Controlled growth of BaMoO4 hierarchical superstructures in functionalized ionic liquids

摘要

Dual-functionalized ionic liquids (ILs) containing both unctionalized cation and anion offer scope for tuning of nucleation and growth steps to achieve crystallographic control. BaMoO4 crystals synthesized in alkyl methylimidazolium trifluoroacetate ([Cnmim]TA, n = 4, 8, 16) aqueous solution display the similar shuttle-like shape. The size of building blocks assembling into the hierarchical architectures has been influenced by the inhibiting effect of the imidazolium substituent alkyl chain. With the increase of imidazolium substituent alkyl chain length, the building blocks change from the truncated octahedron to the nanosheet. The single-crystalline BaMoO4 dendrites were prepared under the direction of [Omim]TA via the oriented attachment mechanism. BaMoO4 porous structures have been successfully synthesized in the [Omim]TA aqueous solution via the manipulation of the growth kinetics. Whether the resultant holes in the BaMoO4 structure are open or clogged depends upon variations in the molar ratio [Ba2+]/[Mo7O24 6–]. Shuttle-like BaMoO4 crystals made of nanosheets with the helical growth features have been successfully synthesized in the presence of [C16mim]TA. In addition, the amount of [C16mim]TA in the solution profoundly influences the morphology and size of the as-obtained products.