Mesoporous TiO2 modified with carbon quantum dots as a high-performance visible light photocatalyst

We report a preparation method for visible light responsive Carbon Quantum Dots (CQDs) embedded in mesoporous TiO2 materials. The as-prepared mesoporous TiO2 (meso-Ti-450) material is a member of the recently designed University of Connecticut (UCT) mesoporous materials family. The UCT materials were synthesized based on sol-gel chemistry. The nanoparticles are randomly packed in inverse surfactant micelles and mesopores are formed by interconnected intraparticles. To achieve full usage of the visible region of sunlight (>400 nm), CQDs were introduced without destroying the mesopores. The photocatalytic performance of the CQDs/meso-Ti-450 was investigated by the degradation of methylene blue. Due to the up-conversion property and electron withdrawing property of CQDs, the photocatalytic activity of the composite material was largely enhanced under visible light irradiation. The highest photocatalytic activity was achieved by 5% CQDs/meso-Ti-450 in an hour. Compared to commercial P25, which is capable of removing 10% methylene blue (MB) under visible light conditions, the 5% CQDs/meso-Ti-450 can mostly remove MB (98%) under the same conditions. To date, the usage of mesoporous titanium oxide and carbon material composites for dye degradation under visible light has not been reported. (C) 2016 Elsevier B.V. All rights reserved.