磁性石墨烯基氧化锌纳米材料的制备及光催化性能的研究

发布时间：2018-01-05 19:06

本文关键词：磁性石墨烯基氧化锌纳米材料的制备及光催化性能的研究　出处：《天津工业大学》2016年硕士论文　论文类型：学位论文

【摘要】：由广泛存在的有机物和金属离子所导致的水污染已经成为世界性的严重的问题,迫切需要更多的环境友好技术。自从Fujishima和Honda在1972年首次使用二氧化钛作为光阳极在紫外线照射下分解水以来,光催化研究领域的序幕由此揭开,人们对金属氧化物半导体光催化剂的制备和应用做了大量的工作,光催化降解有机污染物由于其在环境修复和转换光能为化学能方面具有巨大的潜力在近几十年在全世界范围内引起了越来越多的关注。在众多光催化剂中,ZnO由于其具有宽带隙(3.37 eV)和大的激子束缚能(60 meV)而受到越来越多的关注。然而有4个缺点限制了ZnO光催化剂的实际应用：(1)ZnO的量子产率非常低,吸收光子后产生的电子-空穴对极易再结合,降低光催化活性；(1)ZnO在光照下极易光腐蚀,在重复使用后光降解率下降,光稳定性差；(3)ZnO粉末在水溶液中单独使用时,极易发生团聚,其比表面积大幅度下降,使得反应活性位的数量降低,降低光催化活性；(4)在实际使用后,传统ZnO光催化剂分离困难,分离效率低,影响其重复使用,并对环境造成了一定的影响。将ZnO与磁性石墨烯相结合形成复合材料,能够发挥协同作用,提高光催化性能并且具有磁性,能够快速分离,实现重复使用。分别采用溶剂热法制备得到了8种纳米磁球修饰的磁性石墨烯RGO-Fe_3O_4和RGO-MFe2O4 (M=Mn2+, Zn2+, Co2+, Ni2+, Mg2+, Ca2+ and Cu2+),和溶胶凝胶法制备得到了ZnO纳米粒子,然后通过超声作用将ZnO纳米粒子分别成功地负载到上述8种磁性石墨烯上,得到了8种RGO-Fe_3O_4-ZnO Nanoparticles和RGO-MFe2O4-ZnO Nanoparticles (M=Mn2+, Zn2+, Co2+, Ni2+, Mg2+, Ca2+ and Cu2+)具有磁性的三元复合光催化剂。FESEM图片显示,粒径在200-400nm之间的MFe2O4纳米磁球和粒径在20nm左右的ZnO纳米粒子均匀地分布在石墨烯纳米片上。通过光催化降解罗丹明B的实验发现,RGO-MgFe2O4-ZnO NPs复合材料的光降解率与ZnO纳米粒子相比非常接近,RGO-MgFe2O4-ZnO NPs略低于ZnO纳米粒子,但是RGO-MgFe2O4-ZnO NPs复合材料具有磁性,便于重复使用,在循环使用后仍保持较高的光催化活性。通过以8种磁性石墨烯为基底,以ZnO纳米粒子作为种子层,然后以RGO-Fe_3O_4-ZnO seeds和RGO-MFe2O4-ZnO seeds(M=Mn2+,Zn2+,Co2+,Ni2+,Mg2+,Ca2+ and Cu2+)为模板、硝酸锌和HMT为原料,通过低温湿化学方法制备了8种磁性石墨烯-氧化锌纳米棒阵列三元复合光催化剂RGO-Fe_3O_4-ZnO Nanorod arrays和RGO-MFe2O4-ZnO Nanorod arrays(M=Mn2+,Zn2+,Co2+,Ni2+,Mg2+, Ca2+ and Cu2+)。通过光催化降解罗丹明B的实验发现,RGO-ZnFe2O4-ZnONanorod arrays复合材料的光降解率是Zn0纳米棒的两倍,并且RGO-ZnFe2O4-ZnO Nanorod arrays复合材料具有磁性,便于重复使用,在循环使用后仍保持较高的光催化活性。
[Abstract]:Water pollution caused by the widespread organic compounds and metal ions has become a serious problem in the world, the urgent need for more environmental friendly technology. Since Fujishima and Honda in 1972 for the first time since the use of titanium dioxide as anode decomposition of water under ultraviolet light, a prelude to research field of photocatalysis which opened, people of metal oxide semiconductor photocatalyst preparation and application to do a lot of work, the photocatalytic degradation of organic pollutants in the environment because of its repair and conversion of light into chemical energy has great potential in recent decades has attracted more and more attention all over the world. Among the photocatalysts, due to its wide band gap (ZnO 3.37 eV) and large exciton binding energy (60 meV) is attracting more and more attention. However, there are 4 shortcomings limit the practical application of ZnO photocatalyst: (1) ZnO The quantum yield is very low, the electron hole generated by absorbing photons with extremely easily, reduce the photocatalytic activity; (1) ZnO in the light of easy light corrosion