钴和铝层状双氢氧化物的分解：一种新型单相尖晶石氧化物的相分离。

The decomposition of the layered double hydroxides of Co and Al: phase segregation of a new single phase spinel oxide.

作者信息

Babay Salem, Bulou Alain, Mercier Anne Marie, Toumi Mouhamed

机构信息

Laboratory of the Physico-Chemistry of Solid States, LR11 ES51, University of Sfax, Road of Soukra km 4, Sfax 3038, Tunisia.

LUMAN Université, Université du Maine, CNRS UMR 6283, Institut des Molécules et Materiaux du Mans (IMMM), Avenue O. Messiaen, 7285 LE MANS Cedex 9, France.

出版信息

Spectrochim Acta A Mol Biomol Spectrosc. 2015 Apr 15;141:80-7. doi: 10.1016/j.saa.2015.01.021. Epub 2015 Jan 22.

DOI:10.1016/j.saa.2015.01.021

PMID:25659816

Abstract

Monophasic Co-Al-CO3-like layered double hydroxides has been prepared by the coprecipitation method. It has been characterised by Rietveld refinement of the X-ray powder diffraction pattern, DTA-TGA, infrared and Raman spectroscopies. Its structure is trigonal, R3̅m with cell parameters a=0.3061(4) nm and c=2.252 (3) nm. The decomposition of this hydrotalcite-like structure on heating up to 800 °C yields to a single phase spinel oxide. Besides, infrared and Raman spectroscopies showed the presence of spinel-like domains. The results of Rietveld refinement have revealed that this compound has the Fd3̅m space group (a=0.8088(4) nm), with crystallographic formula Co(II)0.75Al0.25 Co(II)0.252Co(III)0.77Al0.98O4, which is of the general formula Co1.77Al1.23O4. This structure is also validated by the charge distribution (CD) analysis.

摘要

采用共沉淀法制备了单相类Co-Al-CO₃层状双氢氧化物。通过对X射线粉末衍射图谱进行Rietveld精修、差示热分析-热重分析、红外光谱和拉曼光谱对其进行了表征。其结构为三方晶系，R3̅m，晶胞参数a = 0.3061(4) nm，c = 2.252(3) nm。这种类水滑石结构在加热至800℃时分解生成单相尖晶石氧化物。此外，红外光谱和拉曼光谱显示存在类尖晶石畴。Rietveld精修结果表明，该化合物具有Fd3̅m空间群（a = 0.8088(4) nm），晶体化学式为Co(II)₀.₇₅Al₀.₂₅ Co(II)₀.₂₅₂Co(III)₀.₇₇Al₀.₉₈O₄，通式为Co₁.₇₇Al₁.₂₃O₄。该结构也通过电荷分布(CD)分析得到了验证。