Investigation of the electrocatalytic behavior of single-wall carbon nanotube films on an Au electrode

The voltammetric behavior of uric acid (UA) was studied with an Au electrode modified with single-wall carbon nanotubes (SWNTs). In 0.1 M HAc-NaAc buffer solution (pH 5.0), the SWNT-modified electrode shows high electrocatalytic activity toward UA oxidation. The electro-oxidation of UA is an irreversible diffusion-controlled process with a diffusion coefficient (D) of 8.85×10⁻⁶ cm² s⁻¹. The peak current increases linearly with the concentration of UA in the range of 4.0×10⁻⁶-7.0×10⁻⁴ M. The detection limit is 1.0×10⁻⁶ M. The SWNT was characterized with scanning electron microscopy (SEM). Furthermore, the SWNT-modified electrode has favorable electrocatalytic activity toward dopamine and norepinephrine. This SWNT-modified electrode can also separate the electrochemical responses of uric acid, norepinephrine and ascorbic acid.     

富勒烯及其衍生物的质谱研究

本文制备了一系列富勒烯及其衍生物，并利用多种质谱技术进行了鉴定、表征、揭示了它们在离子源条件下的稳定性及解规律。这些富勒烯及其省生物在ＦＤＭＳ、ＩＳＭＳ中均得到了较强的准分子离子峰且碎片峰很少。结果表昨ＦＤＭＳ，ＬＳＩＭＳ技术均适于富勒烯及其衍生物的定性分析，是目前富勒烯分析鉴定中较好的方法。     

提高大分子Fullerene含量的有效方法

通过用掺有异相物质的石墨电极进行电弧反应，所得的混合物中大分子Ｆｕｌｌｅｒｅｎｅ的含量在１０％以上，为进一步分离，提纯以及深入研究大分子Ｆｕｌｌｅｒｅｎｅ打下了基础。研究发现，阳极材料中完整石墨结构的存在是生成Ｆｕｌｌｅｒｅｎｅ的必要条件，异相物质的存在为Ｆｕｌｌｅｒｅｎｅ的生长提供了热的载体，从而使产物中大分子Ｆｕｌｌｅｒｅｎｅ的含量增加。     

纳米管束的合成及结构

用电弧法制备出纳米管及纳米管束，并用高分辨电镜观察其结构．观察到的纳米管管子中空，管壁平行，间距0．34nm，端部封闭；还观察到单层纳米管，洋葱球以及内包晶核的洋葱球结构，纳米管束微结构为纳米管．用扫描电镜观察，为明显的针状晶须，定向排列，晶须互相平行，平行于电场方向生长，晶须直径0．2～0．6mm，长度3～8mm．生成纳米管束的原因可能是由于掺杂碳棒中的杂质提供了晶须生长的晶核．     

Unraveling the Impact of Gold(I)–Thiolate Motifs on the Aggregation‐Induced Emission of Gold Nanoclusters

Aggregation‐induced emission (AIE) provides an efficient strategy to synthesize highly luminescent metal nanoclusters (NCs), however, rational control of emission energy and intensity of metal NCs is still challenging. This communication reveals the impact of surface Au^I‐thiolate motifs on the AIE properties of Au NCs, by employing a series of water‐soluble glutathione (GSH)‐coordinated Au complexes and NCs as a model ([Au₁₀SR₁₀], [Au₁₅SR₁₃], [Au₁₈SR₁₄], and [Au₂₅SR₁₈]^?, SR=thiolate ligand). Spectroscopic investigations show that the emission wavelength of Au NCs is adjustable from visible to the near‐infrared II (NIR‐II) region by controlling the length of the Au^I‐SR motifs on the NC surface. Decreasing the length of Au^I‐SR motifs also changes the origin of cluster luminescence from AIE‐type phosphorescence to Au⁰‐core‐dictated fluorescence. This effect becomes more prominent when the degree of aggregation of Au NCs increases in solution.     

