可见光响应型银基固溶体的制备、表征及性能

发布时间：2017-12-27 13:20

本文关键词：可见光响应型银基固溶体的制备、表征及性能　出处：《内蒙古大学》2016年硕士论文　论文类型：学位论文

【摘要】：环境污染是当今社会面临的严峻挑战之一,基于太阳能的光催化技术有效降解污染物是一种低成本高效治理环境污染的新途径。传统光催化材料面临的问题主要包括太阳光响应范围窄、光催化反应效率低等问题。近年来,开发具有可见光响应活性的新型光催化材料是光催化领域中的研究热点。固溶体光催化材料是利用两种半导体来形成固溶体。它的电子结构受固溶体组成的影响,通过改变成分能够实现对半导体带隙的连续可调。其中,银基固溶体光催化材料在可见光范围内有较大的吸收,同时具有较高的光催化活性和稳定性,在光催化领域有较大的优势和应用潜力。本论文中,介绍了以CH3COONa,Al(NO3)3·9H2O和Ga(NO3)3·nH2O为原料通过改变Al3+与Ga3+的比例,利用溶胶凝胶法制备出β-NaAl1-xGaxO2,然后经过阳离子置换制备出禁带宽度可连续调控的β-AgAl1-xGaxO2。以及SBA-15,CMK-3模板制备。利用CMK-3介孔碳为辅助模板,用浸渍法制备介孔β-AgAl0.4Ga0.6O2。利用光化学沉积法,对β-AgAl0.4Ga0.6O2负载贵金属Ag。通过PANalytical Empyrean X射线衍射仪测试了样品的晶体结构和介观结构。通过Hitachi S-4800型扫描电子显微镜表征了样品的形态、形貌。通过ASAP2020比表面积分析仪对介孔β-AgAl0.4Ga0.6O2进行N2吸-脱附等温测试。通过Hitachi U-3900型紫外分光光度计测试出样品的紫外光谱。然后利用Kubelka-Munk公式计算出样品的禁带宽度。通过Hitachi F-7000型荧光分光光度计测试出样品的荧光光谱。一系列实验结果表明,β-AgAl1-xGaxO2通过改变银基固溶体的成分,实现对光学带隙的连续调控,进而拓展对可见光的响应范围。从而提高银基固溶体的光催化性能。介孔β-AgAl0.4Ga0.6O2提高了银基固溶体的比表面积,为进一步提高光催化性提供可能。负载贵金属Ag也是一个可行的方法进而提高光催化性能。以甲基橙为研究测试对象,测试了β-AgA1-xGaxO2的光催化性能。所合成的β-AgAl1-xGaxO2具有很好的光催化性能,其中β-AgAl0.2Ga0.8O2具有最好的光催化性能。结果表明,通过连续调控银基固溶体的禁带宽度,β-AgAl1-xGaxO2可以更有效利用太阳能降解污水中的有机染料。
[Abstract]:Environmental pollution is one of the severe challenges in today's society. Photocatalytic technology based on solar energy can effectively degrade pollutants, which is a new way to control environmental pollution at low cost and high efficiency. The problems faced by traditional photocatalytic materials include the narrow range of light response and low efficiency of photocatalytic reaction. In recent years, the development of new photocatalytic materials with visible light response activity is a hot topic in the field of photocatalysis. Solid solution photocatalytic material is made of two kinds of semiconductors to form solid solution. Its electronic structure is influenced by the composition of the solid solution, and the continuous tunability of the band gap can be realized by changing the composition. Among them, silver based solid solution photocatalyst has large absorption in visible light range, and has high photocatalytic activity and stability at the same time. It has great potential and application potential in the field of photocatalysis. In this paper, we introduce CH3COONa, Al (NO3) 3. 9H2O and Ga (NO3) 3. NH2O as raw materials, by changing the ratio of Al3+ to Ga3+, we prepare beta -NaAl1-xGaxO2 by sol-gel method, and then prepare the beta -AgAl1-xGaxO2 with continuous forbidden band width after cation exchange. And the preparation of SBA-15, CMK-3 template. Mesoporous beta -AgAl0.4Ga0.6O2 was prepared by impregnation method by using CMK-3 mesoporous carbon as the auxiliary template. By photochemical deposition, the beta -AgAl0.4Ga0.6O2 is loaded with noble metal Ag. The crystal structure and mesoscopic structure of the sample were measured by PANalytical Empyrean X ray diffractometer. The morphology and morphology of the samples were characterized by Hitachi S-4800 scanning electron microscope (SEM). The N2 absorption and desorption isotherms of mesoporous beta -AgAl0.4Ga0.6O2 were tested by ASAP2020 specific surface area analyzer. The UV spectra of the samples were measured by Hitachi U-3900 UV spectrophotometer. Then the band gap of the sample is calculated by the Kubelka-Munk formula. The fluorescence spectra of the samples were measured by the Hitachi F-7000 fluorescence spectrophotometer. A series of experimental results show that beta -AgAl1-xGaxO2 can continuously control the optical band gap by changing the composition of silver based solid solution, and expand the range of response to visible light. Thus the photocatalytic properties of the silver solid solution are improved. Mesoporous beta -AgAl0.4Ga0.6O2 improves the specific surface area of the solid solution of the silver based solid solution, and provides a possibility to further improve the photocatalytic activity. The load of precious metal Ag is also a feasible method to improve the photocatalytic performance. The photocatalytic performance of beta -AgA1-xGaxO2 was tested with methyl orange as the test object. The synthesized beta -AgAl1-xGaxO2 has good photocatalytic properties, and beta -AgAl0.2Ga0.8O2 has the best photocatalytic activity. The results show that by continuously regulating the band gap of the silver solid solution, the beta -AgAl1-xGaxO2 can effectively utilize the solar energy to degrade the organic dyes in the sewage.
【学位授予单位】：内蒙古大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：O643.36

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