A time resolved, in-situ X-ray diffraction study of the de-intercalation of anions and lithium cations from [LiAl2(OH)(6)](n)X center dot qH(2)O (X = Cl-, Br-, NO3-, SO42-)

作者：Tarasov KA; Isupov VP; Chupakhina LE; O'Hare D^*

来源：Journal of Materials Chemistry, 2004, 14(9): 1443-1447.

DOI：10.1039/b314473a

The layered double hydroxides (LDHs), [LiAl2(OH)(6)](n)X.qH(2)O (Xn- = Cl-, Br-, NO3-, SO42-) spontaneously lose both Li+ cations and Xn- anions to give crystalline Al(OH)(3) on stirring in water. The kinetics of this topochemical de-intercalation reaction have been studied using time-resolved, in-situ energy dispersive X-ray powder diffraction. The temperature dependence of the rate of the de-intercalation reaction yields activation energies of 94 +/- 15 kJ mol(-1) for mono-dispersed [LiAl2(OH)(6)]Cl.1.5H(2)O crystallites (particle size 5-10 mum) and 117 +/- 15 kJ mol(-1) for poly-dispersed [LiAl2(OH)(6)]Cl.1.5H(2)O crystallites (particle size 1-30 mum). The rate of ion de-intercalation was found to decrease as the H2O/LDH ratio decreased. The rate of the de-intercalation has also been shown to be dependent on the interlayer anion, with the reaction rates NO3- > Cl- > Br-. In the case of SO42- rapid de-intercalation only goes to 40% completion.

• 出版日期2004-5-7