含碳复合光催化剂及其光催化降解性质研究

发布时间：2018-06-21 21:55

本文选题：CS/Ag_3PO_4 + C_(60)/Ag_3PO_4　；参考：《天津科技大学》2017年硕士论文

【摘要】：环境问题是人们对工业发展的负面影响没有及时控制而引起的世界性重要难题。环境质量的下降会严重的影响人类和生态系统的正常活动。因此人类急需要研究一种高效环保材料来缓解和预防这种由于工业发展引起的环境问题。众所周知,半导体光催化技术是通过太阳能照射半导体所产生的光生载流子把污染物氧化还原为对环境没有污染的二氧化碳和水。许多碳纳米材料本身具有超强吸附、稳定性、耐腐蚀以及很难发生化学反应等优点。本文围绕含碳材料复合Ag_3PO_4以及卤氧化铋系列复合后的光催化剂模拟降解工业污水的性能进行了以下研究。通过简单的沉淀法制备了含碳材料的复合光催化剂CS/Ag_3PO_4,采用X射线衍射仪(XRD),X射线光电子能谱(XPS),透射电子显微镜(TEM),紫外-可见分光光度仪(UV-Vis),扫描电子显微镜(SEM)等对上述合成的含碳材料的光催化剂的表面构成和光学性能等进行了表征。以具有偶氮染料结构的甲基橙(MO)作为目标染料,对Ag_3PO_4和CS/Ag_3PO_4的光催化活性进行了分析与评价,并探究了不同含量的碳材料对CS/Ag_3PO_4复合光催化剂催化降解模拟污水效率的影响。研究可知,在制备复合催化剂的过程中将CS的含量控制在5 mg/L时,才能制备出降解活性最优的复合催化剂CS/Ag_3PO_4。CS/Ag_3PO_4复合光催化剂在降解染料过程中的可能机理是CS把Ag_3PO_4导带上的光生电子储存起来,这样避免了光生电子与光生空穴的重合,从而使CS/Ag_3PO_4的光催化活性能够有效的提高。在降解MO染料过程中,检测出羟基自由基(·OH)发挥了主要的降解活性的作用。通过沉淀法制备了 Ag_3PO_4和C_(60)/Ag_3PO_4复合光催化剂,用XRD,TEM,UV-Vis等对制备的含碳光催化剂的光学性质和表面结构进行了表征,同样以偶氮类染料甲基橙MO作为目标反应物,系统性地评价了 Ag_3PO_4和C_(60)/Ag_3PO_4的光催化降解活性,并检测了不同含量的富勒烯C_(60)对复合催化剂的降解效率的影响。实验结果表明,当复合催化剂中富勒烯C_(60)的含量约为5 mg/L时,与Ag_3PO_4复合后的光催化降解性能表现最优秀,这是由于富勒烯C_(60)能够将光生电子储存起来,能够起到将光生电子-空穴有效分离的作用,从而提高了复合催化剂的降解效率及循环稳定性。通过简便的微波辅助法制备了具有高降解效率的复合材料BiOCl/BiOBr,用XRD,SEM,UV-Vis等对不同摩尔比的BiOCl/BiOBr的光学性质及降解活性进行各种对比表征。结果表明,在模拟可见光条件下BiOCl/BiOBr材料能够非常好的降解罗丹明B溶液。而BiOCl/BiOBr复合光催化剂的光催化降解的可能机理是由于BiOCl/BiOBr能够比纯的BiOCl和BiOBr更好地分离光生电子与空穴,最终提高了该复合光催化剂的光催化降解效率。
[Abstract]:Environmental problem is an important problem in the world caused by people's negative impact on industrial development without timely control. The decline of environmental quality will seriously affect the normal activities of human and ecosystem. Therefore, we urgently need to study a kind of efficient environmental protection material to alleviate and prevent the environmental problems caused by industrial development. It is well known that semiconductor photocatalytic technology is a photogenerated carrier produced by solar irradiation of semiconductors to redox pollutants into unpolluted carbon dioxide and water. Many carbon nanomaterials have the advantages of super adsorption, stability, corrosion resistance and difficult chemical reaction. In this paper, the photocatalytic degradation of industrial wastewater by the composite of carbon material AgS3PO4 and bismuth halide has been studied as follows. Carbon containing composite photocatalyst CS/ Ag3PO4 was prepared by simple precipitation method. X-ray diffraction (XRD) X-ray photoelectron spectroscopy (XPS), transmission electron microscope (TEM), UV-Vis spectrophotometer (UV-Vis) and scanning electron microscope (SEM) were used to prepare carbon containing composite photocatalyst CS/ Ag3PO4, which were compared with each other by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), transmission electron microscope (TEM), UV-Vis and scanning electron microscopy (SEM). The surface composition and optical properties of the photocatalyst were characterized. Using methyl orange (MO) with azo dye structure as the target dye, the photocatalytic activity of AgS3PO4 and CS/ Ag3PO4 was analyzed and evaluated. The effect of carbon materials on the efficiency of CS/ Ag3PO4 photocatalytic degradation of simulated sewage was investigated. The results show that when the content of CS is controlled at 5 mg / L during the preparation of the composite catalyst, The possible mechanism of the CS/ Ag3PO4 composite photocatalyst in the degradation of dyes is that CS stores the photogenerated electrons in the Ag3PO4 lead band, thus avoiding the coincidence between photogenerated electrons and photogenerated holes. Thus, the photocatalytic activity of CS/ Ag3PO4 can be improved effectively. During the degradation of MO dyes, hydroxyl radical (OH) was found to play a major role in the degradation of MO dyes. The composite photocatalysts of AgSh _ 3PO _ 4 and C _ (60) / Ag _ 3PO _ 4 were prepared by precipitation method. The optical properties and surface structure of the prepared photocatalysts were characterized by XRDX TEMX UV-Vis, and the methyl orange MO, an azo dye, was also used as the target reactant. The photocatalytic degradation activity of Ag3PO4 and C60 / Ag-3PO4 was systematically evaluated, and the effects of different contents of fullerene C60 on the degradation efficiency of the composite catalyst were examined. The experimental results show that when the content of fullerene C _ (60) in the composite catalyst is about 5 mg / L, the photocatalytic degradation performance of the composite with Ag3PO4 is the best, because fullerene C _ (60) can store photogenerated electrons. It can effectively separate photogenerated electrons and holes, thus improving the degradation efficiency and cycle stability of the composite catalyst. BiOCl / BiOBr composites with high degradation efficiency were prepared by a simple microwave assisted method. The optical properties and degradation activity of BiOCl / BiOBr with different molar ratios were characterized by XRDX SEMN UV-Vis et al. The results show that BiOCl-BiOBr can degrade Rhodamine B solution very well under simulated visible light. The possible mechanism of photocatalytic degradation of BiOCl / BiOBr composite photocatalyst is that BiOCl / BiOBr can separate photogenerated electrons and holes better than pure BiOCl and BiOBr, and finally improve the photocatalytic degradation efficiency of the composite photocatalyst.
【学位授予单位】：天津科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：O643.36;O644.1

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