Carbon Nanotubes Based Nanoelectrode Arrays: Fabrication,Evaluation, and Application in Voltammetric Analysis

Fabrication, electrochemical characterization, and applications of low‐site density carbon nanotubes based nanoelectrode arrays (CNTs‐NEAs) are reported in this work. Spin‐coating of an epoxy resin provides a new way to create the electrode passivation layer effectively reducing electrode capacitance and current leakage. Cyclic voltammetry showed the sigmoidal shape curves with low capacitive current and scan‐rate‐independent limiting current. Square‐wave voltammetry showed well‐defined peak shapes in voltammograms of K₃Fe(CN)₆ and 4‐acetamidophenol (acetaminophen) and the peak currents to be proportioned to their concentrations, demonstrating the feasibility for voltammetric analysis of the CNTs‐NEAs. The CNTs‐NEAs were also used successfully for voltammetric detection of trace concentrations of lead(II) at ppb level at first‐time. The CNTs‐NEAs provide an excellent platform for ultra sensitive electrochemical sensors for chemical and biological sensing.     

Progress on phthalocyanine-conjugated Ag and Au nanoparticles: Synthesis,characterization, and photo-physicochemical properties

Phthalocyanine (Pc) complexes are an important class of dyes with numerous (e.g., biological, photophysical, and analytical) applications. Among the methods used to improve the properties of these complexes, one should mention the introduction of different substituents, variation of the central metal ion, ligand exchange, and conjugation to nanomaterials (e.g., carbon-based nanomaterials and metal nanoparticles (NPs)). This work briefly reviews Pc complex conjugation to Ag and Au NPs, highlights the different NP shapes, and discusses the diversity of conjugation approaches. Moreover, the use of UV–Vis spectroscopy, powder X-ray diffraction, X-ray photoelectron spectroscopy, transmission electron microscopy, atomic force microscopy, dynamic light scattering and Fourier transform infrared spectroscopy to characterize Pc-NP hybrids is summarized. The effect of conjugation on Pc photo-physicochemical properties (fluorescence, singlet oxygen generation, triplet state formation, and optical limiting behavior) is discussed, and future perspectives for the synthesis and applications of new hybrids are provided.     

SMAI法制备的Cu催化剂的CO加氢催化

用溶剂化金属原子浸渍（SMAI）法制备了SiO2、Cr2O3负载Cu催化剂.XPS测定表明三种载体上的Cu几乎全部以零价态存在．X射线增宽法测定表明随着Cu含量增加Cu颗粒增大．Cu催化剂在CO加氢中的催化活性与载体、Cu颗粒大小和Cu价态有关．Cr2O3对Cu催化活性有促进效应．Cr2O3负载Cu催化剂活性随Cu颗粒减小而增大，而SiO2作载体时，颗粒大小对活性无影响，零价Cu0为催化活性中心     

PtRu纳米线的合成及其在直接甲醇燃料电池阳极中的催化活性

 分别以SBA-15和MCM-41介孔分子筛作模板剂,采用浸渍还原法制备了纵横比及合金度不同的双组元PtRu纳米线和纳米棒电催化剂. 透射电镜、 X射线衍射表征和电化学测试结果表明, PtRu纳米线具有较高的合金度和较大的纵横比,在甲醇硫酸溶液中表现出更好的电催化活性. 初步探讨了PtRu纳米线催化剂的合金度和纵横比对其电催化活性和电极性能的影响.     

Chemical environment of copper at the surface of a CuAl2 model alloy: XPS,MEIS and TEM analyses

Air‐formed oxide on a CuAl₂ model alloy is shown to be free of copper species, with copper enriching in the alloy. With thickening of the oxide by anodizing, copper enriches further to a critical concentration at which its oxidation proceeds with incorporation of Cu(II) species into the film. Such species migrate more rapidly through the film than aluminium species. Incorporation of copper species is associated with generation of oxygen gas within the film and subsequent film rupture is due to release of the gas. Reduction of Cu(II) to Cu(I) species during XPS analysis is characterized and the accelerating role of charge neutralizing is highlighted. Copyright © 2004 John Wiley & Sons, Ltd.     

