10th International Aerosol Conference September 2 - September 7, 2018 America's Center Convention Complex St. Louis, Missouri, USA
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Effect of Loading Concentration on the Photocatalytic Activity of Ag-TiO2 Nanocomposite Films Fabricated by One-Step Gas-Phase Deposition
DIANPING JIANG, K. Kusdianto, Masaru Kubo, Manabu Shimada, Hiroshima University
Abstract Number: 444 Working Group: Materials Synthesis
Abstract It is well known that adding Ag nanoparticles in TiO2 matrix enhances the photocatalytic performances. It is mainly caused by reducing the electron-hole recombination in photocatalytic reaction due to metal-semiconductor junction. For preparation of Ag-TiO2 nanocomposites, varieties of routes have been approached which can be categorized as liquid and gas methods, etc. However, fabrication methods included in the liquid methods have disadvantages of having a large number of processing steps, using high temperatures under vacuum conditions, and concern on impurities involved. In this study, Ag-TiO2 nanocomposite thin films on silicon substrate with different Ag concentrations were synthesized in gas phase by a combination of plasma-enhanced chemical vapor deposition (PECVD) and physical vapor deposition (PVD). The nanocomposite films with different Ag concentrations ranging from 0 to 12.7 wt% were prepared by changing the amount of Ag vapor in the PVD system. It is obviously observed that the crystalline phase, crystallite size, and particle size of the fabricated Ag-TiO2 nanocomposite films after annealing at 500 °C were affected by the concentration of Ag nanoparticles. The existence of very small Ag nanoparticles (~4 nm) in the films was also confirmed by transmission electron microscopy. Photocatalytic activity evaluated by measuring the degradation of methylene blue aqueous solution under UV light irradiation exhibited that a film with Ag nanoparticle concentration of 5.3 wt% showed the highest photocatalytic performance. This work will be significant not only in the preparation of Ag-TiO2 nanocomposite films but also in the preparation of metal-semiconductor nanocomposite films which has wide potential applications in photocatalysis, solar energy conversion, antibacterial application, chemical sensors, and so on.