【作者】 张海玲；

【导师】 廖世军；

【作者基本信息】 华南理工大学 ， 应用化学， 2011， 硕士

【摘要】 由于具有特殊形貌的介孔氧化钛在环境、催化、能源等领域的重要应用前景,有关这类材料的合成及其性能研究已成为近年来介孔材料领域的热点研究课题。本文以十二烷二胺（DADD）和聚乙烯吡咯烷酮（PVP K-30）作为模板剂,钛酸四丁酯为钛源,正硅酸乙酯为硅源,通过水热法合成了具有漂亮球形形貌的介孔TiO₂和SiO₂/TiO₂。采用小角X-射线衍射法（XRD）、氮气吸脱附法和透射电镜（TEM）、扫描电镜（SEM）考察了合成材料的形貌特征,采用光催化降解罗丹明B的实验考察材料的催化性能。实验结果表明:合成的介孔氧化钛具有介孔结构（孔径为5.16 nm）,比表面积为50.92 m²/g,对于罗丹明B的降解具有良好的催化性能;与介孔二氧化钛相比较,掺杂二氧化硅合成的钛硅混合氧化物的孔径有所减小（3.77 nm）,比表面积和光催化活性却得到了大幅度提高,同时,加入二氧化钛合成的钛硅混合氧化物的热稳定性也得到了显著的提高,说明掺杂氧化硅对提高介孔氧化钛的稳定性和光催化性能具有重要意义。另外,为了考察介孔氧化钛做为钛源对钛酸锂性能的影响,本实验中以制备的介孔氧化钛为钛源,碳酸锂为锂源,固相法合成了钛酸锂材料,并以该材料作为电极,以锂片为另一电极制作纽扣电池,通过XRD、SEM、充放电测试仪和内阻测试仪等对材料的结构和性能进行了表征。为了探索合成温度对钛酸锂材料性能的影响,本实验分别在700/750/800度合成钛酸锂;为了探索不同锂源对材料性能的影响,本实验用醋酸锂代替碳酸锂做了对比实验。试验结果表明:本实验固相法合成的钛酸锂材料是尖晶石型结构,与Li4Ti5O12的标准XRD谱图完全吻合,且随着温度的升高,材料的结晶度越好,杂相越少。材料的比容量在140 mAh/g左右,比同等条件下P25为钛源合成的钛酸锂的比容量要小。电池0.1 C倍率下,20个充放电循环内,比容量基本无衰减,说明制备的钛酸锂材料在低倍率下有很好的循环性能。另外本实验通过不同温度下制备的钛酸锂性能的对比,发现在合成温度为700℃时,XRD谱图显示钛酸锂材料中有少量金红石型TiO₂存在,制备温度为750℃时尖晶石型的钛酸锂初步形成,没有其他杂质的存在,但在800℃时合成的钛酸锂材料的XRD谱图峰强比750℃时更强,且更尖锐,说明800℃时制备的钛酸锂结晶度更好,性能测试显示性能更优良;且通过不同锂源的对比实验,发现以碳酸锂为锂源合成的钛酸锂材料的性能明显优于以醋酸锂为锂源合成得到的钛酸锂材料。更多还原

【Abstract】 Mesoporous titania with special morphologies has widely applications in the field of environment, catalysis, energy and so on. Nowadays, the synthesis and performance evaluation of these materials has become a hot topic in mesoporous materials community.Firstly, mesoporous TiO₂ and SiO₂/TiO₂ with spherical morphology were synthesized by using Dodecane diamine （DADD） and polyvinyl pyrrolidone （PVP K-30） as templates, tetrabutyl titanate as titanium source and TEOS as silica source. The structures of the synthesized samples were investigated by X-ray diffraction （XRD）, nitrogen adsorption-desorption, scanning electron microscopy（SEM）and transmission electron microscopy （ TEM）. And then the photocatalytic performances of the synthesized samples were investigated by photodegradation of Rhodamine B.The experimental results showed that the systhesized TiO₂ sample had a mosoporous structure （pore size: ca. ?5.16 nm） with a high specific surface area （ca. 50.92 m²/g） and good photocatalytic performance in photodegradation of Rhodamine B. Comparing with mesoporous TiO₂,the mean pore size of the mesoporous doped-silica TiO₂ was smaller （ca. ?3.77 nm）, but its specific surface area, photocatalytic activity and thermal stability increased greatly because of the addition of silica. Above results showed that the addition of silica to mesoporous TiO₂ is significative for improving the thermal stability and photocatalytic activities of mesoporous TiO₂.In addition, lithium titanate was synthesized by solid phase method, above prepared mesoporous TiO₂ was used as titania source, lithium carbonate as lithium source. And we investigated the performance of the prepared lithium titanate by using it in battery. Button batteries were made by using prepared lithium titanate as anode material and Li piece as cathode material. And the structures and properties of the prepared lithium titanate were investigated by XRD, SEM, charge-discharge and internal resistance testing instruments. The materials were synthesized at 700/750/800℃respectively for exploring the influence of synthesis temperature on the performance of lithium titanate. And lithium acetate was used as lithium sources instead of lithium carbonate for exploring the influence of different lithium sources on the material properties.The experimental results showed the prepared lithium titanate had a spinel structure, its XRD results was consistent with the standard XRD spectrum of Li4Ti5O12 completely. And the higher the synthesis temperatures of the sample,the better its crystallinity and fewer miscellaneous phases in its XRD reflection. Specific capacity of the material was ca. 140 mAh/g, which was smaller than that of the materials synthesized by using P25 as titania source. The prepared lithium titanate had good cycle performances at low magnification. The specific capacity of battery did not decline during the 20 cycles charge-discharge process at 0.1C rate. By comparing the XRD reflection of lithium titanate prepared at different temperatures, we found that lithium titanate material synthesized at 700℃had a few of rutile TiO₂, spar-type lithium titanates were formed at 750℃,and the lithium titanate material prepared at 800℃showed better crystalline and performance than others. At last, we found that the performance of the lithium titanate prepared by using lithium carbonate as lithium sources were better than that of lithium acetate as lithium sources.更多还原