Phase transition in niobium pentoxide supported on silica-alumina

被引：20

作者：

Braga, V. S. ^{[2
]}

Garcia, F. A. C. ^{[1
]}

Dias, J. A. ^{[1
]}

Dias, Silvia C. L. ^{[1
]}

机构：

[1] Univ Brasilia, Inst Quim, Lab Catalise, BR-70904970 Brasilia, DF, Brazil

[2] Univ Fed Bahia, ICADS, BR-47805100 Barreiras, BA, Brazil

来源：

JOURNAL OF THERMAL ANALYSIS AND CALORIMETRY | 2008年 / 92卷 / 03期

关键词：

niobium pentoxide; phase transition; silica-alumina; supported catalyst; thermal analysis;

D O I：

10.1007/s10973-006-8325-4

中图分类号：

O414.1 [热力学];

学科分类号：

摘要：

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 degrees C. This phase transition was studied by XRD, FTIR and Raman spectroscopy. A mixture of orthorhombic (T) and monoclinic (H and M) 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.

引用

页码：851 / 855

页数：5

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