Design and mechanism insight on SiC quantum dots sensitized inverse opal TiO2 with superior photocatalytic activities under sunlight

The combination of SiC quantum dots sensitized inverse opal TiO2 photocatalyst is designed in this work and then applied in wastewater purification under simulated sunlight. From various spectroscopic techniques, it is found that electrons transfer directionally from SiC quantum dots to inverse opal TiO2, and the energy difference between their conduction/valence bands can reduce the recombination rate of photogenerated carriers and provide a pathway with low interfacial resistance for charge transfer inside the composite. As a result, a typical type-II mechanism is proved to dominate the photoinduced charge transfer process. Meanwhile, the composite achieves excellent photocatalytic performances (the highest apparent kinetic constant of 0.037 min−1), which is 6.2 times (0.006 min−1) and 2.1 times (0.018 min−1) of the bare inverse opal TiO2 and commercial P25 photocatalysts. Therefore, the stability and non-toxicity of SiC quantum dots sensitized inverse opal TiO2 composite enables it with great potential in practical photocatalytic applications.