BiOBr基复合光催化剂的制备及性能研究

发布时间：2018-05-21 09:45

本文选题：水热法 + BiOBr　；参考：《华东师范大学》2017年硕士论文

【摘要】：水是生命之源,然而随着社会经济的发展,水体污染日益严重。作为最有前途的技术之一,光催化氧化在降解有机污染物上发挥着重要作用。TiO_2因其化学稳定性高、成本低、无毒等优点引起了研究者们的关注,然而,由于TiO_2能带隙为3.2 eV,其较宽的能带隙只能响应紫外光,大大降低了太阳能的利用率。BiOBr因具有独特的分层结构与较窄的能带隙,因此其拥有非常良好的可见光催化潜力。然而,在实际应用中,纯BiOBr在可见光照射下存在光生电子-空穴对复合速率过快的问题,严重影响其光催化效率。通过在BiOBr中复合其他半导体材料或非金属材料可降低光生电子-空穴对的复合速率,可提高BiOBr的光催化效率。本文采用水热法分别制备了 BiOBr/Bi_2MoO_6、BiOBr/RGO和BiOBr/BiOF复合物,并对其光催化性能进行了研究,发现这些复合物能非常有效地抑制BiOBr光生电子-空穴对的复合,这对于提高BiOBr的光催化性能具有重要的意义。具体内容如下:1.采用水热法制备Bi_2MoO_6,再将Bi2MoOs加入到BiOBr前驱体溶液中,进行水热反应,得到BiOBr/Bi_2MoO_6复合物,并研究了其对罗丹明B和硝基苯的光催化性能。光催化降解实验结果表明:(1)BiOBr/Bi_2MoO_6复合物比纯BiOBr有着更高的光催化效率;(2)BiOBr/Bi2MoOs复合物的光催化效率与Bi_2MoO_6的掺杂量有关,其对罗丹明B和硝基苯的降解率最大达到98%(70 min)和92%(360 min);(3)其光催化性能的提高主要归因于较低的光生电子-空穴对的复合速率和良好的可见光吸收。2.采用改进后的Hummers方法合成GO,通过水热法合成BiOBr/RGO复合物,并研究了其对罗丹明B和硝基苯的光催化性能。光催化降解实验结果表明:(1)与纯BiOBr相比,BiOBr/RGO复合物在降解罗丹明B和硝基苯时表现出更好的光催化性能;(2)当RGO的含量达到0.6 wt.%时,BiOBr/RGO复合物的光催化性能达到最高,对罗丹明B与硝基苯的降解率均达到100%(30 min(罗丹明B),360min(硝基苯));(3)光催化性能的增强主要归因于RGO的引入引起的可见光吸收的增加和电子空穴对复合的减少。3.采用水热法一步制备了 BiOBr/BiOF复合物,并研究了其对罗丹明B和硝基苯的光催化性能。光催化降解实验结果表明:(1)与纯BiOBr相比,BiOBr/BiOF复合物在降解罗丹明B和硝基苯时表现出更高的光催化活性。(2)BiOBr/BiOF复合物的光催化效率与BiOF的掺杂量有关,其对罗丹明B和硝基苯的降解率最大达到100%(25 min)和94%(300 min)。(3)光催化活性的增强是因为BiOBr和BiOF界面之间相互作用的协同效应,造成有效的电荷转移和分离。空穴和·OH在降解罗丹明B和硝基苯过程中是主要的活性氧化因子。
[Abstract]:Water is the source of life, but with the development of social economy, water pollution is becoming more and more serious. As one of the most promising technologies, photocatalytic oxidation plays an important role in the degradation of organic pollutants. Because the band gap of TiO_2 is 3.2eV, its wide band gap can only respond to ultraviolet light, which greatly reduces the utilization of solar energy. BiOBr has a very good visible light catalytic potential because of its unique layered structure and narrow energy band gap. However, in practical application, the photocatalytic efficiency of pure BiOBr is seriously affected by the problem of fast photo-electron-hole recombination rate under visible light irradiation. The photocatalytic efficiency of BiOBr can be improved by combining other semiconductor materials or non-metallic materials in BiOBr, which can reduce the recombination rate of photogenerated electron-hole pairs. In this paper, BiOBr-Bi2MoO-1 / BiOBr-RGO and BiOBr/BiOF complexes were prepared by hydrothermal method, and their photocatalytic properties were studied. It is found that these complexes can effectively inhibit the BiOBr photogenerated electron-hole pairs. It is of great significance to improve the photocatalytic performance of BiOBr. The details are as follows: 1. Bi2MoO _ 6 was prepared by hydrothermal method, then Bi2MoOs was added to BiOBr precursor solution to hydrothermal reaction to obtain BiOBr/Bi_2MoO_6 complex, and its photocatalytic activity for Rhodamine B and nitrobenzene was studied. The results of photocatalytic degradation experiment showed that the photocatalytic efficiency of the 2BiOBr-BiOBr-Bi2MoO6 complex was higher than that of pure BiOBr. The photocatalytic efficiency of the 2BiOBr-BiOBr-Bi2MoOs complex was related to the doping amount of Bi_2MoO_6. The maximum degradation rates of Rhodamine B and nitrobenzene reached 9870 min and 92 min respectively. The improvement of photocatalytic performance was mainly attributed to the low photoelectron hole pair recombination rate and good visible light absorption. GO3 was synthesized by improved Hummers method, and BiOBr/RGO complex was synthesized by hydrothermal method. Its photocatalytic activity for Rhodamine B and nitrobenzene was studied. The results of photocatalytic degradation experiments showed that the BiOBr-RGO complex exhibited better photocatalytic performance in the degradation of Rhodamine B and nitrobenzene than pure BiOBr. When the content of RGO reached 0.6 wt.wt%, the photocatalytic performance of BiOBr-RGO complex was the highest. The degradation rates of Rhodamine B and nitrobenzene reached 100 ~ 30 min. The enhancement of photocatalytic activity was mainly attributed to the increase of visible light absorption caused by the introduction of RGO and the decrease of electron hole recombination. BiOBr/BiOF complexes were prepared by hydrothermal method and their photocatalytic properties for Rhodamine B and nitrobenzene were studied. The photocatalytic degradation results showed that the photocatalytic activity of the BiOBr-BiOF complex was higher than that of the pure BiOBr complex in the degradation of Rhodamine B and nitrobenzene. The photocatalytic efficiency of the BiOBr-BiOF complex was related to the doping amount of BiOF. The enhancement of photocatalytic activity of Rhodamine B and nitrobenzene with maximum degradation rate of 100 ~ 25 min and 94 ~ 300 min 路min ~ (3) is due to the synergistic effect of the interaction between BiOBr and BiOF resulting in effective charge transfer and separation. Hole and OH are the main active oxidation factors in the degradation of Rhodamine B and nitrobenzene.
【学位授予单位】：华东师范大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：O643.36

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