Liu Baoshun, Yang Jingjing, Zhao Xiujian, Yu Jiaguo
State Key Laboratory of Silicate Materials for Architectures, Wuhan University of Technology, Wuhan City, Hubei Province 430070, People's Republic of China.
State Key Laboratory of Advanced Technology for Material Synthesis and processing, Wuhan University of Technology, Wuhan City, Hubei Province 430070, People's Republic of China.
Phys Chem Chem Phys. 2017 Mar 29;19(13):8866-8873. doi: 10.1039/c6cp07328j.
In this research, a combination of in situ photoconductivity (σ) and kinetic simulations was used to study the role of electron interfacial transfer (IT) in the gaseous photocatalysis of formic acid by mesoporous nanocrystalline TiO. The effects of light intensity, initial formic acid concentrations, oxygen amounts, and temperature on the in situ σ and the photocatalytic courses were studied in detail. The temperature dependence of in situ σ clearly shows that the electron transfer is determined by the IT of electrons to O rather than by the transport. It was seen that the electron IT limits the photocatalysis by correlating with the recombination and the hole IT via the dynamic change in electron densities. The numerical simulation of in situ σ shows that the IT of electrons belongs to a thermally activated process that presents a thermal barrier of 0.5 eV. It is considered that this high thermal barrier limits the IT of electrons. It was also seen that the thermal activation of photocatalysis does not relate to that of the electron IT, although the overall photocatalysis is limited by the IT of electrons. Our finding shows that it is an effective way to increase the photocatalytic activity by reducing the thermal barrier of electron IT.
在本研究中，采用原位光电导率（σ）与动力学模拟相结合的方法，研究了电子界面转移（IT）在介孔纳米晶TiO对甲酸的气相光催化过程中的作用。详细研究了光强、初始甲酸浓度、氧气量和温度对原位σ及光催化过程的影响。原位σ对温度的依赖性清楚地表明，电子转移是由电子向O的界面转移决定的，而非由传输决定。可以看出，电子界面转移通过与复合以及空穴界面转移相关联，经由电子密度的动态变化限制了光催化作用。原位σ的数值模拟表明，电子的界面转移属于一个热激活过程，其呈现出0.5 eV的热垒。据认为，这一高热垒限制了电子的界面转移。还可以看出，尽管整体光催化作用受电子界面转移的限制，但光催化的热激活与电子界面转移的热激活并无关联。我们的研究结果表明，降低电子界面转移的热垒是提高光催化活性的有效途径。
