催化学报 ›› 2017, Vol. 38 ›› Issue (2): 253-259.DOI: 10.1016/S1872-2067(16)62576-7

• 论文 • 上一篇    下一篇

基于WO3-x量子点和TiO2构建高效Z型光催化产氢催化剂

潘伦a,b, 张靖雯a,b, 贾旭a,b, 马煜航a, 张香文a,b, 王莅a,b, 邹吉军a,b   

  1. a 天津大学化工学院绿色合成与转化教育部重点实验室, 天津 300072;
    b 天津化学化工协同创新中心, 天津 300072
  • 收稿日期:2016-08-28 修回日期:2016-10-15 出版日期:2017-02-18 发布日期:2017-03-14
  • 通讯作者: Ji-Jun Zou,Tel/Fax:+86-22-27892340;E-mail:jj_zou@tju.edu.cn
  • 基金资助:

    国家自然科学基金(21506156,21676193);天津市自然科学基金(15JCZDJC37300,16JCQNJC05200).

Highly efficient Z-scheme WO3-x quantum dots/TiO2 for photocatalytic hydrogen generation

Lun Pana,b, Jingwen Zhanga,b, Xu Jiaa,b, Yu-Hang Maa, Xiangwen Zhanga,b, Li Wanga,b, Ji-Jun Zoua,b   

  1. a Key Laboratory for Green Chemical Technology of Ministry of Education, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China;
    b Collaborative Innovative Center of Chemical Science and Engineering(Tianjin), Tianjin 300072, China
  • Received:2016-08-28 Revised:2016-10-15 Online:2017-02-18 Published:2017-03-14
  • Contact: 10.1016/S1872-2067(16)62576-7
  • Supported by:

    This work was supported by the National Natural Science Foundation of China (21506156, 21676193) and the Tianjin Municipal Natural Science Foundation (15JCZDJC37300, 16JCQNJC05200).

摘要:

TiO2具有高效、廉价、无毒及光化学稳定性好等优点,因而被广泛应用于光能转化和利用领域,如太阳能电池、光催化分解水制氢和环境污染物降解等.但是,TiO2仍然存在一些缺陷制约了其应用,其中,最关键的问题是光生电荷分离效率低.因此,人们对其进行了掺杂、异质结构建和Z型结构建等来解决这一问题,其中Z型结近年来备受关注.
全固体Z型结的构建目前主要有两种方式:PSI-C-PSII和PSI-PSII.前者PSI与PSII间要插入中间导电层(如Au、rGO等)来实现界面欧姆接触;后者则无中间层,而是基于界面设计来实现欧姆接触.本文以构建PSI-PSII Z型结为目标,以TiO2和WO3为基础半导体材料,采用原位溶剂热生长的方法构建WO3量子点/TiO2结构,借助氢气还原反应在界面处引入氧缺陷.采用透射电子显微镜、X射线衍射和拉曼光谱研究了复合晶体结构,采用X射线光电子能谱、紫外可见光谱和荧光光谱等手段研究了Z型结的界面结构和能带结构.结合光催化分解水产氢活性来建立Z型结结构与光催化性能的关联关系.
表征结果表明,在TiO2上进行原位溶剂热成核反应可点缀WO3量子点,并且量子点粒径随W前驱体用量的增加而变大.两种半导体材料为TiO2锐钛矿和WO3晶体结构,且WO3的XRD特征峰和Raman特征吸收峰会随W前驱体用量增加而变大.通过对WO3/TiO2进行氢气还原处理,使其表面形成大量W5+和氧缺陷,一方面提高了催化剂对可见光的吸收,另一方面在界面形成欧姆接触,实现了Z型结构的构建.Z型结构实现了光催化分解水产氢反应,其中WTH10光催化活性最好.本文为新型Z型光催化剂的设计和构建提供了新思路和策略.

关键词: WO3-x, 二氧化钛, 产氢, 量子点, W5+/氧缺陷

Abstract:

Z-scheme semiconductors are a promising class of photocatalysts for hydrogen generation. In this work, Z-scheme semiconductors composed of WO3-x quantum dots supported on TiO2 (WO3-x QDs/TiO2) were fabricated by solvothermal and hydrogen-reduction methods. Characterization by transmission electron microscopy and X-ray diffraction indicated that the amount and size of the WO3-x QDs could be tuned by modulating the addition of the W precursor. Evidence from X-ray photoelectron spectroscopy and photoluminescence spectroscopy suggested that the hydrogen reduction of the composite induced the formation of oxygen vacancy (W5+/VO) defects in WO3. These defects led to ohmic contact between WO3-x and TiO2, which altered the charge-transfer pathway from type II heterojunction to Z-scheme, and maintained the highly reductive and oxidative ability of TiO2 and WO3-x, respectively. Therefore, the Z-scheme sample showed 1.3-fold higher photoactivity than pure TiO2 in hydrogen generation. These results suggest that the formation of W5+/VO defects at the interface is highly beneficial for the fabrication of Z-scheme photocatalysts.

Key words: WO3-x, Titanium oxide, Hydrogen generation, Quantum dots, W5+/oxygen vacancy defect