催化学报 ›› 2018, Vol. 39 ›› Issue (4): 810-820.DOI: 10.1016/S1872-2067(17)63004-3

• 论文 • 上一篇    下一篇

Bi2WO6/ZnO:一种在可见光下具有优良光催化性能的花状新型复合材料

程娟a, 沈奕a, 陈宽a, 汪曦a, 郭永福a,b, 周晓吉a, 白仁碧a   

  1. a 苏州科技大学分离净化材料与技术研发中心, 江苏苏州 215009;
    b 江苏高校水处理技术与材料协同创新中心, 江苏苏州 215009
  • 收稿日期:2017-11-30 修回日期:2017-12-20 出版日期:2018-04-18 发布日期:2018-04-08
  • 通讯作者: 郭永福, 白仁碧
  • 基金资助:

    国家自然科学基金(51578354);江苏省六大人才高峰(2016-JNHB-067);苏州市科技局科技计划(SS201667);江苏省青蓝工程和江苏省研究生科研与实践创新计划(KYCX17_2067).

Flower-like Bi2WO6/ZnO composite with excellent photocatalytic capability under visible light irradiation

Juan Chenga, Yi Shena, Kuan Chena, Xi Wanga, Yongfu Guoa,b, Xiaoji Zhoua, Renbi Baia   

  1. a Center for Separation and Purification Materials & Technologies, Suzhou University of Science and Technology, Suzhou 215009, Jiangsu, China;
    b Jiangsu Collaborative Innovation Center of Water Treatment Technology and Material, Suzhou 215009, Jiangsu, China
  • Received:2017-11-30 Revised:2017-12-20 Online:2018-04-18 Published:2018-04-08
  • Contact: 10.1016/S1872-2067(17)63004-3
  • Supported by:

    This work was supported by the National Natural Science Foundation of China (51578354), Six Talent Peaks Program (2016-JNHB-067), Suzhou Science and Technology Bureau (SS201667), and Qing Lan Project and Research Innovation Project for College Graduates of Jiangsu Province (KYCX17_2067).

摘要:

印染废水具有水量大、色度高、难生化降解、有毒有害物质多等特点;另外抗生素废水的大量排放对水生和陆地生态系统带来了危害.光催化可有效降解有机物,因而被广泛研究和应用,其多以半导体作为光催化剂.ZnO因价廉、无毒、来源广、光催化活性高而广受关注.但是,由于其带隙较宽,只能被紫外光激发,对太阳光的利用率低,且易发生光腐蚀,光稳定性较差,从而大大降低了光催化活性,不利于其应用.将ZnO与其他半导体复合是改善其光催化活性的最有效方法之一.铋基光催化剂一直是光催化领域的研究热点,作为无机半导体纳米晶之一,Bi2WO6具有无毒性、适当的带隙和优异的光催化性能,因而得到广泛关注.本文将Bi2WO6复合到ZnO上以降低ZnO带隙能,提高其对太阳能的转换,降低电子-空穴的复合几率,促进电荷转移的有效分离,从而提高ZnO的光催化性能.
本文采用两步水热法合成了一种异质结的花状Bi2WO6/ZnO复合材料.通过降解亚甲基蓝(MB)和四环素,研究了其光催化性能.结果表明,该Bi2WO6/ZnO复合材料对MB和四环素具有优异的光催化活性,对它们的光降解效率分别是纯ZnO的246和4500倍,相应地,对这两种污染物的光降解率分别是纯ZnO的120和200倍.活性因子捕获实验结果显示,超氧自由基在光催化降解过程中起主要作用,其次是羟基自由基和光生空穴.
采用X射线衍射、透射电镜、扫描电镜、紫外-可见漫反射、N2吸附脱附、X射线光电子能谱、荧光光谱、光电流等方法对材料的形态结构、孔结构、化学组成、带隙能、光吸收性质、载流子复合效率等进行了分析.复合后Bi2WO6/ZnO的形貌为微米尺寸纳米结构的花状绒球,直径约为4μm,带隙能量从3.2eV降为2.6eV.Bi2WO6/ZnO为介孔结构,复合后比表面积为原来的4.98倍.所制备的Bi2WO6/ZnO光催化剂比纯Bi2WO6和ZnO颗粒具有更高的瞬态光电流密度(约为4.5μA).
综上,Bi2WO6和ZnO成功复合形成了异质结,降低了ZnO的禁带宽度,促进了电子和空穴的有效分离,从而提高了其光催化活性.

关键词: 钨酸铋, 氧化锌, 光催化, 亚甲基蓝, 抗生素

Abstract:

The photocatalytic ability of ZnO is improved through the addition of flower-like Bi2WO6 to prepare a Bi2WO6/ZnO composite with visible light activity. The composite is characterized by X-ray diffraction, transmission electron microscopy, scanning electron microscopy with UV-vis diffuse reflectance spectroscopy, X-ray photoelectron spectroscopy and N2 adsorption-desorption isotherms. After modification, the band gap energy of Bi2WO6/ZnO is reduced from 3.2 eV for ZnO to 2.6 eV. Under visible light irradiation, the Bi2WO6/ZnO composite shows an excellent photocatalytic activity for degrading methylene blue (MB) and tetracycline. The photo-degradation efficiencies of (0.3:1) Bi2WO6/ZnO for MB and tetracycline are approximately 246 and 4500 times higher than those of bare ZnO, respectively, and correspondingly, the photo-degradation rates for the two pollutants are approximately 120 and 200 times higher than those with bare ZnO, respectively. Moreover, the photocatalyst of (0.3:1) Bi2WO6/ZnO exhibits a higher transient photocurrent density of approximately 4.5 μA compared with those of bare Bi2WO6 and ZnO nanoparticles. The successful recombination of Bi2WO6 and ZnO enhances the photocatalytic activity and reduces the band gap energy of ZnO, which can be attributed to the effective separation of electron-hole pairs. Active species trapping experiments display that[O2]- is the major species involved during photocatalysis rather than·OH and h+. This study provides insight into designing a meaningful visible-light-driven photocatalyst for environmental remediation.

Key words: Bismuth tungstate, Zinc oxide, Photocatalysis, Methylene blue, Antibiotics