具有纳米结构的分级多孔ZnO制备及其光催化性能研究

发布时间：2018-05-25 03:07

  本文选题：分级多孔ZnO + 纳米材料　； 参考：《西安理工大学》2017年硕士论文

【摘要】：随着生活质量提高,有机污染物造成的水体污染引起了人们的广泛关注。越来越多的研究学者致力于对有机污染物能进行有效分解的光催化材料的研究,尤其是金属氧化物半导体,具有氧化活性好,化学稳定性好,特别是在光催化方面可以快速对有机物进行降解。具有纳米结构的多孔金属氧化物因其孔的形成、增大的比表面积和良好的抗团聚性能,相比于颗粒金属氧化物将具有更好的光催化性能,基-于此,本文采用真空吸铸与去合金相结合的方法制备具有纳米结构的分级多孔ZnO,通过XRD、SEM、紫外光催化性能、光致发光(PL)等农征手段,对所制分级多孔纳米ZnO不同制备阶段相组成、微观形貌,以及分级多孔纳米ZnO的光催化性能及光致发光性能进行了研究,得出以下结论:(1)用真空吸铸得到Zn-Al合金和NaCl的复合体,在380℃下加热4h固溶处理后,转变成为Zn过饱和的α(Al)固溶体与NaCl颗粒的复合体。(2)Q固溶处理的复合体通过水洗去除NaCl颗粒后得到具有多孔结构Zn过饱和的a(Al)固溶体;然后通过NaOH溶液进行碱洗去掉固溶体中的Al,而使其中固溶的Zn被保留下来或部分转化为ZnO,使得原来多孔材料的孔壁上出现大量的孔,从而得到具有纳米结构的分级多孔Zn/ZnO。(3)在350℃加热8h样品氧化后,分级结构Zn/ZnO中Zn全部氧化成ZnO,从而制备出具有纳米结构的分级多孔ZnO。通过对不同合金配比、NaOH的用量量和去合金时间不同参数下制备出的分级多孔纳米ZnO的研究,结果表明Al含量为55%、NaOH和合金中A1的摩尔比满足n(NaOH): n(Al)=1.10:1和去合金时间为6h的工艺下得到了结构完整、形貌良好的具有纳米结构的分级多孔ZnO。(4)对实验制得的分级多孔ZnO进行了光催化性能研究,结果表明:在6h的紫外光照条件下,分级多孔ZnO对甲基橙的降解率为88.09%,光催化性能优于粉体的TiO2,也优于同课题组制备的多孔纳米ZnO的光催化性能。在较宽的温度范围及甲基橙溶液浓度,分级多孔纳米ZnO仍能保持良好光光催催性能。偏碱性或偏酸性·溶液都会降低分级多孔ZnO的光催化效率,酸性溶液比喊性溶液影响稍高。(5)对分级多孔ZnO材料进行光致发光研究中,表明了分级多孔ZnO在325 nm紫外照射下,会激发出ZnO的375 nm紫外区带边发射光以及宽域的点缺陷黄-绿发射峰。
[Abstract]:With the improvement of quality of life, water pollution caused by organic pollutants has aroused widespread concern. More and more researchers are devoted to the research of photocatalytic materials which can decompose organic pollutants effectively, especially metal oxide semiconductors, which have good oxidation activity and chemical stability. In particular, organic matter can be degraded quickly in photocatalysis. Porous metal oxides with nanostructures have better photocatalytic properties than granular metal oxides because of their pore formation, increased specific surface area and good agglomeration resistance. In this paper, nano-structured layered porous ZnO was prepared by vacuum casting and dealloying. By means of XRD-SEM, UV photocatalytic properties and photoluminescence (PL), the phase composition of the graded porous nano-ZnO at different preparation stages was studied. The micromorphology, photocatalytic properties and photoluminescence properties of ZnO were studied. The following conclusions were drawn: 1) the complex of Zn-Al alloy and NaCl was obtained by vacuum casting, and the solution was heated at 380 鈩，

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