【作者】 刘宗耀；

【导师】 李立清； 唐新村；

【作者基本信息】 湖南大学 ， 环境工程， 2007， 硕士

【摘要】 在人们物质生活水平不断提高的同时,室内污染也日趋严重。由于室内空气质量的下降对人们健康状况和工作效率影响,室内污染日益引起人们的重视。其中挥发性有机物(VOCs)是一种很普遍且对人体危害较大的一类污染物,它主要来自于室内装修材料和家具。它具有种类多、成分复杂、长期低剂量释放、对人体危害大、处理难度大等特点。在现有的处理室内VOCs污染物的方法基础上,人们不断地寻求着更好的空气净化新技术以便更好的解决室内污染问题。自从TiO2被发现时一种高效催化剂以来,人们在水处理和大气净化方面做了大量的研究。用TiO2做催化剂有以下明显的优点:在大范围pH内TiO2具有化学稳定性,成本低,基本不受水中一些常见离子抑制的影响,反应条件温和以及能降解难降解物质等。当光照情况下,TiO2能产生极强的氧化性,能使接触的一些有害物质例如:微生物、真菌、臭气和固体废物等降解为CO2、H2O和其它一些小分子。然而,因为催化效率低下和仅在紫外光下激发限制了TiO2催化剂的大规模实际应用。所以,合成一种可见光响应且具有高效催化效率的催化剂是当今催化领域面临的一大挑战。为了提高催化剂的活性,对TiO2掺杂金属氧化物是一种有效的方法。尽管掺杂机理仍然不是很清楚,但是在过去几十年里吸引了大量科学家的研究,并且在提高TiO2催化效率方面取得了巨大的进展。很多金属氧化物,例如Cd-TiO2、Fe -TiO2、Ni- TiO2、V- TiO2、Mg- TiO2、Ce- TiO2等都被广泛的研究。近年来,掺杂非金属来改善TiO2催化剂的活性成为研究的热点之一,通过掺杂非金属来降低TiO2带隙能来使激发限拓宽至可见光区。有文献报道掺杂非金属N、C或者B使激发限拓宽至可见光区。本文通过简单得Sol-Gel方法制作了共掺杂金属氧化物Fe2O3和非金属元素B的复合催化剂TiO2。用XRD分析了物质的结构,其中样品的物理化学性质通过UV-Vis漫反射光谱(DRS)和荧光光谱(FS)来检测。实验选用常见的室内污染物甲醛为目标降解物。结果表明,掺杂B能使吸收光谱红移至可见光区,而进一步掺杂Fe2O3大大提高了催化剂的活性。更多还原

【Abstract】 At the time of physical life level continuously raises, the indoor air pollution becomes gradually serious in the meantime. The indoor air pollution causes people’s attention day by day because of the descent of the indoor air quality to influence people health and work efficiency. Among of them, the volatility organic compounds ( VOCs ) is a type of pollutant which is very widespread and endanger to the human body, it mainly comes from indoor fitment and furniture. It has the characters: various in category, complicated composition, long-term low doses release, harmful to human body and difficult in disposal etc. People try to find a new better technique to resolve the problem of indoor air pollution in recent times.Since TiO2 was found to be an efficient photocatalyst, it has attracted great attention as an alternative material to use in the purification of water and air. Photocatalysis with TiO2 presents some distinct advantages: high TiO2 chemical stability in a large pH range, low cost of catalyst and chemicals, none or low inhibitions by common ions present in water, relatively mild reaction conditions required and success in the decomposition of several toxic refractory pollutants. When exposed to light, a titanium dioxide photocatalyst generates an extremely strong oxidizing power that oxidizes harmful substances, such as microbes, molds, odors, or soils that come into contact, and eliminates them by decomposition into carbon dioxide, water and other small molecules. Yet, the implementation of photocatalysis for practical use at large scale is still a challenging matter of investigation because of the low photocatalytic activity and working only in the UV region. So, developing a novel photocatalysts with high activity and working in the visible region is one of challenges facing photocatalysis area.To increase the reaction activity, doping TiO2 with metal oxides is one of the most efficiency way. Though the mechanism of the doping is still remain unclear, it has received a lot of attention in the last decades, and it has been made a huge progress in the improvement of enhancing photocatalytic efficiency. Many metal oxides, such as Cd-TiO2, Fe -TiO2 Ni- TiO2, V- TiO2, Mg- TiO2, Ce- TiO2, have commonly been used.Recently, a few innovative methods were proposed to low its band gap and shift its optical response to the visible region by doping TiO2 with nonmetal element. For example, doping TiO2 with N, C, or B can lower its band gap and shift its optical response to the visible region.In this study, we report on doped TiO2 with both a metal oxide, Fe2O3, and a nonmetal element, boron, by a simple method of sol-gel synthesis. X-ray Diffraction (XRD) was used to analyze the structure of the photocatalyst. The physicochemical properties of samples were characterized by UV-Vis diffuse reflectance spectra (DRS) and fluorescence spectrometry (FS). Herein we chose formaldehyde as target pollutant, because of it’s a common component of VOCs (volatile organic compounds) and awfully harmful to human body.According to the experiments and our study, the results showed that the effect of B doping in TiO2 can extend the spectral response to the visible region and that the reaction activity is extraordinarily enhanced when it is further loaded with Fe2O3.更多还原