A Novel Heterojunction BiOBr/Bismuth Oxyhydrate Photocatalyst with Highly Enhanced Visible Light Photocatalytic Properties
A Novel Heterojunction BiOBr/Bismuth Oxyhydrate Photocatalyst with Highly Enhanced Visible Light Photocatalytic Properties
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DOI：
10.1021/jp3009964
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发表时间：
2012-05-24
影响因子：
3.7
通讯作者：
Sasson, Yoel
中科院分区：
文献类型：
--
作者：
Shenawi-Khalil, Sanaa;Uvarov, Vladimir;Sasson, Yoel
在这项研究中，报道了一种通过与水合氧化铋（BHO）制造异质结来改变溴氧化铋（BiOBr）半导体光催化性能的简便有效的方法。通过简单的水热法合成的新型 yBiOBr-(1 - y)BHO 异质结在可见光照射下表现出较高的光催化活性，可光降解水中的典型有机污染物，如罗丹明 B (RhB) 和苯乙酮 (AP)。 BiOBr 和 BHO 组分均表现出非常低的光催化效率。此外，通过涉及将碘化钾（KI）氧化为三碘化物的艰苦光催化反应，证明了新型混合材料独特的光催化性能。耦合系统显着的光催化活性与异质结构的形成所导致的有效载流子分离直接相关。与同一家族的其他成员0.8BiOCl-0.2BHO和0.8BiOI-0.2BHO相比，0.9BiOBr-0.1BHO表现出更高的光催化活性，这直接归因于能带隙结构和载流子通过异质结的流动、表面积和光吸收的协同效应。与TiO2（Degussa P25）相比，新型复合材料在可见光（lambda >= 420 nm）照射下去除水性RhB的活性提高了10.7倍。光催化机理研究表明，可见光照射下所制备的0.9BiOBr-0.1BHO上RhB的降解主要是通过直接空穴氧化机制和超氧化物氧化途径。所得的 yBiOBr-(1 - y)BHO 复合材料表现出高光催化和热稳定性，是非常有前途的光催化剂，用于降解水中的有机污染物和其他应用。
In this study, a facile and effective method to modify the photocatalytic performance of a bismuth oxybromide (BiOBr) semiconductor through the fabrication of a heterojunction with a hydrated bismuth oxide (BHO) is reported. The new yBiOBr-(1 - y)BHO heterojunction, synthesized by a simple hydrothermal method, exhibits a high photocatalytic activity under visible light irradiation for the photodegradation of typical organic pollutants in water, such as Rhodamine B (RhB) and acetophenone (AP). Both the individual BiOBr and BHO components show very low photocatalytic efficiency. Furthermore, the unique photocatalytic performance of the new hybrid material was demonstrated through the uphill photocatalytic reaction that involves the oxidation of potassium iodide (KI) to triiodide. The remarkable photocatalytic activity of the coupled system is directly related to the effectual charge carrier separation due to the formation of the heterostructure. 0.9BiOBr-0.1BHO shows a higher photocatalytic activity as compared with other members of the same family, 0.8BiOCl-0.2BHO and 0.8BiOI-0.2BHO, which is directly ascribed to a synergistic effect of the energy band-gap structure and flow of charge carriers through the heterojunction, surface area, and light absorbance. In comparison with TiO2 (Degussa P25), the new composite material demonstrated 10.7 times higher activity in removing aqueous RhB under visible light (lambda >= 420 nm) irradiation. Study of the photocatalytic mechanism proves that the degradation of RhB under visible light irradiation over the as-prepared 0.9BiOBr-0.1BHO is mainly via a direct hole oxidation mechanism and superoxide oxidation pathways. The resulting yBiOBr-(1 - y)BHO composites exhibit high photocatalytic and thermal stabilities and are very promising photocatalysts for degradation of organic pollutants in water and for other applications.