TiO2 nanoparticles assembled on kaolinites with different morphologies for efficient photocatalytic performance.

Natural kaolinite clays with different dimensionalities (including kaolinite nanoflakes and nanorods) supported TiO₂ nanoparticles were successfully prepared via a facile sol-gel method. Moreover, comparisons between FK/TiO₂ and RK/TiO₂ nanocomposites are conducted in terms of matrix morphology, surface property, energy band structure and interfacial interaction. The effects of kaolinite microstructure, morphology and dimensionality on the interfacial characteristics and photocatalytic properties of the nanocomposites were investigated in detail. The results showed that TiO₂ nanoparticles are more easily attached on the kaolinite nanoflakes, and possess more uniform distribution and smaller particle size than that of kaolinite nanorods. In particular, the FK/TiO₂ nanocatalysts exhibit higher photocatalytic activity for the degradation of tetracycline hydrochloride than that of RK/TiO₂ and bare TiO₂, which is attributed to the stronger surface adsorptivity, higher loading efficiency and smaller grain size. Additionally, FK/TiO₂ composites show excellent stability, which is ascribed to the intimate interfacial contact between two-dimensional kaolinite nanoflakes and TiO₂ nanoparticles. Overall, the enhanced catalytic performance for FK/TiO₂ composites is the synergistic effect of two-dimensional morphology, better adsorption capability and more active photocatalysis TiO₂ species. [ABSTRACT FROM AUTHOR]