催化学报 ›› 2019, Vol. 40 ›› Issue (1): 80-94.DOI: 10.1016/S1872-2067(18)63172-9

• 论文 • 上一篇    下一篇

聚邻苯二胺修饰AgCl/g-C3N4纳米片复合光催化剂的制备及性能

孙林林a, 刘重阳a, 李金择a, 周亚举a, 王会琴b, 霍鹏伟a, 马长畅a, 闫永胜a   

  1. a 江苏大学化学化工学院绿色化学与化工技术研究院, 江苏镇江 212013;
    b 江苏大学能源与动力工程学院, 江苏镇江 212013
  • 收稿日期:2018-07-25 修回日期:2018-09-18 出版日期:2019-01-18 发布日期:2018-11-09
  • 通讯作者: 霍鹏伟, 王会琴
  • 基金资助:

    国家自然科学基金(21576125,21776117);中国博士后科学基金(2017M611716,2017M611734);江苏省六大人才高峰项目(XCL-014);镇江科技计划(SH2016012).

Fast electron transfer and enhanced visible light photocatalytic activity by using poly-o-phenylenediamine modified AgCl/g-C3N4 nanosheets

Linlin Suna, Chongyang Liua, Jinze Lia, Yaju Zhoua, Huiqin Wangb, Pengwei Huoa, Changchang Maa, Yongsheng Yana   

  1. a Institute of Green Chemistry and Chemical Technology, School of Chemistry and Chemical Engineering, Jiangsu University, Zhenjiang 212013, Jiangsu, China;
    b School of Energy and Power Engineering, Jiangsu University, Zhenjiang 212013, Jiangsu, China
  • Received:2018-07-25 Revised:2018-09-18 Online:2019-01-18 Published:2018-11-09
  • Contact: 10.1016/S1872-2067(18)63172-9
  • Supported by:

    This work was supported by the National Natural Science Foundation of China (21576125, 21776117), the China Postdoctoral Science Foundation (2017M611716, 2017M611734), the Six talent peaks project of Jiangsu Province (XCL-014), and the Zhenjiang Science & Technology Program (SH2016012).

摘要:

近年来,工业社会的发展为人们的日常生活带来了便利,然而也引起了环境污染问题.尤其是抗生素的滥用,不仅会导致各种慢性疾病和微生物的传播,而且会使微生物对抗生素产生抵抗力.因此,寻找一种有效且环保的方法来解决抗生素残留问题至关重要.光催化技术作为一种"绿色"技术,具有充分利用太阳光、降低能耗和完全矿化有机物的突出优点,已被广泛应用于消除环境污染.
光敏半导体材料AgCl具有良好的光响应范围、无毒、易制备等优点,成为光催化降解污染物过程中促进光催化剂活性的理想材料.然而,制备的AgCl纳米颗粒易于团聚并发生光腐蚀.目前,片状g-C3N4具有比表面积大和适当的带隙等优点.因此,构筑AgCl/g-C3N4异质结复合光催化剂不仅可以降低光生电子和空穴的复合速率,加快电子传输,还可以解决AgCl纳米颗粒易于团聚的问题.此外,聚邻苯二胺(PoPD)作为一种导电聚合物,具有高效的电子传输能力,用其包裹AgCl可以防止光腐蚀现象的发生.
本文采用沉淀法和光引发聚合法合成了新型高效的PoPD/AgCl/g-C3N4复合材料,并以20mg/L四环素作为目标污染物测试其可见光下的催化性能.用X射线衍射(XRD)、X射线光电子能谱(XPS)、扫描电镜(SEM)和比表面积(BET)测定等方法表征分析了催化剂的结构特征、微观形貌和光学性能.XRD分析发现,PoPD未影响AgCl/g-C3N4催化剂的晶型结构.XPS结果表明,复合材料由C,N,Ag,O,Cl元素组成,并能得到它们的元素价态.由SEM照片可看到不规则薄片状g-C3N4表面均匀地负载着被PoPD包裹的AgCl颗粒.根据BET测试结果,片状的g-C3N4比表面积比块状的增大4倍,使目标污染物能与光催化剂表面活性物质充分接触反应.光催化性能测试结果进一步表明,PoPD/AgCl-35/g-C3N4在可见光下具有优异的光催化性能:可见光照射120min内,四环素的降解效率可达83.06%,降解速率常数是纯g-C3N4的7.98倍.循环实验表明,经过四次循环后催化剂仍具有优异的光催化降解性能,说明所合成的催化剂具有良好的稳定性.
用抗坏血酸、乙二胺四乙酸和异丙醇捕获剂进行了自由基捕获实验,进一步研究PoPD/AgCl/g-C3N4催化剂的光催化机理.结果表明,超氧自由基和空穴在降解四环素过程中起主要作用,羟基自由基的作用相对较小.通过价带谱测试和带隙计算出材料的价导带位置,并对可能的机理进行了相应的分析.总之,PoPD/AgCl/g-C3N4光催化剂具有良好的稳定性和优异的光催化性能,为制备高稳定性复合光催化剂提供了一种新技术.

关键词: 氮化碳纳米片, 氯化银, 聚邻苯二胺, 可见光照射, 光催化

Abstract:

Exfoliation of bulk graphitic carbon nitride (g-C3N4) into two-dimensional (2D) nanosheets is one of the effective strategies to improve its photocatalytic properties so that the 2D g-C3N4 nanosheets (CN) have larger specific surface areas and more reaction sites. In addition, poly-o-phenylenediamine (PoPD) can improve the electrical conductivity and photocatalytic activity of semiconductor materials. Here, the novel efficient composite PoPD/AgCl/g-C3N4 nanosheets was first synthesized by a precipitation reaction and the photoinitiated polymerization approach. The obtained photocatalysts have larger specific surface areas and could achieve better visible-light response. However, silver chloride (AgCl) is susceptible to agglomeration and photocorrosion. The PoPD/AgCl/CN composite exhibits an extremely high photocurrent density, which is three times that of CN. Obviously enhanced photocatalytic activities of PoPD/AgCl/g-C3N4 are revealed through the photodegradation of tetracycline. The stability of PoPD/AgCl/CN is demonstrated based on four cycles of experiments that reveal that the degradation rate only decreases slightly. Furthermore,·O2- and h+ are the main active species, which are confirmed through a trapping experiment and ESR spin-trap technique. Therefore, the prepared PoPD/AgCl/CN can be considered as a stable photocatalyst, in which PoPD is added as a charge carrier and acts a photosensitive protective layer on the surface of the AgCl particles. This provides a new technology for preparing highly stable composite photocatalysts that can effectively deal with environmental issues.

Key words: g-C3N4 nanosheets, AgCl, Poly-o-phenylenediamine, Visible light irradiation, Photocatalytic