【作者】 程晓丽；

【导师】 霍丽华；

【作者基本信息】 黑龙江大学 ， 无机化学， 2012， 博士

【摘要】 本论文主要采用液相化学法控制合成TiO₂基和ZnO基多级结构纳米材料,并探讨其形成机制及内在规律。分别从多级结构材料的制备、形成机理以及性质表征几个方面进行论述。全文旨在探索液相体系中新型多级纳米结构材料组装与性能,在开发新型气敏材料的同时揭示材料结构和形貌与气敏性能间的关系。1.采用液相和静电纺丝法结合原位组装技术制备了TiO₂和Ag-TiO₂球和纤维多级结构材料。对于TiO₂厚膜型气敏元件,纤维较球形形貌材料具有更佳的气敏性能。而纳米Ag在TiO₂球和纤维表面的修饰即提高了材料的有效比表面积,同时其优越的催化性能加速了吸附氧的负离子化及其与被检测气的反应,使得Ag-TiO₂材料的气敏性显著提高。2.利用化学浴沉积方法并结制备了由ZnO和BZA复合构筑的多级结构花,400℃处理后,形成了由0D纳米粒子逐级构筑的多级结构蛛网状ZnO花,且在制备过程中ZnO纳米粒子膜的存在对蛛网状花的形成起到了决定性作用。原位生长法将该多级结构花组装到器件表面,很好的保持了蛛网状形貌。该原位组装器件较涂覆法制备的器件具有灵敏度高（对100μL/L乙醇灵敏度达到50）、电阻（1.2 M?）和工作温度低（350℃）,响应-恢复快速（对100μL/L乙醇分别是1 s和10 s）,稳定性好等优点,最低检测限达到0.1μL/L。3.利用液相反应生长法制备了ZnO纳米棒阵列,而后采用水热法将NiO纳米片沉积到ZnO纳米棒表面,得到异质多级结构材料阵列。采用相同的实验方法将NiO-ZnO材料组装到器件表面,很好的保持了多级结构形貌的完整性。该结构即有效地提高了材料的比表面积,又形成了高活性的p-n结界面。NiO纳米片沉积后,相比纯ZnO纳米棒阵列器件对检测气体的灵敏度大幅度提高。该材料显著增强了材料对NO的灵敏度和选择性,最低检测限为0.001μL/L。更多还原

【Abstract】 The controlled synthesis of ZnO and TiO₂ hierarchical nanostructures through liquid-phase chemical route is investigated in this thesis.The synthesis,formation mechanism and properties are investigated in detail.The thesis mainly focuses on the architecture and properties of novel hierarchical structure of nano-oxides,to illustrate the relationship between hierarchical structure of oxides and their gas sensing properties.1.TiO₂ spheres and TiO₂ fibers were prepared by an aqueous system and electrospinning method,respectively.Heterostructural Ag-TiO₂ spheres and fibers were manipulated by in situ reduction and growth.The gas-sensing properties of the materials to vapor were measured.The results indicated that the Ti O₂ fibers thick film sensors exhibit good sensing property than the TiO₂ spheres.Ag nanoparticles greatly enhanced the sensitivity,selectivity and response characteristic of TiO₂ materials to the tested gases.2.Unprecedented hierarchical ZnO flowers assembled by spider web-like nanostructures,which stepwisely constructed from 0D nanoparticles by chemical bath deposition combined with subsequent calcination.The preservation of the araneose flower-like ZnO hierarchical nanostructures mainly depends on the morphology of the precursors determined by the structure of mixed ZnO and BZA.The ZnO sensing film is fabricated by in situ chemical bath deposition and the sensor exhibits ultrahigh response to ethanol vapor with low detection limit（0.1μL/L）,and ultrafast response and recovery characteristics to 100 ppm ethanol（1 and 10 s）.3.The NiO/ZnO hierarchical heterostructure were constructed by hydrothermal deposition method.The sensing film is fabricated by in situ deposition and the sensor exhibits ultrahigh sensitivity and selectivity to NO with low detection limit（0.001μL/L）.The gas selectivity was explained by the catalytic effect of nanosheet NiO and the extension of the electron depletion layer via the formation of p-n junctions.更多还原