CoZnAl水滑石修饰电极光电催化性能研究

发布时间：2018-05-18 04:47

本文选题：水滑石 + 薄膜修饰　；参考：《沈阳化工大学》2017年硕士论文

【摘要】：层状双金属氢氧化物也称阴离子粘土或水滑石类化合物,它是一类阴离子型层状化合物。其主体层板带正电荷,带有负电荷的阴离子镶嵌在层间。二者通过化学键(共价键)相结合。由于水滑石类化合物具有层板金属阳离子组成和层间阴离子种类的可调换性、结构可复原性及适宜的微孔结构、简单的合成过程、环境友好性等特性,所以其无论在环境保护、催化反应、光电化学方向还是医药制备等领域均展现出光明的应用前景。层状结构对电荷转移有协同作用,可以有效抑制电子-空穴对复合和纳米粒子团聚。通过在电极表面进行水滑石薄膜修饰,可以促进电化学反应时电子的得失发生,使水滑石在光电化学领域有广阔的应用前景。本文利用Co(NO_3)_2、Zn(NO_3)_2、Al(NO_3)_3原料,采用共沉淀方法合成具有不同Co掺杂量的Co Zn Al水滑石,通过XRD和UV-Vis对制备的水滑石粉体进行了表征,以确定水滑石晶体结构和可见光吸收性能;采用涂覆法制备了Co Zn Al水滑石修饰的薄膜电极,采用三电极体系对薄膜电极的光生电流大小及电化学活性进行了测试,考察了不同催化过程、不同pH、不同电解质溶液种类、不同电解质溶液浓度、不同甲基橙浓度、不同Co掺杂量对甲基橙降解率的影响。测试结果表明不同Co掺杂量的水滑石均形成了单一晶相的水滑石结构,且Co Zn Al水滑石在可见光和紫外光区均有光吸收性能,Co Zn Al水滑石修饰电极具有良好的电化学性能和光电响应能力,其中Co:Zn:Al摩尔比为0.2:2:1的Co Zn Al水滑石修饰的薄膜电极的光生电流最大;以该电极作为工作电极,以1 mol/L Na NO_3溶液为电解质溶液,在溶液pH=5的情况下降解5 mg/L甲基橙,240 min后甲基橙降解率可达到90%。
[Abstract]:Layered bimetallic hydroxides, also called anionic clay or hydrotalcite compounds, are anion layered compounds. The main plate is positively charged and anions with negative charge are embedded in the interlayer. The two are combined by chemical bonds (covalent bonds). Because the hydrotalcite compounds have the characteristics of metal cation composition and interlayer anions interchangeability, structure resilience and suitable micropore structure, simple synthesis process, environmental friendliness and so on, the hydrotalcite compounds are protected in the environment. Catalytic reaction, photochemistry and pharmaceutical preparation are promising applications. The layered structure has synergistic effect on charge transfer, which can effectively inhibit the electron-hole pair recombination and nanoparticles agglomeration. The hydrotalcite film modification on the electrode surface can promote the occurrence of electron loss and gain in the electrochemical reaction, which makes the hydrotalcite have a broad application prospect in the field of photochemistry. In this paper, the Co Zn Al hydrotalcite with different Co doping amount was synthesized by coprecipitation method, and the prepared water talcum powder was characterized by XRD and UV-Vis in order to determine the crystal structure and visible light absorption property of hydrotalcite. The Co Zn Al hydrotalcite modified thin film electrode was prepared by coating method. The photogenerated current and electrochemical activity of the film electrode were measured by three-electrode system. The different catalytic processes, different pH and different electrolyte solutions were investigated. The effect of different electrolyte concentration, different concentration of methyl orange and different amount of Co doping on the degradation rate of methyl orange was studied. The results show that the hydrotalcite with different Co doping content forms a single crystal phase hydrotalcite structure. The Co Zn Al hydrotalcite-modified electrode has good electrochemical performance and photoelectric response ability in both visible and ultraviolet region. The photogenerated current of the film electrode modified by Co Zn Al hydrotalcite with Co:Zn:Al molar ratio of 0.2: 2: 1 was the largest. The electrode was used as working electrode and 1 mol/L Na NO_3 solution as electrolyte solution. The degradation rate of methyl orange can reach 90 after degradation of methyl orange for 5 mg/L with pH=5 for 240 min.
【学位授予单位】：沈阳化工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：O646.54

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