NaYF4:Yb,Tm与CdS量子点协同提高二氧化钛光催化性能

NaYF4: Yb,Tm and CdS Quantum Dots Collaborate to Improve Photocatalytic Performance of Titanium Dioxide

上转换材料可将低能红外光转换为高能可见光或紫外光,而量子点敏化可调节TiO2的能带宽度。本实验首先合成nc-TiO2纳米晶胶体,制成nc-TiO2膜,再进行CdS量子点敏化,与制得的NaYF4:Yb,Tm进行复合。对所得的CdS QDs/TiO2/NaYF4:Yb,Tm复合膜采用TEM和XRD,以及上转换荧光表征,并借用探针反应,测试膜的光催化活性。结果表明在全光照射下,CdS QDs/TiO2和TiO2/NaYF4:Yb,Tm及CdS QDs/TiO2/NaYF4:Yb,Tm复合膜的光催化降解速率分别是TiO2的1.8,1.4和2.6倍,说明NaYF4:Yb,Tm与量子点可协同提高二氧化钛全波段光催化性能。

The up-conversion materials can convert the low-energy infrared light into high-energy visible light or ultraviolet light.It is also known that the absorbing edges of TiO2 can be broadened to visible light by the quantum dot sensitization.The nanocrystalline TiO2 was first synthesized and coated on glass substrate to form the nc-TiO2 membrane,and then the nc-TiO2 membrane was sensitized by CdS quantum dots,and combined with the up-conversion materials NaYF4:Yb,Tm prepared by pyrolysis.The obtained CdS QDs/TiO2/NaYF4:Yb,Tm composite membranes were characterized by TEM,XRD and up-conversion fluorescence spectroscopy.The photocatalytic activity of the composite membranes was tested by photocatalytic degradation of Rhodamine B.The results showed that under white light-irradiation,the photocatalytic degradation rates of Rhodamine B on CdS QDs/TiO2 composite membranes and TiO2/NaYF4:Yb,Tm composite membrane were 1.8 and 1.4 times of TiO2,respectively.The photocatalytic performance of the ternary composite membrane,CdS QDs/TiO2/NaYF4:Yb,Tm composite,was even 2.6 times that of TiO2.It can be seen that the up-conversion materials and the quantum dots can synergistically improve the photocatalytic performance of titanium dioxide and enhance the utilization of solar light effectivly through the full band absorption.