二氧化钛异质结的合成及光催化性能研究

发布时间：2018-06-29 10:17

本文选题：TiO_2异质结 + 还原处理　；参考：《南昌航空大学》2017年硕士论文

【摘要】：随着世界人口的急剧增长、经济的突飞猛进、社会的快速进步,人类对赖以生存的环境和日常生活质量的要求也越来越高。与此同时,工业废水、农业污水、生活污水以及生活垃圾、大气污染等,不仅影响着我们的身心健康,更是威胁着子孙后代。光催化是近些年来比较热门的研究课题,其中TiO_2是一种二元过渡金属氧化物,具有无毒、化学性能稳定、合成方法简单等优点,但是也有不可避免的缺点,即一个宽的光禁带导致对太阳光的使用受到限制。本论文成功制备出锐钛矿/金红石异质结材料(Ti AR),锐钛矿/板钛矿异质结材料(Ti AB)和介孔硫化镉/二氧化钛异质结材料(Cd S/TiO_2),并研究了H_2还原过程和H_2O_2氧化过程对锐钛矿/金红石异质结材料(Ti AR)和锐钛矿/板钛矿异质结材料(Ti AB)表面性质的影响及表面化学与光催化性能之间的关系,同时探讨了TiO_2掺杂硫化镉的最佳比例。此外,通过SEM、BET、TEM、XRD、Raman、Uv-Vis、XPS、EPR和Zeta电位对材料的晶型、质构特性、微观形态、晶格结构及材料表面化学状态进行表征,并通过光催化降解实验和光电流实验对材料的光催化性能做出了评估。具体研究内容如下:(1)采用水热法制备锐钛矿/金红石异质结材料(Ti AR),并分别将锐钛矿/金红石异质结材料(Ti AR)在H_2中煅烧进行还原处理,在H_2O_2水溶液中反应进行氧化处理,来研究还原处理和氧化处理对锐钛矿/金红石异质结(Ti AR)性能的影响。结果表明,锐钛矿/金红石异质结(Ti AR)由纳米粒子(锐钛矿)和纳米砖(金红石)组成,且纳米粒子生长在纳米砖的表面。无论是H_2还原处理还是H_2O_2氧化处理,锐钛矿/金红石异质结材料(Ti AR)都会保持原来的形貌、晶相与粒径,只是晶相比例和带隙发生了略微的变化。在降解甲基橙(MO)实验过程中,H_2处理过的Ti AR异质结材料活性有所下降。相反地,H_2O_2氧化的Ti AR的活性却高于未经处理的Ti AR,其中,经过160°C处理的Ti AR(H_2O_2)的活性最高。(2)采用水热法制备锐钛矿/板钛矿异质结材料(Ti AB),并分别将锐钛矿/板钛矿异质结材料(Ti AB)在H_2中煅烧进行还原处理,在H_2O_2水溶液中反应进行氧化处理,来研究还原处理和氧化处理对锐钛矿/板钛矿异质结(Ti AB)性能的影响。结果表明,锐钛矿/板钛矿异质结(Ti AB)由纳米粒子(锐钛矿)和纳米棒(板钛矿)组成,且纳米棒占主导地位。无论是H_2还原处理还是H_2O_2氧化处理,锐钛矿/板钛矿异质结材料(Ti AB)都会保持原来的形貌、晶相与粒径,只是晶相比例和带隙发生了略微的变化。在降解甲基橙(MO)实验过程中,未经处理的锐钛矿/板钛矿异质结材料(Ti AB)由于表面的Ti~(3+)和氧空位可以提高电荷分离,因此表现出的活性最高。还原处理和氧化处理均会使导致Ti AB的活性下降,Ti AB(H_2O_2)活性的降低程度还取决于不同的反应温度。(3)采用溶胶-凝胶法制备介孔TiO_2和一系列不同摩尔比的介孔硫化镉/二氧化钛异质结材料(Cd S/TiO_2),通过调节Cd S的掺入比例来增强TiO_2的光催化能力。结果表明,当Cd S与TiO_2的摩尔比为0.12时,异质结材料的UV-vis光谱有较明显的红移现象,光催化性能优于纯介孔TiO_2和纯Cd S,且具有较高的稳定性,五次循环降解甲基橙溶液之后活性和稳定性仍然很好。这说明当Cd S与TiO_2的摩尔比例为0.12时,负载的Cd S含量最适宜于阻碍电子和空穴的复合,进而改善Cd S/TiO_2复合材料的光催化性能。此外,对于亚甲基蓝、双酚A(BPA)、罗丹明B和孔雀石绿的降解进一步表明了Cd S与TiO_2的摩尔比为0.12时,光催化剂的性能最显著。
[Abstract]:With the rapid growth of the world population, the rapid progress of the economy and the rapid progress of society, the demands for the living environment and the quality of daily life are becoming higher and higher. At the same time, industrial waste water, agricultural sewage, domestic sewage and domestic waste, air pollution and so on, not only affect our physical and mental health, but also threaten our children and grandchildren. Photo catalysis is a hot research topic in recent years. TiO_2 is a kind of two element transition metal oxide, which has the advantages of non-toxic, stable chemical properties, simple synthesis method, but also has the inevitable shortcoming, that is, a wide light band leads to the use of the sun light. This paper has successfully prepared anatase / anatase. Rutile heterojunction material (Ti AR), anatase / plate titanium heterojunction material (Ti AB) and mesoporous cadmium / titanium dioxide heterojunction (Cd S/TiO_2), and the influence of the H_2 reduction process and H_2O_2 oxidation on the surface properties of anatase / rutile heterojunction materials (Ti AR) and anatase / plate titanate heterojunction materials (Ti AB) are studied. The relationship between chemical and photocatalytic properties, and the optimum proportion of TiO_2 doped cadmium sulfide. In addition, the crystal, texture, microstructure, lattice structure and surface chemical state of the material are characterized by SEM, BET, TEM, XRD, Raman, Uv-Vis, XPS, EPR and Zeta potentials, and through photocatalytic degradation experiments and photocurrent experiments. The photocatalytic properties of the materials were