermal Synthesis, Crystal Structure, and Magnetic Properties of FeVO4-II

Preparation of Crystalline CrVO<sub>4</sub> Catalyst by Soft Chemistry Technique and Application for Vapor-phase Oxidation of Picolines

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Structure du vanadate d'indium: InVO4

Cited by 72 publications

References 14 publications

Characterization of nano-InVO4 powders synthesized by the hydrothermal process on various In/V molar ratio and soaking conditions

Characterization of nano-InVO4 powders synthesized by the hydrothermal process on various In/V molar ratio and soaking conditions

Hydrothermal Synthesis, Crystal Structure, and Magnetic Properties of FeVO4-II

Preparation of Crystalline CrVO<sub>4</sub> Catalyst by Soft Chemistry Technique and Application for Vapor-phase Oxidation of Picolines

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Structure du vanadate d'indium: InVO₄