Study of Dispersion and Thermal Stability of V2O5/TiO2−SiO2 Catalysts by XPS and Other Techniques

Reddy, Benjaram M.; Ganesh, Ibram; Reddy, E. Padmanabha

doi:10.1021/jp963091o

Cited by 131 publications

(80 citation statements)

References 46 publications

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“…[23] reported the formation of ZrMo2O8 by heating ZrO2 with MoO3 together which showed the IR bands at 980, 920 and 800 cm -1 . Beside that anatase and rutile phase of titania normally exhibits the strong absorption band in the region of 850-650 cm -1 and 800-650 cm -1 respectively [28]. Absence of any band around 1000 cm -1 confirms that Mo oxide is in highly dispersed state in to a titania zirconia mixed oxide support, which is inline with the XRD results.…”

Section: Ft-irsupporting

confidence: 83%

Mixed Oxide Supported MoO3 Catalyst: Preparation, Characterization and Activities in Nitration of o-xylene

Kemdeo

Sapkal

Chaudhari

2010

Bull. Chem. React. Eng. Catal.

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TiO2-ZrO2 mixed oxide support was prepared and impregnated with 12 wt % MoO3 and calcined at various temperatures. The resultant catalyst systems were characterized by XRD, FT-IR, BET, SEM, NH3-TPD and pyridine adsorbed FT-IR methods to know the physico-chemical changes occurred in course of thermal treatment. Activities of these catalysts were tested by employing them in the nitration of o-xylene. Mostly, 500 oC calcined catalyst sample was found to be most active for nitration reaction. Catalyst calcined at higher temperatures showed the negative influence on o-xylene conversion and 4-nitro-o-xylene selectivity. Conversion can be correlated with the presence of strong Brönsted acid sites over the catalyst surface whereas change in selectivity was found attributed to the pore diameter of the catalyst. These catalysts also performed satisfactorily, when used for nitration of other aromatics. No use of corrosive sulfuric acid and efficient reusability of the catalyst make the process environmentally friendly and economic. © 2010 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0)

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Section: Ft-irsupporting

confidence: 83%

Mixed Oxide Supported MoO3 Catalyst: Preparation, Characterization and Activities in Nitration of o-xylene

Kemdeo

Sapkal

Chaudhari

2010

Bull. Chem. React. Eng. Catal.

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“…It is generally agreed that TiO 2 as anatase phase gives rise to superior active catalysts as compared to TiO 2 as rutile phase [8,9,[11][12][13][14][15].…”

Section: Introductionmentioning

confidence: 99%

Surface Characterisation of V2O5/TiO2 Catalytic System

Rodella

Nascente

Franco

et al. 2001

phys. stat. sol. (a)

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Samples of the V 2 O 5 /TiO 2 system were prepared by the sol-gel method and calcined at different temperatures. Surface species of vanadium, their dispersion, as well as the structural evolution of the system were analysed by XRD, Raman, EPR, and XPS techniques. The results of XRD showed the evolution of TiO 2 from anatase phase to rutile phase. The Raman spectra for calcination temperatures up to 500 C showed a good dispersion of vanadium over titania in the form of monomeric vanadyl groups (V 4þ ) and polymeric vanadates (V 5þ ). At least three families of V 4þ ions were identified by EPR investigations. Two kinds of isolated V 4þ species are placed in sites of octahedral symmetry, substituting Ti 4þ in the rutile phase. The third is formed by pairs of V 4þ species on the surface of titania. Above 500 C part of superficial V 4þ is inserted into the matrix of titania and part is oxidized to V 5þ . The XPS results showed that the V/Ti ratio rises with increasing calcination temperature, indicating a smaller dispersion of vanadium.

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“…This may be ascribed to the blockage of the support pores by CeO 2 , which can be observed in the impregnated sample [29]. While for 8Ce-SBA-15 synthesized by the direct hydrothermal method, CeO 2 was better dispersed, which is supported by the XRD patterns in Fig.…”

Section: Catalytic Testing Of Co/ce-sba-15mentioning

confidence: 58%

Synthesis of mesoporous Co/Ce-SBA-15 materials and their catalytic performance in the catalytic oxidation of benzene

Tian

et al. 2008

Materials Research Bulletin

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Cerium-containing SBA-15 mesoporous materials, with different Ce/Si molar ratios, were synthesized by a direct hydrothermal synthesis method and further modified by impregnation with 10, 15 and 20 wt.% Co. Characterizations by powder X-ray diffraction (XRD), N 2 sorption, inductively coupled plasma (ICP) and UV-vis spectroscopy were carried out. The small-angle XRD and N 2 sorption characterizations showed that these Co supported materials have less-ordered mesoporous structures with partial blockage of pores, and their specific surface area, pore volume and pore size were relatively lower than those of unsupported ceriumcontaining SBA-15. Spinel Co 3 O 4 constituted the predominant cobalt phase in the prepared catalysts, and CeO 2 was also detected. All the Co supported catalysts exhibited high catalytic activity in the oxidation of benzene. #

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Study of Dispersion and Thermal Stability of V₂O₅/TiO₂−SiO₂ Catalysts by XPS and Other Techniques

Cited by 131 publications

References 46 publications

Mixed Oxide Supported MoO3 Catalyst: Preparation, Characterization and Activities in Nitration of o-xylene

Mixed Oxide Supported MoO3 Catalyst: Preparation, Characterization and Activities in Nitration of o-xylene

Surface Characterisation of V2O5/TiO2 Catalytic System

Synthesis of mesoporous Co/Ce-SBA-15 materials and their catalytic performance in the catalytic oxidation of benzene

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