Characterization of the Nanoscale Microstructure of an Immersion Silver on Sputtered Copper

1 INTRODUCTION Silver and its compounds have received much attention due to their current and potential applica- tions in many areas[1, 2]. As a metal with the highest electrical and thermal conductivities, silver was one of the most important noble metals used in electrical industries in the last century. Several decades ago, however, the development of silver application in electronic area seemed not so quick. The fear for some undesirable phenomena involving silver, like “electrochemi…     

LaPO4纳米微粒的制备及表征

Surface-modified LaPO4 nanoparticales were synthesized in the mixture solvent of water-ethanol with the surface modification age of dialkylphosphate. The conditions of synthesis and characterization were discussed. The results indicated that nanoparticle core of LaPO4 and surface-modified layer were formed. The surface-modified nanoparticles of LaPO4 can be dispersed in organic solvent and has better lubricating properties.     

示差脉冲伏安法测定乳酸脱氢酶活性及纳米微粒生物毒性检测新方法研究

采用示差脉冲伏安法，在乳酸脱氢酶(LDH)酶促体系“丙酮酸盐 + NADH +H⁺ (?) 乳酸盐 + NAD⁺”中，通过检测NAD⁺还原峰电流的变化，测定了不同条件下(不同酶用量、缓冲液pH值以及温度)LDH的活性、酶促体系的米氏常数K_m^NADH以及最大反应速率v_max。并且在最佳实验条件下，通过检测LDH活性的改变，实验考察了3种纳米物质(ZnS，TiO₂(R)和TiO₂(A))对乳酸脱氢酶酶促体系的影响。     

DNA-mediated coordinative assembly of upconversion hetero-nanostructures for targeted dual-modality imaging of cancer cells

We reported a simple and universal strategy for DNA-mediated assembly of CdTe quantum dots (QDs) and lanthanide-doped upconversion nanoparticles (UCNPs). Such DNA-QD/UCNPs heterostructures not only maintains both fluorescent properties of QDs and upconversion luminescence behaviors of UCNPs, but also offers a polyvalent DNA surface, allowing for targeted dual-modality imaging of cancer cells using an aptamer     

Amperometric Glucose Biosensor Based on Platinum Nanoparticles Combined Aligned Carbon Nanotubes Electrode

A sensitive amperometric glucose biosensor based on platinum nanoparticles (PtNPs) combined aligned carbon nanotubes (ACNTs) electrode was investigated. PtNPs which can enhance the electrocatalytic activity of the electrode for electrooxidating hydrogen peroxide by enzymatic reaction were electrocrystallized on 4‐aminobenzene monolayer‐grafted ACNTs electrode by potential‐step method. These PtNPs combined ACNTs' (PtNPs/ACNTs) surfaces were characterized by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The highly dispersed PtNPs on ACNTs can be obtained. The enzyme electrode exhibits excellent response performance to glucose with linear range from 1×10^?5–7×10^?3 mol L^?1 and fast response time within 5 s. Furthermore, this glucose biosensor also has good reproducibility. It is demonstrated that the PtNPs/ACNTs electrode with high electrocatalytic activity is a suitable basic electrode for preparing enzyme electrodes.     

Selenium Nanoparticles Prepared from Reverse Microemulsion Process

Selenium nanoparticles were prepared by a reverse microemulsion system. Sodium selenosulfate was used as selenium source. The results showed that hydrochloric acid concentration and reaction temperature had great influence on the morphology of products. The crystalline selenium nanowires and amorphous selenium nanorods were obtained in given condition.     

CO Oxidation on Cu/MgO-SiO2 Sol-Gel Derived Catalysts

Sol-gel Cu//MgOSiO₂ catalysts were prepared gelling tetraethoxysilane (TEOS), magnesium ethoxide and copper acetylacetonate at pH 3 and pH 9. The catalysts shown specific surface areas ca. 500 m²/g and 140 m²/g for pH 9 and pH 3 preparations respectively. Si(OH) and Si(OH)₂ hydroxy groups were observed by MAS-RMN spectroscopy in both preparations. CO₂-TPD and NH₃-TPD desorption thermograms showed that acid and basic sites were formed on the catalysts surface. It has been found that the catalysts having the highest density of basic sites were the catalysts showing the highest activity for the CO oxidation. It is proposed that the catalytic activity depends of the relative Cu⁼¹/Cu⁼² stability given by the support acidity.     

