Liu Baoshun, Wu Hao, Parkin Ivan P
State Key Laboratory of Silicate Materials for Architectures, Wuhan University of Technology, Wuhan City, Hubei Province 430070, People's Republic of China.
Department of Chemistry, Materials Chemistry Centre, University College London, 20 Gordon Street, London WC1H 0AJ, U.K.
ACS Omega. 2020 Jun 15;5(24):14847-14856. doi: 10.1021/acsomega.0c02145. eCollection 2020 Jun 23.
Although photocatalysis has been studied for many years as an attractive way to resolve energy and environmental problems, its principle still remains unclear. Some confusions and misunderstandings exist in photocatalytic studies. This research aims to elaborate some new thoughts on the fundamental principle of semiconductor photocatalysis. Starting from the basic laws of thermodynamics, we first defined the thermodynamic potential of photocatalysis. A concept, the Gibbs potential landscape, was thus then proposed to describe the kinetics of photocatalysis. Photocatalysis is therefore defined as a light-driven chemical reaction that still needs heat activation, in that light and heat play their different roles and interact with each other. Photocatalysis should feature an activation energy functioning with both light and heat. The roles of light and heat are correlative and mutually inhibit at both levels of thermodynamics and kinetics, so it is impossible for an intrinsic light-heat synergism to happen. Two criteria were further proposed to determine an intrinsic light-heat synergism in photocatalysis. Experiments were also carried out to calculate the thermodynamic potential and can agree well with the theory. Experimental results proved that there is no intrinsic light-heat synergism, in accordance with our theoretical prediction. This research clarified some misunderstandings and gained some new insights into the nature of photocatalysis; this is important for the discipline of semiconductor photocatalysis.
尽管光催化作为解决能源和环境问题的一种有吸引力的方法已被研究多年，但其原理仍不清楚。光催化研究中存在一些混淆和误解。本研究旨在阐述关于半导体光催化基本原理的一些新思想。从热力学基本定律出发，我们首先定义了光催化的热力学势。因此提出了一个概念，即吉布斯势景观，以描述光催化的动力学。因此，光催化被定义为一种仍需热激活的光驱动化学反应，因为光和热发挥着不同的作用并相互作用。光催化应具有同时依赖光和热的活化能。光和热的作用在热力学和动力学两个层面上都是相关的且相互抑制，所以不可能发生内在的光热协同作用。进一步提出了两个标准来确定光催化中的内在光热协同作用。还进行了实验来计算热力学势，实验结果与理论吻合良好。实验结果证明，与我们的理论预测一致，不存在内在的光热协同作用。本研究澄清了一些误解，并对光催化的本质有了一些新的认识；这对半导体光催化学科很重要。
