大学化学 >> 2016, Vol. 31 >> Issue (6): 72-79.doi: 10.3866/PKU.DXHX201510022

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光电子寿命与介电常数的关系及其对光催化效果的影响

林则东,戴玉华*(),李可心*()   

  • 发布日期:2016-06-29
  • 通讯作者: 戴玉华,李可心 E-mail:dyh-8808@sohu.com;likx880@hotmail.com

Relationship between Photoelectron Lifetime and Dielectric Constant and Its Effect on the Photocatalysis

Ze-Dong LIN,Yu-Hua DAI*(),Ke-Xin LI*()   

  • Published:2016-06-29
  • Contact: Yu-Hua DAI,Ke-Xin LI E-mail:dyh-8808@sohu.com;likx880@hotmail.com

摘要:

通过理论推导给出了描述光催化剂导带上光电子寿命与光催化剂介电常数关系的方程。根据该方程和光催化剂的催化机理,通过理论分析我们发现,光催化剂的催化效果与光催化剂的介电常数之间满足如下关系:光催化剂的介电常数越大,光催化剂导带上的光电子寿命就越长,光催化剂导带上的光电子越不容易通过受激辐射和自发辐射跃迁回到价带与价带上的空穴复合,提供给空穴氧化光催化剂表面的氢氧根离子和水分子形成羟基自由基的时间就越长,越有利于光催化反应的进行。

关键词: 光催化效果, 光电子寿命, 介电常数

Abstract:

In this article, the relationship equation between the photoelectron lifetime of the conduction band of photocatalyst and the dielectric constant of photocatalyst is derived. According to the photocatalytic mechanism and the derived equation, the relationship between the photocatalytic and the dielectric constant of the photocatalyst is elucidated as follows: the larger dielectric constant of the photocatalyst, the longer the photoelectron lifetime. Consequently, the transition of the photoelectrons from conduction band to the valence band to combine with the holes becomes harder through the stimulated emission and spontaneous emission, facilitating effective production of hydroxyl free radicals via the sufficient oxidation of hydroxyl ion and water by the holes occurring on the surface of photocatalyst.

Key words: Effect of photocatalysis, Photoelectron lifetime, Dielectric constant

MSC2000: 

  • O6