Chang Menglei, Hu Huawen, Zhang Yuyuan, Chen Dongchu, Wu Liangpeng, Li Xinjun
College of Materials Science and Energy Engineering, Foshan University, Foshan 528000, Guangdong, China.
Key Laboratory of Renewable Energy, Chinese Academy of Sciences, Guangzhou 510640, Guangdong, China.
Nanomaterials (Basel). 2017 May 9;7(5):104. doi: 10.3390/nano7050104.
This study presents a novel visible light-active TiO₂ nanotube anode film by sensitization with Bi₂O₃ nanoparticles. The uniform incorporation of Bi₂O₃ contributes to largely enhancing the solar light absorption and photoelectric conversion efficiency of TiO₂ nanotubes. Due to the energy level difference between Bi₂O₃ and TiO₂, the built-in electric field is suggested to be formed in the Bi₂O₃ sensitized TiO₂ hybrid, which effectively separates the photo-generated electron-hole pairs and hence improves the photocatalytic activity. It is also found that the photoelectric conversion efficiency of Bi₂O₃ sensitized TiO₂ nanotubes is not in direct proportion with the content of the sensitizer, Bi₂O₃, which should be carefully controlled to realize excellent photoelectrical properties. With a narrower energy band gap relative to TiO₂, the sensitizer Bi₂O₃ can efficiently harvest the solar energy to generate electrons and holes, while TiO₂ collects and transports the charge carriers. The new-type visible light-sensitive photocatalyst presented in this paper will shed light on sensitizing many other wide-band-gap semiconductors for improving solar photocatalysis, and on understanding the visible light-driven photocatalysis through narrow-band-gap semiconductor coupling.
本研究通过用Bi₂O₃纳米颗粒敏化制备了一种新型的可见光活性TiO₂纳米管阳极薄膜。Bi₂O₃的均匀掺入极大地提高了TiO₂纳米管的太阳光吸收和光电转换效率。由于Bi₂O₃和TiO₂之间的能级差，在Bi₂O₃敏化的TiO₂复合材料中形成了内建电场，有效地分离了光生电子-空穴对，从而提高了光催化活性。还发现Bi₂O₃敏化的TiO₂纳米管的光电转换效率与敏化剂Bi₂O₃的含量不成正比，为实现优异的光电性能，应仔细控制其含量。相对于TiO₂，敏化剂Bi₂O₃具有更窄的能带隙，能够有效地捕获太阳能产生电子和空穴，而TiO₂则收集和传输电荷载流子。本文提出的新型可见光敏感光催化剂将为敏化许多其他宽带隙半导体以改善太阳能光催化，以及通过窄带隙半导体耦合理解可见光驱动的光催化提供启示。
