Dehydration and Dehydroxylation of Layered Double Hydroxides: New Insights from Solid-State NMR and FT-IR Studies of Deuterated Samples

作者：Yu Guiyun; Zhou Yahui; Yang Rong; Wang Meng; Shen Li; Li Yuhong; Xue Nianhua; Guo Xuefeng; Ding Weiping; Peng Luming^*

来源：Journal of Physical Chemistry C, 2015, 119(22): 12325-12334.

DOI：10.1021/acs.jpcc5b01449

The dehydration and dehydroxylation processes (25-375 degrees C) of a variety of Mg and Al containing layered double hydroxides (LDHs), (Mg1-xAlx(OH)(2)(A(n-))(x/n)center dot yH(2)O, where x = 0.197-0.273 and A(n-) = NO3-, ClO4-, Cl-, or CO32-) were carefully investigated by using high resolution solid-state H-1 and Al-27 solid-state NMR, as well as FT-IR spectroscopy on deuterated samples. Dehydration is found to occur at a lower temperature (usually below 150 degrees C) than dehydroxylation (usually above 150 degrees C), the latter consisting of two subprocesses. Definitive evidence shows that the dehydroxylation of Mg2AlOH species start at a lower temperature than Mg3OH, however, the temperature ranges for the two processes overlap significantly. Furthermore, dehydration and dehydroxylation are affected by both the nature of the charge compensating anions in the interlayer and the ratio of the intralayer cations (Mg/Al). The fact that FT-IR spectra with higher resolution can be obtained on deuterated samples implies this approach can be readily used for in situ study of LDHs.

• 出版日期2015-6-4
• 单位盐城工学院; 南京大学