Template Synthesis and UV-Vis Absorption Spectra of the Nanowire Arrays of Cadmium Chalcogenides

以多孔氧化铝为模板 ,用交流电分别通过含有相应的CdCl2 、ZnCl2 、单质S、Se等的二甲亚砜 (DMSO)溶液 ,沉积CdS、CdSe以及CdxZn1-xS半导体纳米线阵列并研究其紫外可见吸收光谱 .实验结果表明 ,当半导体纳米线的直径小于 2 5nm时 ,其吸收边相对于体相的吸收边产生蓝移 ,而且蓝移的幅度随着半导体纳米线直径的减小而增加 ,显示了明显的量子限域效应 .XU Shi_min, XUE Kuan_hong , KONG Jing_lin, SUN Dong_mei, FENG Yu_ying, LU Hai_yan (Dept. of Chem., Nanjing Normal Univ., Nanjing 210097, China) WANG Guang_hou (National Laboratory of Solid State Microstructures, Nanjing Univ., Nanjing 210093, China)The porous alumina membrane formed in the anodic oxidation of highly pure aluminum foil has attracted a great deal of attention in recent years [1] . It can be served as a desired template to prepare nanometer scale materials [2] due to its unique structure of discrete and cylindrical nanopores, paralleled one another, with the homogeneous size and distribution [3] . Chalcogenide semiconductors have promising prospect in the applications of photovoltaic [4] and photoconducting devices [5] and have been extensively exploited for many years. Olbright and his co_workers studied experimentally and theoretically the optical nonlinearties of CdS xSe 1-x _doped glass [6] ; Britt and Ferekides reported that the conversion efficiency in a solar cell of thin_film CdS/CdTe could be as high as 15.8% [7] . Here we report the fabrication and UV_Vis absorption spectra of CdS、CdSe and Cd xZn 1-x S nanowire arrays deposited into the template matrix of porous alumina. The diameters of these nanowires were varied from 10 nm to 50 nm in our experiments.作者联系地址：南京师范大学化学系!江苏南京210097,南京师范大学化学系!江苏南京210097,南京师范大学化学系!江苏南京210097,南京师范大学化学系!江苏南京210097,南京师范大学化学系!江苏南京210097,南京师范大学化学系!江苏南京210097,南京大学固体微结构国家重点实验室!江苏南京21009

Raman and AFM Characterization of Au and Cu Nanorod and Nanowire Arrays

通过电化学氧化法制备具有不同孔径氧化铝模板 ,利用交流电镀的方法在模板中沉积金属 ,再用酸溶解模板可以得到相应尺度的金属纳米线或纳米棒的阵列 .本文利用原子力显微镜和表面增强拉曼技术分别表征了金和铜两种金属纳米线阵列 .研究结果表明 ,作为探针分子的硫氰(SCN )在金属纳米线上的碳氮三键的振动频率随纳米线直径的增大而蓝移 .这一现象可能是因为尺寸效应对纳米线的费米能级造成影响 ,使不同直径的金属纳米线电子结构存在微小的差别 .Recently metal nanowires (nanorods) have aroused tremendous interest because of their novel properties and potential applications in wide fields [1] . Many two?dimensional nanowire arrays of semiconductors and metals with different diameter and length have been made by using template synthesis method. To characterize the novel optical, electronic and magnetic properties of these materials, UV?Vis and fluorescence spectroscopies are two of the most wildly used methods [2, 3] . Raman spectroscopy has, however, only been applied to the characterizing of semiconductor nanowires and carbon nanotubes [4,5] . Important and meaningful information can be obtained in these cases, as some forbidden Raman modes in the bulk materials become Raman active [4, 5] . Raman spectroscopy is apparently not suitable to study metal nanowires since it can only detect the mechanical vibration bands located in the extremely low frequency region. Consequently, an alternative way has to be established to study the metal nano?wires (?rods) with Raman spectroscopy. In the present work, we have taken the probe molecule strategy and used surface?enhanced Raman spectroscopy (SERS) to characterize metal nanorods (nanowires). It is well known that for a molecule which interacts strongly with a surface, its vibrational band frequency and shape are very sensitive to the electronic property, the chemical environment and the morphology of the surface. Hence Raman spectroscopy has long been used to analyze the atomic structures and the electronic properties of the surface indirectly through assessing carefully the spectral changes of the adsorbate known as a probe molecule. On that account, it is of great interest to diagnose the electronic structures of the metal nanorods with the vibrational spectrum of a probe molecule. We have examined the changes in the electronic properties of the nanorods through analyzing the spectral changes of the probe molecule. For this purpose a typical SERS molecule of SCN - was employed. The nanorod arrays of Au and Cu with different diameter from about 15 nm to 130 nm were fabricated electrochemically by means of the anodic aluminum oxide (AAO) templates. To partially expose metal nanowires with various lengths, the AAO template was chemically etched off to a certain extent by an aqueous solution of phosphoric acid or sodium hydroxide as shown in Fig. 1. After the template was etched off, the nanowires can be characterized by TEM, see Fig. 2. The tapping mode AFM image was obtained on a scanning probe microscope (Nanoscope IIIa). SERS measurements were performed on a confocal microprobe Raman system (LabRam I).作者联系地址：厦门大学固体表面物理化学国家重点实验室!化学系福建厦门361005,厦门大学固体表面物理化学国家重点实验室!化学系福建厦门361005,南京师范大学化学系!江苏南京,210097,厦门大学固体表面物理化学国家重点实验室!化学系福建厦门361005,厦门大学固体表面物理化学国家重点实验室!Author's Address: State Key Lab.for Phys.Chem.of Solid Surf.,Xiamen Univ.,Xiamen 361005, China; 1 Dept. of Chem., Nanjing Norm

