高等学校化学学报 ›› 2020, Vol. 41 ›› Issue (7): 1615-1624.doi: 10.7503/cjcu20200107

• 物理化学 • 上一篇    下一篇

量子点自修饰TiO2p-n同质结的构建及光催化性能

王非凡,王松博,姚柯奕,张蕾,杜威,程鹏高,张建平,唐娜*()   

  1. 天津科技大学化工与材料学院, 天津市卤水化工与资源生态化利用重点实验室, 天津 300457
  • 收稿日期:2020-03-02 出版日期:2020-07-10 发布日期:2020-04-26
  • 通讯作者: 唐娜 E-mail:tjtangna@tju.edu.cn
  • 基金资助:
    国家自然科学基金(21808172);天津市自然科学基金(18JCQNJC05800);天津市卤水化工与资源生态化利用重点实验室开放基金(BCERE201909)

Construction and Photocatalytic Performance of Quantum Dots Self-decorated TiO2 p-n Homojunction

WANG Feifan,WANG Songbo,YAO Keyi,ZHANG Lei,DU Wei,CHENG Penggao,ZHANG Jianping,TANG Na*()   

  1. Tianjin Key Laboratory of Brine Chemical Engineering and Resource Eco-utilization, College of Chemical Engineering and Materials Science, Tianjin University of Science & Technology, Tianjin 300457, China
  • Received:2020-03-02 Online:2020-07-10 Published:2020-04-26
  • Contact: Na TANG E-mail:tjtangna@tju.edu.cn
  • Supported by:
    † National Natural Science Foundation of China(21808172);Tianjin Municipal Natural Science Foundation, China(18JCQNJC05800);Fund of Tianjin Key Laboratory of Brine Chemical Engineering and Resource Eco-utilization, China(BCERE201909)

摘要:

在n型TiO2纳米片表面原位沉积p型TiO2量子点构建了量子点自修饰的TiO2 p-n同质结(PNT-x), 并利用透射电子显微镜(TEM)、 X射线衍射(XRD)、 傅里叶变换红外光谱(FTIR)、 X射线光电子能谱(XPS)、 稳态荧光光谱(PL)、 拉曼光谱(Raman)、 紫外-可见漫反射光谱(UV-Vis DRS)、 电化学测试及电化学交流阻抗谱(EIS)对复合物的组成、 结构和光催化性能进行了表征和研究. 结果表明, PNT-x具有TiO2量子点自修饰的结构, 量子点和纳米片中分别含有金属缺陷和氧缺陷, 其含量随组成变化可控, 并使得PNT-x表现出p-n同质结的典型特征, 与n-n Ⅱ型同质结以及块状p-n同质结相比, PNT-x中费米能级相差更大, 界面内电场更强, 具有更高的电荷分离和传递效率. 光照下, 样品的光催化活性顺序为PNT-400>p-25>PNT-600>PNT-200>p-TiO2>n-TiO2, 其中PNT-400的光催化产氢速率高达41.7 mmol·g-1·h-1, 分别为n-TiO2纳米片、 Ⅱ型同质结和块状p-n同质结的4.3倍、 3.6倍和2.3倍, 并表现出优异的催化稳定性.

关键词: 二氧化钛, p-n同质结, 缺陷调控, 电荷分离, 光催化产氢

Abstract:

Quantum dots(QDs) self-decorated TiO2 p-n homojunction(PNT-x) samples were fabricated by in-situ depositing p-type TiO2 QDs on the surface of n-type TiO2 nanosheets. The composition and structure of the samples were characterized by transmission electron microscopy(TEM), X-ray diffraction(XRD), Fourier transform infrared spectroscopy(FTIR), X-ray photoelectron spectroscopy(XPS), photoluminescence spectrometry(PL), Raman spectrometry, UV visible diffuse reflectance spectrometry(UV-Vis DRS), photoelectrochemical test and electrochemical impedance spectroscopy(EIS) analyses. The results indicate that PNT-x exhibits TiO2 QDs self-decorated structure. Meanwhile, there exist metal and oxygen vacancies in QDs and nanosheets, respectively, and the content of vacancies can be modulated by the composition. Therefore, the as-prepared PNT-x show typical characteristics of p-n homojunction, and the difference of Fermi level and internal electrical field is stronger than that in n-n type Ⅱ homojunction and bulk p-n homojunction, thus leading to a significantly high charge separation and transfer efficiency. Under illumination, the order of photocatalytic activity is PNT-400>p-25>PNT-600>PNT-200>p-TiO2>n-TiO2, and PNT-400 display the photocatalytic hydrogen evolution rate as high as 41.7 mmol·g-1·h-1, which is 4.3, 3.6 and 2.3 times that of n-TiO2 nanosheets, type Ⅱ homojunction and bulk p-n homojunction, respectively, as well as a good catalytic stability.

Key words: TiO2, p-n Homojunction, Defect modulation, Charge separation, Photocatalytic H2 evolution

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