Light-Intensity-Dependent Semiconductor–Cocatalyst Interfacial Electron Transfer: A Dilemma of Sunlight-Driven Photocatalysis
Light-Intensity-Dependent Semiconductor–Cocatalyst Interfacial Electron Transfer: A Dilemma of Sunlight-Driven Photocatalysis
复制标题
光强度依赖性半导体-助催化剂界面电子转移：阳光驱动光催化的困境
DOI：
10.1021/acs.jpclett.0c00315
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发表时间：
2020
影响因子：
5.7
通讯作者：
Jiazang Chen
中科院分区：
文献类型：
--
作者：
Zhijian Wang;Wei Qiao;Mi Yuan;Na Li;Jiazang Chen
在光催化反应中，电子从半导体纳米结构到助催化剂的界面转移是决定光生电荷利用率的关键步骤，并且受该电子过程的行为的敏感影响。在弱光照下，光催化反应速率与入射光强呈非线性关系（r=kss·Pincα，α → 0.5），这是因为界面电荷复合占主导地位。当辐照强度较高时，理论上主要的电子过程为电子发射（r=kte·Pincα，α → 2）。光催化反应速率与入射光强的比值主要反映了光催化反应的能量利用率，随着光强的变化，反应速率与入射光强的比值沿着出现最小值。然而，这一关键关系几乎没有被有意识地考虑过。在这项工作中，受理论模拟的启发，我们证明了太阳光驱动的光催化剂通常是在某些常见的半导体（CdS，TiO 2，或C3N4）的能量利用曲线的底部。
In photocatalytic reactions, the interfacial transfer of electrons from semiconductor nanostructures to cocatalysts is the key step that determines the utilization of photogenerated charges and is sensitively influenced by the behaviors of this electronic process. Under weak illumination, photocatalytic reaction rates deviate from linearity to incident light intensity (r=kss·Pincα, with α → 0.5), because charge recombination predominates interfacial transfer. When the irradiation intensity is high, theoretically, thermionic emission would be the major electronic process (r=kte·Pincα, with α → 2). The ratio of photocatalytic reaction rate to incident light intensity that mainly reflects the energy utilization would encounter a minimum along the variation of irradiation intensity. This crucial relationship, however, has hardly been consciously considered. In this work, inspired by theoretical simulation, we demonstrate that sunlight-driven photocatalysis is generally on the bottom of the energy utilization curves for certain common semiconductors (CdS, TiO2, or C3N4).