二氧化钛形貌和氧缺陷与光催化降解性能关联规律研究
发布时间：2018-08-20 20:33
【摘要】：二氧化钛,作为一种重要的过渡金属氧化物,在环境净化方面具有巨大的潜力。本文对二氧化钦光催化剂形貌结构与性能之间的构效关系,进行了深入的研究。选择特定形貌,在紫外光照射条件下,对花状二氧化钛降解直接蓝溶液的光催化反应动力学进行了初步的研究。通过氢化还原法制备氧缺陷型二氧化钛光催化剂。并首次利用H2-TpR定量研究氧缺陷浓度与光催化性能之间的关系。主要研究内容如下:第一部分:二氧化钛光催化降解直接蓝的形貌效应通过水热合成法制备四种不同形貌(片状、双锥状、花状、球状)的二氧化钛。借助一系列表征测试手段,对所得二氧化钛的相结构和形貌等进行分析。在自制的光催化装置中对二氧化钛光催化降解直接蓝的性能进行评价测试,以揭示形貌结构与光催化活性之间的构效关系。实验结果表明:不同形貌的二氧化钛对直接蓝的降解,展现出不同的光催化活性。其中,花状二氧化钛表现出较为优异的光催化性能。紫外漫反射的研究为揭示形貌效应提供了直接的证据。实验表明不同形貌的二氧化钛,其禁带宽度的差异是影响光催化活性的主要因素。第二部分:二氧化钛光催化降解直接蓝的动力学研究在紫外光照射下,对花状二氧化钛光催化降解直接蓝溶液的动力学进行了初步研究。一系列可能的操作影响因素被系统地研究,包括pH值、催化剂及H202添加量、有无Ag改性。在紫外光条件下,发现光催化降解直接蓝的反应过程满足二级反应动力学反应模型,并具有高回归系数。实验结果表明,直接蓝溶液的初始浓度及其相关的因素影响了光催化降解效率和对应的动力学参数。并且,动力学参数k随着降解效率增加而增加。第三部分:二氧化钛氧缺陷构筑及其光催化降解直接蓝性能的研究光催化反应过程中,光生电荷-空穴对分离效率低和光吸收波长范围窄是导致光催化剂活性不高的本质原因。通过氢化还原的方法制得具有氧缺陷的二氧化钛,以窄化其禁带宽度,促进光生电荷分离和迁移速率,提高光催化效率。实验结果表明,不同还原温度条件下,所形成的氧缺陷浓度不同。在紫外光照射条件下,氢化还原后的二氧化钛均显示出较高的光催化活性。通过在可见光照射条件下对光催化降解直接蓝的研究,发现氧缺陷型二氧化钛的光响应范围由紫外光扩展到可见光范围,并展现出较好的可见光光催化活性。并首次使用H2-TpR技术定量研究氧缺陷浓度,建立氧缺陷浓度与可见光光催化活性之间的构效关系。在测试条件范围内,随总氧缺陷浓度的增加,可见光光催化活性能先增大后趋于平稳;而随表面氧缺陷浓度的增加,可见光光催化活性随之增大。表面缺陷的引入是光催化剂活性提高的有效途径。
[Abstract]:Titanium dioxide, as an important transition metal oxide, has great potential in environmental purification. In this paper, the structure-activity relationship between the morphology, structure and properties of the photocatalyst was studied. The kinetics of photocatalytic degradation of direct blue solution by flower-like TIO _ 2 was studied under UV irradiation. Oxygen defect titanium dioxide photocatalyst was prepared by hydrogenation reduction method. The relationship between oxygen defect concentration and photocatalytic activity was quantitatively studied by H2-TpR for the first time. The main research contents are as follows: the first part: the morphology effect of photocatalytic degradation of direct blue was prepared by hydrothermal synthesis of titanium dioxide with four different morphologies (flake, double cone, flower, spherical). The phase structure and morphology of TIO _ 2 were analyzed by a series of characterization methods. The photocatalytic degradation of direct blue by titanium dioxide was evaluated in a self-made photocatalytic device to reveal the structure-activity relationship between morphology and photocatalytic activity. The results showed that the degradation of direct blue by titanium dioxide with different morphology showed different photocatalytic activity. Among them, flower-like titanium dioxide showed excellent photocatalytic performance. The study of UV diffuse reflection provides direct evidence for revealing morphologic effects. The experimental results show that the difference of bandgap is the main factor affecting the photocatalytic activity of titanium dioxide with different morphology. Part two: kinetic study on photocatalytic degradation of Direct Blue by Titanium dioxide under UV irradiation, the kinetics of photocatalytic degradation of Direct Blue solution was studied. A series of possible operational factors were systematically studied, including pH value, catalyst and H202 addition, and Ag modification. It was found that the photocatalytic degradation of direct blue could satisfy the second-order kinetic reaction model and had a high regression coefficient. The experimental results show that the initial concentration of direct blue solution and its related factors affect the photocatalytic degradation efficiency and the corresponding kinetic parameters. Moreover, the kinetic parameter k increases with the increase of degradation efficiency. Part III: construction of oxygen defects in TIO _ 2 and its photocatalytic degradation of Direct Blue; in the process of photocatalytic reaction, the low separation efficiency of photogenerated charge-hole and the narrow wavelength range of photoabsorption are the essential reasons leading to the low photocatalytic activity. Titanium dioxide with oxygen defects was prepared by hydrogenation reduction to narrow the band gap, promote the separation and migration rate of photogenerated charges, and improve the photocatalytic efficiency. The experimental results show that the oxygen defect concentration is different at different reduction temperature. Under UV irradiation, the hydrogenated TIO _ 2 showed high photocatalytic activity. The photocatalytic degradation of direct blue was studied under visible light irradiation. It was found that the photoresponse range of oxygen deficient titanium dioxide was extended from ultraviolet to visible light, and showed good visible photocatalytic activity. The H2-TpR technique was used to quantitatively study the oxygen defect concentration for the first time, and the structure-activity relationship between the oxygen defect concentration and the visible light catalytic activity was established. In the range of test conditions, with the increase of the total oxygen defect concentration, the photocatalytic activity of visible light increases first and then tends to steady, and with the increase of surface oxygen defect concentration, the photocatalytic activity of visible light increases. The introduction of surface defects is an effective way to improve the activity of photocatalyst.