evaluated. The specific contents were as follows: (1) anatase / rutile heterojunction materials (Ti AR) were prepared by hydrothermal method, and the anatase / rutile heterojunction material (Ti AR) was calcined in H_2, and the reaction was oxidized in the solution of H_2O_2 water to study the reduction treatment and oxidation. The effects on the performance of anatase / Jin Hongshi heterojunction (Ti AR) were treated. The results showed that anatase / Jin Hongshi heterojunction (Ti AR) was composed of nanoparticles (anatase) and nano brick (Jin Hongshi), and nanoparticles were grown on the surface of nano brick. The H_2 reduction treatment was also oxidized by H_2O_2, anatase / Jin Hongshi heterojunction (Ti AR). In the process of degradation of methyl orange (MO), the activity of Ti AR heterojunction materials treated by H_2 decreased. On the contrary, the activity of H_2O_2 oxidized Ti AR was higher than that of Ti AR, which was treated by 160 degree C. (2) anatase / plate titanium heterojunction material (Ti AB) was prepared by hydrothermal method, and anatase / plate titanium heterojunction material (Ti AB) was calcined in H_2, and the oxidation treatment was carried out in H_2O_2 water solution to study the properties of anatase / plate titanium heterojunction (Ti AB) by reduction treatment and oxidation treatment. The results show that the anatase / plate titanium heterojunction (Ti AB) is composed of nanoparticles (anatase) and nanorods (plate titanium), and nanorods dominate. Both H_2 reduction and H_2O_2 oxidation treatment, anatase / plate titanium heterojunction material (Ti AB) will maintain the original morphology, crystal phase and particle size, only the proportion and band of crystalline phase. In the process of degradation of methyl orange (MO), untreated anatase / plate titanium heterojunction material (Ti AB) can increase the charge separation due to the surface Ti~ (3+) and oxygen vacancy, so the activity of the reduction treatment and oxidation can lead to the decrease of the activity of Ti AB and the Ti AB (H_2O_2) activity. The degree of reduction also depends on the different reaction temperatures. (3) the mesoporous TiO_2 and a series of mesoporous cadmium sulfide / titanium dioxide heterojunction materials (Cd S/TiO_2) are prepared by the sol-gel method, and the photocatalytic ability of TiO_2 is enhanced by adjusting the proportion of Cd S. The results show that when the molar ratio of Cd S to TiO_2 is 0.12, the heterostructure is different. The UV-vis spectra of the materials have obvious red shift. The photocatalytic performance is better than pure mesoporous TiO_2 and pure Cd S, and has high stability. After five cycles of degradation of methyl orange solution, the activity and stability are still good. This shows that when the molar ratio of Cd S to TiO_2 is 0.12, the Cd S content of negative load is most suitable for blocking electrons and holes. In addition, the photocatalytic properties of Cd S/TiO_2 composites were improved. In addition, the degradation of methylene blue, bisphenol A (BPA), Luo Danming B and peacock green showed that the photocatalyst performance was the most significant when the molar ratio of Cd S to TiO_2 was 0.12.
【学位授予单位】：南昌航空大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：O643.36

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