有序多孔氧化锌石墨烯复合膜制备及性能研究

发布时间：2018-04-18 07:11

  本文选题：纳米氧化锌 + 石墨烯　； 参考：《大连理工大学》2015年硕士论文

【摘要】：纳米氧化锌(ZnO)由于其独特的性能,在光催化和太阳能电池领域应用前景广阔。但是,较低的量子产率和光能利用率使纳米ZnO的光催化活性不高,这限制了其高效的应用。此外,无法高效低能分离回收光催化后的ZnO,也是一个亟需解决的问题。针对上述两种问题,本论文利用石墨烯修饰改性纳米ZnO薄膜,并提出以玻璃基片为固定纳米ZnO的载体,得到固化的有序多孔ZnO薄膜及其复合膜,对其光学性能、光催化活性及使用寿命进行研究。以玻璃基片为固定载体,本研究通过浸渍提拉法制备了纳米ZnO薄膜,解决了纳米ZnO易流失、不易回收的问题。用扫描电镜(SEM)、X衍射射线(XRD)等手段对薄膜进行表征,考察其光学性能和光催化活性。结果表明,纳米ZnO平铺在玻璃基板上,晶型为六方纤锌矿结构,尺寸为13.6nm；在500W汞灯下,60min纳米ZnO薄膜光催化降解水溶液中亚甲基蓝(MB)和甲基橙(MO)的效率分别为87.3%和54.2%；另外,随甲基橙溶液浓度的增大,ZnO薄膜对甲基橙的降解率呈先增大后减小的趋势,当浓度为3mg/L时,甲基橙的降解率达到最大(92.8%)；使用寿命测试表明,90min回收的纳米ZnO薄膜对甲基橙降解率在70%以上,光催化效果良好。为提高纳米ZnO薄膜的光催化活性,以聚苯乙烯(Polystyrene)为模板,通过浸渍提拉法得到有序多孔ZnO薄膜,考察该薄膜光学性能及光催化活性。与纳米ZnO薄膜相比,多孔ZnO薄膜的多孔结构增大了膜的比表面积,并加快甲基橙在材料内部传递,反应活性位增多使催化活性增高；也增强了光吸收强度。500W汞灯下、90mmin有序多孔ZnO薄膜对甲基橙的降解率为94.7%,较纳米ZnO薄膜80.2%的降解率有所提高。为进一步提高纳米ZnO薄膜的光催化活性,利用石墨烯改性纳米ZnO薄膜,制备了ZnO-石墨烯复合膜和有序多孔ZnO-石墨烯复合膜,用XRD等手段对复合膜进行表征,考察复合膜的光学性能、光催化活性和使用寿命。石墨烯的引入使ZnO光吸收强度上升,并且将光谱响应范围拓展到可见光区,对ZnO晶型的六方纤锌矿结构未产生影响；在500W汞灯下,90mmin内石墨烯修饰的ZnO有序多孔复合膜降解甲基橙的效率最高(99.7%),致密复合膜次之(93.5%),纳米ZnO薄膜最低(80.2%)：此外,随氧化石墨烯溶胶浓度的增加,由于石墨烯负载量不同,ZnO-石墨烯复合膜对甲基橙的降解率呈先增大后减小的趋势。使用寿命测试表明,90min内回收的ZnO-石墨烯复合膜降解甲基橙的效率均在90%以上,优于ZnO薄膜70%的效率,光催化活性良好。
[Abstract]:Nanocrystalline zinc oxide (ZnO) is widely used in photocatalysis and solar cells due to its unique properties.However, the low quantum yield and utilization efficiency of light energy make the photocatalytic activity of nanometer ZnO low, which limits its high efficiency.In addition, it is an urgent problem that ZnO can not be separated efficiently and low energy after photocatalytic recovery.In order to solve the above two problems, in this paper, graphene was used to modify the nano-scale ZnO film, and the glass substrate was used as the carrier to immobilize the nanometer ZnO. The ordered porous ZnO film and its composite film were obtained, and the optical properties of the film were analyzed.The photocatalytic activity and service life were studied.Nanocrystalline ZnO thin films were prepared by dipping Czochralski method with glass substrate as the stationary carrier. The problem of easy loss of nanometer ZnO and difficult recovery was solved.The thin films were characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD), and their optical properties and photocatalytic activity were investigated.The results showed that the nanocrystalline ZnO was coated on glass substrates with hexagonal wurtzite structure with a size of 13.6 nm, and the photocatalytic degradation efficiency of methylene blue blue MBb and methyl orange molybdenum in aqueous solution was 87.3% and 54.2%, respectively, under 500W Hg lamp for 60min.With the increase of the concentration of methyl orange solution, the degradation rate of methyl orange film increased first and then decreased. When the concentration was 3mg/L,The degradation rate of methyl orange was up to 92.8%, and the test of service life showed that the degradation rate of methyl orange was more than 70% and the photocatalytic effect was good.In order to improve the photocatalytic activity of nano-sized ZnO films, the ordered porous ZnO thin films were prepared by dipping Czochralski method using polystyrene polystyrene as template. The optical properties and photocatalytic activity of the films were investigated.Compared with nanometer ZnO thin films, porous ZnO films increase the specific surface area of the films, accelerate the transfer of methyl orange in the materials, and increase the catalytic activity due to the increase of reactive sites.The degradation rate of methyl orange by 90 mmin ordered porous ZnO film was 94.7%, which was higher than that of nano-sized ZnO film (80.2%).In order to further improve the photocatalytic activity of nanometer ZnO films, ZnO-graphene composite films and ordered porous ZnO-graphene composite films were prepared by using graphene modified nano- films. The composite films were characterized by XRD.The optical properties, photocatalytic activity and service life of the composite films were investigated.With the introduction of graphene, the light absorption intensity of ZnO is increased, and the spectral response range is extended to the visible region, which has no effect on the hexagonal wurtzite structure of ZnO crystal.Under a 500W mercury lamp, the highest degradation efficiency of methyl orange was obtained by graphene modified ZnO ordered porous composite membrane within 90mmin, followed by dense composite film (93.5A), and nanometer-sized ZnO film (80.2cm). In addition, with the increase of graphene oxide sol concentration,The degradation rate of methyl orange by ZnO- graphene composite film increased firstly and then decreased due to the different loading amount of graphene.The test of service life showed that the efficiency of degradation of methyl orange by ZnO-graphene composite membrane recovered within 90 minutes was above 90%, which was superior to that of ZnO film by 70%, and the photocatalytic activity was good.
【学位授予单位】：大连理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TQ132.41;TB33

【共引文献】

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1 龙亚平;曾葆青;杨云;柳建龙;吴U，

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