【摘要】 以六水合硝酸镉为镉源,硝酸锌为锌源,通过硼氢化钠还原硒单质制得NaHSe,并作为硒源,通过胶体化学法制备了一系列具有不同组分的水溶性Cd1-xZnxSe三元量子点。利用X射线粉末衍射仪(XRD)和高分辨透射电镜(HRTEM)分析所制得的Cd1-xZnxSe的晶体结构和形貌,表明所制得三元量子点为立方结构,呈规则球状,平均粒径约为4nm。通过改变三元量子点的Cd和Zn元素的配比,调节Cd1-xZnxSe的能带结构,有效调控其光谱学性质;与ZnSe和CdSe等二元量子点相比,Cd1-xZnxSe的紫外可见光吸收光谱及荧光发射光谱都发生明显的红移。采用直接浸渍法,制备Cd0.5Zn0.5Se三元量子点敏化TiO2纳米管(TNTs)复合材料(Cd0.5Zn0.5Se@TNTs)。TEM结果显示Cd0.5Zn0.5Se三元量子点紧密结合在纳米管表面,红外谱图表明TiO2和Cd0.5Zn0.5Se之间形成Ti—Se键,有利于提高复合材料的稳定性。相对于纯TNTs,复合材料的紫外可见光吸收光谱在可见光区的吸收明显增强,吸收带边从400nm红移至700nm左右;同时,复合Cd0.5Zn0.5Se三元量子点后,可以有效地抑制光生电子-空穴对的复合,提高复合材料在可见光区域的光催化效率。可见光照射60 min后,催化剂Cd0.5Zn0.5Se@TNTs对罗丹明B(RhB)光降解率可达到100%,分别约为纯TNTs和纯Cd0.5Zn0.5Se的3.3倍和2.5倍。更多还原

【Abstract】 In this work,cadmium nitrate hexahydrate[Cd(NO3)2·6H2O]is as a source of cadmium,zinc nitrate[Zn(NO3)2]as a source of zinc source,and NaHSe as a source of selenium which was prepared through reducing the elemental selenium with sodium borohydride(NaBH4).Then water-soluble Cd1-xZnxSe ternary quantum dots with different component were prepared by colloid chemistry.The as-prepared Cd1-xZnxSe ternary quantum dots exhibit stable fluorescent property in aqueous solution,and can still maintain good dispersivity at room temperature for four months.Powder X-ray diffraction(XRD)and high resolution transmission electron microscope(HRTEM)were used to analyze crystal structure and morphology of the prepared Cd1-xZnxSe.It is found that the as-prepared ternary quantum dots are cubic phase,show as sphere,and the average of particle size is approximate 4nm.The spectral properties and energy band structure of the as-prepared ternary quantum dots were modulated through changing the atom ratio of elements Zn and Cd.Compared with binary quantum dots CdSe and ZnSe,the ultraviolet-visible(UVVisible)absorption spectrum and fluorescence(FL)emission spectrum of ternary quantum dots are both red-shift.The composites(Cd0.5Zn0.5Se@TNTs)of Cd0.5Zn0.5Se ternary quantum dots and TiO2nanotubes(TNTs)were prepared by directly immerging TNTs into quantum dots dispersive solution for 5hours.TEM image shows that the Cd0.5Zn0.5Se ternary quantum dots were closely combined to nanotube surface.The infrared spectra show that the Ti-Se bond was formed between Cd0.5Zn0.5Se ternary quantum dots and TiO2 nanotubes,which improve the stability of the composite.Compared to pristine TNTs,UV-Visible absorption spectrum of the composites is significantly enhanced in the visible region of light.And the absorption band edge of Cd0.5Zn0.5Se@TNTs red-shift from 400 to 700nm.The recombination of the photogenerated electron-hole pairs was restrained with the as-prepared ternary quantum dots.Therefore,the visible-light photocatalytic efficiency was greatly improved.After visible-light irradiation for 60 min,the degradation of Cd0.5Zn0.5Se@TNTs photocatalysts for RhB is nearly 100%,which is about 3.3times of that of pristine TNTs and 2.5times of that of pure Cd0.5Zn0.5Se ternary quantum dots,respectively.更多还原