【作者】 江元；

【导师】 李越湘；

【作者基本信息】 南昌大学 ， 无机化学， 2010， 硕士

【摘要】 本文研究了用氟化铵处理氮掺杂二氧化钛半导体光催化剂的制备、性能及其在以蓝色发光二极管为光源的条件下降解甲醛的活性研究,主要分为三个部分：一、以Ti(SO4)2为原料,通过氨水水解法制备氮掺杂二氧化钛前驱体,煅烧前驱体制备氮掺杂纳米二氧化钛(N-TiO2)。用X射线衍射(XRD)、紫外-可见吸收光谱(UV-vis)、透射电镜(TEM)、热重-差热分析(TG-DTA)和比表面(BET)等方法对制备的样品进行表征。以蓝色发光二极管为光源,用甲醛降解反应考察了光催化剂的活性。结果表明：制备的样品均为锐钛矿,氮掺杂使二氧化钛在可见光区的光吸收明显增强；低温烘干制备的催化剂相对高温烘干的具有较小的粒子尺寸和较大的比表面。烘干温度显著影响光催化性能,低温烘干的催化剂活性较高。二、NH4F浸渍煅烧法处理以第一部分所得N-TiO2制得F-N-Ti02。催化剂(F-N-TiO2)用X射线衍射(XRD)、紫外-可见吸收光谱(UV-vis)、红外吸收(FT-IR)、比表面(BET)和X射线光电子能谱(XPS)等方法进行表征。以蓝色发光二极管(LED)为光源,通过催化剂对甲醛气体的降解作用来考察其光催化活性。结果表明：NH4F的处理能够显著地增加N-TiO2的光催化活性,NH4F处理不仅使得催化剂对可见光的吸收增加,而且也减少了F-N-TiO2的氧空位和比表面积。可见光吸收增强是因为在制备N-Ti02时,N掺杂产生的大量氧空位促成了NH4F处理时N元素的进一步掺入,同时氟掺入能降低催化剂的缺陷。F-N-TiO2的光催化活性取决于对可见光的吸收、样品的比表面积和缺陷。诸如煅烧温度和NH4F与N-TiO2的起始物质的量之比等制备条件都显著影响着光催化活性。三、同时本试验还研究了各种外部反应条件对F-N-TiO2光催化降解甲醛性能的影响,包括光照强度、反应的温度和反应湿度。更多还原

【Abstract】 In this thesis, the preparation and modification of N-TiO2 semiconductor photocatalyst as well as its photocatalytic performance for degradation of formaldehyde were searched. The reseach works is composed of three parts:The first part, a nitrogen-doped TiO2 (N-TiO2) photocatalyst consisted of nanoparticles was prepared by the calcination of the hydrolysis product of Ti(SO4)2 with aqueous ammonia. The prepared samples were characterized by XRD, UV-vis diffuse reflectance spectra (DRS), transmission electron microscope (TEM), thermogravimetric and differential thermal analysis (TG-DTA) and BET. Its photocatalytic activity was evaluated by degradation of formaldehyde under visible irradiation using blue light LED as light source. The catalyst is consisted of anatase phase. Nitrogen-doping leads to extend optical absorption to the visible-light region. The photocatalyst prepared at lower drying temperature has smaller particle size and larger specific surface area than that prepared at higher drying temperature. The drying temperature has significant influence on its photoctalytic activity and the photocatalyst dried at lower temperature has higher photocatalyitic activity than that dried at higher temperature.In the second part, the nitrogen-doped TiO2 (N-TiO2) photocatalyst prepared by the above method (part 1) was treated with NH4F (F-N-TiO2) by an impregnation-calcination method. The photocatalyst (F-N-TiO2) was characterized by X-ray diffraction (XRD), Fourier Transform Infrared (FT-IR), UV-vis diffusive reflectance spectroscopy (DRS), BET and X-ray photoelectron spectroscopy (XPS). With blue light-emitting diode (LED) as light source, its photocatalytic activity for degradation of formaldehyde was investigated. NH4F treatment increases markedly photocatalytic activity of N-TiO2. The NH4F treatment not only increases its visible absorption but also decreases the oxygen vacancies of F-N-TiO2 and the specific surface area. Increase of the absorption can be attributed to further nitrogen doping due to oxygen vacancies derived from previous nitrogen doping, while fluorine doping can decrease the defects. The photocatalytic activity of F-N-TiO2 depends on the visible absorption, the specific surface area and the defects. The preparation conditions, such as calcination temperature and initial molar ratio of NH4F to N-TiO2, have a great influence on the photocatalytic activity.In the third part, the efects of reaction conditions on photocatalytic performance for degradation of formaldehyde, such as the temperature, humidity and light intensity are investigated.更多还原