Preparation and characterisation of mesoporous photoactive Na-titanate microspheres

Mesoporous Na-titanate microspheres were fabricated by a simple low temperature hydrothermal synthesis. Microspheres were obtained after treating TiO2 (Degussa P-25) with a mixture of sodium hydroxide (NaOH) and hydrogen peroxide (H2O2) at 25 °C and 80 °C. The as-prepared powders were characterised by X-ray diffraction, N2 adsorption–desorption measurements and scanning electron microscope/energy dispersive X-ray spectroscopy. The as-prepared microspheres were calcined at 550 °C to investigate the effect of calcination on morphology and characteristics. Microspheres were tested for the adsorption and photodecomposition of methylene blue (MB) under ultraviolet light. The results revealed that microspheres with average diameter of 700 nm were formed by self-assembly of tiny TiO2 nanoparticles during the reaction at 25 °C, whereas spherical aggregation of nanofibres was detected in powders produced at 80 °C. Calcination of samples had low impact on morphology, adsorption and photocatalytic degradation of MB. These novel materials are effective adsorbents of MB, and also capable of its photodecolorisation.