Preparation And Properties Of The TiO₂-CDs Composite Materials

Solar energy is a renewable clean energy, developing and utilizing solar energy is one of the important ways to solve the energy problem. Titanium dioxide has been widely used for the application in solar cell and photocatalysis. However, due to its wide bandgap, TiO2can only excited with ultra violet (UV) light, which is the minority of solar light. Therefore in order to obtain materials with excellent light response activity, modification is very necessary for TiO2. The carbon dots(CDs) are new functional materials with advantages of non-toxic, biocompatibility, fluorescence stability, wide range absorb spectral, size-dependent photoluminescence, simple preparation, wide source and low cost. TiO2-CDs possess environment friendly and higher photoresponse activity than pure titanium dioxide, and they are a promising candidates for solar energy utilization.In this work, we used two different methods to preparare TiO2-CDs composite materials, and researched their performances.We prepared the TiO2-CDs nanostructure fibers with diameters mainly distributed in the250-500nm range by combining TiO2fibers and CDs with silane coupling agent APS. The TiO2fibers were obtained by electrospinning technique, and CDs were synthesized by using an impregnation method with hard templates as nanoreactors and citric acid as the carbon precursor. TiO2-CDs nanostructure fibers exhibited strong fluorescence and absorption of visible light. And they had higher photoelectric conversion performances and photocatalytic efficiency than pure TiO2fibers or P25in the photocatalytic degradation RhB under visible light irradiation. In addition, the composite fibers had good repeatability, which can be easily recycled through centrifugation.TiO2-CDs with a grain diameter of12-13nm were synthesized by one-pot solvothermal reaction the TiO2precursor, which was mixed carbon source citric acid into the precursor by electrospinning technique. Compare with the TiO2nanoparticles preparared with the same method, the visible and ultra violet light absorption of the TiO2-CDs nanoparticles had been enhanced significantly, and the photocurrent density was nearly doubled. Their photocurrent density was increased with the solvothermal time.