發(fā)布時(shí)間：2018-06-24 04:01

  本文選題：石墨烯 + P25��； 參考：《上海大學(xué)》2015年碩士論文

【摘要】：針對(duì)單一的半導(dǎo)體光催化劑在環(huán)境污染物降解應(yīng)用中存在量子效率低、自然光利用率低、難以回收循環(huán)利用等缺陷,本論文利用新型碳材料石墨烯對(duì)現(xiàn)有的單一半導(dǎo)體光催化劑進(jìn)行改性,制備了一系列石墨烯基光催化復(fù)合材料,分別利用X-射線衍射(XRD)、透射電子顯微鏡(TEM)、振動(dòng)樣品磁強(qiáng)計(jì)(VSM)、比表面積分析(BET)等手段對(duì)這些材料進(jìn)行了表征,并以光催化降解有機(jī)染料的降解效率評(píng)價(jià)了這些材料的光催化活性。本論文獲得的主要研究結(jié)果和結(jié)論如下:(1)采用改進(jìn)的Hummer氧化法制備了氧化石墨,通過(guò)水熱法制備了商用Ti O2(P25)和石墨烯的納米復(fù)合材料;然后在此二元復(fù)合材料的基礎(chǔ)上,負(fù)載磁性納米顆粒Fe3O4,成功制備了三元P25/石墨烯/Fe3O4光催化復(fù)合材料。以羅丹明B、亞甲基藍(lán)、甲基橙的光催化降解作為探針?lè)磻?yīng),研究了P25/石墨烯/Fe3O4磁性光催化復(fù)合材料的光催化性能。結(jié)果表明,該材料對(duì)各種有機(jī)染料均展現(xiàn)出良好的光催化降解性能,且在光催化反應(yīng)完成后,可通過(guò)外加磁場(chǎng)進(jìn)行分離。另外,對(duì)該材料反復(fù)使用后的光催化性能進(jìn)行了考察,結(jié)果顯示在經(jīng)歷5次光催化使用后,光催化性能未出現(xiàn)任何衰減。(2)以氧化石墨烯、硝酸鈰為原料,通過(guò)一步水熱法制備了Ce O2/石墨烯光催化復(fù)合材料,并考察了反應(yīng)溶劑、表面活性劑PVP添加量、水熱時(shí)間、反應(yīng)溫度對(duì)Ce O2/石墨烯復(fù)合材料的結(jié)構(gòu)和形貌的影響。結(jié)果表明,以C2H5OH作為反應(yīng)溶劑,表面活性劑PVP的濃度為2.5g/L,水熱溫度為120℃,反應(yīng)時(shí)間為24小時(shí),可以得到大小均一、形貌規(guī)則的Ce O2/石墨烯復(fù)合材料。然后,以羅丹明B為模式污染物,對(duì)該材料的光催化降解性能進(jìn)行了考察,結(jié)果表明所制備的Ce O2/石墨烯光催化復(fù)合材料具有良好的光催化降解性能,相比單一的Ce O2納米顆粒,太陽(yáng)光下降解效率提高了60%。(3)以硝酸鈰為前驅(qū)體,水熱法合成Ce O2納米顆粒,然后利用超聲輔助法將Ce O2負(fù)載于氧化石墨烯表面,添加Ag NO3,經(jīng)過(guò)電子束輻照法處理,在還原氧化石墨烯的同時(shí),將還原所得的Ag納米顆粒負(fù)載于Ce O2/石墨烯表面,得到三元Ag/Ce O2/石墨烯光催化復(fù)合材料。通過(guò)光催化降解羅丹明B,考察該材料的光催化降解性能,并對(duì)可能的光催化機(jī)理進(jìn)行了探討。結(jié)果表明,Ag納米顆粒的引入大大促進(jìn)了Ag/Ce O2/石墨烯的光催化性能,這是由于Ag納米顆粒能夠迅速轉(zhuǎn)移光生電子,抑制電子空穴再?gòu)?fù)合。對(duì)復(fù)合材料的光催化機(jī)理研究表明,光催化過(guò)程中產(chǎn)生的羥基自由基(·OH)是光降解的最主要因素。綜上所述,本文利用石墨烯作為載體,合成出三種石墨烯基光催化復(fù)合材料。從實(shí)驗(yàn)結(jié)果可以得出石墨烯的存在極大地提高了半導(dǎo)體材料的光催化降解性能,主要原因是石墨烯能夠有效地轉(zhuǎn)移光照半導(dǎo)體產(chǎn)生的電子,避免了電子空穴快速?gòu)?fù)合以及光腐蝕磁性材料,同時(shí),石墨烯的負(fù)載增大材料的比表面積,促進(jìn)復(fù)合材料對(duì)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，

本文編號(hào)：2059917