Phase transition in niobium pentoxide supported on silica-alumina |
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| Authors: | V. S. Braga F. A. C. Garcia J. A. Dias Sílvia C. L. Dias |
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| Affiliation: | (1) Universidade Federal da Bahia (UFBA), Instituto de Ciências Ambientais e Desenvolvimento Sustentável (ICADS) Rua Professor José Seabra S/N, Barreiras-BA, 47805-100, Brazil;(2) Universidade de Brasília, Instituto de Química, Laboratório de Catálise, caixa postal 04478, Brasília-DF, 70904-970, Brazil |
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| Abstract: | Nb2O5 supported on SiO2-Al2O3 were prepared with a wide loading range (2, 5, 10, 15, 20 and 25 mass%) and analyzed by simultaneous thermogravimetric (TG) and differential thermal analysis (DTA). The materials presented a phase transition close to 1364°C. This phase transition was studied by XRD, FTIR and Raman spectroscopy. Amixture of orthorhombic (T) andmonoclinic (H andM) crystalline phases was evidenced in the supported samples, which is coverage dependent, in contrast to the formation of only the monoclinic phase (H and M) when pure Nb2O5 is heated under the same conditions. These results indicate the stabilization of Nb2O5 on silica-alumina surface. |
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| Keywords: | niobium pentoxide phase transition silica-alumina supported catalyst thermal analysis |
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