Probing The Thermal Decomposition Process Of Layered Double Hydroxides Through In Situ 57fe Mössbauer And In Situ X-ray Diffraction Experiments

The thermal decomposition properties of Mg-Fe hydrotalcites were studied through in situ 57Fe Mössbauer spectroscopy and in situ X-ray diffraction. Abrupt changes in the quadrupolar splitting measured in the Mössbauer spectra revealed a phase transition from the starting lamellar structure to a new crystalline arrangement. By analyzing the Mössbauer parameters we show that the material is highly disordered in the 300-400 °C temperature range. This hypothesis is confirmed by the X-ray results whose diffractograms indicated the collapse of the lamellar structure and the formation of a solid solution. © Springer Science+Business Media, LLC 2007.422534538Cavani, F., Trifirò, F., Vaccari, A., (1991) Catal Today, 11, p. 173De Roy, A., Forano, C., El Malki, K., Besse, J.P., (1992) Expanded clays and other microporous materials, 2, p. 108. , Occelli ML, Robson HE Eds, Reinhold, New York, pChoudary, B.M., Chowdari, N.S., Jyothi, K., Kantam, M.L., (2003) J Mol Catal A, 196, p. 151Hermosín MC Pavlovic, I., Ulibarri, M.A., Cornejo, J., (1996) Water Res, 30, p. 171Parker, L.M., Milestone, N.B., Newman, R.H., (1995) Ind Eng Chem Res, 34, p. 196Diaz-Nava, C., Solache-Rios, M., Olguin, M.T., (2003) Sep Sci Technol, 38, p. 131Kovanda, F., Grygar, T., Dornicak, V., (2003) Solid State Sci, 5, p. 1019Newman, S.P., Jones, W., (1998) New J Chem, 22, p. 105Khan, A.I., O'hare, D., (2002) J Mater Chem, 12, p. 3191Kooli, F., Depege, C., Ennaqadi, A., De Roy, A., Besse, J.P., (1997) Clays Clay Miner, 45, p. 92Rocha, J., Del Arco, M., Rives, V., Ulibarri, M.A., (1999) J Mater Chem, 9, p. 2499Rajamathi, M., Nataraja, G.D., Ananthamurthy, S., Kamath, P.V., (2000) J Chem Mater, 10, p. 2754Hibino, T., Tsunashima, A., (2000) J Mater Sci Lett, 19, p. 1403Ulibarri, M.A., Pavlovic, I., Hermosín, M.C., Cornejo, J., (1995) Appl Clay Sci, 10, p. 131Shin, H.S., Kim, M.J., Nam, S.Y., Moon, H.C., (1996) Water Sci Technol, 34, p. 161Rey, F., Fornes, V., Rojo, J.M., (1992) J Chem Soc Faraday Trans, 88, p. 2233Hudson, M.J., Carlino, S., Apperley, D.C., (1995) J Mater Chem, 5, p. 323Del Arco, M., Malet, P., Trujillano, R., Rives, V., (1999) Chem Mater, 11, p. 624Rives, V., (2002) Mater Chem Phys, 75, p. 19Aisawa, S., Hirahara, H., Uchiyama, H., Takahashi, S., Narita, E., (2002) J Solid State Chem, 167, p. 152Kovanda, F., Balek, V., Dornicak, V., Martinec, P., Maslan, M., Bilkova, L., Kolousek, D., Bountsewa, I.M., (2003) J Therm Anal Calorim, 71, p. 727Seida, Y., Nakano, Y., (2000) Water Res, 34, p. 1487Kumbhar, P.S., Sanches-Valente, J., Millet, J.M.M., Figueras, F., (2000) J Catal, 191, p. 467Tu, M., Shen, J., Chen, Y., (1997) Thermochim Acta, 302, p. 117Ge, X., Li, M., Shen, J., (2001) J Solid State Chem, 161, p. 38Rives, V., Dubey, A., Kannan, S., (2001) Phys Chem Chem, 3, p. 4826Rives, V., Kannan, S., (2000) J Mater Chem, 10, p. 489Kanezaki, E., (1998) Solid State Ionics, 106, p. 279Ferreira, O.P., Alves, O.L., Gouveia, D.X., Souza Filho, A.G., Paiva, J.A.C., Mendes Filho, J., (2004) J Solid State Chem, 177, p. 3058Vaysse, C., Guerlou-Demourgues, L., Delmas, C., (2002) Inorg Chem, 41, p. 6905Kanezaki, E., (1998) Inorg Chem, 37, p. 2588Goldannskii, V.I., Herber, R.H., (1968) Chemical application of Mössbauer spectroscopy, , Academic Press, London(1971) Mössbauer spectroscopy, , Greenwood NN, TC Gibb ed, Chapman and Hall, Londo

Thermally Stimulated Depolarization Current And Mössbauer Spectroscopy Of Iron-doped Niobophosphate Glasses

Niobophosphate glasses (P2O5-PbO-Nb2O5-K2O-XFe2O3), were studied using thermally stimulated depolarization currents and Mössbauer spectroscopy in samples of different iron concentrations, and were subjected to oxidation and reduction processes. The use of both techniques provided new information about the distribution of iron and niobium between tetrahedral and octahedral sites. © 1993 Chapman & Hall.28164305431