Mechanochemical approaches to synthesize layered double hydroxides: a review

• The syntheses of LDH by mechanochemistry, the processes and the characterization methods of the products have been reviewed.
• The mechanochemical intercalations of LDH with and without solvent have been compared.
• The characterization techniques used in mechanochemical approaches to synthesize LDH has been summarized.
• The mechanochemical approaches may contribute new applications for LDH.

Layered double hydroxides (LDH) have been extensively studied because of their unique characteristics. The available reviews have dealt with the applications of LDH normally prepared with aqueous solution approaches. Recently mechanochemical ways to synthesize LDH and intercalated LDH have received more and more attention from researchers and several mechanochemical processes have been reported. This article reviews the recent advances in the preparation and intercalation of layered double hydroxides by mechanochemical approaches. Although conventional solution methods for the syntheses of LDH were widely studied, several problems remain to be resolved; such as treatment of aqueous waste, high energy consumption, complex operation etc. It is believed that mechanochemical methods may have potentials to effectively overcome the difficulties and also to synthesize various new types of LDH with further development of this new technique.