纳米二氧化锆在甲醇合成催化剂Cu/Ga2O3/ZrO2中的作用

The introduction of mesoporous nanosize zirconia to the catalyst for methanol synthesis dedicates the nanosized catalyst and mesoporous duplicated properties. The catalyst bears the larger surface area, larger mesoporous volume and more uniform diameter, more surface metal atoms and oxygen vacancies than the catalyst prepared with the conventional coprecipitation method. The modification of microstructure and electronic effect could result in the change of the reduced chemical state and decrease of reducuction temperature of copper, donating the higher activity and methanol selectivity to the catalyst. The results of methanol synthesis demonstrate that the Cu^＋ is the optimum active site. Also, the interaction between the copper and zirconia shows the synergistic effect to fulfil the methanol synthesis.     

AFM电化学阳极氧化制备二氧化钛纳米线

当材料的微观尺度进入纳米量级后，由于量子效应，材料常常会显现出特殊的性能。因此近年来制备量子点、量子线，以及具有量子效应的量子器件受到深入的研究。一些新的纳米尺度加工技术如原子力显微镜(AFM)微细加工技术受到研究者的重视。     

Concentrated electrolyte solutions at high temperatures and pressures

A survey is given of recent experimental results obtained from high-temperature, high-pressure investigations with water, aqueous solutions, and ionic fluids. Data on the static dielectric constant of water to 550°C and 5 kbar are given and discussed with respect to their relation to water structure. Infrared and Raman spectra of HDO in pure water have been obtained to 400°C and 4 kbar, which give information on hydrogen bonding. Xe–H₂O and CO₂–H₂O mixtures were investigated in the infrared. Ni(II) and Cu(II) complexes were investigated by absorption spectroscopy in aqueous solutions of high chloride content to 350°C and 2–6 kbar. The gas-liquid critical point of ammonium chloride was found at 880°C and 1635 bars. This fluid appears to be predominantly ionic even in the critical region. The possibility of converting pure polar fluids such as ammonia and water into concentrated ionic solutions by self-ionization at very high pressures is mentioned.This paper was presented at the symposium, The Physical Chemistry of Aqueous Systems, held at the University of Pittsburgh, Pittsburgh, Pennsylvania, June 12–14, 1972, in honor of the 70th birthday of Professor H. S. Frank.     

STUDY OF Cu-Mu CATALYST FOR THE SYNTHESIS OF METHYL FORMATE AND METHANOL FROM SYNTHESIS GAS

将一种新型的ＣｕＭｎ催化剂用于由合成气合成甲酸甲酯和甲醇，该催化剂表现出良好的反应活性和甲酸甲酯选择性。考察了反应温度、合成气压力及催化剂制备方法等对合成甲酸甲酯和甲醇的反应活性及选择性的影响。在反应条件下，产物收率最高达６０．１０ｇ／（Ｌ·ｈ），产物甲酸甲酯的选择性很高。用ＢＥＴ、ＸＲＤ及ＸＰＳＡｕｇｅｒ等测试方法对催化剂的比表面、晶相组成以及铜、锰在催化剂中的价态进行了表征，并探讨了催化剂失活的原因。     

Kinetics of heterogeneous decomposition of hydrogen peroxide

The kinetics of the decomposition of hydrogen peroxide was studied in aqueous medium in the temperature range 25–40°C in the presence of Wofatit KPS-resin in the form of Cu(II)-ammine complex ions. The rate constant was deduced at various degrees of resin cross-linkage and different concentrations of hydrogen peroxide. The order of the decomposition reaction varied from first order to half order, i.e., the order of the reaction decreased with increasing the concentration of H₂O₂. The decomposition process was found to be a catalytic reaction which was controlled by the chemical reaction of H₂O₂ molecules with the active species inside the resin particles. The mechanism of the reaction can be summarized by the equation in which the subsequent reactions of the probable active complex are discussed.