反相微乳液法制备纳米Al2O3颗粒及其形成反应机理的研究

通过聚乙二醇辛基苯基醚(曲拉通X-100)/正丁醇/环己烷/水溶液形成的体系, 采用反相微乳液法合成了Al₂O₃纳米粒子. 对前驱体进行热分析(TG-DTG-DTA), 确定了合适的煅烧温度为1150 ℃. 采用X射线衍射(XRD)、透射电镜(TEM)、紫外可见分光光度法(UV-vis)分别对产物的结构、粒度和形貌进行了表征, 考察了微乳液中水与表面活性剂的物质的量之比(ω_o)、煅烧温度和煅烧时升温速率等关键因素对产物形貌和晶相的影响, 并通过分析进一步揭示了Al₂O₃纳米粒子的形成机理. 结果表明, 控制ω_o为10、煅烧温度为1150 ℃可得到分散性好、粒径分布均匀的Al₂O₃纳米粒子, 且2 ℃/min的升温速率更有利于产物向稳定的α晶相转变.     

载体对Au-Pd双金属催化剂加氢脱硫性能的影响

研究了Al_2O_3,TiO_2-Al_2O_3等载体对Au-Pd双金属催化剂的噻吩加氢脱硫性能的影响,并运用XRD,TPD,BET,TPR等手段对Au-Pd双金属催化剂进行了表征.结果表明,Au-Pd/TiO_2-Al_2O_3催化剂有较好的噻吩加氢脱硫反应活性和稳定性,与Au-Pd/Al_2O_3催化剂相比,Au-Pd/TiO_2-Al_2O_3催化剂有较高的酸密度和酸强度、活性表面积、H_2及CO的吸附量.     

四苯硼钠-甲苯胺蓝缔合物纳米微粒体系减色效应研究

在PH4.0醋酸-醋酸钠介质中，甲苯胺蓝在600nm处有一个吸收峰，随着四苯硼钠浓度的增大甲苯胺蓝在600nm处吸收峰降低，颜色减弱，这是由于甲苯胺蓝-四苯硼钠缔合物分子间存在较强的疏水作用及分子间作用力，聚集形成纳米微粒所致，甲苯胺蓝-四苯硼钠纳米微粒体系亦在600mm处有1个吸收峰，在400mm、470mm和580mm处产生3共振散射峰，其中400mm和580mm为甲苯胺蓝-四苯硼钠复合纳米微粒产生的特征共振散射峰，这也表明有纳米微粒存在，丙酮浓度的影响实验结果等表明，纳米微粒的形成是产生其减色效应的原因。     

Target-triggered inhibiting oxidase-mimicking activity of platinum nanoparticles for ultrasensitive colorimetric detection of silver ion

The development of efficient methods for the detection of hazardous and toxic elements is extremely important for environmental security and public health. In this work, we developed a facile colorimetric assaying system for Ag⁺ detection in aqueous solution. Chitosan-stabilized platinum nanoparticles (Ch-PtNPs) were synthesized and severed as an artificial oxidase to catalyze the oxidation of the substrate 3,3′,5,5′-tetramethylbenzidine (TMB) and generate color signal. In the presence of Ag⁺, due to the strong metallophilic interactions between Ag⁺ and Pt²⁺ on the surface of Ch-PtNPs, Ag⁺ can weaken the affinity to the substrates and inactivate the catalytic activity of Ch-PtNPs, leading to decreased absorbance signal to varying degrees depending on Ag⁺ amount. Combing the specific binding between Ch-PtNPs and Ag⁺ with signal amplification procedure based on the Ch-PtNPs-catalyzed TMB oxidation, a sensitive, selective, simple, cost-effective, and rapid detection method for Ag⁺ can be realized. Ag⁺ ions in tap and lake waters have been successfully detected. We ensured that the proposed method can be a potential alternative for Ag⁺ determination in environmental samples.     

