Chugenji Tatsuya, Pan Zhenhua, Nandal Vikas, Seki Kazuhiko, Domen Kazunari, Katayama Kenji
Department of Applied Chemistry, Chuo University, Tokyo 112-8551, Japan.
Global Zero Emission Research Center (GZR), National Institute of Advanced Industrial Science and Technology (AIST), Onogawa 16-1 AIST West, Tsukuba 305-8569, Japan.
Phys Chem Chem Phys. 2022 Jul 27;24(29):17485-17495. doi: 10.1039/d2cp02808e.
Visible-light responsive photocatalytic materials are expected to be deployed for practical use in photocatalytic water splitting. One of the promising materials as a p-type semiconductor, oxysulfides, was investigated in terms of the local charge carrier behavior for each particle by using a home-built time-resolved microscopic technique in combination with clustering analysis. We could differentiate electron and hole trapping to the surface states and the following recombination on a micron-scale from the nanosecond to microsecond order. The map of the charge carrier type revealed that charge trapping sites for electrons and holes were spatially separated within each particle/aggregate. Furthermore, the effect of the rhodium cocatalyst was recognized as a new electron pathway, trapping to the rhodium site and the following recombination, which was delayed compared with the original electron recombination process. The Rh effect was discussed based on the phenomenological simulation, revealing a possible reason for the decay was due to the anisotropic diffusion of charge carriers in oxysulfides or the interfacial energy barrier at the interface.
可见光响应型光催化材料有望在光催化水分解中得到实际应用。作为一种p型半导体，氧硫化物是一种很有前景的材料，通过使用自制的时间分辨显微镜技术结合聚类分析，研究了每个颗粒的局部电荷载流子行为。我们可以在从纳秒到微秒的时间尺度上，在微米尺度上区分电子和空穴在表面态的俘获以及随后的复合。电荷载流子类型图显示，电子和空穴的电荷俘获位点在每个颗粒/聚集体内空间上是分离的。此外，铑助催化剂的作用被认为是一种新的电子途径，即俘获到铑位点并随后复合，这与原始电子复合过程相比有所延迟。基于唯象模拟讨论了铑效应，揭示了衰减的一个可能原因是由于氧硫化物中电荷载流子的各向异性扩散或界面处的界面能垒。
