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.