Nanotechnology. 2014 Jan 24;25(3):035603. doi: 10.1088/0957-4484/25/3/035603.
CdS nanoparticles were confined within titanate nanotubes (TNTs) by an ion-exchange reaction and a subsequent sulfurization process. Prior to the ion-exchange reaction, the exterior surfaces of the TNTs were modified by a silane coupling agent to make CdS nanoparticles selectively deposit on the inner wall. The composites were characterized by high-resolution transmission electron microscopy, powder x-ray diffraction, inductively coupled plasma atomic emission spectrometry, N2 adsorption–desorption and UV–vis absorption spectra. The results confirm that CdS in the range of 2–3 nm in diameter are confined within the inner cavity of the TNTs. CdS confined within TNTs shows a significant blue-shift of the absorption band edge compared with CdS nanoparticles deposited on the exterior surface of TNTs. Also the TNTs-confined CdS composite exhibits enhanced photocatalytic activity and photostability for hydrogen evolution under visible light illumination due to the quantum size effect of CdS as a result of the spatial confinement effect of the TNTs.
CdS 纳米颗粒通过离子交换反应和随后的硫化过程被限制在钛酸盐纳米管（TNTs）内。在离子交换反应之前，TNTs 的外表面通过硅烷偶联剂进行修饰，以使 CdS 纳米颗粒选择性地沉积在内壁上。通过高分辨率透射电子显微镜、粉末 X 射线衍射、电感耦合等离子体原子发射光谱、N2 吸附-脱附和紫外-可见吸收光谱对复合材料进行了表征。结果证实，直径在 2-3nm 范围内的 CdS 被限制在 TNTs 的内腔内。与沉积在 TNTs 外表面的 CdS 纳米颗粒相比，TNTs 内限制的 CdS 表现出吸收带边的显著蓝移。由于 TNTs 的空间限制效应导致 CdS 的量子尺寸效应，TNTs 限制的 CdS 复合材料在可见光照射下表现出增强的光催化活性和光稳定性，用于氢气的产生。
