Oversized Titania Nanosheet Crystallites Derived from Flux-Grown Layered Titanate Single Crystals

This paper reports on the synthesis and characterization of oversized titania nanosheets derived from single crystals of a potassium lithium titanate, K0.8Ti1.73Li0.27O4. The single crystals with a lateral size of over 1 mm were obtained via a melt and recrystallization process in a flux melt. The crystals were converted into an acid-exchanged form of H1.07Ti1.73O4·H2O, and then was reacted with aqueous tetrabutylammonium (TBA) ions at various concentrations. X-ray diffraction analysis revealed that the titanate crystals exhibited high degrees of swelling, and exfoliated single sheets were obtained at a molar TBA dose of 0.5−1 with respect to the exchangeable protons in H1.07Ti1.73O4·H2O. Observations by transmission electron microscopy and atomic force microscopy detected very large nanosheet crystallites with a lateral size of several tens of micrometers. Some wrinkles and cracks within the crystallites indicated that they were highly flexible and also fragile.