Photocatalytic Activity of Zirconium- and Manganese-Codoped Titania in Aqueous Media: The Role of the Metal Dopant and its Incorporation Site

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• 作者：Dr. Oleksii Pliekhov ; Prof. Dr. Iztok Arčon ; Prof. Dr. Nataša Novak Tušar and Prof. Dr. Urška Lavrenčič Štangar
• 刊名：ChemCatChem
• 出版年：2016
• 出版时间：June 21, 2016
• 年：2016
• 卷：8
• 期：12
• 页码：2109-2118
• 全文大小：577K
• ISSN：1867-3899

文摘

The development of efficient TiO₂-based photocatalysts for water treatment is mainly performed by doping with transition metals or by establishing junctions between different phases, metal–semiconductor or semiconductor–semiconductor. We present, for the first time, the synthesis of Zr- and Mn-modified TiO₂ by a redesigned sol–gel technique that allows the formation of heterometallic bridges on the TiO₂ surface. Cations of the doping metals are located in the pores of mesoporous anatase and attached to the crystalline TiO₂ walls. The presence of the Zr enhances the photoactivity of the TiO₂ catalyst. However, the introduction of Mn decreases the photocatalytic efficiency in a nonadditive manner. The inhibition effect was assigned to the side reaction between hydroxyl radicals and Mn ions. The fact that Mn effectively scavenges the hydroxyl radicals and, consequently, inhibits the whole oxidation process is direct proof that hydroxyl radicals are the main reactive species in the photocatalytic oxidative processes on TiO₂ surfaces in aqueous media and the process of ^.OH generation is the rate-determining step, which was confirmed using a method based on the decolorization of a commercial dye Bezaktiv Blau in a reaction with Fenton's reagent as a source of hydroxyl radicals.