在可溶性聚合物体系中光化学法制备Pd纳米粒子的研究

研究了在可溶性聚合物体系中Pd纳米粒子的光化学合成.Pd(Ⅱ)-PEG-丙酮溶液以紫外波长300nm光辐照,获得了胶体Pd纳米粒子并对其进行TEM表征.结果表明,Pd粒子的平均粒径为1.8～5.7nm,具有好的分散性.研究了各种组分的影响,探讨了体系中Pd(Ⅱ)的快速光化学还原和纳米Pd粒子的稳定性机理.     

乙二醇水热还原法制备纳米银

利用乙二醇在高温下的还原特性,在水热条件下制备了纳米银粒子,并通过透射电镜、X射线衍射、紫外吸收光谱对其结构进行了表征.研究结果表明:所制备的纳米银具有面心立方相的多晶结构,平均粒径在30nm左右,紫外吸收峰的位置在380 nm左右.分散剂和体系中含水量对纳米银的粒径有一定影响.     

ZnO nanoneedles fabricated by a simple approach and their optical properties

Spoke-like ZnO nanoneedles have been successfully synthesized at the ambient pressure through thermally oxidizing Zn powders containing Au nanoparticles. X-ray diffraction analysis indicates that the ZnO nanoneedles have a hexagonal wurtzite structure of the crystalline ZnO. The morphology of the products was examined by FESEM. The photoluminescenee(PL) spectrum under 325 nm exhibits both an UV emission and a green emission. It is interesting to note that the heating rate plays a key role in the synthesis of ZnO nanoneedles. Based on this discovery we propose to explain the special growth behavior as novel mechanism that a large temperature gradient and Au nanoparticles simultaneously result in the spoke-like ZnO nanoneedles growth.     

纳米CeO2单晶的制备与热处理对粒径的影响

以Ce(NO3)3·6H2O为铈源、NH3·H2O为沉淀剂,用化学沉淀法通过对陈化时间的控制,制备了单分散的单晶纳米CeO2粒子,并用XRD、TEM、ED、BET、TG-DTA等测试手段对产物的物相结构、形貌和纳米尺度进行了表征.XRD分析表明,制得的纳米CeO2粒子为萤石结构且晶型比较完整. 通过控制热处理的温度和陈化时间可以控制粒子的大小.TEM和ED分析表明产物颗粒基本为球形,分散性较好且为单晶. 通过TG-DTA结果可以断定所制备的前驱体结构式为CeO2·1/2H2O.     

ZnO／Ag纳米复合材料光催化性能研究

通过XRD、TEM测试研究了自制ZnO／Ag纳米复合材料的结构和形貌，通过UV检测确定了以该纳米复合材料为光催化剂，在不同条件下对甲基橙的光催化降解率。结果表明：与空气煅烧相比，真空煅烧所得纳米复合材料的光催化降解效果更好，且光催化降解率随纳米复合材料用量增加而增大：甲基橙溶液的pH在5左右时，光催化降解率最高：H2O2浓度为0．9g／L时，光催化降解率可达100％。     

Synthesis and characterization of La0.8Sr0.2MO3−δ (M=Mn, Fe, or Co) cathode materials by induction plasma technology

In this work, nanopowders of perovskite cathode materials (La_0.8Sr_0.2MnO_3−δ, La_0.8Sr_0.2FeO_3−δ, and La_0.8Sr_0.2CoO_3−δ), for use in solid oxide fuel cells (SOFC), were successfully synthesized, using induction plasma techniques. Their compositions, structures, morphology, particle size distributions, and BET specific surface areas were determined for comparison with their counterparts prepared by the Pechini method and by the glycine-nitrate combustion (GNC) technique. The particle sizes of the plasma-synthesized powders are mostly around 63 nm. These plasma-synthesized powders are generally globular, their BET specific surface areas being about 26 m²g⁻¹, approximately twice those of powders prepared by the GNC and Pechini methods. These plasma-synthesized powders are readily reproducible and are not agglomerated. Their individual particle sizes and distributions are very independent of their composition.     

超声和微波作用下制备纳米氧化铜

以氢氧化铜为前驱体，在超声和微波作用下制备纳米氧化铜。借助透射电镜（TEM）、X射线衍射（XRD）、粒度分析等手段，研究了超声、分散剂、微波等制备条件的影响。结果表明：采用该法可以制备粒径小（15nm）、分散良好的纳米氧化铜粉体；超声可使前驱体Cu（OH）2转变为CuO，并粉碎颗粒间形成的团聚；分散剂通过表面修饰抑制颗粒的团聚；微波加热促进了前驱体的转化，并抑制颗粒的长大。     

Preparation of flee-standing diamond films for high frequency SAW devices

Free-standing diamond films were prepared by hot filament chemical vapor deposition （HFCVD） method under different conditions. Inter-digital transducers （IDTs） were formed on the nucleation sides of free-standing diamond films by photolithography technique. Then piezoelectric ZnO films were deposited by radio-frequency（RF） reactive magnetron sputtering to obtain the ZnO/diamond film structures. Surface morphologies of the nucleation sides and the IDTs were characterized by means of scanning electron microscopy （SEM）, atomic force microscope （AFM） and optical microscopy. The results indicate that the surfaces of nucleation sides are very smooth and the IDTs are of high quality without discontinuity and short circuit phenomenon. Raman spectra show the sharp diamond feature peak at about 1 334 cmI and the small amount of non-diamond carbon in the nucleation side. X-ray diffraction （XRD） patterns of the structure of ZnO/diamond films show a strong diffraction peak of ZnO （002）, which indicates that as-sputtered ZnO films are highly c-axis oriented.     

工艺参数对合成ZnO／Ag纳米复合抗菌剂产率的影响

通过正交实验，研究了反应温度、反应时间、反应物配比对ZnO／Ag纳米复合抗菌剂合成产率的影响规律。获得了高产率合成ZnO／Ag纳米复合抗菌剂的优选工艺条件：反应温度为10～25℃，ZnSO4与NH4HCO3的摩尔比为1：2-2．5，ZnSO4与NH4HCO3的反应时间为2．5～3h，AgNO3与NH4HCO3的摩尔比为1：1．5～2，反应时间为0．5h，ZnO／Ag的产率超过98％。XRD、TEM和SAED结果表明：ZnO／Ag纳米复合抗菌剂为具有纤锌矿结构的ZnO和立方结构的Ag组成。粒径为15～25nm，分散性较好。     

基于纳米金颗粒放大的电化学传感器用于三聚氰胺的检测

三聚氰胺与胸腺嘧啶（T）之间能够通过三个氢键结合,以富T的DNA探针为识别元件,结合DNA修饰的纳米金颗粒放大技术,以电活性物质钌胺作为信号分子,发展了一种高灵敏检测三聚氰胺的电化学传感器,该传感器具有良好的特异性和灵敏度,检测下限低至0．5nmol／L。