氧化镁纳米粉体的制备

以氢氧化镁和草酸为原料,通过控制实验条件制得纳米氧化镁。研究聚乙烯醇(PVA)、聚乙二醇-400,十二烷基硫酸钠和烷基磷酸酯钾盐等分散剂对氧化镁产品粒径的影响,通过X射线衍射(XRD)、透射电子显微镜(TEM)、扫描电子显微镜(SEM)对氧化镁产物的物相形貌进行表征。结果表明,以聚乙烯醇为分散剂,通过研磨方式合成出草酸镁前驱体,在600℃煅烧1 h,可制得粒度均匀的球形纳米氧化镁粒子。样品经XRD分析为MgO纯相,TEM图像显示制备的MgO纳米粒子粒径为10~20 nm,颗粒分布较均匀。     

Characteristics and Photoeatalytie Effects of Zn/ZnO Nanowhiskers Compared with ZnO Nanopartieles

ZnO nanopowders were prepared by oxidizing Zn vapor in the atmosphere of mixture gas of At and O2 at low pressure. Tetrapod nanowhiskers synthesized at a pressure of 1.6 kPa show pure ZnO feet and Zn phase in the core of the nanopowder. The ellipsoid ZnO nanoparticles were produced at the pressure of 10 kPa. The photodegradation rate of aniline and chemical oxygen demand removal demonstrate that the photocatalytic efficiency of Zn/ZnO nanowhiskers with UV irradiation is higher than that ofZnO nanoparticles. The tetrapod morphology and Zn phase inside nanowhiskers play key a role in photodegradation process.     

Characteristics and Photoeatalytie Effects of Zn/ZnO Nanowhiskers Compared with ZnO Nanoparticles

ZnO nanopowders were prepared by oxidizing Zn vapor in the atmosphere of mixture gas of Ar and O_2 at low pressure.Tetrapod nanowhiskers synthesized at a pressure of 1.6 kPa show pure ZnO feet and Zn phase in the core of the nanopowder.The ellipsoid ZnO nanoparticles were produced at the pressure of 10 kPa.The photodegradation rate of aniline and chemical oxygen demand removal demonstrate that the photocatalytic efficiency of Zn/ZnO nanowhiskers with UV irradiation is higher than that of ZnO nanoparticles. The tetrapod morphology and Zn phase inside nanowhiskers play key a role in photodegradation process.     

化学沉淀法制备纳米α-Fe_2O_3及其气敏性能研究

以Fe(NO3)3.9H2O和Na2CO3为起始物,采用化学沉淀法制备了纳米级α-Fe2O3粉体材料.采用XRD、TG-DTA和TEM等技术对产物的晶型、晶粒大小及形貌进行了表征.结果表明,沉淀法所制备的α-Fe2O3粉体材料为分散均匀的球形颗粒,平均粒径大小约40 nm.气敏性能测试结果表明该材料具有可观的气敏性能,对H2S气体表现出较高的灵敏度及良好的选择性,且对乙醇气体的灵敏度明显高于市售样品.在对所制备的α-Fe2O3纳米材料的结构及气敏性能进行系统研究的基础上,初步讨论了其对还原性气体的敏感机理.     

NiFe2O4纳米冷冻机油的红外光谱分析

采用Nicolet 6700型傅立叶变换红外光谱仪对矿物基3GS纳米NiFe2O4冷冻机油的红外光谱进行采集,逐步分析了矿物基冷冻机油、试样空白纳米冷冻机油及纳米冷冻机油的红外光谱变化情况,并与POE冷冻机油160SZ的红外光谱进行了对比分析.发现促使POE油与R134a相溶的可能因素是脂肪族酸、脂肪族醚和脂肪族伯醇的存在,矿物基3GS纳米NiFe2O4冷冻机油中出现了与POE冷冻机油160SZ相似的吸收峰,使其与R134a的相溶性得到改善.     

