TiO_2光催化剂的形貌与晶面调控

Morphology and Crystal Face Control of TiO_2 Photocatalyst

二氧化钛(TiO2)具有化学稳定性高、无毒、价格低廉、来源广泛及光电性能优异等优点,被广泛应用于太阳能电池和光催化等领域,尤其是在污染物的光催化降解方面,可很好地解决当前的环境污染问题。但一方面受带隙宽度限制,使其对太阳光的利用率不足5%,不能充分利用太阳光中的可见光;另一方面由于光生电子-空穴容易结合,催化效率低,从而使TiO2的实际应用受到限制。因此必须采取合适的措施,一方面要增强TiO2对可见光的吸收,提高对太阳光的利用率;另一方面要抑制光生电子-空穴的复合,提高光催化效率。目前越来越多的科学家通过控制TiO2的形貌、晶型、特殊晶面暴露等手段来提高TiO2光生电子-空穴的传输速率和光电转换效率。本文主要综述了近年来在TiO2光催化剂的特殊形貌和特殊晶面暴露等方面的研究进展,对未来的研究和发展方向作了展望。

Titanium dioxide（TiO2） is widely used in solar cells and photocatalysis, due to its high chemical stability, non-toxicity, low prices, easy to access, and excellent photoelectric properties. What interests us most is its potential use as a solid photocatalyst for environmental purification. However, on the one hand, the large band gap of TiO2（-3.2 eV） makes the utilization of total solar energy less than 5%, which, cannot make full use of the visible portion of the sun. On the other hand, the photo-generated electrons and holes is easily recombinated,making the catalytic efficiency low, which limits the practical application of TiO2. Therefore, it is crucial to enhance the light harvesting of TiO2 in the visible region to improve the utilization of visible light. In addition,the combination of photo-generated electrons and holes should be well suppressed to improve the photocatalytic efficiency. Currently, scientists have tried to improve the photoelectric conversion efficiency of TiO2 by controlling the morphology, crystal structure, exposuring special crystal, which can improve the range of visible light response of TiO2 and transfer rate of photo-generated electrons and holes. This article reviews the recent development of methods for improving the photoelectric conversion efficiency, including special morphology control and special crystal face exposing. The future research direction and development of TiO2 photocatalyst is prospected.