Summary
The preparation of V2O5/SiO2 mixed gels by the sol-gel process provides a novel class of active catalysts for the selective catalytic reduction (SCR) of nitric oxide [1]. Raman spectroscopy is used to obtain information on the structure of these systems, in which the vanadia species are molecularly dispersed in an amorphous SiO2 matrix. This three-dimensionally linked network exhibits a high stability against thermal aggregation of the vanadia particles. At high vanadia contents small crystalline domains of V6O13 and V3O7 are detected in the Raman spectrum, in accordance with high resolution electron microscopy studies. The controlled grafting of vanadia layers onto the surface of oxidic supports is another attractive route to highly active SCR catalysts. The interaction of the carrier material with the immobilized vanadia layers can be tuned by using TiO2/SiO2 mixed oxide supports. Raman spectroscopy has been used to characterize monolayers of vanadia, which had been immobilized on a 20% TiO2/80% SiO2 mixed oxide from a vanadyl alkoxide precursor. Characteristic vibrations observed in the Raman spectrum, as well as UV-visible reflection data, indicate that the most abundant vanadia species on the surface consists of disordered polymeric arrays: the central vanadium ion is surrounded by one tightly bound vanadyl oxygen, four oxygen ions in the basal plane, and a distant sixth oxygen ligand in bridging position to the support.
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References
Baiker A, Dollenmeier P, Glinski M, Reller A, Sharma VK (1988) J Catal 111:273–285
Baiker A, Dollenmeier P, Glinski M, Reller A (1987) Appl Catal 35:365–380
Wokaun A, Schraml M, Baiker A (1989) J Catal 116:595–599.
Walther KL, Schraml-Marth M, Wokaun A (1990) Catal Lett 4:327–338
Kijenski J, Baiker A, Glinski A, Dollenmeier P, Wokaun A (1986) J Catal 101:1–11.
Baiker A, Dollenmeier P, Glinski M, Reller A (1987) App Catal 35:351–364
Schraml M, Fluhr W, Wokaun A, Baiker A (1989) Ber Bunsenges Phys Chem 93:852–857
Sharma VK, Wokaun A, Baiker A (1986) J Phys Chem 90:2715–2718.
Baiker A, Glinski A, Kijenski J, Sharma VK, Wokaun A (1986) J Phys Chem 90:4217–4218
Cristiani C, Forzatti P, Busca G (1989) J Catal 116:586–589
Le Costumer LR, Taouk B, Le Meur M, Payen E, Guelton M, Grimblot J (1988) J Phys Chem 92:1230–1235
Gilson TR, Bizri OF, Cheetham N (1973) J Chem Soc Dalton Trans, pp 291–294
Beattie IR, Gilson TR (1969) J Chem Soc A:2322–2327
Griffith WP, Wickins TD (1966) J Chem Soc A:1087–1090
Griffith WP, Lesniak JB (1969) J Chem Soc A:1066–1071
Onodera S, Ikegami Y (1980) Inorg Chem 19:615–618
Roozeboom F, Medema J, Gellings PJ (1978) Z Phys Chem 111:215–224
Roozeboom F, Mittelmeijer-Hazeleger MC, Moulijn JA, Medema J, de Beer VHJ, Gellings PJ (1980) J Phys Chem 84:2783–2791
Wachs IF, Saleh RY, Chan SS, Chersich CC (1985) Appl Catal 15:339–352
Bond GC, Brückman K (1981) Faraday Discuss Chem Soc 72:235–246.
Bond GC, Zurita JP, Flamerz S, Gellings JP, Bosch H, van Ommen JG, Kip BJ (1986) Appl Catal 22:361–378
Busca G, Lavalley GC (1986) Spectrochim Acta 42A:443–445
Miyata H, Fujii K, Ono T, Kubokawa Y, Ohno T, Hatayama F (1987) J Chem Soc Faraday Trans I 83:675–685
Bystrom A, Wilhelmi KA, Brotzen O (1950) Acta Chem Scand 4:1119–1130.
Bachmann HG, Ahmed FR, Barnes WH (1961) Z Kristallogr 115:110–131
Iwaki T, Miura M (1971) Bull Chem Soc Jpn 44:1754–1758
Flynn CM, Pope MT (1970) J Am Chem Soc 92:85–90
Schraml-Marth M, Wokaun A, Baiker A (1990) J Catal 124:86–96
Busca G, Centi G, Marchetti L, Trifiro F (1986) Langmuir 2:568–577
Hanke W, Bienert R, Jerschkewitz HG (1975) Z Anorg. Allg Chem 414:109–129
Beattie IR, Gilson TR (1968) Proc Roy Soc A 307:407–429
Fabbri G, Baraldi P (1972) Anal Chem 44:1325–1326.
Frederickson LD, Hansen DM (1963) Anal Chem 35:818–827
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Schraml-Marth, M., Wokaun, A. & Baiker, A. Characterization of V2O5/SiO2- and TiO2/SiO2-mixed gel catalysts by Raman spectroscopy. Fresenius J Anal Chem 341, 87–91 (1991). https://doi.org/10.1007/BF00322114
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DOI: https://doi.org/10.1007/BF00322114