π-π共轭提高光催化性能的研究

发布时间：2018-05-06 02:20

本文选题：π-π共轭 + 核壳结构　；参考：《华北理工大学》2017年硕士论文

【摘要】：在光催化领域广泛研究的TiO_2和Zn O等催化剂存在仅能利用紫外线以及量子效率较低等缺点,其催化能力还不能满足在环境净化领域大规模应用的需求。具有共轭π结构的导电聚合物由于具有较强的可见光吸收能力以及在电荷传输过程中能加速电荷分离而获得广泛重视。聚苯胺(PANI)和聚吡咯(PPy)作为共轭π材料的典型代表,因其较高的电荷迁移速率、良好的热稳定性、环境稳定性以及优良的电子和空穴的传输能力,被称为目前具有希望得到实际应用的共轭导电高分子。通过π-π共轭导电聚合物包覆Ag_3PO_4,合成核壳结构的可见光催化剂:Ag_3PO_4@PANI、Ag_3PO_4@PPy。采用多种表征考察复合光催化剂的形貌、结构、光学特性以及降解有机污染物的能力。通过红外以及XPS分析证明PANI和Ag_3PO_4形成了强烈的化学键合作用;光电测试证明Ag_3PO_4@PANI具有良好的电荷迁移效率,与淬灭实验结合研究PANI和Ag_3PO_4复合后降解污染物的机理。Ag_3PO_4@PANI(5 wt.%)在可见光下对苯酚和2,4-二氯酚的的降解率高达100%和95.3%,分别是纯Ag_3PO_4的1.4倍和1.3倍;5次循环后,Ag_3PO_4@PANI的催化活性仍保持在85%以上,而机械混合催化剂M-Ag_3PO_4/PANI以及单体Ag_3PO_4降解率仅为42%和27%,实验表明PANI包覆Ag_3PO_4极大地增强了磷酸银的光稳定性;同理,通过活性测试证明Ag_3PO_4@PPy对苯酚的降解效率高达100%,对2,4-二氯酚测试后同样证明有很高的催化性能,24 min内可将97.5%的2,4-二氯酚降解。核壳型催化剂具有高稳定性和光催化性能是由于磷酸银和π-π共轭聚合物之间的协同作用,壳层结构促进两者接触面积增大,能级结构相互匹配以及两者产生的化学键作用,此外还有导电聚合物的π-π共轭作用,极大的提高了光生空穴和电子的分离和迁移速率,明显增强了磷酸银的光催化性能以及稳定性。
[Abstract]:The catalysts such as TiO_2 and Zno, which have been widely studied in the field of photocatalysis, have the disadvantages of only utilizing ultraviolet light and low quantum efficiency, and their catalytic ability can not meet the needs of large-scale application in the field of environmental purification. Conductive polymers with conjugated 蟺 structure have attracted much attention due to their strong visible light absorption and the ability to accelerate charge separation during charge transmission. Polyaniline (pani) and polypyrrole (Pyrrolidine) are typical representatives of conjugated 蟺 materials because of their high charge transfer rate, good thermal stability, environmental stability and excellent electron and hole transport ability. It is called the conjugated conductive polymer which has the hope of practical application at present. Through 蟺-蟺 conjugated polymer coated with Ag3PO4, the visible light catalyst of core-shell structure was synthesized. The morphology, structure, optical properties and the ability to degrade organic pollutants of the composite photocatalysts were investigated by various characterizations. Infrared and XPS analysis proved that PANI and Ag_3PO_4 formed strong chemical bond cooperation, and optoelectronic test proved that Ag_3PO_4@PANI has good charge transfer efficiency. Study on Mechanism of degradation of Pollutant after PANI and Ag_3PO_4 Composites with quenching experiment. Ag-S _ 3PO _ 4R _ PANI5wt.) degradation rates of phenol and 2o _ 4-dichlorophenol in visible light are as high as 100% and 95.3% respectively, which are 1.4 times of that of pure Ag_3PO_4 and 1.3 times of that of Ag_3PO_4 after 5 cycles. The catalytic activity of Ag3PO _ 4follow-up pani is as high as 100% and 95.3%, respectively. Still above 85%, However, the degradation rates of M-Ag_3PO_4/PANI and monomer Ag_3PO_4 were only 42% and 27% respectively. The results showed that PANI coated Ag_3PO_4 greatly enhanced the photostability of silver phosphate. The degradation efficiency of phenol by Ag_3PO_4@PPy was as high as 100 by activity test, and the degradation of 97.5% of 2-trichlorophenol in 24 min was also proved by the test of 2-di-4-dichlorophenol. The core-shell catalyst has high stability and photocatalytic performance because of the synergism between silver phosphate and 蟺-蟺 conjugated polymer, the shell structure promotes the increase of contact area, the matching of energy level structure and the chemical bond between them. In addition, the 蟺-蟺 conjugation of conducting polymers greatly improves the separation and migration rate of photogenerated holes and electrons, and obviously enhances the photocatalytic performance and stability of silver phosphate.
【学位授予单位】：华北理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：O643.36;O644.1

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