【作者】 李洁；

【导师】 杜高辉；

【作者基本信息】 浙江师范大学 ， 物理化学， 2011， 硕士

【摘要】 纳米材料学是近二十多年来科学家们一直潜心研究的学科。纳米材料的尺寸在100 nm之内,具有小尺寸效应、表面效应、量子尺寸效应和宏观量子隧道效应,在光、电、力、磁、声等领域有着广泛应用和潜在价值。金属氧化物纳米材料是近年来人们研究的热点之一,其在光电、催化、气敏、磁性、污染物处理以及锂电池等领域有着广泛的应用前景,而形貌、尺寸、维度等的调控对纳米材料最终进入应用领域具有重要意义。本论文采用多种制备方法合成了尺寸、形貌、维度不同的纳米金属氧化物,并研究了其相关物性和应用,主要包括以下内容：1.氧化钛基纳米结构的合成与物性分析(1)采用水热方法合成了H2Ti307纳米管和Na2Ti307纳米线,通过XRD、SEM、TEM对产物的形貌、晶相、结构组成等进行了表征；使用光吸收、光催化、荧光实验和热重分析得出纳米管有更好的光吸收和光催化性能,纳米线具有更强的荧光发射和更好的热稳定性。电化学循环伏安曲线表明钛酸纳米管和钛酸钠纳米线在0-1.0v的电压范围内对H202没有电催化作用,对半胱氨酸都有电催化作用。此外利用在原水热反应体系中引入过渡金属离子(Zn2+、Co2+),对纳米管进行了锌源和钴源的掺杂,通过紫外可见光(UV-vis)吸收测试发现掺杂样品在一定程度上拓宽了光吸收范围,由紫外区向可见光区或红外区偏移。(2)通过一种低温常压的合成方法—复合氢氧化物媒介法(composite-hydroxide-mediated, CHM)合成出多层Ti02(B)纳米片,并进行了后处理：在450℃煅烧2h后多层Ti02(B)纳米片转变成方形Ti02(B)纳米粒子；在130℃水热反应3d后多层Ti02(B)纳米片变成了多层锐钛矿Ti02纳米片。通过XRD、SEM、TEM等表征对产物的形貌、尺寸、结构组成、晶相等变化进行了分析和比较；多层Ti02(B)纳米片在400℃之后发生形貌改变、450℃烧结后得到的方形Ti02(B)纳米粒子稳定性变得更好、锐钛矿Ti02纳米片在约650℃时会转变晶型；多层Ti02(B)纳米片用于吸附Cr(VI)达到一定的效果；锐钛矿Ti02纳米片在光吸收和光催化方面性能较优越。2.氧化铈纳米结构的合成与物性分析采用简单的溶剂热法合成了球状纳米Ce02,高分辨的透射电镜显示出球状纳米CeO2是由大量3-5 nm的小球团聚而成的,并且由于小球之间的空隙使得Ce02纳米球具有了多孔性。光学实验证明,带隙值为2.70 ev的多孔Ce02纳米球有着优于块体CeO2(Eg=3.19 ev)的光学吸收性能,并具有蓝光发射和红光发射的光致发光性能；光催化50mg/L的甲基橙降解率为44.55%；多孔Ce02纳米球在处理模拟废水中的Cr(Ⅵ)和罗丹明(RhB)时表现出优越的吸附性能,吸附效率分别达到了94%和85%以上；电催化实验显示,多孔Ce02纳米球在0-1.0 v电压范围内能电催化半胱氨酸。3.氧化铜纳米结构的合成与物性分析通过以无水的复合氢氧化钠和氢氧化钾为溶剂,三水硝酸铜为原料用复合氢氧化物媒介法在200℃反应24h合成了花状CuO纳米结构,由叶层叠组装而成,形似花状；叶形呈两头尖中间宽,单片叶的厚度小于50 nm,叶宽约200-500 nm,叶长约2μm在叶片上有许多凸起的微粒,使叶面呈现毛糙感。光学实验证明,花状CuO纳米结构的光吸收范围在红外光区；在吸附模拟污水中的RhB时显示为慢速的化学吸附过程,吸附效率约为53%。更多还原