CoCr_2O_4/TiO_2复合薄膜光阳极的制备及其在DSSC中的应用

采用柠檬酸凝胶法制备了尖晶石型CoCr2O4纳米粉体,通过X射线衍射光谱分析了煅烧温度对CoCr2O4纳米粉体晶型及粒度的影响;通过紫外-可见吸收光谱测试了CoCr2O4/纳米粉体和CoCr2O4/TiO2复合薄膜的吸光度。以CoCr2O4/TiO2复合薄膜为光阳极制备了DSSC,应用太阳光模拟器及数字源表测试了DSSC的光电性能,分析了CoCr2O4纳米粉体复合量对电池性能的影响;应用分光计器测试了复合薄膜电池的单色光转换效率。结果表明,CoCr2O4纳米粉体的最佳煅烧温度为700℃,禁带宽度为1.6eV;当CoCr2O4纳米粉体的复合量质量分数为1%时,电池的短路电流和转换效率提高较多,分别提高了61%和55%。     

溶胶-凝胶法与冷冻干燥技术结合制备纳米氧化铁

采用溶胶 -凝胶法 ,结合冷冻干燥技术制得了粒径在 2 0～ 30 nm之间的均分散球形 α- Fe2 O3纳米粒子。用 TEM、XRD等手段对样品进行了表征 ,考察了制备条件对产物粒径、形貌的影响。结果表明 :初始铁盐浓度对产物粒径影响不明显 ,可以在较高初始浓度下制备纳米 α- Fe2 O3;p H值、焙烧温度对粒子形貌和大小有一定的影响 ,但焙烧时间对产物粒径影响不大     

尖晶石型MAl_2O_4(M=Cu、Ni)粉体的制备及其光电性能

采用柠檬酸法制备了尖晶石型粉体MAl2O4(M=Cu、Ni),并采用XRD、UV-vis对粉体进行表征。将两种粉体分别复合到TiO2光阳极中,测试MAl2O4(M=Cu、Ni)/TiO2复合光阳极的光电性能。结果表明,MAl2O4(M=Cu、Ni)纳米粒子为窄禁带半导体材料;将MAl2O4(M=Cu、Ni)纳米粒子复合到TiO2中,电池的性能都有所提高;当MAl2O4(M=Cu、Ni)纳米粒子的质量分数为2%时,电池性能最好,且CuAl2O4/TiO2复合薄膜电池的性能优于NiAl2O4/TiO2复合薄膜电池,转化效率分别提高了61%和30%。     

固相法合成钴铝蓝色颜料的研究

以工业纯氧化钴和氧化铝为原料,通过固相法合成CoAl2O4尖晶石型钴蓝颜料。采用色度分析、X射线衍射(XRD)、扫描电镜(SEM)、微型光谱仪等测试手段,研究煅烧温度、保温时间以及矿化剂等工艺参数对样品呈色、反射强度、晶相结构及CoAl2O4尖晶石晶粒大小和发育程度的影响。     

溶胶-凝胶法合成二氧化铈纳米晶

用溶胶－凝胶法合成了不同粒径的CeO2纳米晶。XRD分析表明，不同焙烧温度下所合成的CeO2纳米晶均属于立方晶系，空间群为O^5H-FM3M。TEM分析表明，CeO2纳米粒子呈球形，粒度分布集中，粒度随焙烧温度的增加而增大。X射线线宽法计算表明，CeO2纳米粒子越小，晶格畸变越大，晶粒发育越不完整，衍射强度越低。热失重分析表明，热失重率主要受焙烧温度的影响，焙烧时间的影响很小。红外光谱分析表明，纳米CeO2比普通CeO2具有更高的表面活性。     

LYSO∶Ce纳米粉体的溶胶-共沉淀法制备及其发光性能

采用溶胶-共沉淀法,分别以NH_3·H_2O和NH_4HCO_3为沉淀剂,制备了Lu2(1-x-y)Y2xSiO5∶yCe~(3+)(LYSO∶Ce)纳米粉体。采用XRD、SEM和荧光光谱测试手段对样品进行分析,讨论了沉淀剂、煅烧温度、Y~(3+)掺杂比例对粉体晶相的影响,分析了Ce~(3+)含量和Y~(3+)含量对样品发光性能的影响。结果表明,以NH_4HCO_3为沉淀剂,在煅烧温度为1300℃下,Ce~(3+)含量为0.01,Y~(3+)含量为0.05时LYSO∶Ce样品发光性能最好,并且样品的发光强度高于Lu_2SiO_5∶Ce样品,粉体粒度分布均匀、纯度高、分散性好,粒径在100nm~200nm范围。     

