High-Efficiency Visible-Light-Driven Ag3PO4/AgI Photocatalysts: Z-Scheme Photocatalytic Mechanism for Their Enhanced Photocatalytic Activity

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• 作者：Zhihong Chen ; Weilin Wang ; Zhengguo Zhang ; Xiaoming Fang
• 刊名：Journal of Physical Chemistry C
• 出版年：2013
• 出版时间：September 26, 2013
• 年：2013
• 卷：117
• 期：38
• 页码：19346-19352
• 全文大小：415K
• 年卷期：v.117,no.38(September 26, 2013)
• ISSN：1932-7455

文摘

High-efficiency visible-light-driven Ag₃PO₄/AgI photocatalysts with different mole fractions of AgI have been synthesized via an in-situ anion-exchange method and characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS), and UV鈥搗is diffuse reflectance spectroscopy (DRS). Under visible light (>420 nm), the Ag₃PO₄/AgI photocatalysts exhibit enhanced photocatalytic activity compared to pure Ag₃PO₄ or AgI for the degradation of methyl orange and phenol, and the highest activity is reached by the Ag₃PO₄/AgI hybrid photocatalyst with 20% of AgI. The quenching effects of different scavengers suggest that the reactive h⁺ and O₂^{鈥⑩€?/sup> play the major role in the MO degradation. Detailed X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM) analysis reveals that Ag nanoparticles (NPs) form on the surface of Ag₃PO₄/AgI in the early stage of the photocatalytic oxidation process, thus leading to the transformation from Ag₃PO₄/AgI to Ag₃PO₄/AgI@Ag. The excellent photocatalytic activity of the Ag₃PO₄/AgI photocatalysts can be ascribed to the efficient separation of photogenerated electron鈥揾ole pairs through a Z-scheme system composed of Ag₃PO₄, Ag, and AgI, in which the Ag nanoparticles acted as the charge transmission bridge. The Ag₃PO₄/AgI hybrid remains good photocatalytic activity after five cycling runs.}