微波水研法制备纳米TiO₂光催化粉体及改性研究

【作者】 杨坤；

【导师】 朱红波； 史谊峰；

【作者基本信息】 昆明理工大学 ， 冶金工程（专业学位）， 2014， 硕士

【摘要】 目前,由于人们对资源和环境的过度开发利用,致使环境污染及能源短缺问题越来越严重地威胁社会的可持续发展。为解决这牵扯到亿万人民福祉的问题,广大科研工作者开展了各种各样的工作。利用太阳光催化氧化污染物以达到治理环境污染的技术具有降解速率快、无二次污染、能源来源丰富等优点,从而引起了人们极大的兴趣。在众多的半导体氧化物中,Ti02由于具有氧化性强、无毒、化学稳定性好等优点,在治理环境污染方面展现出了广阔的应用前景。本文采用微波水研法制备了纳米二氧化钛光催化粉体,并对其进行了铁离子掺杂改性。利用TG-DSC、XRD、SEM、Raman、N2吸附、UV-vis吸收光谱等多种检测手段对改性前后的TiO2光催化粉体的各方面性能进行了表征,在分析了微波水研法反应过程的基础上,首次全面系统地研究了焙烧温度、保温时间和铁离子掺杂量对样品的晶型、晶粒尺寸、比表面、紫外可见吸收光谱和光催化活性等方面影响的规律研究发现：微波水研法所制备的TiO2光催化粉体的前驱体为Ti(C204)2·2H2O。氧化焙烧过程中,Ti(C2O4)2·2H2O在112℃左右会脱附结晶水吸热生成Ti(C2O4)2,并在220℃左右分解放热生成TiO2。微波水研法制备二氧化钛光催化粉体最佳焙烧温度为400-600℃,所得的TiO2粉体呈圆球状,粒径均匀,晶粒尺寸主要在180nm左右。铁离子掺杂改性的TiO2光催化粉体,以500℃焙烧,保温30min,掺铁量为0.5%的二氧化钛光催化性能较好。与常规焙烧相比,微波焙烧所制备的样品结晶度高,结晶能量低,加热均匀好,粒径尺寸与BET比表面积小,样品的吸收带边也明显红移,对亚甲基蓝的初始吸附和降解率也明显要高于常规水研法。本论文采用微波技术为辅助加热手段,利用加水研磨的方法制备了TiO2光催化粉体,并对其进行了铁离子掺杂改性研究,证明了微波加热在功能材料制备方面的优越性,通过系统全面地考察微波焙烧温度、保温时间及掺杂量对二氧化钛光催化粉体的晶型、晶粒尺寸、比表面、紫外可见吸收光谱和光催化活性等方面的影响,得到了一些规律性认识。更多还原

【Abstract】 Nowadays, environmental pollution and energy shortage have been increasingly clamping down our sustainable development strategy owing to the over-exploitation. To solve this problem, millions of people and researchers from all fields carried out varieties of work and showed great interests in solar photocatalytic oxidized degradation for its rapid degradation rate, non-second pollution, and abundant energy. Among all semiconductor oxides, TiO2is the most extensively studied and applied material in environmental pollution control owing to the strong oxidization, non-toxic property and outstanding chemical stability.In this thesis, nano-TiO2photocatalytic powder were prepared by microwave-assisted grinding method, and modified by doping iron-ion. The pure and modified TiO2photocatalytic powder were characterized by various teniques. such as therm ogravimetry-differential scanning calorimetry (TG-DSC), X-ray diffraction (XRD) and scanning electron microscopy (SEM). Raman spectroscopy. BET surface. UV-vis absorption spectra and so on. Based on analysis of microwave-assisted grinding process, the influence of roasting temperature, holding time and doping amount on crystal type, grain size, BET surface. UV-vis absorption spectra and catalytic activity were studied by the first time.It was showed that on the process of roasting, Ti(C2O4)2·2H2O would desorbe crystal water around112℃forming Ti(C2O4)2, and at about220℃the Ti(C2O4)2would decompose to TiO2.The photocatalytic activity of pure TiO2photocatalytic powder calcined between400-600℃phase was better and the particles of prepared power were round shap with uniform particulates, and their grain size existed mainly around180nm. The best prepared conditions for iron-doped TiO2photocatalytic powder was calcining at500℃. holding up30min, and doped with0.5%Fe ion. Compared to conventional calcination, the prepared samples roasted by microwave was characterized by high crystallinity, low crystallinity energy, uniformity heating, small particle size and high BET surface, and the absorption edges was also obviously red shift. The initial adsorption and degradation rate of methylene blue was significantly higher than conventional solid-state grinding method.In this paper, TiO2photocatalyt powder were prepared by solid state grinding method assisted by microwave heating technology and modified by Fe ions doping. It showed that microwave heating had advantage in the preparation of functional materials. The influence of roasting temperature, holding time and doping amount on TiO2photocatalytic powder crystallize type, particle size, BET surface, UV-vis absorption spectra and photocatalytic activity were got through systematieally experimental study and various data analysis.更多还原