Platinized WO3 as an Environmental Photocatalyst that Generates OH Radicals under Visible Light
Platinized WO3 as an Environmental Photocatalyst that Generates OH Radicals under Visible Light
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DOI：
10.1021/es101981r
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发表时间：
2010-09-01
影响因子：
11.4
通讯作者：
Choi, Wonyong
中科院分区：
文献类型：
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作者：
Kim, Jungwon;Lee, Chul Wee;Choi, Wonyong
本研究旨在了解载铂WO 3（Pt/WO 3）可见光催化降解水中污染物的活性及主要光氧化剂的作用。已知在WO 3上存在Pt有利于O-2的多电子还原，这使得O-2能够充当电子受体，尽管对于O-2的单电子还原而言导带电子（在WO 3中）的还原电势不足。同时氧化反应发生在WO 3上的Pt的存在下，显着增强，并伴随着在可见光下的OH自由基的产生，这是证实了荧光方法（使用化学陷阱）和自旋陷阱方法。OH自由基的产生主要来自于O-2在Pt/WO 3上还原原位生成的H2 O2的还原分解。在可见光下原位产生H2 O2的速率明显快于Pt/WO 3比WO 3。在Pt/WO 3上测试了六种可见光（λ> 420 nm）诱导降解的底物，包括二氯乙酸盐（DCA）、4-氯苯酚（4-CP）、四甲基铵（TMA）、亚砷酸盐（As（111））、亚甲基蓝（MB）和酸性橙子7（A07）。Pt/WO 3催化剂成功地实现了所有六种基质的降解（或转化），并且OH自由基在Pt/WO 3催化剂中的作用似乎因基质的种类而异。在叔丁醇（TBA：OH自由基清除剂）的存在下，光催化降解4-CP显着减少或完全抑制DCA和TMA，而As（III），MB，和A07的影响不大。Pt/WO 3光催化剂在可见光下氧化各种基材，具有足够的光稳定性，可用于太阳能水处理。
This study aims to understand the visible light photocatalytic activities of platinized WO3(Pt/WO3) on the degradation of aquatic pollutants and the role of main photooxidants. The presence of Pt on WO3 is known to facilitate the multielectron reduction of O-2, which enables O-2 to serve as an electron acceptor despite the insufficient reduction potential of the conduction band electrons (in WO3) for the one-electron reduction of O-2. The concurrent oxidative reactions occurring on WO3 were markedly enhanced in the presence of Pt and accompanied the production of OH radicals under visible light, which was confirmed by both a fluorescence method (using a chemical trap) and a spin trap method. The generation of OH radicals mainly comes from the reductive decomposition of H2O2 that is produced in situ from the reduction of O-2 on Pt/WO3. The rate of in situ production of H2O2 under visible light was significantly faster with Pt/WO3 than WO3. Six substrates that were tested for the visible light (lambda > 420 nm) induced degradation on Pt/WO3 included dichloroacetate (DCA), 4-chlorophenol (4-CP), tetramethylammonium (TMA), arsenite (As(111)), methylene blue (MB), and acid orange 7 (A07). The degradation (or conversion) of all six substrates was successfully achieved with Pt/WO3 and the role of OH radicals in Pt/WO3 photocatalysis seemed to be different depending on the kind of substrate. In the presence of tert-butyl alcohol (TBA: OH radical scavenger), the photocatalytic degradation was markedly reduced for 4-CP or completely inhibited for DCA and TMA whereas that of As(III), MB, and A07 was little affected. Pt/WO3 photocatalyst that oxidizes various substrates under visible light with a sufficient photostability can be applied for solar water treatment.