【作者】 王作辉；

【导师】 黄婉霞；

【作者基本信息】 四川大学 ， 纳米材料与纳米技术， 2007， 硕士

【摘要】 半导体TiO₂作为一种性能优异的光催化材料，可将许多化学法、生物法无法降解的有机污染物降解为CO₂、H₂O等无机小分子，且成本低廉，不造成二次污染，因而在空气净化、王业废水处理以及自清洁等方面有非常广泛的应用前景。近年来，TiO₂光催化技术应用于环境污染物的治理已经成为环境科学研究的热点。但由于TiO₂粉末光催化剂在使用过程中存在分离与回收困难等问题，因而TiO₂薄膜光催化剂逐渐成为一个新的研究热点。钠钙玻璃应用范围广泛且价格便宜，在其表面涂上高光催化活性的TiO₂薄膜将会使其在自清洁玻璃等环保材料领域具有广阔的应用前景。本文在对TiO₂半导体光催化和亲水性工作原理、存在问题及发展前景进行综述的基础上，系统研究了采用溶胶—凝胶法在普通钠钙玻璃表面进行纳米TiO₂薄膜制备的工艺以及工艺参数与薄膜光催化性能和亲水性能之间的关系。本文针对纯TiO₂在实际应用中存在光吸收范围窄（仅限于紫外区）以及光生载流子很容易重新复合等缺陷，从TiO₂掺杂改性和结构修饰着手，用溶胶—凝胶浸渍提拉法在玻璃基体上制备了掺铁TiO₂薄膜。用X射线衍射（XRD）测量了纳米TiO₂粉体的晶型和晶粒尺寸，扫描电镜（SEM）观察了纳米TiO₂薄膜的表面形貌，紫外可见光谱（UV-VIS）表征了镀有纳米TiO₂薄膜玻璃的透光率和吸收阀值。并用甲基橙水溶液的光催化脱色来评价TiO₂纳米薄膜的光催化活性，利用测量紫外光照前后水滴在薄膜表面接触角的变化来评价TiO₂薄膜的亲水性能。本论文主要研究了离子掺杂量、镀膜层数、不同光源及煅烧温度四个方面对纳米TiO₂薄膜自清洁性能的影响。掺杂了Fe³⁺的TiO₂薄膜在薄膜的紫外光吸收、光催化性能以及亲水性能等都较未掺杂的有明显改善；Fe³⁺的掺杂量不宜过大，过大会使光催化性能及亲水性能都有所降低；适量的Fe³⁺掺杂到TiO₂后，不仅可以提高TiO₂对光的吸收强度，而且使吸收范围发生红移，可以拓展太阳光的利用范围；热处理温度对TiO2薄膜的性能的影响主要体现在TiO₂的结构上：过低的温度下TiO₂不能完全结晶为光催化及亲水性能良好的锐钛矿结构，温度过高则使玻璃发生软化甚至变形。研究结果表明：铁离子掺杂浓度为0.5％（摩尔比）、镀膜层数为4层、煅烧的时间为1.5h和退火温度为500℃时，所制备出的薄膜致密均匀，光滑透明，无彩虹效应且不开裂；紫外光照后，薄膜具有超亲水性和较强的光催化活性，在可见光下掺杂的薄膜较未掺杂的相比光催化性能也有一定的提高。更多还原

【Abstract】 Titanium dioxide （YiO₂）, as an excellent photocatalyst material, can degrademost organic contaminations which can not been done through chemical andbiologic methods into CO₂、H₂O. Furthermore it costs little and does not producenew contaminations. These advantages lead to a very optimistic application futureof titanium dioxide in the fields of air purification, waste water treatment andself-cleaning. In recent decades, studies on photocatalysis of TiO₂ have attractedconsiderable attention. For the reason of disadvantages of powder, TiO₂ film hasbecome a new focus of study. Soda lime glass is common and low in cost. Highphotoactive TiO₂ thin film on the surface of soda line glass will make it have awidespread application in self-cleaning glass.On the basis of summarization of principle of photocatalysis andhydrophile、problems and prospect, technics of preparation of TiO₂ films on glassthrough sol-gel and relationship to parameters and property of photocatalysis andhydrophile were studied.Because of the deficiencies of narrow absorption range, high recombinationrate of charge carrier and low efficiency of quantization, TiO₂ films doped withFe³⁺ were prepared through sol-gel method. The morphology of the film wasinvestigated by using a scanning electron microscopy （SEM）. The grain size andcrystallinity of the films were determined by a X-Ray diffractometer （XRD）. The transmittance and the absorption threshold of the films were measured byUV-visible spectrophotometer. Photocatalytic activity of TiO₂ films wasmeasured by photocatalytic decoloration of methyl orange aqueous solution andhydrophilic activity by measurement of angle change of water drop on glassbefore and after UV illumination.The impacts of Fe³⁺ quantity, number of film layer, different lamp-housesand temperature of heat treatment on performance of self-cleaning glass wereinvestigated. TiO₂ thin films doped with Fe³⁺ have better activities of optics,photocatalysis and hydrophile than undoped; overmuch Fe³⁺ will reduce thephotocatalysis and hydrophile activities of the films; appropriate quantity of Fe³⁺not only increases absorption to UV but also makes absorption range "red shift";heat treatment has great influence to film’s properties: too low temperaturecannot make TiO₂ transit to anatase crystal which has better photocatalysis andhydrophile activities and too high temperature will transmogrify the substrate ofglass.The TiO₂ films fabricated by dipcoating onto glass substrate for 4 time witha heat treatment at a temperature of 500℃for 1.5 hours were compact, uniformand transparent without iridescent appearance.The films exhibited the mostexcellent hydrophilic and photocatalytic performance when the doping ionconcentration of Fe³⁺ is 0.5%. The obtained TiO₂ films still have superhydrophilic and good photocatalytic ability even under visible light after UVillumination,.更多还原