Direct observation of grafting interlayer phosphate in Mg/Al layered double hydroxides
Direct observation of grafting interlayer phosphate in Mg/Al layered double hydroxides
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DOI：
10.1016/j.jssc.2011.11.034
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发表时间：
2012-02
影响因子：
3.3
通讯作者：
Akihiro Shimamura;E. Kanezaki;M. Jones;J. Metson
中科院分区：
文献类型：
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作者：
Akihiro Shimamura;E. Kanezaki;M. Jones;J. Metson
用X射线衍射仪、TG/DTA、FT-IR、XPS和XANES研究了合成的镁铝层状双氢氧化物(LDH-HPO4)与层间磷酸盐的接枝反应。LDH-HPO4晶体的晶层间距随温度的升高分两个阶段减小，第一个转变温度为333K时为1.06 nm至0.82 nm，第二个转变温度为453K时为0.722 nm。第一阶段是由于层间水的损失和层间HPO42−的重排。在第二个转变中，层间磷酸盐通过与层中金属阳离子的直接键合而接枝到层上，并伴随着晶体结构的多型性的变化。接枝的磷酸盐被固定，不能通过与1-辛烷磺酸盐的阴离子交换来去除。LDH在743K时为非晶态，加热到1273K时分解为Mg_3(PO_4)_2、AlPO_4、MgO和MgAl_2O_4。
The grafting of interlayer phosphate in synthetic Mg/Al layered double hydroxides with interlayer hydrogen phosphate (LDH-HPO4) has been studied by XRD, TG/DTA, FT-IR, XPS and XANES. The basal spacing of crystalline LDH-HPO4decreases in two stages with increasing temperature, from 1.06nm to 0.82nm at 333K in the first transition, and to 0.722nm at 453K in the second. The first stage occurs due to the loss of interlayer water and rearrangement of the interlayer HPO42−. In the second transition, the interlayer phosphate is grafted to the layer by the formation of direct bonding to metal cations in the layer, accompanied by a change in polytype of the crystalline structure. The grafted phosphate becomes immobilized and cannot be removed by anion-exchange with 1-octanesulfonate. The LDH is amorphous at 743K but decomposes to Mg3(PO4)2, AlPO4, MgO and MgAl2O4after heated to 1273K.