Zhang Haimin, Zhao Huijun, Zhang Shanqing, Quan Xie
Griffith School of Environment, Gold Coast Campus, Griffith University, Queensland 4222, Australia.
Chemphyschem. 2008 Jan 11;9(1):117-23. doi: 10.1002/cphc.200700406.
A simple photoelectrochemical method was proposed to quantitatively evaluate the electron transport process of photoelectrocatalytic oxidation of water at vertically aligned nanotubular TiO2 photoanodes. The photoelectrocatalysis reaction resistance (R=k/J(sph)+R(0)=R(I)+R(0)) was measured and used to express the electron transport characteristics of a nanotubular TiO(2) electrode. The overall resistance was found to consist of a variant (R(I)) and an invariant component (R(0)). R(I) was found to be inversely proportional to the saturation photocurrent and it depends on the experimental conditions. The proportional constant, k, represents the minimum applied potential bias required to remove 100 % of the photogenerated electrons from the photocatalyst layer and was found to be independent of the anodization time. The invariant component of the resistance (R(0)) is an inherent property of the semiconductor photocatalyst that represents the sum of Ohmic contact impedance at the conducting substrate/TiO2 interface and crystalline boundary impedance. The magnitude of R(0) linearly increased with anodization time. The real saturated photocurrent density (J(real-sphd)) was found to be independent of R(0) indicating that the electron collection efficiency is independent of the nanotube length.
提出了一种简单的光电化学方法来定量评估垂直排列的纳米管TiO₂光阳极上水的光电催化氧化过程中的电子传输过程。测量了光电催化反应电阻（R = k/J(sph)+R(0)=R(I)+R(0)），并用于表示纳米管TiO₂电极的电子传输特性。发现总电阻由一个可变部分（R(I)）和一个不变部分（R(0)）组成。发现R(I)与饱和光电流成反比，并且它取决于实验条件。比例常数k表示从光催化剂层中去除100%光生电子所需的最小外加电势偏压，并且发现它与阳极氧化时间无关。电阻的不变部分（R(0)）是半导体光催化剂的固有属性，它代表导电基底/TiO₂界面处的欧姆接触阻抗和晶界阻抗之和。R(0)的大小随阳极氧化时间线性增加。发现实际饱和光电流密度（J(real-sphd)）与R(0)无关，这表明电子收集效率与纳米管长度无关。
