催化学报 ›› 2018, Vol. 39 ›› Issue (8): 1411-1417.DOI: 10.1016/S1872-2067(18)63080-3

• 论文 • 上一篇    下一篇

微波辅助离子热合成具有高光催化活性的BiOBr片层微米立方体

缪应纯a,b, 廉志超b, 霍宇凝b, 李和兴b   

  1. a 曲靖师范学院资源与环境化学重点实验室, 云南曲靖 655400;
    b 上海师范大学上海市稀土功能材料重点实验室, 上海 200234
  • 收稿日期:2018-03-03 修回日期:2018-04-25 出版日期:2018-08-18 发布日期:2018-07-04
  • 通讯作者: 缪应纯, 李和兴
  • 基金资助:

    国家自然科学基金(20937003,21261140333,21237003,21207091,21577092,2171101231);上海市政府项目(12230706000,11JC1409000,12YZ091,15520711300);云南省应用基础研究项目(2013FZ109,2016FB016);云南省教育部门重点项目(2015Z183,2016ZZX207).

Microwave-assisted ionothermal synthesis of hierarchical microcube-like BiOBr with enhanced photocatalytic activity

Yingchun Miaoa,b, Zichao Lianb, Yuning Huob, Hexing Lib   

  1. a Faculty of Chemical and Environmental Science, Key Laboratory of Environment Chemistry, Qujing Normal University, Qujing 655000, Yunnan, China;
    b The Education Ministry Key Laboratory of Resource Chemistry, Shanghai Key Laboratory of Rare Earth Functional Materials, Shanghai Normal University, Shanghai 200234, China
  • Received:2018-03-03 Revised:2018-04-25 Online:2018-08-18 Published:2018-07-04
  • Contact: 10.1016/S1872-2067(18)63080-3
  • Supported by:

    This work was supported by the National Natural Science Foundation of China (20937003, 21261140333, 21237003, 21207091, 21577092, 2171101231), Shanghai Government (12230706000, 11JC1409000, 12YZ091, 15520711300), Yunnan Applied Basic Research Project of Province (2013FZ109, 2016FB016), and Key Projects of Yunnan Provincial Department of Education (2015Z183, 2016ZZX207).

摘要:

微波辅助离子热合成技术因其加热和反应速度快、反应时间短、产物选择性高、环保、节能等优点,而广泛应用于纳米棒、纳米线和中空纳米微球等各种形貌功能材料的合成.BiOBr光催化剂具有毒性低、光生空穴氧化能力强、光降解活性高等优点,在光催化降解污染物方面研究非常广泛.虽然各种形貌的BiOBr光催化剂可以通过传统的溶剂热法合成,但仍然需要开发绿色和高效节能的合成方法,来设计新型结构和高光催化降解活性的BiOBr光催化剂.本文首次报道了由微波辅助离子热自组装的方法合成新型结构的BiOBr微米立方体.该BiOBr由规则的多层纳米片组成,其通过在Br-端表面上选择性吸附离子液体形成,随后形成氢键的π-π堆叠.结果显示BiOBr是由厚度小于50nm的纳米片组装成为4 μm左右的纳米立方块.其中Bi:Br:O摩尔比为1:1:1,表明生成纯化学计量比的BiOBr,且具有高结晶度的纯四方相.我们通过添加不同的表面活性剂,进一步确认氢键-co-π-π叠层在BiOBr片层立方块形成中的重要性.
将BiOBr片层立方块研磨粉碎后其BET表面积为从2.30急剧增至17.3m2/g,但其降解RhB活性却大幅度下降.由于纳米片层的层间反射和散射,有效地提升了BiOBr的可见光吸收,光学带隙由2.66窄化为2.56 eV,因而具有高的可见光光降解活性和优异的稳定性及矿化能力.光催化降解180min后,罗丹明B的转化率约为99.57%,而有机碳去除率高达12.24%;对于磨碎的BiOBr罗丹明B的转化率和有机碳去除率分别为68.68%和8.62%.光催化反应前后的BiOBr中,Bi3+离子的XPS峰位置没有明显的变化,进一步表明BiOBr光催化剂具有较高的稳定性.这种具有高活性、优异的稳定性以及高矿化能力的BiOBr,在实际应用光催化降解染料废水和清洁能源方面显示出很好的潜力.此外,通过光催化反应过程中不同捕获剂的添加确定了光降解的主要活性物种.当加入硝酸银溶液的时候,由于光生电子快速被Ag+离子捕获,光降解活性明显下降.活性物种的捕获实验表明,光生电子为主要的活性物种.

关键词: 微波, BiOBr片状立方体, 自组装, 光催化降解, 矿化能力

Abstract:

Bismuth oxybromide (BiOBr) with a hierarchical microcube morphology was successfully synthesized via microwave-assisted ionothermal self-assembly method. The as-obtained BiOBr was composed of regular multi-layered nanosheets, which were formed by selective adsorption of ionic liquids on the Br-terminated surface, followed by the formation of hydrogen bond-co-π-π stacking. The synthesized BiOBr exhibited high activity, excellent stability, and superior mineralization ability in the photocatalytic degradation of organic dyes under visible light owing to its enhanced light absorbance and narrow bandgap. Furthermore, photo-generated electrons were determined to be the main active species by comparison with different trapping agents used in the photocatalytic reactions.

Key words: Microwave, BiOBr microcubes, Self-assembly, Photocatalytic degradation, Mineralization ability