Dispersed-Nanoparticle Loading Synthesis for Monodisperse Au-Titania Composite Particles and Their Crystallization for Highly Active UV and Visible Photocatalysts

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• 作者：Takeshi Sakamoto ; Daisuke Nagao ; Masahiro Noba ; Haruyuki Ishii ; Mikio Konno
• 刊名：Langmuir
• 出版年：2014
• 出版时间：June 24, 2014
• 年：2014
• 卷：30
• 期：24
• 页码：7244-7250
• 全文大小：391K
• ISSN：1520-5827

文摘

Submicrometer-sized amorphous titania spheres incorporating Au nanoparticles (NPs) were prepared in a one-pot synthesis consisting of a sol鈥揼el reaction of titanium(IV) isopropoxide in the presence of chloroauric acid and a successive reduction with sodium borohydride in a mixed solvent of ethanol/acetonitrile. The synthesis was allowed to prepare monodisperse titania spheres that homogeneously incorporated Au NPs with sizes of ca. 7 nm. The Au NP-loaded titania spheres underwent different crystallization processes, including 500 掳C calcination in air, high-temperature hydrothermal treatment (HHT), and/or low-temperature hydrothermal treatment (LHT). Photocatalytic experiments were conducted with the Au NP-loaded crystalline titania spheres under irradiation of UV and visible light. A combined process of LHT at 80 掳C followed by calcination at 500 掳C could effectively crystallize titania spheres maintaining the dispersion state of Au NPs, which led to photocatalytic activity higher than that of commercial P25 under UV irradiation. Under visible light irradiation, the Au NP-titania spheres prepared with a crystallization process of LHT at 80 掳C for 6 h showed photocatalytic activity much higher than a commercial product of visible light photocatalyst. Structure analysis of the visible light photocatalysts indicates the importance of prevention of the Au NPs aggregation in the crystallization processes for enhancement of photocatalytic activity.