Exfoliation of one-dimensional TiO5 chain in K2TiO3.

Potassium titanate, K2TiO3, with a chain structure of TiO5 polyhedra was exfoliated in an aqueous nitric acid solution of pH ≤ 1 and Tyndall scattering due to the colloid formed by the exfoliation was observed. The colloidal particle size measured by dynamic light scattering was approximately 300 nm. The stripe pattern observed by transmission electron microscopy for the aggregated grains after their drying suggested that the TiO5 chains were exfoliated in acid solution. X-ray absorption showed that the coordination polyhedron around Ti(4+) changed from a square pyramid in K2TiO3 powder to a distorted octahedron formed with the additional hydronium ions in the acidic solution.