Revisiting the Thermal Decomposition of Layered γ-Titanium Phosphate and Structural Elucidation of Its Intermediate Phases

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• 作者：Santiago Garca-Granda ; Sergei A. Khainakov ; Aranzazu Espina ; Jos R. Garca ; Germn R. Castro ; Joo Rocha ; Lus Mafra
• 刊名：Inorganic Chemistry
• 出版年：2010
• 出版时间：March 15, 2010
• 年：2010
• 卷：49
• 期：6
• 页码：2630-2638
• 全文大小：955K
• 年卷期：v.49,no.6(March 15, 2010)
• ISSN：1520-510X

文摘

The thermal transformations of γ-titanium phosphate, Ti(PO₄)(H₂PO₄)·2H₂O, have been studied by thermal analyses (thermogravimetry (TG) and differential thermal analysis (DTA)) and variable-temperature ³¹P magic-angle spinning (MAS)/CPMAS and 2D ³¹P−³¹P spin-exchange NMR. The structure of this material has been refined from synchrotron powder X-ray diffraction data (monoclinic, P2₁, a = 5.1811(2) Å, b = 6.3479(2) Å, c = 23.725(2) Å, β = 102.57(1)°). Vyazovkin’s model-free kinetic algorithms have been applied to determine the apparent activation energy to both dehydration and dehydroxylation of γ-titanium phosphate. In these processes, several overlapped steps have been detected. Structural models for Ti(PO₄)(H₂PO₄)·H₂O and Ti(PO₄)(H₂P₂O₇)_0.5 intermediate layered phases have been proposed.