钨酸铋量子点和纳米片修饰石墨相氮化碳复合催化剂的制备及其可见光催化活性增强

摘要/Abstract

摘要：

利用超声-水热法、使用油酸钠辅助合成钨酸铋(Bi₂WO₆)量子点/纳米片修饰的石墨相氮化碳(g-C₃N₄)(Bi₂WO₆/g-C₃N₄)复合光催化剂。通过X射线粉末衍射(XRD)、透射电子显微镜(TEM)、傅里叶变换红外光谱(FT-IR)、紫外可见漫反射光谱(UV-Vis DRS)、N₂吸附-脱附等技术手段获得Bi₂WO₆/g-C₃N₄催化剂的组成、结构和光吸收性能,分析合成机理。以罗丹明B(RhB)水溶液为模拟污染物,考察Bi₂WO₆/g-C₃N₄复合催化剂的可见光催化活性。结果表明:g-C₃N₄和Bi₂WO₆的质量比为3:7的Bi₂WO₆/g-C₃N₄-30具有最有效的异质界面,电化学阻抗和光电流测试结果显示该催化剂的光生载流子传输速率快、复合率低,可见光照射120 min对RhB的降解率达到95.8%;通过活性物质捕捉实验获知光生空穴是光催化反应中的主要活性物质,分析异质界面对光催化活性的影响,进而提出光催化反应机理。

关键词: 表面修饰, 钨酸铋/石墨相氮化碳复合催化剂, 可见光催化, 合成反应和光催化反应的机理

Abstract:

Bismuth tungstate/graphitic carbon nitride (Bi₂WO₆/g-C₃N₄) composite photocatalyst modified by Bi₂WO₆ quantum dots and nanosheets was prepared through ultrasonic-hydrothermal method using sodium oleate as auxiliary reagent. The compositions, structures and light absorption properties of Bi₂WO₆/g-C₃N₄ were characterized by X-ray powder diffraction (XRD), transmission electron microscopy (TEM), Fourier transform infrared spectra (FT-IR), ultraviolet-visible diffuse reflectance spectroscopy (UV-Vis DRS), Brunauer-Emmett-Teller (BET) and other techniques. The mechanism of synthetic reaction was proposed. Photocatalytic reduction of aqueous rhodamine B (RhB) was employed to assess the visible light photocatalytic activity of Bi₂WO₆/g-C₃N₄. Electrochemical impedance spectroscopy (EIS) and photocurrent characteriations demonstated that Bi₂WO₆/g-C₃N₄ with the heterogeneous interface separated the photo-generated electron-hole paris effectively. Hence, a rapid RhB degradation by Bi₂WO₆/g-C₃N₄-30(the number 30 represents the mass fraction(%) of g-C₃N₄) under visible light irradiation was achieved at 95.8% in 120 min. The results confirmed that the photogenerated holes were main active specie in the photodegradation process. Moreover, the relationship of heterogenrous interface and photocatalytic performance was investigated, and involved photocatalytic mechanism was revealed.

Key words: surface modification, bismuth tungstate/graphitic carbon nitride composite catalyst, visible light photocatalysis, mechanism of synthesis reaction and photocatalytic reaction

李靖, 吴海波, 王瑜, 杨华美, 宋明, 堵锡华, 张永才. 钨酸铋量子点和纳米片修饰石墨相氮化碳复合催化剂的制备及其可见光催化活性增强[J]. 应用化学.

LI Jing, WU Haibo, WANG Yu, YANG Huamei, SONG Ming, DU Xihua, ZHANG Yongcai. Preparation and Enhanced Visible-Light Photocatalytic Activity of Bismuth Tungstate/Graphitic Carbon Nitride Composite Modified by Bi₂WO₆ Quantum Dots and Nanosheets[J]. Chinese Journal of Applied Chemistry.

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