催化学报 ›› 2019, Vol. 40 ›› Issue (8): 1187-1197.DOI: 10.1016/S1872-2067(19)63377-2

• 论文 • 上一篇    下一篇

UiO-66-NH2表面修饰Ag/AgCl:利用等离子态银和异质结的协同作用实现高效可见光催化

赵琬玥, 丁彤, 王亚婷, 武墨青, 金文峰, 田野, 李新刚   

  1. 天津大学化工学院, 天津化学化工协同创新中心, 天津市应用催化科学与工程重点实验室, 天津 300072
  • 收稿日期:2019-03-12 修回日期:2019-04-11 出版日期:2019-08-18 发布日期:2019-06-21
  • 通讯作者: 李新刚
  • 基金资助:
    This work was supported by the National Natural Science Foundation of China (21676182), the National Basic Research Program of China (973 Program, 2014CB932403), and the Program for Introducing Talents of Discipline to Universities of China (B06006).

Decorating Ag/AgCl on UiO-66-NH2: Synergy between Ag plasmons and heterostructure for the realization of efficient visible light photocatalysis

Wanyue Zhao, Tong Ding, Yating Wang, Moqing Wu, Wenfeng Jin, Ye Tian, Xingang Li   

  1. Collaborative Innovation Center of Chemical Science and Engineering(Tianjin), Tianjin Key Laboratory of Applied Catalysis Science and Engineering, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China
  • Received:2019-03-12 Revised:2019-04-11 Online:2019-08-18 Published:2019-06-21
  • Supported by:
    This work was supported by the National Natural Science Foundation of China (21676182), the National Basic Research Program of China (973 Program, 2014CB932403), and the Program for Introducing Talents of Discipline to Universities of China (B06006).

摘要: 人工合成染料广泛应用于制革、涂料、化妆品等行业,是工业废水中的常见污染物.染料残留物即使浓度较低也可以对环境和生物造成严重危害,因此在排放前将工业废水中的染料降解为无毒无害物质十分必要.光催化为降解有机污染物提供了一个利用太阳能且无二次污染的途径.UiO-66-NH2是具有可见光吸收性能的金属-有机骨架化合物(MOFs),近年来引起了光催化领域研究人员的广泛关注.但吸光能力不足和载流子的快速复合限制了它在光催化领域的进一步应用.
本文通过沉淀-光沉积法制备了一系列不同银含量的UiO-66-NH2/Ag/AgCl复合物,通过XRD、SEM、TEM及XPS等手段对该体系进行了表征.结果表明,UiO-66-NH2表面成功负载了Ag/AgCl,形成了异质结,并且没有改变MOFs的骨架结构.UV-vis结果表明,UiO-66-NH2/Ag/AgCl结构中的Ag具有表面等离子体共振效应(SPR).随后,通过在可见光条件下降解罗丹明B测试了UiO-66-NH2/Ag/AgCl系列样品的光催化性能,其中Ag含量为16.2 wt.%的UiO-66-NH2/Ag/AgCl表现出最高的光降解速率,分别是UiO-66-NH2和Ag/AgCl的10倍和4倍.我们认为,Ag的SPR效应增强了复合物吸收可见光的能力,异质结的形成加速了光生电子和空穴的分离,二者的协同作用极大地提高了光降解活性.通过活性物种俘获实验确定了在该体系的光降解反应过程中超氧自由基(·O2-)是主要活性物种.此外,通过对电子传输路径的研究,结果发现Ag的SPR效应加剧了光生电子的产生,有利于·O2-的形成.实验还发现含有过量Ag的UiO-66-NH2/Ag/AgCl样品的光降解效率有一定程度的下降,通过对样品形貌的考察,推测过量Ag会造成Ag/AgCl颗粒团聚,降低UiO-66-NH2和Ag/AgCl之间的作用力,不利于异质结的形成,进而影响光降解活性.
总之,本文通过UiO-66-NH2与Ag/AgCl的结合,克服了其各自的缺陷,提升了可见光吸收能力和载流子分离效率,大幅度改善了光降解性能,并且对该体系的反应机理做了一定程度的研究.希望本研究可以为MOFs材料光催化体系的构建提供有价值的参考.

关键词: UiO-66-NH2, Ag/AgCl, 异质结, 可见光催化, 超氧自由基

Abstract: UiO-66-NH2, as typical visible light responsive Zr-based metal-organic frameworks (MOFs), has attracted great interest in recent years. However, rapid combination of the photoinduced carriers limits its further application. Here, we designed a facile precipitation-photoreduction method to post-synthetically decorate Ag/AgCl on the surface of UiO-66-NH2 and form a heterostructure. Metallic Ag can not only transmit electrons between UiO-66-NH2 and AgCl but also absorb visible light, because of the surface plasmon resonance (SPR) effect. The rhodamine B photodegradation rate of UiO-66-NH2/Ag/AgCl (16.2 wt.% Ag) is about 10 and 4 times those of UiO-66-NH2 and Ag/AgCl, respectively. The SPR effect of Ag NPs and the formation of a heterostructure synergistically increase the absorbability of visible light, accelerate the separation of photoinduced charges, and promote the formation of superoxide radicals. We expect that our work could provide a new viewpoint for constructing efficient MOF-based photocatalytic systems.

Key words: UiO-66-NH2, Ag/AgCl, Heterostructure, Visible light photocatalysis, Superoxide radical