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甲苯是一种最常见的室内有毒挥发性有机物(VOCs),目前消除方法主要有吸附、催化燃烧和光催化氧化,其中光催化是一种最高效和经济可行的方法,能在较温和条件下将甲苯完全矿化为CO_2.作为研究最广泛的光催化剂,TiO_2在应用中通常有锐钛矿(ATiO_2)和金红石(RTiO_2)两种物相,但单物相TiO_2的低量子产率和光生电子-空穴对的快速复合严重限制了它的应用.本文选择兼具锐钛矿和金红石两种物相的P25为催化剂载体,通过负载少量ZnO和构建多组分并具备多通道载流子分离功能的异质结以提高TiO_2基光催化剂的性能.利用一步浸渍法制备了一系列ZnO/P25复合光催化剂,考察了其光催化降解气相甲苯性能.X射线粉末衍射结果表明,ZnO/P25异质光催化剂是由ATiO_2,RTiO_2和红锌矿三种物相结构组成.高分辨透射电镜结果表明,ZnO/P25具备三相异质结ZnO(002)/ATiO_2(101)/RTiO_2(110).紫外可见光谱、荧光光谱和光电流表征结果表明,ZnO/P25所形成的三相异质结不但增强了光吸收能力,还实现了多通道电子/空穴分离.催化降解实验表明,ZnO/P25异质光催化剂能在室温紫外光辐射下将甲苯完全矿化为CO_2和H2O.基于三相异质结和多通道光生电子-空穴对分离的形成及促进作用,ZnO/P25光催化活性和速率均明显高于P25.本文报道的多通道载流子分离理念可为高效光催化剂设计和应用提供一种新思路.
Toluene is one of the most common indoor toxic volatile organic compounds (VOCs). At present, toluene, as the most commonly used indoor VOCs, is mainly adsorbed, catalyzed and photocatalyzed. Among them, photocatalysis is one of the most efficient and economically feasible methods, Toluene is completely mineralized into CO 2. As the most widely studied photocatalyst, TiO 2 usually has two phases of anatase (ATiO 2) and rutile (RTiO 2). However, the low quantum yield of single phase TiO 2 and photogenerated electron - rapid recombination of hole pairs has severely limited its application.In this paper, P25 with both anatase and rutile phases as the catalyst carrier, by loading a small amount of ZnO and constructing multi-component and multi-channel carrier separation Functional heterojunction to improve the performance of TiO 2 -based photocatalysts.A series of ZnO / P 25 composite photocatalysts were prepared by one-step impregnation method and the photocatalytic degradation of toluene in the gas phase was investigated.The X-ray powder diffraction results showed that ZnO / P25 The photo-photocatalysts consist of three phase structures: ATiO_2, RTiO_2 and red zinc.High resolution transmission electron microscopy results show that ZnO / P25 possesses three-phase heterojunction ZnO (002) / ATiO_2 (101) / RTiO_2 (110). UV-visible spectrum , Fluorescence spectra and photocurrent characterization results show that the three-phase heterojunction formed by ZnO / P25 not only enhances the optical absorption capacity but also realizes the multi-channel electron / hole separation.The catalytic degradation experiments show that ZnO / P25 heterogeneous photocatalyst Toluene can be completely mineralized into CO_2 and H 2 O under ultraviolet radiation at room temperature.Based on the formation and promotion of photo-electron-hole pair separation by three-phase heterojunction and multi-channel, the photocatalytic activity and the rate of ZnO / P25 are obviously high At P25. The concept of multi-channel carrier separation reported in this paper can provide a new idea for the design and application of efficient photocatalysts.