含中心裂纹梯度纳晶金属的数值模拟

梯度纳晶金属由于其微观组织的梯度分布,力学属性也呈现梯度变化,这使得其表现出不同于传统均匀材料的断裂行为．利用材料力学参数的梯度分布来表征梯度纳晶金属中晶粒尺寸的梯度变化,并编写ABAQUS和MATLAB脚本程序建立分层有限元模型．通过数值模拟计算了含有初始中心裂纹的梯度纳晶金属在受远端均匀拉应力作用下的裂尖J积分,分别研究了屈服应力梯度、裂纹角度和裂纹长度对金属材料断裂韧性的影响,并与传统粗晶进行了对比．结果表明梯度纳米结构的存在导致梯度纳晶金属内部的中心裂纹两端表现出不同的断裂韧性,小晶粒一侧裂尖的抗裂韧性优于大晶粒一侧裂尖,且屈服应力梯度绝对值越大,两者差距越大．梯度纳晶金属的断裂韧性受中心裂纹角度和长度变化的影响与传统粗晶金属基本一致,同时在晶粒尺寸梯度的作用下梯度纳晶的裂尖J积分略低于粗晶,即整体上拥有更好的抗裂韧性．     

某些生物分子在C60—γ—环糊精／Nafion化学修饰电极上的电催化行为

研究了Ｃ６０－γ－环糊精（Ｃ６０－γ－ＣＤ）（１：１）／Ｎａｆｉｏｎ和Ｃ６０－γ－ＣＤ（１： ２）／Ｎａｆｉｏｎ化学修饰电极在水溶液中的电化学行为，发现它们都有一对一电子转移的可逆表面波，而且它们对某些生物分子有电催化作用。     

Direct imaging of the alkali metal site in K-doped fullerene peapods

The structure of K-doped fullerene peapods has been investigated by means of high-resolution transmission electron microscopy and electron energy-loss spectroscopy (EELS). It is proven that the potassium atoms can be doped at the intermolecular sites within C60 peapods. The EELS spectrum of potassium (K) L edge clearly exhibits the feature of K+ in the doped peapod and consequently suggests n-type doping. These results encourage the realization of a one-dimensional superconducting wire based on the nanotube peapods.     

Adsorption and manipulation of carbon onions on highly oriented pyrolytic graphite studied with atomic force microscopy

Carbon onions produced by DC arc discharge method were deposited on highly oriented pyrolytic graphite (HOPG) surface and their adsorption and manipulation was studied using an atomic force microscopy (AFM). Well-dispersed adsorption of carbon onions on HOPG surface was obtained and aggregations of onions were not observed. The van der Waals interaction between the onion and HOPG surface and that between two onions, were calculated and discussed using Hamaker's theory. The manipulation of adsorbed onions on HOPG surface was realized using the AFM in both the raster mode and the vector mode. The controllability and precision of two manipulation modes were compared and the vector mode manipulation was found superior, and is a useful technique for the construction of nano-scale devices based on carbon onions.     

Electrochemical survey: the effect of the cage size and structure on the electronic structures of a series of ytterbium metallofullerenes

The electrochemical properties of a series of metallofullerenes with different cages, namely, Yb@C74(II), Yb@C76(I, II), Yb@C78, Yb@C80, Yb@C82(I, II, III), and Yb@C84(II, III, IV), have been systematically investigated by cyclic and differential pulse voltammetry experiments for the first time. This article discusses the electronic structures of these metallofullerenes based on the results from these experiments. From previous electrochemical work and the above discussion, it is concluded that the nondegenerate LUMO is a common characteristic of the electronic structures of the higher fullerenes and monometallofullerenes. In addition, the effect of the cage on the electronic structure and properties of the metallofullerene is estimated from the plot of the reduction potential versus the carbon number of the metallofullerene. This estimation shows that usually the electronic structure and properties of the metallofullerene vary with cage size and structure. The cage structure is of particular importance for determining the electronic structure and properties. Moreover, an explanation concerning the abundance and stability of C82-based trivalent monometallofullerenes is given from an electronic structural standpoint.