局域表面等离激元效应增强TiO_2-SiO_2-Ag复合薄膜光催化性能

Enhanced Photocatalytic Efficiency of TiO_2-SiO_2-Ag Nanocomposites Induced by Localized Surface Plasmonic Effect

用高纯度的Ag靶,采用直流溅射法在石英衬底上通过退火处理,得到Ag纳米颗粒薄膜;然后通过射频溅射法在Ag纳米颗粒上沉积不同厚度的SiO2隔离层,再通过直流反应溅射在SiO2隔离层上沉积TiO2薄膜(膜厚60nm),得到TiO2-SiO2-Ag复合薄膜.对样品进行了紫外-可见吸收光谱、拉曼散射光谱、扫描电子显微镜及光催化性能研究.研究结果表明,TiO2-SiO2-Ag复合薄膜结构由于Ag纳米颗粒的局域表面等离激元效应,而与入射光场耦合,使TiO2对紫外光的吸收增强,从而增加了电子-空穴对的产生率,表现出较TiO2更强的光催化性能;通过调节SiO2的厚度可以调控Ag纳米颗粒的局域表面等离激元与TiO2的相互作用,从而提高TiO2的光催化性能.

TiO2-SiO2-Ag nanocomposites were fabricated by depositing TiO2 films on SiO2 layer embedded with Ag nanoparticles by means of magnetron sputtering and then subsequent rapid thermal annealing （RTA）, and investigated by UV-vis-NIR dual-beam spectrometer, Raman spectrum, scanning electron microscopy （SEM） and the photocatalytic efficiency. The nanocomposites show higher photocatalytic efficiency compared with the pure TiO2 film due to enhancement of light absorption. The enhanced light absorption originated from the near-field enhancement caused by the plasmonic effect of Ag nanoparticles. The enhancement of the photocatalytic efficiency of TiO2 could be adjusted by changing the thickness of the SiOz protective layer from 0 to 20 nm to control the surface plasmonic effect of Ag nanopaticles.