K_(3)ScF_(6)∶Tm^(3+),Yb^(3+)/CdS光催化复合材料的制备及其光催化性能研究

Preparation and Photocatalytic Properties of K_(3)ScF_(6)∶Tm^(3+),Yb^(3+)/CdS Photocatalytic Composites

上转换材料与光催化剂复合可以产生吸收光谱“红移”的效果,对提高光催化剂的降解效率具有重要意义。为了提高CdS对近红外光的利用率,通过高温固相反应法合成了冰晶石结构上转换发光材料K_(3)ScF_(6)∶Tm^(3+),Yb^(3+),并采用高能球磨法将其与CdS复合制备出一种新型光催化复合材料K_(3)ScF_(6)∶Tm^(3+),Yb^(3+)/CdS。采用X射线粉末衍射(XRD)、场发射扫描电镜(SEM)、荧光光谱(PL)和紫外-可见漫反射吸收光谱对其成分、结构和性能进行了系统表征。同时,对不同复合比例下制备的复合催化剂对罗丹明B(RhB)的光降解效率和K_(3)ScF_(6)∶Tm^(3+),Yb^(3+)/CdS光催化复合材料的光催化机理进行了研究。结果表明,K_(3)ScF_(6)∶Tm^(3+),Yb^(3+)和CdS的最佳复合比为3.6∶1,上转换发光材料K_(3)ScF_(6)∶Tm^(3+),Yb^(3+)的引入协同促进了CdS的光催化作用,光催化过程中·OH与·O^(2-)均参与了对RhB的降解,并且·OH起主要作用。此外,在最佳复合比下,经过80 min,K_(3)ScF_(6)∶Tm^(3+),Yb^(3+)/CdS样品降解率达到99.9%,与未复合的CdS相比,降解率提高了近50倍。所有结果表明K_(3)ScF_(6)∶Tm^(3+),Yb^(3+)/CdS光催化复合材料在光催化领域具有潜在的应用价值。

The combination of up-conversion materials and photocatalysts can produce the effect of“redshifting”of absorption spectrum,which is of great significance for improving the degradation efficiency of photocatalysts.To improve the utilization of CdS in near-infrared light,the up-conversion luminescent material K_(3)ScF_(6)∶Tm^(3+),Yb^(3+)with cryolite structure was synthesized by high-temperature solid-phase reaction method,and a new photocatalytic composite material K_(3)ScF_(6)∶Tm^(3+),Yb^(3+)/CdS was prepared by combining it with CdS by high-energy ball milling method.The composition,structure and properties were systematically characterized by X-ray powder diffractometer(XRD),field emission scanning electron microscopy(SEM),fluorescence spectroscopy(PL)and UV-Vis diffuse reflection absorption spectroscopy.Simultaneously,the photodegradation efficiency and mechanism of K_(3)ScF_(6)∶Tm^(3+),Yb^(3+)/CdS to rhodamine B(RhB)were studied.The results show that the optimal mass composition ratio of K_(3)ScF_(6)∶Tm^(3+),Yb^(3+)and CdS is 3.6∶1,and the introduction of up-conversion luminescent materials K_(3)ScF_(6)∶Tm^(3+),Yb^(3+)synergistically promots the photocatalytic efficiency of CdS.The·OH and·O^(2-)participated in the degradation of RhB,and·OH plays a major role.In addition,under the optimal recombination ratio,the degradation rate of K_(3)ScF_(6)∶Tm^(3+),Yb^(3+)/CdS samples reaches 99.9%,which is nearly 50 times higher than that of uncompounded CdS after 80 min.All results show that K_(3)ScF_(6)∶Tm^(3+),Yb^(3+)/CdS photocatalytic composites has potential application value in the field of photocatalysis.