Morphological control of layered double hydroxide through a biomimetic approach using carboxylic and sulfonic acids

• Layered double hydroxides (LDHs) were synthesized in the presence of organic acids.
• Stacked-disc-shaped LDH crystals were formed in the presence of monoacids.
• Flower-shaped LDH crystals were formed in the presence of diacids and a triacid.
• Morphology of LDH was controlled by the number of functional group on organic acids.

Layered double hydroxides (LDHs) have intercalation properties and are used in various applications. The performances of the LDH materials can be improved by controlling crystal morphology. Morphology of inorganic crystals is controlled by organic molecules in biomineralization. Inspired by biomineralization, we investigated the effect of the addition of mono, di and triacids as morphological control agents on crystal morphology of LDH synthesized by the homogeneous precipitation method. Morphology of LDH was changed from hexagonal plate to stacked disc by addition of monoacids, namely acetic acid and methanesulfonic acid, in the reaction solution. Flower-shaped LDH crystals were formed in the presence of diacids and a triacid, namely succinic acid, 1,2-ethanedisulfonic acid and 1,2,3-propanetricarboxylic acid. We found that the morphology of the LDH crystals was controlled by the number of functional group on the morphological control agent rather than the type of functional group. These findings can contribute for the development of novel and functional LDH materials with precisely controlled morphology.