The use of imidazolium ionic liquids for the formation and stabilization of ir0 and rh0 nanoparticles: efficient catalysts for the hydrogenation of arenes

Stable transition-metal nanoparticles of the type [M(0)](n) are easily accessible through the reduction of Ir(I) or Rh(III) compounds dissolved in "dry" 1-n-butyl-3-methylimidazolium hexafluorophosphate ionic liquid by molecular hydrogen. The formation of these [M(0)](n) nanoparticles is straightforward; they are prepared in dry ionic liquid whereas the presence of the water causes the partial decomposition of ionic liquid with the formation of phosphates, HF and transition-metal fluorides. Transmission electron microscopy (TEM) observations and X-ray diffraction analysis (XRD) show the formation of [Ir(0)](n) and [Rh(0)](n) nanoparticles with 2.0-2.5 nm in diameter. The isolated [M(0)](n) nanoparticles can be redispersed in the ionic liquid, in acetone or used in solventless conditions for the liquid-liquid biphasic, homogeneous or heterogeneous hydrogenation of arenes under mild reaction conditions (75 degrees C and 4 atm). The recovered iridium nanoparticles can be reused several times without any significant loss in catalytic activity. Unprecedented total turnover numbers (TTO) of 3509 in 32 h, for arene hydrogenation by nanoparticles catalysts, have been achieved in the reduction of benzene by the [Ir(0)](n) in solventless conditions. Contrarily, the recovered Rh(0) nanoparticles show significant agglomeration into large particles with a loss of catalytic activity. The hydrogenation of arenes containing functional groups, such as anisole, by the [Ir(0)](n) nanoparticles occurs with concomitant hydrogenolysis of the C-O bond, suggesting that these nanoparticles behave as "heterogeneous catalysts" rather than "homogeneous catalysts".     

Metallic Particles from Complexing Microcapsules Dispersed in a Silica Gel

A new process to control the distribution of metal nanoparticles is proposed. It involves the use of complexing microcapsules obtained by interfacial polycondensation. The latter are hollow spheres constituted of a polymer membrane, containing an insoluble active ingredient, such as a polyacrylic acid, which can complex Co²⁺ ions. These capsules are dispersed in a silica sol followed by thermal treatments and reduction under H₂ which results in metallic Co nanoparticles confined in the capsules domains. The particles do not diffuse in the matrix.     

Photocatalytic degradation of methylene blue on Fe3+-doped TiO2 nanoparticles under visible light irradiation

Fe³⁺-doped TiO₂ composite nanoparticles with different doping amounts were successfully synthesized using sol-gel method and characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM) and ultravioletvisible spectroscopy (UV-Vis) diffuse reflectance spectra (DRS). The photocatalytic degradation of methylene blue was used as a model reaction to evaluate the photocatalytic activity of Fe³⁺/TiO₂ nanoparticles under visible light irradiation. The influence of doping amount of Fe³⁺ (ω: 0.00%–3.00%) on photocatalytic activities of TiO₂ was investigated. Results show that the size of Fe³⁺/TiO₂ particles decreases with the increase of the amount of Fe³⁺ and their absorption spectra are broaden and absorption intensities are also increased. Doping Fe³⁺ can control the conversion of TiO₂ from anatase to rutile. The doping amount of Fe³⁺ remarkably affects the activity of the catalyst, and the optimum efficiency occurs at about the doping amount of 0.3%. The appropriate doping of Fe³⁺ can markedly increase the catalytic activity of TiO₂ under visible light irradiation. __________ Translated from Journal of Northwest Normal University (Natural Science), 2006, 42(6): 55–56 [译自: 西北师范大学学报(自然科学版)]