Characterization and photocatalytic activity of noble-metal-supported surface TiO₂/SiO₂

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• 作者：Hu ; Chun ; Tang ; Yuchao ; Jiang ; Zheng ; Hao ; Zhengping ; Tang ; Hongxiao ; Wong ; Po Keung
• 关键词：Azo dyes ; Adsorption ; Noble metal ; Surface modification ; Titania/silica
• 刊名：Applied Catalysis A: General
• 出版年：2003
• 出版时间：October 28, 2003
• 年：2003
• 卷：253
• 期：2
• 页码：389-396
• 全文大小：166 K

文摘

M-TiO₂/SiO₂ photocatalysts were prepared by the photodeposition method using noble-metal salts (M: Pt⁴⁺, Pd²⁺, and Ag⁺) as precursors and the surface bond-conjugated TiO₂/SiO₂ as supporter in N₂ atmosphere. The photocatalysts were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), UV-Vis diffuse reflection spectra (DRS), photoluminescence (PL) spectra, and zeta-potential. Their photocatalytic activities were evaluated using reactive Brilliant Red K-2G (K-2G) and Cationic Blue X-GRL (CBX) that showed different types of adsorption behavior on the oxides. XPS analysis verified that the introduction of noble metal led to the changes of the electronic environmental of Ti cations and the zeta-potential of oxides. As a result, K-2G has higher adsorption on Pt-TiO₂/SiO₂ than on TiO₂/SiO₂, while the adsorption of CBX has little change on the modified TiO₂/SiO₂ catalysts. At the same time, Pt-modified catalyst shows 2.8 times higher photoactivity than TiO₂/SiO₂ for the photodegradation of K-2G, but has a decrease in activity for CBX degradation. These noble-metal-supported TiO₂/SiO₂ can efficiently extend the light absorption to the visible region. The PL results demonstrated that the noble metal dopant acted as electron acceptor to hinder the recombination of the photoinduced electron–hole pairs.