Multi-component in situ and in-step formation of visible-light response C-dots composite TiO2 mesocrystals

Carbon dots (C-dots) modified mesocrystal TiO2 photocatalysts have been synthesized by a solvothermal process with L-ascorbic acid (LA) as a carbon source. The novel photocatalyst exhibited considerable visible light absorption, large specific surface area (>100 m(2) g(-)1) and abundant mesopore structures. Compared with P25 and the prepared single mesocrystal TiO2, C-dots modified mesocrystal TiO2 demonstrated robustly visible photoactivity for the degradation of methyl orange (MO). Based on the characterization and analysis, an in situ and in-step formation mechanism for C-dots and mesostructured TiO2 composites via the complexation of LA with Ti-precursors has been proposed. The experimental results with other carbon precursors confirmed the supposition. This work contributed novel, high surface area and mesopore structured photocatalysts responding to visible light and provided a simple strategy for the preparation of C-dots-TiO2 composite structures.