金属氧化物硫化物的光催化性能探究

发布时间：2018-04-06 07:38

  本文选题：金属氧化物　切入点：金属硫化物　出处：《安徽工业大学》2017年硕士论文

【摘要】：随着人口的增长和经济的发展,大量染料及重金属离子排放到水中造成环境污染,如何克服环境污染已然成为人们急需解决的问题。文中围绕重金属、有机染料污染现状危害以及常见的处理方式进行了简要介绍,特别是对光催化降解技术进行了重点阐述,继而开展了金属氧化物、硫化物复合材料的制备及其应用研究工作。具体研究内容如下:首先采用溶剂热法合成g-C3N4/SnS2@SnO2纳米复合材料,并以此考察对Cr(VI)的光催化还原性能。SEM、TEM、DRS等测试表明,六角结构的SnS2@SnO2覆盖在多孔的二维g-C3N4表面,其禁带宽度为2.35~2.60 eV。对合成温度、时间、比例、光催化条件等参数进行优化时发现,当SnS2@SnO2与g-C3N4比例为3:1时,其光催化反应速率常数(k=0.04092 min-1),分别是g-C3N4和SnS2@SnO2的39.7倍及5.9倍;而加0.2 mol L-1的乙醇能够有效捕捉空穴,进而促进光催化还原反应的进行。其次利用水热和高温煅烧法制备SrTiO3@Bi2O3,并分别研究了在紫外和可见条件下其对不同染料的降解效率。多种分析技术显示,该材料具有多孔结构和较窄的禁带宽度(2.1~3.1 eV)。当Bi2O3质量分数为30%,于600℃下煅烧5 h时,所获得的复合材料在420 nm Xe灯照射下,能够100%催化降解50 mg L-1罗丹明B(40min)。在365nm紫外条件下,180 min可以达成100%降解50 mg L-1甲基橙;当向反应体系添加罗丹明B后,甲基橙降解速率可提升1倍,推测其机理可能与染料敏化有关。最后探讨了钛前驱体等因素对TiO2光催化性能的影响。数据表明钛酸正丁酯(Ti(OBu)4)和四氯化钛(TiCl4)为原料时,均能够100%降解10 mg L-1罗丹明B(60min以内),而相同条件下四异丙醇钛(TTIP)仅为20%。光催化还原20 mg L-1Cr(VI)时,三种前驱体则没明显区别。此外不同前驱体时,合成温度对材料性能影响规律也不同。
[Abstract]:With the increase of population and the development of economy, a large number of dyes and heavy metal ions have been discharged into the water to cause environmental pollution. How to overcome the environmental pollution has become a problem that people need to solve urgently.In this paper, the present situation of heavy metal and organic dyes pollution and the common treatment methods are briefly introduced, especially the photocatalytic degradation technology, and then metal oxides are developed.Preparation and Application of Sulfide Composites.The main contents are as follows: firstly, g-C3N4/SnS2@SnO2 nanocomposites were synthesized by solvothermal method, and the photocatalytic reduction properties of CrVI were investigated. The results showed that the hexagonal SnS2@SnO2 was covered on the porous two-dimensional g-C3N4 surface, and its band gap was 2.35 ~ 2.60 EV.When the synthesis temperature, time, ratio and photocatalytic conditions were optimized, it was found that when the ratio of SnS2@SnO2 to g-C3N4 was 3:1, the rate constant of photocatalytic reaction was 0.04092 min-1 ~ (-1), which was 39.7 times and 5.9 times of that of g-C3N4 and SnS2@SnO2, respectively.The addition of 0.2 mol L-1 ethanol could effectively capture the holes and promote the photocatalytic reduction reaction.Secondly, SrTiO3- @ Bi2O3 was prepared by hydrothermal and high temperature calcinations, and the degradation efficiency of different dyes under UV and visible conditions was studied.A variety of analytical techniques show that the material has a porous structure and a narrow band gap of 2.1 ~ 3.1 EV ~ (-1).When the mass fraction of Bi2O3 was 30 and calcined at 600 鈩，

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