Y（P，V）O4：Eu3＋荧光粉的制备及发光特性

采用水热辅助溶胶凝胶法在较低温度下合成了Y（P,V）O4：Eu3＋荧光粉。通过综合热分析、X射线衍射（XRD）、扫描电镜（SEM）、能谱分析（EDS）和光谱分析等手段对试样进行表征．结果表明：对前驱体进行水热处理能使YPO4：Eu^3＋和YVO4：Eu^3＋更好地固溶,提高了其结晶性能和发光性能．制备的样品呈分散性好的球形颗粒,粒度分布均匀,平均粒径为1μm．对前驱体的水热处理提高了Y（P,V）O4：Eu3＋荧光粉的发光性能．     

Sol-gel preparation and characterization of Co_3O_4 nanocrystals

A new citrate acid-hydrazine sol-gel route for preparation of Co3O4 nanoparticles has been developed. Co3O4 nanoparticles with different particle-sizes and morphology were prepared at different heat-treatment temperatures and the pure cubic nanocrystals of Co3O4 were obtained at 600℃. The synthesis process was monitored by infrared spectroscopy (IR), thermal gravimetric and differential thermal analysis (TG-DTA). The structure and morphology of Co3O4 nanocrystals were characterized by X-ray powder diffraction (XRD), transmission electron microscopy (TEM) and X-ray-photoelectron spectroscopy (XPS). The infrared absorption bands blue-shifted with particle size decreasing, which could be attributed to increasing surface effect. XPS results showed that predominant species at surface layers of Co3O4 nanocrystals are octahedral Co (Ⅲ).     

反应介质对硅烷基磁性纳米粒子表面修饰磷酸胆碱后稳定性的影响

通过改变反应介质,采用原子转移自由基聚合(ATRP)法在硅烷基Fe3O4纳米粒子表面修饰2-甲基丙烯酰氧乙基磷酸胆碱(PMPC),并对复合粒子的稳定性进行观察比较。通过红外光谱、透射电子显微镜、动态光散射手段,对复合粒子进行结构、形貌和尺寸的表征。与单纯用水作反应介质相比,用乙醇和水的混合溶液作反应介质所得到的复合粒子分散性更好,稳定性也更高,为进一步研究ATRP法中单体和引发剂对复合纳米粒子的分散性和稳定性的影响打下了基础。     

Synthesis of nanocrystalline NiCrC alloy feedstock powders for thermal spraying by cryogenic ball milling

Nanocrystalline NiCrC alloy powders with a qualified particle size distribution for thermal spraying were synthesized us-ing the cryogenic ball milling (cryomilling) method.The morphology,microstructure,size distribution,and phase transformation of the powders were characterized by scanning electron microscopy (SEM),laser scattering for particle size analysis,X-ray diffraction (XRD),and transmission electron microscopy (TEM).After cryomilling for 20 h,the average grain size of the as-milled powders ap-proached a constant value of 30 nm by XRD measurement.The average particle size slightly increased from 17.5 to 20.3 μm during the 20-h milling.About 90vo1% of the powders satisfied the requirement for thermal spraying with the particle dimension of 10-50 grn,and most of the powders exhibited spherical morphology,which were expected to have good fluidity during thermal spraying.The Cr2O3 phase formed during the cryomilling process as revealed in the XRD spectra,which was expected to enhance the thermal stability of the as-milled powders during the followed thermal spraying or other heat treatment.     

