形貌可控钨酸铋材料的制备及其性能研究

发布时间：2018-04-05 15:13

  本文选题：钨酸铋　切入点：F127　出处：《河南师范大学》2015年硕士论文

【摘要】：随着工业的不断发展,人们的生活水平得以大幅度提升。然而在人们享受工业化带来方便的同时,我们的生存环境也受到了严重的破坏。环境问题关系到国计民生,治理环境造福于子孙后代。半导体光催化技术可以将水体或大气中的有机污染物直接氧化为无毒无害的水、二氧化碳等小分子,具有低碳节能、环境友好等优点而受到广泛的关注。在众多的半导体材料中,钨酸铋(Bi2WO6)由于其较低的禁带宽度,在可见光照射下容易被激发,对太阳能的利用率高,同时具有高效的有机物降解能力和较高的催化活性而备受研究者的关注。本论文中通过添加不同的模板剂,利用水热合成的方法,制备出具有特定形貌的Bi2WO6光催化剂。采用XRD、SEM、TEM及UV-Vis等对制备样品的形貌、晶相结构和光学性能进行表征,并通过比较样品对罗丹明B的降解效果来评价其光催化性能。主要研究内容如下:(1)以嵌段共聚物F127(EO106-PO70-EO106)作为模板剂,利用水热合成法制备出花球状Bi2WO6。考察了前驱体溶液的pH值、水热过程中的反应温度、模板剂F127与硝酸铋的摩尔比和水热过程中的反应时间等参数对Bi2WO6光催化剂样品的晶相、表面微观结构及其光催化性的影响。研究发现,水热过程中的反应时间能显著影响产物的形貌;在相同的反应时间时,pH为3时所得花球状结构的Bi2WO6样品具有较高的催化活性。此外,根据不同时间所得样品SEM的结果,提出了形貌演变过程的可能生长机理。(2)以L-赖氨酸作为形貌调控剂,采用水热法成功地制备出花球状结构的Bi2WO6光催化剂。考察了水热过程中的反应温度、形貌调控剂L-赖氨酸的添加量和水热过程中的反应时间对合成Bi2WO6光催化剂的晶相结构、形貌及其光催化活性的影响。结果表明:形貌调控剂L-赖氨酸的添加量以及水热反应温度对其形貌的影响起到决定性作用。在300W氙灯作为模拟太阳光下进行催化降解罗丹明B,发现在前驱体溶液的pH为1,水热过程的反应温度为160℃,水热过程中的反应时间为20h时合成的样品具有最高的光催化性能。
[Abstract]:With the continuous development of industry, people's living standards have been greatly improved.However, while people enjoy the convenience of industrialization, our living environment has also been seriously damaged.Environmental problems are related to the national economy and people's livelihood, governance of the environment for future generations.Semiconductor photocatalytic technology can directly oxidize organic pollutants in water or atmosphere to non-toxic and harmless water, carbon dioxide and other small molecules.Bismuth tungstate Bi2WO6) is easily excited by visible light because of its low band gap.At the same time, it has attracted the attention of researchers because of its high degradation ability and high catalytic activity.In this paper, Bi2WO6 photocatalysts with specific morphology were prepared by hydrothermal synthesis with different templates.The morphology, crystal phase structure and optical properties of the prepared samples were characterized by TEM and UV-Vis. The photocatalytic properties of Rhodamine B were evaluated by comparing the degradation effects of the samples.The main research contents are as follows: (1) using block copolymer F127 EO106-PO70-EO106) as template, the spherical Bi2WO6 was prepared by hydrothermal synthesis.The effects of pH value of precursor solution, reaction temperature in hydrothermal process, molar ratio of template F127 to bismuth nitrate and reaction time in hydrothermal process on the crystal phase, surface microstructure and photocatalytic properties of Bi2WO6 photocatalyst were investigated.It is found that the reaction time in hydrothermal process can significantly affect the morphology of the product, and that the Bi2WO6 sample with flower-like structure obtained at the same reaction time at pH 3 has higher catalytic activity.In addition, according to the results of SEM obtained at different time, the possible growth mechanism of morphology evolution was proposed. The Bi2WO6 photocatalyst with flower-like structure was successfully prepared by hydrothermal method with L- lysine as the morphology regulator.The effects of the reaction temperature, the amount of L- lysine, and the reaction time during hydrothermal process on the crystal structure, morphology and photocatalytic activity of Bi2WO6 photocatalyst were investigated.The results show that the addition of L- lysine and hydrothermal reaction temperature play a decisive role in the morphology of L- lysine.Rhodamine B was degraded by 300W xenon lamp under simulated sunlight. It was found that the synthesized samples had the highest photocatalytic performance when the pH of the precursor solution was 1, the reaction temperature of hydrothermal process was 160 鈩，

本文编号：1715312