Tuneable ultra high specific surface area Mg/Al-CO3 layered double hydroxides

Abstract

We report the synthesis of tuneable ultra high specific surface area Aqueous Miscible Organic solvent-Layered Double Hydroxides (AMO-LDHs). We have investigated the effects of different solvent dispersion volumes, dispersion times and the number of re-dispersion cycles specific surface area of AMO-LDHs. In particular, the effects of acetone dispersion on two different morphology AMO-LDHs (Mg₃Al-CO₃ AMO-LDH flowers and Mg₃Al-CO₃ AMO-LDH plates) was investigated. It was found that the amount of acetone used in the dispersion step process can significantly affect the specific surface area of Mg₃Al-CO₃ AMO-LDH flowers while the dispersion time in acetone is critical factor to obtain high specific surface area Mg₃Al-CO₃ AMO-LDH plates. Optimisation of the acetone washing steps enables Mg₃Al-CO₃ AMO-LDH to have high specific surface area up to 365 m² g⁻¹ for LDH flowers and 263 m² g⁻¹ for LDH plates. In addition, spray drying was found to be an effective and practical drying method to increase the specific surface area by a factor of 1.75. Our findings now form the basis of an effective general strategy to obtain ultrahigh specific surface area LDHs.