【作者】 贾志刚；

【导师】 徐铸德； 岳林海；

【作者基本信息】 浙江大学 ， 物理化学， 2007， 博士

【摘要】 金属氧化物广泛应用于制作催化剂、精细陶瓷、磁性材料、荧光材料及红外吸收材料等领域。过渡金属氧化物由于过渡金属原子存在着不同的氧化态,具有比硅铝材料优异的电磁、光电以及催化等性能,特别在固体催化、光催化、择形分离、微型电磁装置、光致变色材料、电极材料、信息储存等领域存在诱人的应用前景。金属氧化物纳米材料既不同于体块材料,也不同于单个的原子。其特殊的结构层次使它具有表面效应、体积效应、量子尺寸效应等,拥有一系列新颖的物理和化学特性。但金属氧化物纳米颗粒在制备及其应用过程中,存在以下问题:一、容易发生团聚;二、使用过程中容易长大,逐渐失去纳米颗粒的特性等。针对以上问题,本论文设想用纳米颗粒构筑成多孔材料,则既可保持纳米颗粒的优越物理和化学特性,同时又具有多孔材料所具有的大比表面、高透气性等优点。论文中选择系列过渡金属有机酸盐为前驱体,通过煅烧处理,制备了由纳米晶构筑、具有较大比表面的多孔过渡金属氧化物。采用SEM、XRD、TEM、TG-DTA、UV、IR、粒度分析等现代分析测试手段,对材料的微观结构、物相、物理性质等进行表征。用N₂吸附-脱附方法对材料多孔性表征。初步探讨了以草酸盐为前驱体制备多孔性氧化物的孔结构形成机理。研究发现,在常温常压水溶液中制备了不同形貌草酸铜前驱体,不同铜源、溶剂组成等是影响草酸铜形貌的主要因素。通过煅烧工艺处理,可制得单分散、高比表面的介孔氧化铜。其最高比表面达295 m²/g。紫外吸收光谱法测得纳米晶构筑的多孔氧化铜具有催化活性。CuO/ZnO/Al₂O₃系催化剂在催化合成甲醇领域的广泛应用,CuO/ZnO催化剂则常常作为理解催化过程的简易模型。利用草酸盐沉淀法制备了单分散的、由纳米晶构筑、钟掺杂的氧化铜。发现煅烧温度对掺锌氧化铜的形貌影响较大。当升温速率较慢时,锌在氧化铜基质中呈分散状态;当升温速率较快时,锌在氧化铜基质中聚集,自成一相,根据掺锌量的不同,形成氧化铜颗粒表面的纳米丝或纳米带。氧化锌是当前研究十分活跃的无机功能材料之一。也是低压甲醇合成所用催化剂的重要组分。采用以溶剂热法合成的一维棒状草酸锌为前体,通过煅烧制备了由纳米晶构筑、具有介孔结构的一维穗状氧化锌,且荧光光谱分析表明氧化锌纳米晶粒具有不同的缺陷结构。锰氧化物具有独特的磁性、传输性能,在高频高磁感应材料、新型陶瓷材料、电子元件、传感器、催化剂、高能二次电池电极以及高温超导材料等高新技术领域具有潜在的应用价值。采用不同溶剂体系调控草酸锰前驱体结晶,发现与水互溶的有机-水溶剂体系对草酸锰具有显著的晶相、形貌调控作用。草酸锰结晶体形成过程中晶相的选择和形貌的形成与所用有机溶剂性质和结构有关。在乙醇-水体系中合成的正交二水草酸锰煅烧后得到了新颖的柱状多孔纳米组装体,而水体系产物则无此微观结构。说明草酸盐多孔结构的形成不仅与煅烧条件有关,与草酸盐分子中各配位离子的链接方式也有关。在对以草酸铜、草酸锌、草酸锰制备介孔金属氧化物研究的基础上,对过渡金属系草酸盐多孔结构的形成做了进一步探讨。认为纳米孔洞的孔体积与纳米颗粒的尺寸有关,只有纳米颗粒过小,也不利于纳米晶构筑较大孔体积多孔氧化物材料的形成。同样,我们对以其它形式的有机金属盐为前驱体（苯二甲酸盐、丁二酸盐）制备多孔材料也进行了初步探讨。更多还原