Gold nanoparticle-enhanced surface plasmon resonance measurement with a highly sensitive quantification for human tissue inhibitor of metalloproteinases-2

Two different methods for the quantification of human tissue inhibitor of metalloproteinases-2 (TIMP-2) were developed using surface plasmon resonance (SPR) and gold nanoparticles for signal enhancement. The first method, a competitive assay, used TIMP-2 immobilized to the sensor surface and the inactive form of matrix metalloproteinase-2 (proMMP-2) (EC 3.4.24.24) adsorbed to gold nanoparticles. The sensor signals resulting from the interaction of MMP-2-gold nanoparticles with immobilized TIMP-2 were inversely proportional to the amounts of TIMP-2 of the sample. The measuring range for TIMP-2 was about 15–180 pM. The second method, a one-step sandwich assay, used proMMP-2 immobilized to the sensor surface and an anti-TIMP-2 monoclonal antibody coupled to gold nanoparticles. The lower detection limit of this assay format was 0.5 pM of TIMP-2. The binding signals were highly reproducible up to 100 pM of the inhibitor. The improvements obtained in TIMP-2 quantification over already existing tests could contribute to a better understanding and diagnosis of diseases like cancer.     

Ab initio and DFT studies on tautomerism of indazole in gaseous and aqueous phases

Electronic structure of optimized Ge₅, Ge₁₇, Ge₅–O and Ge₅ embedded in SiO₂ nanoparticles have been studied by density functional theory to find out the effect of cluster size and Ge–O bond(s) on the optical energy gap between LUMO and HOMO. It was found that the optical energy gap depends on both cluster size and the number of Ge–O bonds nonlinearly. The optical energy gap was found to be in visible light range when the Ge₅ nanoparticle has been embedded in SiO₂ matrix.     

油溶性金属Ni纳米微粒的制备与表征

纳米材料的制备、性能与应用已成为近年来的研究热点之一犤１犦。由于在催化、光学和电学材料中的广泛应用，超细单分散的金属微粒的制备与性质已引起人们的广泛兴趣。通常制备金属纳米微粒的方法有两种：一是把固体金属材料分裂为纳米尺寸的颗粒，如机械粉碎、电弧放电及金属原子蒸气沉积犤２犦，用这种方法制备的金属微粒粒径一般都比较大，且粒子尺寸分布宽，另一种是把金属原子制成纳米尺度的颗粒，如乳液聚合法犤３犦、热解犤４犦、γ－射线辐照犤５犦、脉冲电沉积犤６犦和化学还原犤７犦等，这种方法制备的微粒粒径通常分布窄且粒子小…     

铂-金交替修饰的铂核纳米颗粒的制备与表征

通过吸附在铂纳米颗粒表面的氢交替还原氯金酸和氯铂酸,得到了复合型纳米颗粒Pt@Au/Pt,用UV-Vis光谱、TEM和XRD对其进行了表征.     

In Situ Processing of Nano Crystalline Oxide Particles/Polymer Hybrid

Nano sized crystalline particles/polymer hybrids were synthesized form designed metal-organic precursors. The newly developed method is composed of the synthesis of organic matrix by polymerization and the in situ nucleation and growth of crystalline oxide particles in the organic matrix below 100°C. The design of metal-organic precursor modified with polymerizable ligand and the selection of reaction conditions does influence the size and crystallinity of ceramic particles in organic matrix. The nano-sized magnetic particle/polymer hybrid exhibits the interesting feature of superparamagnetism and quantum size effect. The crystalline particles of BaTiO₃/, PbTiO₃/, and KNbO₃/polymer hybrids behave to be dielectric and show the typical electro-rheological behavior.     

Pt3Co核-Pt壳型纳米粒子的制备及磁性

Pt₃Co alloy nanoparticles were prepared by the reduction of H₂PtCl₆ and Co(OOCCH₃)₂ using NaBH₄ as a reducing agent. The Pt₃Co core-Pt shell nanoparticles (Pt₃Co@Pt) were synthesized using hydrogen absorption reduction and characterized by plasma-atomic emission spectrometry (ICP), transmission electron microscopy (TEM), X-ray diffraction (XRD) and SQUID magnetometer. The results show that average size of Pt₃Co@Pt nanoparticles is 3.6 nm with a standard deviation of 0.9 nm. Heating Pt₃Co nanoparticles in air at 700 ℃ for 1 h, Co in Pt₃Co nanoparticles was oxidized to Co₃O₄ and CoO; while no oxidation tendency was detected for Pt₃Co@Pt nanoparticles. The crystallize structure of Pt₃Co@Pt changed from the face centered cube (fcc) to the face centered tetragonal (fct) after the heating treatment. The coercivity of the heated Pt₃Co@Pt reached to 276 Oe at room temperature.