Preparation Of Layered Double Hydroxides And Layered Double Oxides Films

Layered double hydroxides (LDHs), also known as hydrotalcite-like materials, are a class of synthetic anionic clays. Recently ternary layered double hydroxides (LDHs) and layered double oxides (LDO) have been intensively studied and potentially applied to many fileds, especially much attention has been paid to catalysts or catalyst support. This present work is aimed at the synthesis of ternary LDHs and LDO films as potential catalytic materials easy to separate and recycle. The main results are as follows:On the base of optimum conditions of MgAl LDH powders prepared by urea coprecipitation, ternary LDH films have been prepared on the surface of Anode Aluminum Oxide (AAO) at 120℃for 72 hours by urea method. The resulting films were characterized by XRD, FT-IR, SEM, EDS and BET. The results show that reslting films consist of single phase crystal plates of LDHs grown vertically on the AA0/A1 substrate, and film thickness is about 4 micron. The effect of preparation conditions on microstructure of the films was also investigated, such as reaction time, additive amount of urea, total concentration of M²⁺ and the ratio of M₁²⁺/M₂²⁺.