【Abstract】 Metal oxides were widely applied to many fields such as catalysis,ceramics, magnetic material,fluorescent material and infrared absorption materials.The oxides of transitional metal process more excellent properties than silicoaluminate materials, especially in solid catalysis,photocatalysis,shape-selective separation,micro electromagnetic device,photochromic materials,electrode materials and information storage fields.Nanostructured metal oxides are not only different from bulk materials, but from a single atom,and their special structures endow them with unique properties such as surface effect,little size effect,quantum measure effect.Therefore Nanostructured metal oxides own serials of novel physical and chemical properties.However,the following problems for nanoparticles of metal oxides have happened during the preparation and application:nanoparticles are reliable to aggregate because of huge surface energy.The second,nanoparticles might grow into bulk particle and lost the properties of nanomaterials.We suppose that nanoparticles were used as a building block to construct porous materials,thus this kind of materials not only keep the activity of nanoparticles but also own the good performance of porous materials.In my research,organic acid transitional metallic salts were chosen as the precursor,porous metal oxides built by nanoparticles were prepared after the calcination of the precursor.SEM、XRD、TEM、TG-DTA、UV、IR were used to investigate the morphology,size,texture,and structure of the products.BET was used to characterize the porosity of the obtained oxide. Furthermore,the formation mechanism of porous metal oxides was explored.The results show that the morphology of copper oxalate synthesized in room temperature can be mainly tuned by different copper source and the solvent system. The monodispersed,porous copper oxide was obtained by the calcination of copper oxalate precursor.The largest specific surface area reached 295 m²/g.Further experiments show that the obtained porous copper oxide displays the catalysis activity for H₂O₂ decomposition.The serial catalysis of CuO/ZnO/Al₂O₃ was widely used as catalysis for the CH₃OH synthesis.The composite of CuO/ZnO was often used as model for understanding the catalytic process of CuO/ZnO/Al₂O₃ Monodispersed,Zn-doping copper oxide was prepared by the oxalate coprecipitation.The experimental results show that the heating-up method during calcination strongly influenced the Zn distribution in the copper oxide products.Zn distribution was more even when the heating-up rate was low;however,the Zn phase tends to be separate from copper oxide.The nanobelts or nanofilaments on the surface of copper oxide particle were formed with the increasing of Zn content in the precursor.ZnO,as one of the important inorganic materials,was intensively researched currently.At the same time,ZnO was also the indispensable component of catalysis for the CH₃OH synthesis.One-dimensional,porous zinc oxide was prepared by the thermal decomposition of zinc oxalate sub-micro rods,which was synthesized by solvothermal method.The specific surface area and total pore volume are 126 m²·g^-1 and 0.13 cm³·g^-1,respectively.The PL spectra related with defects in ZnO nanoparticles were explored for porous zinc oxide samples.The manganese oxides have unique magnetic,transport performance,and possess optional application in the fields such as catalysis,ceramics,electronic device and so on.The manganese oxalate precursor was synthesized in different solvent system.The results show that organic-water solvent can be tuned the phase and morphology of manganese oxalate dihydrate.The phase and morphology formation depended on the organic solvent.Most importantly,porous manganese oxide built by nanoparticles was formed through calcination of the orthogonal manganese oxalate dihydrate precursor obtained from ethanol-water mixed solvent,while the porous manganese oxide can not be obtained though calcination of the monoclinic manganese oxalate dihydrate precursor obtained from aqueous system.That is to say,the porosity formation was related with the molecular structure of the precursor.Based on the research for porous oxide obtained from copper oxalate,zinc oxide, manganese oxalate,systematic study for the formation mechanism of porous, transitional metal oxide from corresponding oxalate was explored.It was supposed that the formation of porous structure was related with the size of nanoparticles,and the size of nanoparticles,which was too small,was not good for formation of the larger pore volume in materials.At the same time,utilizing other organic acid transitional metallic salt to obtained porous materials was also discussed primarily.更多还原