in repeated use after the degradation rate decreased, poor light stability; (3) using a separate ZnO powder in aqueous solution, easy to aggregation, the surface area decreased greatly, so that the number of reactive sites decreased, reduce the photocatalytic activity; (4) in actual use, the traditional ZnO photocatalyst separation difficulties, low separation efficiency, the effect of repeated use, and on the environment caused by a certain impact. ZnO and magnetic properties of graphene the combination of the formation of composite materials, can play a synergistic role in improving the photocatalytic performance and has a magnetic, can be rapidly separated, can be reused. Were prepared by solvothermal method and obtained 8 kinds of magnetic nano spheres modified magnetic graphene RGO-Fe_3O_4 (M=Mn2+, Zn2+ and RGO-MFe2O4, Co2+, Ni2+, Mg2+, Ca2+, and, Cu2+) and sol gel prepared ZnO nanoparticles, then ZnO nanoparticles were successfully loaded to the above 8 kinds of magnetic graphene by ultrasonic, and obtained 8 kinds of RGO-Fe_3O_4-ZnO Nanoparticles and RGO-MFe2O4-ZnO Nanoparticles (M=Mn2+, Zn2+, Co2+, Ni2+, Mg2+, Ca2+ and Cu2+ three yuan) with magnetic composite photocatalyst.FESEM images show that the particle size of MFe2O4 nano magnetic ball between 200-400nm and diameter of 20nm ZnO nanoparticles were uniformly dispersed on graphene nanosheets. The photocatalytic degradation of rhodamine B was found, RGO-MgFe2O4-ZnO NPs composites the photodegradation rate of ZnO nanoparticles compared with very close to RGO-MgFe2O4-ZnO, NPs is slightly lower than that of ZnO nanoparticles, but the RGO-MgFe2O4-ZnO NPs composites with magnetic, repeated use, still remain in circulation after use A higher photocatalytic activity. By 8 kinds of magnetic graphene as substrate, ZnO nanoparticles as a seed layer, and then to RGO-Fe_3O_4-ZnO seeds and RGO-MFe2O4-ZnO seeds (M=Mn2+, Zn2+, Co2+, Ni2+, Mg2+, Ca2+ and Cu2+) as the template, zinc nitrate and HMT as raw materials, 8 kinds of magnetic graphene - Zinc Oxide nanorod arrays the three element composite photocatalyst RGO-Fe_3O_4-ZnO Nanorod arrays and RGO-MFe2O4-ZnO Nanorod arrays through the low temperature wet chemical preparation methods (M=Mn2+, Zn2+, Co2+, Ni2+, Mg2+, Ca2+, and Cu2+). The photocatalytic degradation of Luo Danming B found that RGO-ZnFe2O4-ZnONanorod arrays composite degradation rate is two times of Zn0 nanorods, and RGO-ZnFe2O4-ZnO Nanorod arrays composite materials with magnetism, repeated use, recycling still keeps high photocatalytic activity.

【学位授予单位】：天津工业大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：O643.36

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