热处理对电沉积Ni-W-P合金催化析氢性能的影响

 采用电沉积方法制备了Ni-W-P合金镀层,并在不同温度下进行热处理,通过极化曲线和交流阻抗谱研究了热处理温度对Ni-W-P合金催化析氢性能的影响. 结果表明,经200 ℃热处理的Ni-W-P合金电极析氢过电位最低,在电流密度为8.0 mA/cm2时,其析氢过电位较未经热处理的Ni-W-P合金电极减小约110 mV. 该样品的析氢电化学反应电阻为17.1 Ω·cm2, 交换电流密度约为未经热处理的Ni-W-P合金的5.0倍,析氢反应表观活化能降低. 差示扫描量热法、 X射线衍射和扫描电镜测试结果表明, Ni-W-P合金镀层经200 ℃热处理后发生低温结构弛豫,平均晶粒尺寸由1.1增大到2.8 nm, 合金由非晶结构转变为纳米晶结构,镀层表面形成宽度约为0.2 μm的微裂纹.     

聚吡咯纳米阵列电极的光电化学

以多孔的铝阳极氧化膜(AAO)为模板制备了直径约为80 nm聚吡咯(PPy)纳米线的阵列电极, 并研究了它的光电化学响应. 结果表明, 在电极电位低于－0.1 V(vs Ag/AgCl)时出现的阴极光电流是由聚吡咯纳米线的p型半导体性质引起的, 其平带电位为－0.217 V. 聚吡咯纳米线的长度对光电流的影响较大, 最佳长度为42 nm. 这是因为在很短的聚吡咯纳米线阵列中PPy太少, 产生的光电流弱, 而在过长的聚吡咯纳米线阵列中光生电子在到达电极基底前易于与光生空穴复合而消失. 聚吡咯纳米线有可能作为纳米光电器件用于未来微器件系统.     

大长径比有序多孔阳极氧化铝模板的制备及用于镍纳米线阵列

报道一种恒电流二次氧化制备大长径比(>1000)阳极氧化铝(AAO)模板的方法,研究氧化时间和氧化电流密度分别对制备的AAO模板的表面形貌、孔径大小、厚度等的影响.结果表明,AAO模板的表面形貌及厚度n受m氧、厚化度电约流为密2度00及μ氧m、化长时径间比的为影10响0;-当13氧00化的电高流质密量度A为AO8模m板A·.c采m用-2电时化,氧学化沉1积8方h能法在制制备备出的孔A径A为O模15板0-的20孔0中成功制备了Ni纳米线阵列,分别用扫描电镜(SEM)、高分辨透射电镜(HRTEM)、X射线衍射(XRD)和X射线能量散射光谱(EDS)对其进行了表征;结果显示,制备的Ni纳米线排列整齐有序,每根Ni纳米线直径几乎相同,约150nm,长度约为180-200μm,长径比为1200-1300,与AAO模板的参数一致.研究了Ni纳米线阵列的长径比对其磁性能的影响,发现大长径比的Ni纳米线阵列具有明显的磁各向异性,而长径比约为200的Ni纳米线阵列未表现出明显的磁各向异性.本文结果表明,恒电流二次氧化方法能制备大长径比的AAO模板,并能用于制备大长径比的一维纳米材料阵列,可望在制备具有特殊光学、磁学等性能材料方面得到应用.     

泡沫镍负载的NiCo2O4纳米线阵列电极的超级电容性能

采用无模板自然生长法制备了泡沫镍支撑的NiCo₂O₄纳米线阵列电极, 利用扫描电镜(SEM)和透射电镜(TEM)观测了纳米线的表面形貌, 利用X射线衍射(XRD)分析了纳米线的结构, 通过循环伏安、恒流充放电和交流阻抗测试了电极的超级电容性能. 结果表明: NiCo₂O₄纳米线直径约为500-1000 nm、长度约为10 μm, 垂直且密集地生长在泡沫镍骨架上. 纳米线阵列电极的放电比容量高达741 F·g^-1, 循环420次后比容量仍保持在655 F·g^-1, 电化学阻抗测试其电荷传递电阻仅为0.33 Ω, 420次循环后电荷传递电阻仅增加0.06 Ω.     

