石墨烯基光催化复合材料的制备及其性能研究

发布时间：2018-06-24 04:01

  本文选题：石墨烯 + P25　； 参考：《上海大学》2015年硕士论文

【摘要】：针对单一的半导体光催化剂在环境污染物降解应用中存在量子效率低、自然光利用率低、难以回收循环利用等缺陷,本论文利用新型碳材料石墨烯对现有的单一半导体光催化剂进行改性,制备了一系列石墨烯基光催化复合材料,分别利用X-射线衍射(XRD)、透射电子显微镜(TEM)、振动样品磁强计(VSM)、比表面积分析(BET)等手段对这些材料进行了表征,并以光催化降解有机染料的降解效率评价了这些材料的光催化活性。本论文获得的主要研究结果和结论如下:(1)采用改进的Hummer氧化法制备了氧化石墨,通过水热法制备了商用Ti O2(P25)和石墨烯的纳米复合材料;然后在此二元复合材料的基础上,负载磁性纳米颗粒Fe3O4,成功制备了三元P25/石墨烯/Fe3O4光催化复合材料。以罗丹明B、亚甲基蓝、甲基橙的光催化降解作为探针反应,研究了P25/石墨烯/Fe3O4磁性光催化复合材料的光催化性能。结果表明,该材料对各种有机染料均展现出良好的光催化降解性能,且在光催化反应完成后,可通过外加磁场进行分离。另外,对该材料反复使用后的光催化性能进行了考察,结果显示在经历5次光催化使用后,光催化性能未出现任何衰减。(2)以氧化石墨烯、硝酸铈为原料,通过一步水热法制备了Ce O2/石墨烯光催化复合材料,并考察了反应溶剂、表面活性剂PVP添加量、水热时间、反应温度对Ce O2/石墨烯复合材料的结构和形貌的影响。结果表明,以C2H5OH作为反应溶剂,表面活性剂PVP的浓度为2.5g/L,水热温度为120℃,反应时间为24小时,可以得到大小均一、形貌规则的Ce O2/石墨烯复合材料。然后,以罗丹明B为模式污染物,对该材料的光催化降解性能进行了考察,结果表明所制备的Ce O2/石墨烯光催化复合材料具有良好的光催化降解性能,相比单一的Ce O2纳米颗粒,太阳光下降解效率提高了60%。(3)以硝酸铈为前驱体,水热法合成Ce O2纳米颗粒,然后利用超声辅助法将Ce O2负载于氧化石墨烯表面,添加Ag NO3,经过电子束辐照法处理,在还原氧化石墨烯的同时,将还原所得的Ag纳米颗粒负载于Ce O2/石墨烯表面,得到三元Ag/Ce O2/石墨烯光催化复合材料。通过光催化降解罗丹明B,考察该材料的光催化降解性能,并对可能的光催化机理进行了探讨。结果表明,Ag纳米颗粒的引入大大促进了Ag/Ce O2/石墨烯的光催化性能,这是由于Ag纳米颗粒能够迅速转移光生电子,抑制电子空穴再复合。对复合材料的光催化机理研究表明,光催化过程中产生的羟基自由基(·OH)是光降解的最主要因素。综上所述,本文利用石墨烯作为载体,合成出三种石墨烯基光催化复合材料。从实验结果可以得出石墨烯的存在极大地提高了半导体材料的光催化降解性能,主要原因是石墨烯能够有效地转移光照半导体产生的电子,避免了电子空穴快速复合以及光腐蚀磁性材料,同时,石墨烯的负载增大材料的比表面积,促进复合材料对染料的吸附。
[Abstract]:In view of the disadvantages of single semiconductor photocatalyst in environmental pollutant degradation, such as low quantum efficiency, low utilization rate of natural light and difficulty in recycling, etc. In this paper, a series of graphene based photocatalytic composites were prepared by modifying the single semiconductor photocatalyst with a new carbon material, graphene. These materials were characterized by means of X-ray diffraction (XRD), transmission electron microscope (TEM), vibrating sample magnetometer (VSM) and specific surface area analysis (BET). The photocatalytic activity of these materials was evaluated by photocatalytic degradation efficiency of organic dyes. The main results and conclusions obtained in this thesis are as follows: (1) Graphite oxide was prepared by modified Hummer oxidation method, and commercial TIO _ 2 (P25) and graphene nanocomposites were prepared by hydrothermal method. Supported magnetic nanoparticles Fe _ 3O _ 4, ternary P25 / graphene / Fe _ 3O _ 4 photocatalytic composites were successfully prepared. The photocatalytic properties of P25 / graphene / Fe _ 3O _ 4 magnetic photocatalytic composites were studied by using the photocatalytic degradation of Rhodamine B, methylene blue and methyl orange as probes. The results showed that the material exhibited good photocatalytic degradation performance for various organic dyes and could be separated by external magnetic field after the photocatalytic reaction was completed. In addition, the photocatalytic properties of the materials after repeated use were investigated. The results showed that the photocatalytic performance did not decrease after 5 times of photocatalytic use. (2) graphene oxide and cerium nitrate were used as raw materials. Ce O 2 / graphene photocatalytic composites were prepared by one step hydrothermal method. The effects of reaction solvent, amount of surfactant PVP, hydrothermal time and reaction temperature on the structure and morphology of ce O 2 / graphene composite were investigated. The results show that when C _ 2H _ 5OH is used as the reaction solvent, the concentration of surfactant PVP is 2.5 g / L, the hydrothermal temperature is 120 鈩，

本文编号：2059917