导　　师： 王海增

学科专业： 070702

授予学位： 博士

作　　者： ;

机构地区： 中国海洋大学

摘　　要： 半导体TiO/_2可有效降解环境中难生物降解的有机污染物。本文采用水热法、利用廉价原料,制备了纯TiO/_2、卤族元素/( F、Cl、Br、I /)掺杂TiO/_2 /(HDT/),并以硅胶为载体、利用水热原位负载法制备了硅胶负载卤族元素掺杂TiO/_2 /(HDTS/)。运用X射线粉末衍射/(XRD/)表征了催化剂的晶相组成、X射线光电子能谱/(XPS/)和X射线荧光光谱/(XRF/)测定了催化剂的元素组成、低温氮吸附/(BET/)测定了催化剂比表面积和孔结构、电子透射电镜/(TEM/)观察了催化剂的形貌结构,最后通过紫外-可见漫反射吸收光谱/(UV-Vis DRS/)测定了催化剂的吸光特性。以苯酚为模型污染物考察了催化剂的光催化性能,研究不同的制备条件对光催化性能的影响,筛选出最佳催化剂。 以硫酸钛为钛源,含卤盐为卤源,去离子水为溶剂,制备HDT纳米粒子。制备工艺参数对其光催化活性影响较大,其影响主要为卤盐加入量、煅烧温度。卤族元素的掺杂可促进锐钛矿相TiO/_2的生成、抑制其向金红石相的转化,拓宽TiO/_2的光吸收范围。适量F、Cl、Br、I的掺杂可提高TiO/_2的光催化活性,最佳掺杂量nx//nTi分别为0.30、0.15、0.40、1.00。煅烧温度可影响催化剂的晶粒尺寸、晶型、光吸收特性、晶格畸变和膨胀程度以及掺杂离子进入TiO/_2晶格的能力,从而对掺杂纳米TiO/_2的光催化性能产生影响。F、Cl、Br、I掺杂TiO/_2的最佳煅烧温度依次为80℃、750℃、700℃、340℃。 I掺杂TiO/_2在低于340℃的煅烧条件下,在紫外部分具有强烈的吸收、从而体现很好的光催化活性;在340℃的煅烧条件下,I掺杂TiO/_2形成紫色的TiO/_2包裹碘单质纳米颗粒,该催化剂在可见光范围具有强烈的吸收、并且呈现很高的可见光光催化活性。 HDT经硅胶负载后,在保持纳米光催化剂光催化活性的前提下,形成了较大的颗粒,使催化剂易于分离;硅胶进一步� Semiconductor TiO/_2 can degrade organic pollutants in environment efficiently, which is difficult to be degraded by biologic methods. In the current work, pure TiO/_2, halogen elements /(F, Cl, Br and I/)doped TiO/_2 /(HDT/) were prepared by hydrothermal method, using cheapness stuff. Halogen elements doped TiO/_2 supported on SiO/_2 /(HDTS/) were prepared by in situ hydrothermal method. The crystal phase composition of catalysts was studied by using the X-ray powder diffraction /(XRD/). The elements component of catalysts was mensurated by using the X-ray photoelectron spectroscopy /(XPS/) and the X-ray fluorescence spectrometry /(XRF/). The surface area and pore structure was studied by using BET. The morphology was observed by using TEM. The optical absorbance performance of catalysts was studied by using the UV - visible diffuse reflectance absorption spectra /(UV-Vis DRS/). The photocatalytic degradation of phenol is used as model reaction to evaluate the photocatalytic activity of the photocatalysts. The effects of preparation and reaction conditions on the photocatalytic performances are studied. The HDT was prepared through a mild hydrothermal route, using Ti/(SO/_4/)/_2 as the precursor, containing halogen salt as the halogen source and deionized water as solvent. The photocatalytic activity of samples was influenced greatly by processing parameter. The influence factors were mainly the volume of containing halogen salt and the calcination temperature. Halogen elements, which were doped in TiO/_2, can promote anatase phase formation, can inhibit anatase to rutile phase, can broaden the scope of TiO/_2 optical absorption. When the amounts of the doping F, Cl, Br and I were moderate, halogen elements can enhance photocatalytic activity of TiO/_2. The best doping amounts of F, Cl, Br and I were 30.0/%, 15.0/%, 40.0/% and 100.0/%, respectively. Calcined temperature could influence crystal size, phase transformation, light absorption property, distortion and expansion degree of crystal lattice and the a

关 键 词： 二氧化钛 光催化 掺杂 卤族元素 负载 硅胶

领　　域： [理学] [理学] [理学] [理学]