p型单晶硅上电镀纳米Ni-W-P合金电极及其光照析氢研究

半导体;纳米晶;催化析氢;p型单晶硅上电镀纳米Ni-W-P合金电极及其光照析氢研究     

Pt纳米线阵列的氧还原催化性能

采用阳极氧化铝(AAO)模板法电化学沉积制备了Pt纳米线阵列(Pt NWs)氧还原催化剂, 通过扫描电子显微镜(SEM)、透射电子显微镜(TEM)和电化学测试对Pt纳米线阵列催化剂的形貌和电催化性能进行了表征. 循环伏安法(CV)研究表明Pt纳米线阵列催化剂的电化学活性面积大于其几何面积; 旋转圆盘电极(RDE)测试研究发现, 制备的Pt纳米线阵列催化剂的氧还原反应(ORR)曲线的半波电势相对Pt/C的有正移, 并且Pt纳米线阵列催化剂的极限扩散电流比Pt/C大.     

阳极氧化铝模板法可控制备金属纳米线和纳米管阵列的生长机制

利用阳极氧化铝模板(AAO)进行Ni的电化学沉积, 通过在溶液中引入螯合剂控制电解质的有效浓度和电沉积的过电位, 实现了Ni纳米线和纳米管阵列的可控制备. 通过分析电沉积过程中纳米线和纳米管在不同位置生长速率(侧壁(Vw)和底端(Vb))的控制因素, 我们提出了纳米线和纳米管生长的可能机制. 当电解质浓度高而还原电位更负(如-1.5 V)时, 或者当电解质浓度低而还原电位较负(如-0.5 V)时, Vw>Vb, 可以获得Ni纳米管阵列; 当电解质浓度高而还原电位较负(如-0.5 V)时, 或者当电解质浓度低而还原电位更负(如-1.5 V)时, Vw≈Vb, 可以获得Ni纳米线阵列. 这种生长机制适用于多种金属纳米管或者纳米线阵列的可控制备.     

自支撑镍纳米线阵列电极的制备及电催化性能

采用低熔点合金和多孔聚碳酸酯模板辅助制备了自支撑镍纳米线阵列电极,并研究了其催化肼电氧化的性能. SEM,XRD和TEM测试结果表明,该电极由镍平板和支撑在其上的镍纳米线阵列构成;镍纳米线的絮状表面增加了电极的比表面积.循环伏安和计时电位测试结果表明,当肼的浓度为24. 6 mmol/L时,该电极的起始氧化电位低至-0. 25 V,氧化电流密度高达163 m A/cm~2;当肼浓度较低时,肼电氧化反应和电极自身的Ni(OH)_2/NiOOH转化反应共存;当肼浓度较高时,仅发生肼电氧化反应;肼的反应分级数约为1,反应活化能为16. 13～21. 24 kJ/mol;镍纳米线阵列电极的一体化、开放式结构使其电催化性能明显优于商业镍片和泡沫镍,并表现出良好的稳定性.     

还原氧化石墨烯表面聚苯胺纳米阵列的制备及电化学电容性能

本文以阳极氧化铝(AAO)膜为模板,通过恒电位法在自组装还原氧化石墨烯(rGO)膜表面制备有序聚苯胺(PANI)纳米线阵列。通过拉曼光谱和场发射扫描电子显微镜分别对其结构和微观形貌进行了表征,并对PANI纳米线阵列的电化学电容性能进行了测试。结果表明,rGO膜表面可电沉积PANI,电沉积得到的PANI纳米线阵列具有比PANI薄膜材料更高的电容和比电容。     

吡咯-(3,4-乙烯二氧噻吩)共聚物有序纳米阵列薄膜的制备及表征

采用阳极氧化铝(AAO)模板电化学沉积方法, 合成了1种新型吡咯-(3,4-乙烯二氧噻吩)(PE)共聚物纳米线阵列薄膜, 作为锂离子电池电极材料, 其表现出较高的比容量(1426.1 mA·h/g, 充放电电流密度为100 mA/g)和很好的循环稳定性(在充放电循环300圈之后, 比容量仍然保持在1400 mA·h/g以上). 这种多组分共聚物纳米线阵列有可能成为下一代长寿命、 高性能的锂离子电池电极材料而被广泛开发.     

