改性二氧化钛纳米管阵列电极光电化学降解有机污染物并产氢的研究

发布时间：2018-03-27 08:28

本文选题：光电化学　切入点：二氧化钛纳米管阵列　出处：《华南理工大学》2015年硕士论文

【摘要】：光催化是治理环境污染的一种新的有效技术,而催化剂是光催化技术的核心,纳米Ti O2对一般环境污染(有机污染物为主)的光催化降解效果显著。当前研究的重点为提高Ti O2对太阳光的利用率和光催化活性,非金属掺杂可以提高其对可见光的利用率,光电化学方法则能有效提高Ti O2光催化活性。本研究结合阳极氧化和化学沉积的方法合成碳氮共掺杂的二氧化钛纳米管阵列(C-N-TNTAs),并采用XRD、FESEM、UV-vis、XPS等技术对材料进行表征。光电化学体系中,碳氮共掺杂二氧化钛纳米管阵列作为阳极,环境有机污染物(甲基橙和全氟辛酸溶液)作为光电催化氧化的对象,对光催化剂的氧化性能进行考察,以此同时,在阴极实现光解水产氢,在PEC体系中实现同时降解有机污染物和产氢。XRD的结果表明C-N-TNTAs主要形态为锐钛矿型,并没有出现金红石相,结晶度良好;FESEM的结果说明说明了掺杂之后并未改变其阵列结构,有利于在环境上的运用;UV-vis的结果表明,经过碳氮掺杂之后,拓宽了其光响应范围;XPS检测了其元素组成为C,N,O,Ti,这些表征结果说明明,碳氮成功地掺入到了二氧化钛纳米管阵列中,并未破坏其多孔有序的结构,而且比二氧化钛纳米管阵列具有更宽的光响应范围。光电催化降解有机污染物的实验中,运用PEC的方法在30分钟内可以使5 mg/L的甲基橙降解完全;全氟辛酸的降解结果表明,由于光电协同的作用,导致PEC具有最高的氧化效率,其降解效率随外加电压的增大而升高,同时也具有较高的产氢速率(2.66 mmol/h)。电化学的研究结果表明:在PEC体系中,在外加电场的作用下,电子-空穴对复合的几率将会减少,增加其光电催化活性,且外加电压越大,其所产生的光电流密度越大,光电催化效果越好。本研究在PEC体系中实现了氧化物的降解和还原水产氢,此实验体系可能在光电催化降解污水中的有机污染物同时产氢方面具备良好的应用前景。
[Abstract]:Photocatalysis is a new and effective technology to control environmental pollution, and catalyst is the core of photocatalytic technology. The photocatalytic degradation effect of nano-TiO _ 2 on general environmental pollution (organic pollutants mainly) is remarkable. At present, the emphasis of the research is to improve the utilization ratio and photocatalytic activity of TIO _ 2 to solar light, and non-metallic doping can improve the utilization ratio of visible light. Photochemical method can effectively improve photocatalytic activity of TIO _ 2. In this study, carbon and nitrogen co-doped titanium dioxide nanotube arrays (C-N-TNTAsN) were synthesized by anodic oxidation and chemical deposition, and the materials were characterized by X-ray diffraction (XRD) FESEMU UV-vis-XPS. In photochemical systems, Carbon and nitrogen co-doped titanium dioxide nanotube arrays were used as anode and environmental organic pollutants (methyl orange and perfluorooctanoic acid solution) as photocatalytic oxidation objects. The results of photodissociation of aquatic hydrogen in cathode, simultaneous degradation of organic pollutants and hydrogen production in PEC system showed that the main morphology of C-N-TNTAs was anatase, and no rutile phase appeared. The results of FESEM with good crystallinity indicate that the array structure has not been changed after doping, and the results of UV-vis are beneficial to the application of UV-vis in the environment. The results show that carbon and nitrogen have been successfully doped into the TiO2 nanotube array without destroying the porous and ordered structure of the TiO2 nanotube array, and the elemental composition of the TiO2 nanotube array has been determined by XPS, and the results show that the carbon and nitrogen has been successfully doped into the TiO2 nanotube array without destroying the porous and ordered structure of the TiO2 nanotube array. In the experiment of photocatalytic degradation of organic pollutants, PEC can completely degrade 5 mg/L methyl orange within 30 minutes, and the degradation results of perfluorooctanoic acid show that the photocatalytic degradation of organic pollutants is more effective than that of TiO2 nanotube arrays. Because of the photoelectricity synergism, PEC has the highest oxidation efficiency, its degradation efficiency increases with the increase of applied voltage, and it also has a high hydrogen production rate of 2.66 mmol / h.Electrochemical results show that in PEC system, Under the action of an external electric field, the probability of electron-hole recombination will be reduced, and the photocatalytic activity of the electron-hole pair will be increased, and the higher the applied voltage, the greater the photocurrent density will be. The better the photocatalytic effect is, the better the degradation of oxide and the reduction of aquatic hydrogen in PEC system. This experimental system may have a good prospect in photocatalytic degradation of organic pollutants in wastewater hydrogen production at the same time.
【学位授予单位】：华南理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TQ134.11;X703

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