层状前体法制备氧化锌复合材料及其光催化性能研究

发布时间：2018-06-22 05:07

  本文选题：ZnO + 复合薄膜　； 参考：《北京化工大学》2010年硕士论文

【摘要】： 本论文针对氧化锌在实际应用中尚存在不足,如光催化效率低、光谱吸收范围窄和粉末回收困难等问题,提出采用在LDHs层板上引入过渡金属的三元类水滑石(LDHs)为前驱体,再经涂敷热分解法制备得到改性的ZnO复合薄膜材料。采用X-射线衍射(XRD)、紫外-可见吸收光谱(UV-Vis)、傅立叶变换红外光谱(FT-IR)、热重-差热分析(TG-DTA)、比表面-孔径分析(BET)、场发射扫描电镜-能量散射谱分析(SEM-EDS)等测试手段对所得改性Zn0复合材料进行结构、组成、形貌以及性能等进行表征,并分别以甲基橙和亚甲基蓝作为目标降解物,考察其在紫外光和可见光下的光催化活性,对其改性效果进行评价。具体研究结果如下： (1)制备了不同投料比的铜锌铝层状前体,并考察了不同焙烧温度对三元ZnO复合薄膜的结构及催化性能的影响,结果表明,煅烧温度为500℃时,[Cu2+]/[Zn2+]/[Al3+]投料比为1/6/2的三元ZnO复合薄膜的光催化能力最强；在此条件下,在6h内在紫外光和可见光照射下,对甲基橙和亚甲基蓝的降解率可分别达到92.6%和92.5%。分析结果表明,最优条件下制备的三元ZnO复合薄膜由于ZnO高度均匀分散在其它基质金属氧化物相中,从而使整体组成和结构高度均匀,有利于催化性能的提高；同时由于Cu2+对ZnO的改性,使得ZnO的带隙宽度随Cu2+含量的增加而减小,增强了ZnO的可见光催化降解能力。 (2)制备了不同比例钴锌铝层状前体,考察了不同焙烧温度对三元ZnO复合薄膜的结构和性能的影响,发现焙烧温度越高,制得的三元ZnO复合薄膜就越致密,但是随着焙烧温度的升高,其催化活性渐降低。最佳制备条件下(500℃焙烧,[Co2+]/[Zn2+]/[Al3+]投料比为1/6/2)制得的氧化锌复合薄膜具有最强的光催化能力,在紫外光和可见光照射下,6h对甲基橙和亚甲基蓝的降解率可分别达到93.6%和84.0%。而900℃焙烧得到的薄膜没有光催化能力。分析结果表明,最优条件下制备的三元ZnO复合薄膜由于Co2+在可见光范围内具有较强的响应,同时还能使ZnO复合薄膜的光吸收带边向可见光区域扩展,因此,随着Co2+含量的增加,ZnO的可见光催化降解能力逐渐增强。
[Abstract]:In order to solve the problems of zinc oxide in practical application, such as low photocatalytic efficiency, narrow spectrum absorption range and difficulty in powder recovery, the ternary hydrotalcite (LDHs) which introduced transition metal into LDHs laminates was proposed as the precursor. The modified ZnO composite films were prepared by thermal decomposition method. X-ray diffraction (XRD), UV-Vis absorption spectroscopy (UV-Vis), Fourier transform infrared spectroscopy (FT-IR), thermogravimetric differential thermal analysis (TG-DTA), specific surface pore size analysis (BET), field emission scanning electron microscopy (SEM) and energy scattering spectroscopy (SEM-EDS) were used to improve the results. The structure of Zn0 composite, The composition, morphology and properties of methyl orange and methylene blue were characterized. The photocatalytic activity of methyl orange and methylene blue were investigated under UV and visible light, respectively, and the modification effect was evaluated. The results are as follows: (1) the layered precursors of copper, zinc and aluminum with different feed ratios were prepared, and the effects of calcination temperature on the structure and catalytic performance of ZnO composite films were investigated. The photocatalytic activity of [Cu _ 2] / [Zn _ 2] / [Al3] composite films with the ratio of [Cu _ 2] / [Zn _ 2] / [Al3] was the strongest at 500 鈩，

本文编号：2051710