聚乙烯吡咯烷酮与柠檬酸钠的加入量对葡萄糖还原法制备Cu_2O颗粒形貌的影响

利用葡萄糖与本尼迪特试剂反应制备Cu2O颗粒,以X射线衍射、扫描电镜为表征手段,研究了聚乙烯吡咯烷酮(PVP)与柠檬酸钠的加入量对Cu2O颗粒形貌的影响。结果表明,通过改变PVP量可调控Cu2O的形貌与大小,即随着PVP量的增加,Cu2O颗粒由边长约为500nm的立方体变为大小约为1μm的切角八面体再演变为大小约为2μm的八面体。研究结果还表明,在没有柠檬酸钠存在的情况下,产物是由Cu2O小纳米晶自组装而成的、大小不均的球形颗粒;柠檬酸钠的加入有助于Cu2O晶体的生长,随着柠檬酸钠加入量的增加,球形Cu2O颗粒逐渐变为大小均一的晶体。     

热物理法制备纳米ZnO晶须的研究

采用高频感应加热法制备纳米ZnO晶须,讨论了反应压力变化对纳米ZnO晶须的形态的影响.并且尝试建立反应压力与分形维数之间的函数关系式,这将对其开发具有显著的意义.实验证明这种四针状的纳米ZnO晶须的形态可用分形维数进行表征,纳米ZnO晶须的针愈长,分形维数愈大,发光性能也越好.     

Effects of hydrothermal temperatures on properties of magnetic titanate nanotubes

NiFe2O4 dopeded with magnetic titanate nanotubes(MTNT)were prepared by a hydrothermal method using magnetic nanoparticles TiO2/SiO2/NiFe2O4 as the precursor.The effects of hydrothermal temperatures on their composition,morphologies and magnetic properties of products were characterized by transmission electron microscopy(TEM),scanning electron microscopy(SEM),X-ray diffraction(XRD),vibration sample magnetometer(VSM)and energy dispersive X-ray spectroscopy(EDS).The results show that the hydrothermal temperature has a significant impact on the morphology of the products.The MTNT is synthesized in the temperature range of 120-160 ℃ and the inner diameter of MTNT is about 3-10 nm,the wall thickness 4-12nm and the length 100-200 nm.The components of MTNT are Na0.8H1.2Ti3O7 and a little of anatase TiO2 and NiFe2O4.The ferrimagnetisms and magnetic hysteresis phenomena are shown in the prepared MTNT.The hydrothermal temperature has no clear effect on the magnetic properties in the range of 120-180 ℃.The visible-light photo-catalytic activity of the products decreases as the temperature increases.The decolorization of methylene blue is 94.6% by the MTNT obtained at 120 ℃ and the recovery rate of MTNT is more than 95 percent.The MTNT has excellent photocatalytic activity and is easy to recovery.     

不同形貌氧化锌的红外发射率研究

在水热条件下,以硝酸锌、氢氧化钠、六次甲基四胺等为原料合成球形、棒状、束状和花状等不同微观形貌的ZnO粒子。采用透射电镜（TEM）、扫描电镜（SEM）和X射线衍射（XRD）等对其形貌和物相进行分析,利用IR-1红外发射率测量仪测量了不同形貌ZnO粒子在8~14μm波段的红外发射率,探讨ZnO的形貌对其红外发射率性能的影响。结果表明：各产物均为六方纤锌矿结构的ZnO,微米ZnO的红外发射率值比纳米的小,棒状、束状ZnO的发射率值比球形的要低,花状结构的ZnO的发射率值最低,为0.673。     

Preparation and characterization of nanometer-sized barium titanate powder by complex-precursor method

A new complex-precursor method was proposed to prepare nanometer-sized BaTiO3 powder. Firstly,Ti2O（O2）2（ta）24-complex ions were prepared by the reaction of H2O2,Ti^4＋ and ta^3-（ta=[C6H6O6N]^3-） with a desirable amount of surface active agent,and then the Ba2[Ti2O（O2）2（ta）2]·2H2O precursor was obtained by reaction between [Ti2O（O2）2（ta）2]^4-and Ba^2＋. Finally,the precursor was annealed at 800 ℃ for 2 h to obtain BaTiO3 powder. The morphology,the particle size distribution,the purity and the molar ratio of Ba to Ti of BaTiO3 powder were investigated systematically by TEM,XRD,IR,Raman and chemical analysis,respectively. The results show that the BaTiO3 powders with the grain size of about 40 nm have a tetragonal crystalline structure at room temperature and a spherical morphology.