Nano Ag@AgBr surface-sensitized Bi2WO6 photocatalyst: oil-in-water synthesis and enhanced photocatalytic degradation
Nano Ag@AgBr surface-sensitized Bi2WO6 photocatalyst: oil-in-water synthesis and enhanced photocatalytic degradation
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纳米Ag@AgBr表面敏化Bi2WO6光催化剂：水包油合成和增强光催化降解
DOI：
10.1016/j.apsusc.2014.10.101
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发表时间：
2015-01-01
影响因子：
6.7
通讯作者：
Cui, Wenquan
中科院分区：
文献类型：
--
作者：
Lin, Shuanglong;Liu, Li;Cui, Wenquan
采用水包油自组装法制备了花状Bi 2 WO 6表面修饰的纳米Ag@AgBr（以下简称Ag@AgBr/Bi 2 WO 6）。采用X射线衍射（XRD）、扫描电子显微镜（SEM）、透射电子显微镜（TEM）、紫外-可见漫反射光谱（DRS）等手段对催化剂进行了表征。Ag@AgBr/Bi 2 WO 6复合材料由于Ag@AgBr的量子尺寸效应、Ag纳米粒子的表面等离子体共振（SPR）和Bi 2 WO 6特殊的花状结构而具有优异的紫外-可见吸收性能。光电化学测试结果表明，Ag@AgBr和Bi 2 WO 6的带电位以及金属Ag的存在是复合材料电荷分离效率高的主要原因。以亚甲基蓝（MB）为目标染料，研究了Ag@AgBr/Bi 2 WO 6样品在可见光照射下的光催化活性。由于Bi 2 WO 6、AgBr和Ag纳米粒子的协同作用，该复合材料表现出优异的光催化活性。Ag@AgBr（20重量%）/ Bi 2 WO 6的光催化活性最高，光照2 h后MB的降解率达到95.03%，分别是Ag@AgBr和Bi 2 WO 6光催化剂的1.29倍和1.28倍。同时对苯酚和水杨酸进行了降解实验，进一步证明了Ag@AgBr/Bi 2 WO 6的降解能力。此外，使用自由基清除剂进行的研究表明，O2（-中心点），中心点OH和Br-0作为主要的反应物种。在此基础上，提出了Ag@AgBr/Bi 2 WO 6光催化降解有机物的机理。(C)2014爱思唯尔有限公司版权所有。
Nano Ag@AgBr decorated on the surface of flower-like Bi2WO6 (hereafter designated Ag@AgBr/Bi2WO6) were prepared via a facile oil-in-water self-assembly method. The photocatalysts were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), UV-vis diffuse reflectance spectroscopy (DRS), etc. The characterization results indicated that nano Ag@AgBr was observed to be evenly dispersed on the surface of Bi2WO6, and was approximately 20 nm in size. Ag@AgBr/Bi2WO6 composites exhibited excellent UV-vis absorption, due to quantum dimension effect of Ag@AgBr, the surface plasmonic resonance (SPR) of Ag nanoparticles and the special flower-like structure of Bi2WO6. The photoelectrochemical measurement verified that the suitable band potential of Ag@AgBr and Bi2WO6 and the existence of metal Ag resulted in the high efficiency in charge separation of the composite. The photocatalytic activities of the Ag@AgBr/Bi2WO6 samples were examined under visible-light irradiation for the degradation of methylene blue (MB). The composite presented excellent photocatalytic activity due to the synergetic effect of Bi2WO6, AgBr, and Ag nanoparticles. The Ag@AgBr(20 wt.%)/Bi2WO6 sample exhibited the best photocatalytic activity, degrading 95.03% MB after irradiation for 2 h, which was respectively 1.29 times and 1.28 times higher than that of Ag@AgBr and Bi2WO6 photocatalyst. Meanwhile, phenol and salicylic acid were degraded to further prove the degradation ability of Ag@AgBr/Bi2WO6. Additionally, studies performed using radical scavengers indicated that O2(-center dot),center dot OH and Br-0 acted as the main reactive species. Based on above, a photocatalytic mechanism for organics degradation over Ag@AgBr/Bi2WO6 was proposed. (C) 2014 Elsevier B.V. All rights reserved.