二氧化铈及其改性材料的制备和光催化性能研究

发布时间：2018-07-25 07:09

【摘要】：工业化的极速发展使得能源短缺和环境污染成为我们现阶段面临的严重问题,因此,目前尤为重要的是如何有效的解决我们所面临的问题,利用半导体光催化材料的光催化性能降解工业废水及空气中的污染物是现阶段高效解决环境污染问题的有效途径,并且,由于光催化技术的很多优势,成为近年来研究热点之作为地球含量最丰富的稀土元素之一的铈,其氧化物二氧化铈又能够表现出类似于典型光催化剂二氧化钛的性能,成为一种可替代二氧化钛的潜在光催化剂。但由于其禁带较宽,降低了其光催化效率,因此,本文采用燃烧法以不同试剂对二氧化铈进行了改性,并研究了改性后样品的形貌、结构和成分等对其光催化性能的影响,得到以下几点研究成果：(1)采用燃烧法制备了面心立方萤石型结构的CeO2纳米颗粒。采用同样的方法将制备的纯净CeO2进行了掺杂F,通过调节氟化钠的量控制掺杂样品的光催化活性,亚甲基蓝的降解效率图证明适量的氟化钠使得F掺杂的CeO2样品表现出很强的光催化活性。(2)通过调节氟与铈的原子摩尔比,制备出纯CeO2,纯CeF3以及CeO2/CeF3复合纳米颗粒,以亚甲基蓝为目标降解物,在紫外光下对制备的样品进行了光催化实验,实验结果表明,纯CeF3光催化活性高于纯CeO2和复合物。通过第一性原理对CeF3和CeO2进行计算,从理论方面解释了CeF3有较高光催化性能的原因,此项工作从实验和理论方面证实了CeF3可作为光催化剂的潜在价值。(3)采用燃烧法制备了不同量磷酸对CeO2进行改性的纳米材料。随着磷酸量的增加,样品形貌、比表面积和光催化活性发生变化,结果表明,加入磷酸对CeO2改性后可明显提高其光催化活性。
[Abstract]:With the rapid development of industrialization, energy shortage and environmental pollution have become a serious problem we are facing at the present stage. Therefore, it is particularly important to solve the problems we face effectively. The degradation of industrial wastewater and air pollutants by using the photocatalytic properties of semiconductor photocatalytic materials is an effective way to solve the environmental pollution problem efficiently at present, and because of the advantages of photocatalytic technology, Cerium oxide, one of the most abundant rare earth elements in the earth, has become a hot research topic in recent years, and its oxide cerium oxide can also exhibit properties similar to those of titanium dioxide, a typical photocatalyst. It can be used as a potential photocatalyst instead of titanium dioxide. However, because of the wide band gap, the photocatalytic efficiency was reduced. In this paper, the effect of the morphology, structure and composition of the modified samples on the photocatalytic performance was studied by using different reagents. The main results are as follows: (1) CeO2 nanoparticles with face-centered cubic fluorite structure were prepared by combustion method. The pure CeO2 was doped by the same method. The photocatalytic activity of the doped samples was controlled by adjusting the amount of sodium fluoride. The degradation efficiency diagram of methylene blue shows that proper amount of sodium fluoride makes F-doped CeO2 samples exhibit strong photocatalytic activity. (2) by adjusting the molar ratio of fluorine to cerium, pure CEO _ 2, pure CeF3 and CeO2/CeF3 composite nanoparticles are prepared. The photocatalytic activity of pure CeF3 was higher than that of pure CeO2 and complex in UV light. The photocatalytic activity of pure CeF3 was higher than that of pure CeO2 and complex. Through the first-principle calculation of CeF3 and CeO2, the reason why CeF3 has high photocatalytic performance is explained theoretically. This work confirmed the potential value of CeF3 as photocatalyst in both experimental and theoretical aspects. (3) Nanomaterials modified by different amounts of phosphoric acid were prepared by combustion method. The morphology, specific surface area and photocatalytic activity of the samples changed with the increase of phosphoric acid content. The results showed that the photocatalytic activity of CeO2 modified by phosphoric acid could be improved obviously.
【学位授予单位】：湖南大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：O643.36;O644.1

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