Studies on the Transport Properties of Zn~2+ in the Zn/V_2O_5 Secondary Battery with Aqueous Medium

利用间歇性恒电流测定法和ＸＲａｙ衍射法，研究水相介质的Ｚｎ／Ｖ２Ｏ５二次电池中的锌离子在正极材料中的迁移性能及其放电机理；讨论锌离子在正极材料中发生迁移时的某些动力学参数与放电深度的关系．实验结果表明，该电池的正极放电反应为锌离子在ＺｎｘＶ２Ｏ５中的嵌入过程．The transport properties and the reaction mechanism of Zn~2+ in the cathode material of Zn/V_2O_5 secondary battery with aqueous medium were studied by use of intermittent titration experiments and X-Ray diffraction analysis. The relations of some kinetic parameters to the discharge depth were discussed. The results of the experiments show that the cathodic discharge reaction is an intercalation process.作者联系地址：南京师范大学化学系Author's Address: Dept. of Chem., Nanjing Normal University, Nanjing 21009

Cyclic Voltammetry and in-situ FTIR Spectroscopic Studies on Electro-oxidation of Formaldehyde at a Gold Electrode

The electro-oxidation of Formaldehyde on a gold electrode in a gold electrode in a solution containing0.1mol ·L -1 Na2 CO3＋0.1mol·L - 1NaHCO3＋0.1 mol·L, - 1 HCHO was investigated bycyclic voltammetry and in -situ FTIR spetroscopy .The experimental results demonstrated that the oxidation of Formaldehyde at diFFerent potential range connected with diFFerent surFace species of gold.At lower potentials, the main product of Formaldehyde oxidationwas HCOO-, and at higher potentials, the products HCOO- and CO2 were detected simultaneously.From the results, a possible reaction mechanism was proposed.厦门大学固体表面物理化学国家重点实验室对本课题的部分资

Electrocatalytic Oxidation of Methanol on Polythionine Film ModiFied with Pt Microparticles

