The Institute of Scientific and Industrial Research (SANKEN), Osaka University , Mihogaoka 8-1, Ibaraki, Osaka 567-0047, Japan.
J Am Chem Soc. 2014 Jan 8;136(1):458-65. doi: 10.1021/ja410994f. Epub 2013 Dec 17.
Plasmonic photocatalysts were successfully synthesized by the modification of TiO2 mesocrystals with Au nanoparticles (NPs) by a simple impregnation method. The Au NP sensitizers show a strong photoelectrochemical response in the visible-light region (400-800 nm) due to their surface plasmon resonance (SPR). The diffuse reflectance spectroscopy measurements on a wide range of time scales (from picoseconds to minutes) demonstrate that a substantial part of electrons, injected from the Au NPs to the TiO2 mesocrystals through the SPR excitation, directionally migrate from the basal surfaces to the edges of the plate-like mesocrystals through the TiO2 nanocrystal networks and are temporally stored there for further reactions. This anisotropic electron flow significantly retarded the charge recombination of these electrons with the holes in the Au NPs, thereby improving the visible-light-photocatalytic activity (for organic-pollutant degradation) by more than an order of magnitude, as compared to that of conventional Au/TiO2 NP systems.
通过简单的浸渍法，用金纳米粒子（NPs）修饰 TiO2 介孔晶体成功合成了等离子体光催化剂。由于其表面等离子体共振（SPR），Au NP 敏化剂在可见光区域（400-800nm）表现出很强的光电化学响应。在广泛的时间尺度（从皮秒到分钟）上的漫反射光谱测量表明，相当一部分电子通过 SPR 激发从 Au NPs 注入到 TiO2 介孔晶体中，通过 TiO2 纳米晶网络从基面定向迁移到板状介孔晶体的边缘，并在那里暂时储存，以进行进一步的反应。这种各向异性的电子流显著抑制了这些电子与 Au NPs 中的空穴的复合，从而将可见光光催化活性（用于有机污染物降解）提高了一个数量级以上，与传统的 Au/TiO2 NP 系统相比。
