内嵌硫化镉与上转换纳米颗粒的二氧化钛复合纳米管用于近红外光驱动光催化（英文）

发布时间：2019-03-29 14:40

【摘要】：由于近红外光在太阳光谱中占44%,因此,近红外光驱动的光催化剂的研制具有十分重要的意义.上转换发光材料可将低能量的近红外光子转换为高能光子,这种高能光子可以通过构建荧光共振转移系统将能量转移并活化量子效率较高的半导体材料,对于太阳能的转化利用具有潜在的应用前景.在本文中,通过胶体化学的过程在电纺丝制备的内嵌CdS纳米颗粒以及上转换荧光纳米颗粒(UCNPs)的二氧化硅复合纳米纤维表面外延生长一层二氧化钛层,通过高温煅烧得到二氧化钛复合纳米管.我们通过二氧化硅结构将CdS纳米颗粒与上转换荧光纳米颗粒紧紧束缚在一起,实现较高的荧光共振能量转移.而且,选择β-NaYF_4:Yb(30%),Tm(0.5%)@NaYF_4:Yb(20%),Er(2%)作为纳米能量转换器,替代以前研究工作中使用的β-NaYF_4:Yb(30%),Tm(0.5%)或者β-NaYF_4:Yb(30%),Tm(0.5%)@NaYF_4纳米颗粒,来进一步提高近红外光的转换效率.通过透射电子显微镜照片很清楚的观察到制备的Ti O2复合纳米管内部内嵌有大量的CdS与上转换纳米颗粒.通过X-射线衍射以及X-射线光电子能谱能仪器对产物的物相以及表面的化学组成进行了细致的表征.结果显示,通过本实验方法已经成功获得了Ti O2复合纳米管.用稳态与瞬态荧光仪研究了最终样品的荧光性质.研究结果揭示,与上转换纳米颗粒以及二氧化硅复合纳米纤维相比,复合二氧化钛纳米管可以将上转换荧光纳米颗粒的(UV-Vis)部分荧光完全淬灭了.特别是,铒离子的荧光(650 nm)也被有效淬灭转移,说明本研究采用β-NaYF_4:Yb(30%),Tm(0.5%)@NaYF_4:Yb(20%),Er(2%)纳米能量转换器,可以提高近红外光的转换效率,紫外-可见吸收光谱证实,这种二氧化钛纳米管在紫外-可见光区中的吸收光谱与β-NaYF_4:Yb(30%),Tm(0.5%)@NaYF_4:Yb(20%),Er(2%)纳米颗粒的荧光光谱具有较大的重叠,使得上转换荧光纳米颗粒与CdS以及二氧化钛组分之间的荧光共振转移的效率大大提高,进而会显著提高光催化的效果.以罗丹明染料作为污染物为模型,我们研究了罗丹明染料在氙灯下或者近红外光光照下的光催化分解实验.研究结果表明,90%的罗丹明染料分子在20 min内就被降解掉,效率高于其它的近红外光催化剂.上转换荧光纳米颗粒的能量转换效率可以得到大幅度提高,本研究工作中制备的光催化剂利用太阳能的效率将会得到极大提高,在未来为能源危机以及环境保护提供一种可供选择的方法与技术.
[Abstract]:As near infrared light accounts for 44% of the solar spectrum, the development of photocatalysts driven by near infrared light is of great significance. Up-conversion luminescent materials can convert low-energy near-infrared photons into high-energy photons, which can transfer energy and activate quantum-efficient semiconductor materials by constructing a fluorescence resonance transfer system. It has potential application prospect for the conversion and utilization of solar energy. In this paper, CdS nanoparticles embedded in electrospinning and Sio _ 2 composite nanofibers with up-conversion fluorescent nanoparticles (UCNPs) were epitaxial grown by colloid chemistry process, and a layer of TIO _ 2 layer was grown on the surface of Sio _ 2 composite nanofibers prepared by electrospinning and upconversion fluorescent nanoparticles (UCNPs). Titanium dioxide composite nanotubes were obtained by high temperature calcination. We tightly bound CdS nanoparticles and up-converted fluorescent nanoparticles through silica structure to achieve high fluorescence resonance energy transfer. Furthermore, 尾-NaYF_4:Yb (30%), Tm (0.5%) @ NaYF_4:Yb (20%), Er (2%) was chosen as a nano-energy converter to replace 尾-NaYF_4:Yb (30%) used in previous research work, Tm (0.5%) or 尾-NaYF_4:Yb (30%), Tm (0.5%) @ NaYF_4 nanoparticles can further improve the conversion efficiency of near-infrared light. A large number of CdS and up-conversion nanoparticles were clearly observed in the Ti-O _ 2 composite nanotubes by transmission electron microscopy (TEM). The phase and chemical composition of the product were characterized by X-ray diffraction and X-ray photoelectron spectroscopy. The results show that Ti O 2 composite nanotubes have been successfully obtained by this method. The fluorescence properties of the final samples were studied by steady-state and transient fluorometers. The results show that compared with the upconversion nanoparticles and silica composite nanofibers, the partial fluorescence of up-converted fluorescent nanoparticles (UV-Vis) can be completely quenched by the composite TiO2 nanotube. In particular, the fluorescence of erbium ions (650 nm) was effectively quenched and transferred, indicating that 尾-NaYF_4:Yb (30%), Tm (0.5%) @ NaYF_4:Yb (20%), Er (2%) nano-energy converter was used in this study. It can improve the conversion efficiency of near-infrared light. UV-vis absorption spectra confirm that the absorption spectra of this TIO _ 2 nanotube in the UV-vis region and 尾-NaYF_4:Yb (30%). The fluorescence spectra of Tm (0.5%) @ NaYF_4:Yb (20%), Er (2%) nanoparticles overlap greatly. The efficiency of fluorescence resonance transfer between up-conversion fluorescent nanoparticles and CdS and TIO _ 2 components is greatly improved, and then the photocatalytic effect is greatly improved. The photocatalytic decomposition of Rhodamine dye under xenon lamp or near infrared light was studied using Rhodamine dye as a model. The results show that 90% of rhodamine dye molecules are degraded in 20 min, and the efficiency is higher than that of other near infrared photocatalysts. The energy conversion efficiency of up-conversion fluorescent nanoparticles can be greatly improved, and the efficiency of photocatalyst prepared in this study will be greatly improved by using solar energy. Provide an alternative method and technology for energy crisis and environmental protection in the future.
【作者单位】：合肥工业大学生物与医学工程学院;合肥工业大学化学与化工学院;合肥工业大学分析测试中心;
【基金】：supported in part by the National Natural Science Foundation of China(21471043,21304028,51403195,31501576)~~
【分类号】：O643.36;O644.1

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