利用电化学循环伏安和现场fTIr反射光谱等技术研究了甲醇在铂微粒修饰的聚硫堇电极上的电催化氧化.结果表明，循环伏安法制备的铂微粒均匀分散于聚合物膜上，其粒径大小约为30-130uM；复合修饰电极对甲醇电化学氧化呈现了较高的假化活性，其催化活性的大小依赖于PT载量现场fTIr光谱实验揭示了线性吸附的CO物种是甲醇在复合电极上氧化的唯一中间体，这种吸附的CO物种在复合修饰电极上更容易被氧化为最终产物CO2，增强的电催化活性可归属于PT微粒在聚合物膜中的高度分散和金属微粒与聚合物的协同效应.依据实验结果，提出了甲醇在复合电极上电化学氧化可能的反应机理.The electrocatalytic oxidation of methanol on polythionine(PTn) Film modiFied with Pt ndcroparticles has been studied by means of cyclic voltammetry and in-situ FTIR spectroscopy The Pt microparticles produced by cyclic voltammetry were highly dispersed in and on the PTn Film.The modiFied electrodes exhibit signiFicant electrocatalytic artivity For the oxidation of methanol and the catalytic activity was Found in dependence on the Pt loading.The linearly adsorbed CO species is the only intermediate in the okidation of methanol and the abnormal IR spectra For adsorbed CO were observed.On such modiFied electrodes, adsorbed CO species derived From methanol can be readily oxidized.The enhanced electrocatalytic activity may be ascribed to the high dispersion of Pt microparticles in and on the PTn Film and the synergestic eFFect between Pt microparticles and the polymer.Frtom the above results, a possible reaction mechanism was proposed.国家自然科学基金;厦门大学固体表面物理化学国家重点实验室基

镍纳米线电极的电化学氧化还原行为及其对乙醇的电化学氧化催化作用

以铝在磷酸介质中形成的多孔氧化铝膜为模板 ,采用交流电沉积结合化学镀的方法制得镍纳米线电极 .用原子力显微镜和透射电子显微镜表征了电极形貌 .循环伏安实验表明 ,在碱性溶液中镍纳米线电极较之本体电极具有高得多的氧化还原峰电流密度和还原电量 ,而且前者对乙醇的电化学氧化具有高的催化活性 ,显示镍纳米线电极具有应用于镍的二次电池和有关有机电合成的良好前景

铜纳米线阵列的表面增强拉曼光谱和AFM研究

通过以有序的多孔氧化铝为模板，利用交流电在孔中沉积金属铜，并以此作为ＳＥＲＳ活性基底。原子力显微镜（ＡＦＭ）研究了氧化铝溶解过程中铜纳米线形貌，共焦显微拉曼则研究表面吸附ＳＣＮ的ＳＥＲＳ光谱的变化。结果表明：铜纳米线表面ＳＥＲＳ强度和纳米金属在表面直立的高度有关；而其频率和直立的高度无关。ＳＣＮ吸附在纳米线上比普通电化学粗糙的电极表面ＳＥＲＳ强度高，说明纳米线（点）有望成为一种活性高，稳定性好的ＳＥＲＳ基底

铜和金纳米线阵列上SCN-的表面增强拉曼光谱

Two_dimensional arrays of Cu and Au nanowires have been fabricated by template synthesis method, using the anodic aluminum oxidation films as the template. The morphology of the nanowire array was monitored by atomic force microscope (AFM) in the dissolution processes of the alumina film. Based on the probe molecule strategy, the spectral feature of SCN - adsorbed at the Cu and Au nanowires with different diameters has been investigated by surface enhanced Raman spectroscopy (SERS). The results reveal that the intensity of the SERS bands depends on the length of the exposed nanowires. The C≡N stretching vibration frequency (ν CN ) of SCN - up_shifted significantly with the increase of the diameter of the nanowires in the range of 15 nm to 50 nm. This interesting phenomenon is briefly discussed

纳米阵列铂电极的样模法制备与应用

以多孔氧化铝为样模，利用直流沉积法自组装纳米阵列Ｐｔ电极。该电极在Ｆｅ（ＣＮ）６４－溶液中的线性扫描伏安图呈现Ｓ型稳态曲线，对甲醇的氧化具有很高的电催化活性。另外，以该电极作为表面增强拉曼散射的活性基底，现场研究甲醇的电化学氧化过程，检测出了中间产物单端吸附的ＣＯ

吡啶在几种金属纳米线阵列上的表面增强喇曼光谱

Nanowire arrays of various metals were fabricated from the template of porous alumina. We observed the strong surface enhanced Raman scattering(SERS) signals of the adsorbed molecules such as pyridine not only at the noble metals nanowires that exhibit a high SERS activity, but also at Ni, Co nanowires that are normally considered to be non SERS active substrates. The intensity of the species adsorbed at Ni nanowires is stronger than that on the conventionally roughened metal surface, and depends on the length of the nanowires out of alumina matrix. The metal nanowire arrays can be used as SERS active substrates