Local Environments and Lithium Adsorption on the Iron Oxyhydroxides Lepidocrocite (-FeOOH) and Goethite (
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- 作者：Jongsik Kim ; Ulla Gro Nielsen ; Clare P. Grey
- 刊名：Journal of the American Chemical Society
- 出版年：2008
- 出版时间：January 30, 2008
- 年：2008
- 卷：130
- 期：4
- 页码：1285 - 1295
- 全文大小：652K
- 年卷期：v.130,no.4(January 30, 2008)
- ISSN：1520-5126
文摘
fchars/gamma.gif" BORDER=0 >-FeOOH). 2H variable-temperature (VT) MAS NMRexperiments were performed, showing the presence of short-range, strong antiferromagnetic correlations,even at temperatures above the Néel temperature, TN, 77 K. The formation of a Li+ inner-sphere complexon the surface of lepidocrocite was confirmed by the observation of a signal with a large 7Li hyperfine shiftin the 7Li MAS NMR spectrum. The effect of pH and relative humidity (RH) on the concentrations of Li+inner- and outer-sphere complexes was then explored, the concentration of the inner sphere complexincreasing rapidly above the point of zero charge and with decreasing RH. Possible local environments ofthe adsorbed Li+ were identified by comparison with other layer-structured iron oxides such as fchars/gamma.gif" BORDER=0 >-LiFeO2and o-LiFeO2. Li+ positions of Li+-sorbed and exchanged goethite were reanalyzed on the basis of thecorrelations between Li hyperfine shifts and Li local structures, and two different binding sites were proposed,the second binding site only becoming available at higher pH.