金属氧化物复合二氧化钛光催化降解气相甲苯研究

发布时间：2018-01-28 03:46

本文关键词： 二氧化钛水滑石氧化亚铜气相甲苯　出处：《山东大学》2017年硕士论文　论文类型：学位论文

【摘要】：近几年来,雾霾污染和室内空气质量问题日渐严重,挥发性有机污染物(VOCs)作为雾霾和室内大气污染的主要污染源之一,也因此受到了人们的广泛关注。光催化降解VOCs是目前最具有应用前景的环境友好净化技术之一。在众多光催化剂中,Ti02作为一种无毒无害、光稳定性好、廉价易得、对污染物降解彻底的半导体催化剂,已经成为目前应用最为广泛的半导体光催化剂。但是,Ti02作为光催化剂降解VOCs仍然存在着以下缺陷:(1)在光催化降解过程中,TiO2受光激发产生的电子-空穴对复合机率大;(2)Ti02的宽禁带度较宽(3.2eV),光能利用率低,只能利用太阳光中的紫外光部分。因此,目前改进Ti02光催化技术的重点集中在了提高TiO2光生电子-空穴的分离效率和扩大Ti02对可见光的响应范围上。本论文分别通过将二氧化钛与水滑石、氧化亚铜两种金属氧化物复合,有效提高了二氧化钛的光催化效率和可见光利用率。主要研究成果如下:(1)本文提出利用紫外分光光度法原位检测气相甲苯浓度的方法;紫外分光光度法操作简单,测试费用少,分析速度快。通过绘制标准曲线、测试精密度和稳定性,确定了紫外可见分光光度法检测甲苯浓度的可行性;(2)通过共沉淀法和水解法成功制备了以水滑石(LDHs)作为基底的复合型光催化剂Ti02-LDHs,并从各项表征结果中观察到晶体Ti02与LDHs复合情况良好;在模拟光照射下,催化剂Ti02-LDHs对浓度为171.6mg/m3的气相甲苯的降解率达到了 86%,在实际太阳光下达到了 92%;在重复实验中,重复使用4次后,TiO2-LDHs对于气相甲苯的降解率依然保持在60%以上;(3)通过水解法和还原法成功制备了结晶性良好的复合型光催化剂Ti02-Cu20;通过表征测试,观察到复合催化剂Ti02-Cu20形成了 p-n异质结,具有可见光活性;在光催化降解甲苯的具体实验中,催化剂Ti02-Cu20在模拟光下对浓度为171.6 mg/m3的气相甲苯降解率达到了 79%,在可见光下达到了 70%。
[Abstract]:In recent years, haze pollution and indoor air quality problems have become more and more serious. Volatile organic pollutants (VOCs) are one of the main sources of haze and indoor air pollution. Photocatalytic degradation of VOCs is one of the most promising environmentally friendly purification technologies. Semiconductor catalysts, which have good photostability, low cost and easy to obtain, have become the most widely used semiconductor photocatalysts for the complete degradation of pollutants. Ti02 as a photocatalyst for VOCs degradation still has the following defects: 1) in the photocatalytic degradation process, the electron-hole recombination probability of the photoexcited VOCs is high. The wide band gap of Ti02 is 3.2eV ~ (-1), and the utilization ratio of light energy is low, only the ultraviolet part of the solar light can be utilized. At present, the emphasis of improving Ti02 photocatalytic technology is to improve the efficiency of TiO2 photogenerated electron-hole separation and expand the response range of Ti02 to visible light. Talc. Cuprous oxide is a composite of two kinds of metal oxides. The photocatalytic efficiency and visible light utilization ratio of titanium dioxide are improved effectively. The main research results are as follows: (1) in this paper, the method of in situ detection of gas phase toluene by UV spectrophotometry is proposed. UV spectrophotometry is simple in operation, low in testing cost and fast in analytical speed. By drawing standard curve, measuring precision and stability, the feasibility of determination of toluene concentration by UV-Vis spectrophotometry is determined. (2) the composite photocatalyst Ti02-LDHs with hydrotalcite as substrate was prepared by co-precipitation method and hydrolysis method. From the results of various characterization, it was observed that the crystal Ti02 and LDHs were in good combination. Under simulated light irradiation, the degradation rate of gas phase toluene with 171.6 mg / m ~ 3 concentration of catalyst Ti02-LDHs reached 86% and reached 92% in actual solar light. In the repeated experiment, the degradation rate of TiO2-LDHs to gaseous toluene remained above 60% after repeated use for 4 times. (3) Ti02-Cu20, a composite photocatalyst with good crystallinity, was successfully prepared by hydrolysis and reduction. The p-n heterojunction was observed in Ti02-Cu20 with visible light activity. In the experiment of photocatalytic degradation of toluene, the degradation rate of toluene in gaseous phase with 171.6 mg/m3 concentration reached 79% under simulated light. It reaches 70 in visible light.
【学位授予单位】：山东大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：X51

【参考文献】