双极纳米电极阵列实现单个铂纳米颗粒上氢气析出反应的电致化学发光成像

本文制备了嵌于多孔阳极氧化铝（AAO）膜中直径为200 nm,间距为450 nm的高密度（5.7 × 10⁸ cm^-2）的金纳米电极阵列,纳米电极分布规则,尺寸高度均一。我们将该金纳米电极阵列作为双极电极阵列,可将电极一侧的电化学法拉第信号在另一侧电极上转化成电致化学发光（ECL）信号,从而实现对单个铂纳米颗粒上氢气析出反应（HER）进行亚微米空间分辨率的电化学成像。本文介绍的方法为高空间分辨率成像电催化材料、能源材料以及细胞过程的局部电化学活性提供了一个良好的平台。     

一维有序聚苯胺纳米阵列的制备及电化学储能性能

以导电玻璃FTO为基底电极, 在硫酸溶液中, 分别研究了苯胺单体浓度和恒定电流大小对聚苯胺(PANI)形貌的影响; 同时恒定苯胺单体的浓度和工作电流, 探究了不同类型的质子酸对PANI阵列形貌的影响. 结果表明, 采用恒电流方法可以制备出一维有序PANI纳米线阵列, 而且当苯胺的浓度为0.1 mol/L, 恒电流法的工作电流密度为0.03 mA/cm²时, 所制备的PANI纳米线阵列形貌最佳; 当用HCl, HNO₃和对甲苯磺酸(p-TSA)作为合成PANI的支持液时, 得到树桩状的PANI 纳米结构, 不能得到均一的纳米线阵列结构. 电化学性能测试结果表明, 制备的最佳形貌PANI纳米线阵列的比电容值可达560 F/g; 循环1000周后电容损失率为11%.     

Structural, magnetic, and magnetoresistive properties of electrodeposited Ni5Zn21 alloy nanowires

Ni5Zn21 alloy nanowires were fabricated through template-assisted electrochemical deposition method. The morphology and microstructures of as-deposited nanowires were determined by field-emission scanning electron microscope (FE-SEM), X-ray diffraction (XRD), high-resolution transmission electron microscope (HRTEM), electron diffraction (ED), and electron probe microanalysis (EPMA). The accurate composition was measured via induced coupling plasma atomic emission spectroscopy. SEM results show that Ni5Zn21 nanowires are deposited in most of the nanopores of the template, and they are continuous and dense throughout the whole length. The XRD result demonstrates that the nanowires are mainly composed of a cubic gamma phase Ni5Zn21 alloy, but there also exists a trace of Zn-rich eta phase. HRTEM and ED reveal that the alloy nanowires are polycrystalline with the crystallite size of several tens of nanometers. EPMA of a single nanowire illustrates that there exist Ni-rich microzones in as-deposited nanowires. Subsequent magnetic measurements of the array also confirmed the existence of them. In addition, it can be further inferred that the shape of Ni-rich microzones is probably barlike or disklike, from the anisotropy of zero field cooling/field cooling (ZFC/FC) curves as well as the vortex magnetization behavior of the Ni5Zn21 nanowire array. The low-temperature magnetoresistance of the Ni5Zn21 nanowire array was also measured. Giant magnetoresistance instead of anisotropic magnetoresistance is suggested to be responsible for contributing to the magnetoresistance.     

