量子点自修饰TiO2p-n同质结的构建及光催化性能  

Construction and Photocatalytic Performance of Quantum Dots Self-decorated TiO2p-n Homojunction

作　　者：王非凡 王松博 姚柯奕 张蕾 杜威 程鹏高 张建平 唐娜 WANG Feifan;WANG Songbo;YAO Keyi;ZHANG Lei;DU Wei;CHENG Penggao;ZHANG Jianping;TANG Na(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)

机构地区：[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

出　　处：《高等学校化学学报》2020年第7期1615-1624,共10页Chemical Journal of Chinese Universities

基　　金：国家自然科学基金(批准号:21808172);天津市自然科学基金(批准号: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(批准号:BCERE201909)资助.

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TiO2p-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-nⅡ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.Quantum dots(QDs)self-decorated TiO 2 p-n homojunction(PNT-x)samples were fabricated by in-situ depositing p-type TiO 2 QDs on the surface of n-type TiO 2 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 TiO 2 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 typeⅡhomojunction 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-TiO 2>n-TiO 2,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-TiO 2 nanosheets,typeⅡhomojunction and bulk p-n homojunction,respectively,as well as a good catalytic stability.

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 

分 类 号：O643.3[理学—物理化学]