【Abstract】 Nanomaterials science is a discipline which has been extensively studied by scientists during the last twenty years. Nanomaterials is below 100 nm in size, with size effect, surface effect, quantum size effect, macroscopical quantum tunneling effect, and have extensive applications and potential value in optics, electrics, mechanics, magnetics, acoustics, and so on. Metal oxide nanomaterials have been a hot topic in recent years, which hold broad application prospect in photoelectricity, catalysis, gas sensor, magnetism, pollutant removal, lithium-ion battery, and so on. Howerver, the size, morphology, dimensionality, and so forth, have important impacts on such applications of metal oxide nanomaterials. In this dissertation, several metal oxide nanostructures were synthesized with different size, morphology, dimensionality by various preparation methods, and their properties and applications were also researched. The work mainly includes the following aspects:1. The synthesis and property of titanium oxide-based nanostructures(1) H2Ti3O7 nanotubes and Na2Ti3O7 nanowires were synthesized through hydrothermal method, and the morphology, crystalline phase, chemical component were analyzed by XRD, SEM and TEM. UV-vis absorption, photocatalysis, photoluminescence and TG-DTA experiments showed that the nanotubes had better optical properties and higher photocatalysis efficiency, whereas the nanowires had stronger fluorescence-emission and better thermal stability. Electrochemical cyclic voltammetry curves revealed that the nanotubes and nanowires could electro-catalyze cysteine, but could not electro-catalyze H2O2 in the voltage range of 0-1.0v. Moreover, by adding transition metal ions (Zn2+, Co2+) into primary hydro-thermal reaction solution, nanotubes were doped with zinc and Cobalt. And Uv-vis absorption test showed that the light absorption ranges of titanic acid nanotubes were broadened in a certain extent after doping transition metals, from ultraviolet region to visible region or infraredlight region.(2) Through a synthetic method at low temperature and atmospheric pressure, namely composite-hydroxide-mediated method (CHM), multilayer TiO2(B) nanosheets were synthesized. Post-treatments of the multilayer TiO2(B) nanosheets were also carried out:multilayer TiO2(B) nanosheets changed into quadrate TiO2(B) grains after calcining for 2h at 450℃; multilayer TiO2(B) nanosheets turned into anatase titania nanosheets after hydrothermal treatment for 3 days at 130℃. For the three samples, the transformations of the morphology, size, structural component and crystalline phase were characterized and compared by XRD, SEM and TEM. The crystal structures and surface absorptions were observed and studied by FT-IR and Raman tests, and thermal stability was mensurated and contrasted by TG-DTA: multilayer TiO2(B) nanosheets held change of the morphology over 400℃, quadrate TiO2(B) grains got better thermal stability after calcining for 2h at 450℃, anatase titania nanosheets maybe had transformation of crystalline phase above 650℃. Then multilayer TiO2(B) nanosheets have definite effect in removal of Cr(VI), and anatase titania nanosheets have preferable optical properties such as light absorption and photocatalysis.2. The synthesis and property of cerium oxide nanostructuresCeO2 nanospheres were synthesized through simple solvothermal method, high resolution TEM shows the as-prepared CeO2 consists of plenty of highly aggregated spheres of 3-5 nm, and is porous as a result of interspace between aggregated spheres. Porous CeO2 nanospheres have nicer optical performance in UV-vis light absorption with a optical band of 2.70 ev, which is smaller than that of the bulk CeO2(3.19 ev); they exhibited red and blue PL emission, and photocatalysis degrading efficency of 44.55% of 50 mg/L methyl orange. Porous CeO2 nanospheres showed predominant adsorbability in the removals of Cr(VI) and RhB in simulated waste water, and the adsorbent efficiency reached over 94% and 85%, respectively. Moreover, electrochemical experiments revealed that the porous CeO2 nanospheres could electro-catalyze cysteine but could not electro-catalyze H2O2 in the voltage range of 0-1.0 v.3. The synthesis and property of cupric oxide nanostructuresThrough nonaqueous synthetic method in low temperature and atmospheric pressure, namely composite-hydroxide-mediated method, flowerlike cupric oxide were synthesized with aquiferous cupric nitrate as raw materials after reacting for 24 h under 200℃. Cupric oxide nanostructures look like blooms composed of stromatolithic leafages which are acuate on two sides and wide in the middle with a thickness of below 50 nm, a width of 200-500 nm and a length of 2μm. The leaf surfaces is harsh because of some particulates on the surfaces. Optical experiments proved that the flowerlike cupric oxides have light absorption in infrared region. The cupric oxide undergoed a slow chemical process during adsorbing RhB in waste water, with an adsorbent efficiency of 53%.更多还原