Visible鈥揕ight鈥揑nduced Photodegradation of Rhodamine B over Hierarchical TiO2: Effects of Storage Period and Water-Mediated Adsorption Switch

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• 作者：Lun Pan ; Ji-Jun Zou ; Xin-Yu Liu ; Xiao-Jing Liu ; Songbo Wang ; Xiangwen Zhang ; Li Wang
• 刊名：Industrial & Engineering Chemistry Research
• 出版年：2012
• 出版时间：October 3, 2012
• 年：2012
• 卷：51
• 期：39
• 页码：12782-12786
• 全文大小：392K
• 年卷期：v.51,no.39(October 3, 2012)
• ISSN：1520-5045

文摘

Hierarchical TiO₂ was prepared via hydrolysis method and characterized by XRD, N₂ adsorption鈥揹esorption, UV鈥搗is diffusion, and NH₃鈥揟PD. With the increase of calcination temperature, the surface area and surface hydroxyls of prepared materials decrease rapidly. The photoactivity was evaluated using the self-sensitized photodegradation of rhodamine B under visible light. The fresh samples show higher activity than P-25 due to higher surface area and more effective light utilization. After stored in air for ca. half a year, the materials show significantly increased photoactivity, due to the prebonding of water on surface bridging hydroxyls, which induces water-mediated adsorption switch from covalent mode to electrostatic one. Water treatment further promotes the photoactivity of stored samples, because more water are bonded on TiO₂ surface. It is found that the water-mediated effect closely depends on the surface area and amount of surface bridging hydroxyls.