【学位授予单位】：西南石油大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：O643.36
本文编号：2194908
[Abstract]:Titanium dioxide, as an important transition metal oxide, has great potential in environmental purification. In this paper, the structure-activity relationship between the morphology, structure and properties of the photocatalyst was studied. The kinetics of photocatalytic degradation of direct blue solution by flower-like TIO _ 2 was studied under UV irradiation. Oxygen defect titanium dioxide photocatalyst was prepared by hydrogenation reduction method. The relationship between oxygen defect concentration and photocatalytic activity was quantitatively studied by H2-TpR for the first time. The main research contents are as follows: the first part: the morphology effect of photocatalytic degradation of direct blue was prepared by hydrothermal synthesis of titanium dioxide with four different morphologies (flake, double cone, flower, spherical). The phase structure and morphology of TIO _ 2 were analyzed by a series of characterization methods. The photocatalytic degradation of direct blue by titanium dioxide was evaluated in a self-made photocatalytic device to reveal the structure-activity relationship between morphology and photocatalytic activity. The results showed that the degradation of direct blue by titanium dioxide with different morphology showed different photocatalytic activity. Among them, flower-like titanium dioxide showed excellent photocatalytic performance. The study of UV diffuse reflection provides direct evidence for revealing morphologic effects. The experimental results show that the difference of bandgap is the main factor affecting the photocatalytic activity of titanium dioxide with different morphology. Part two: kinetic study on photocatalytic degradation of Direct Blue by Titanium dioxide under UV irradiation, the kinetics of photocatalytic degradation of Direct Blue solution was studied. A series of possible operational factors were systematically studied, including pH value, catalyst and H202 addition, and Ag modification. It was found that the photocatalytic degradation of direct blue could satisfy the second-order kinetic reaction model and had a high regression coefficient. The experimental results show that the initial concentration of direct blue solution and its related factors affect the photocatalytic degradation efficiency and the corresponding kinetic parameters. Moreover, the kinetic parameter k increases with the increase of degradation efficiency. Part III: construction of oxygen defects in TIO _ 2 and its photocatalytic degradation of Direct Blue; in the process of photocatalytic reaction, the low separation efficiency of photogenerated charge-hole and the narrow wavelength range of photoabsorption are the essential reasons leading to the low photocatalytic activity. Titanium dioxide with oxygen defects was prepared by hydrogenation reduction to narrow the band gap, promote the separation and migration rate of photogenerated charges, and improve the photocatalytic efficiency. The experimental results show that the oxygen defect concentration is different at different reduction temperature. Under UV irradiation, the hydrogenated TIO _ 2 showed high photocatalytic activity. The photocatalytic degradation of direct blue was studied under visible light irradiation. It was found that the photoresponse range of oxygen deficient titanium dioxide was extended from ultraviolet to visible light, and showed good visible photocatalytic activity. The H2-TpR technique was used to quantitatively study the oxygen defect concentration for the first time, and the structure-activity relationship between the oxygen defect concentration and the visible light catalytic activity was established. In the range of test conditions, with the increase of the total oxygen defect concentration, the photocatalytic activity of visible light increases first and then tends to steady, and with the increase of surface oxygen defect concentration, the photocatalytic activity of visible light increases. The introduction of surface defects is an effective way to improve the activity of photocatalyst.
【学位授予单位】：西南石油大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：O643.36
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相关硕士学位论文 前1条
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