The role of potassium chlorate on expansion of dickite layers and the preparation of a novel TiO2 impregnated dickite photocatalyst using expanded dickite as carrier

Abstract

The layered dickite particles were expanded by rapidly heating the mixture of dickite–urea intercalation complex and KClO₃. Then a novel TiO₂ impregnated dickite photocatalyst was prepared from expanded dickite (used as a carrier) and TiOSO₄ aqueous suspension. The resulting expanded dickite particles and the reaction mechanism were characterized by X-ray diffraction, infrared spectroscopy, scanning electron microscopy, transmission electron microscopy, energy-dispersive spectrometry and specific surface area test. Results showed KClO₃ reacted rapidly with the urea molecules remaining on the surfaces of the dickite–urea intercalation complex in the rapid heating process. A large number of gases produced from the reaction expanded the dickite layers. The expanded layers could reach 20 nm thick and their average specific surface area was nearly ten times larger than that of raw dickite. The exposed inner surfaces of the expanded dickite were new places where TiO₂ particles deposited. Photocatalytic activity was evaluated by the degradation of methyl orange in aqueous solutions. The TiO₂/dickite photocatalyst had a porous layer structure and nano-size TiO₂ particles, and demonstrated an enhanced adsorption and photocatalytic ability for the removal of methyl orange.