Synthesis and Characterization of ZnO Nanowires

Zinc oxide is a wide bandgap (3.37 eV) semiconductor with a hexagonal wurtzite crystal structure. ZnO prepared in nanowire form may be used as a nanosized ultraviolet light-emitting source. In this study, ZnO nanowires were prepared by vapor-phase transport of Zn vapor onto gold-coated silicon substrates in a tube furnace heated to 900 ?C. Gold serves as a catalyst to capture Zn vapor during nanowire growth. Size control of ZnO nanowires has been achieved by varying the gold film thickness…     

Co/Cu多层纳米线阵列的制备与磁性能

利用双槽直流电沉积技术在阳极氧化铝(AAO)模板的纳米孔中获得调制波长为50 和200 nm 的Co/Cu多层纳米线, 多层纳米线的调制波长由电沉积时间控制. 运用扫描电子显微镜(SEM)和透射电子显微镜(TEM)表征纳米线的形貌, Co/Cu多层纳米线的长度约20 μm, 直径约80 nm; 用X射线衍射(XRD)研究多层线的结构; 用振动样品磁强计(VSM)测试纳米线阵列的磁性能; 利用可变磁场结合高灵敏度恒流装置研究巨磁电阻(GMR)特性. 结果表明, Co/Cu多层纳米线具有磁各向异性. 当磁场与纳米线平行和垂直时, 调制波长为50 nm的多层线的矫顽力分别为87500 和34200 A·m-1, 而调制波长为200 nm的多层线阵列的矫顽力分别为28600 和8000 A·m-1. 调制波长为50 nm的多层纳米线的磁电阻变化率高达-%, 而调制波长为200 nm的多层线未产生明显的GMR效应.     

Conducting Polyaniline Nanowire Arrays Modified Electrode for High Performance Supercapacitor and Enhanced Catalysis of Nitrite Reduction

Vertically aligned conducting polymer nanowire arrays had great potential applications in supercapacitor electrode material and exhibited enhanced electrocatalytic behavior towards the reduction of nitrite. In this paper, a facial template‐free approach to synthesize large arrays of vertically aligned polyaniline (PANI) nanowires on electrochemically pretreated glassy carbon electrodes was reported by using a galvanostatic current method. The as‐prepared large arrays of PANI nanowires had very narrow diameters and were oriented perpendicular to the substrate, which was a benefit to the ion diffusion when being used as the supercapacitor electrode. The highest specific capacitance of PANI nanowire arrays was measured and kept high at a large charge‐discharge current density. Furthermore, it also can detect nitrite with ultrahigh sensitivity of 62.99 µA mM^?1 cm^?2 and a remarkable fast response time of less 1 s. The results indicated that the vertically aligned PANI nanowires could dramatically enhance the electrochemical performance.     

Ni-B非晶态合金电极上乙醇的电氧化及其动力学参数的测定

应用循环伏安法研究了碱性介质中Ni-B非晶态合金纳米粉末微电极和化学镀Ni-B非晶态合金微盘电极上乙醇的电催化氧化. 结果表明, Ni-B非晶态合金纳米粉末微电极和化学镀Ni-B非晶态合金微盘电极对碱性溶液中乙醇的氧化均具有很高的电催化作用, 且前者的电催化氧化活性高于后者. 运用稳态极化曲线测定了Ni-B非晶态合金纳米粉末微电极上乙醇的电催化氧化动力学参数. 与高择优取向(220)镍电极比较, 碱性介质中Ni-B非晶态合金纳米粉末微电极上乙醇的电催化氧化速率显著提高. 采用循环伏安法测定的Ni-B非晶态合金纳米粉末微电极上Ni(OH)2的质子扩散系数高出文献报道的镍纳米线电极和表面化学镀Co的球形Ni(OH)2粉末电极约2个数量级.     

Ni-Pt multilayered nanowire arrays with enhanced coercivity and high remanence ratio

Highly ordered Ni-Pt multilayered nanowire arrays have been fabricated using a porous anodic aluminum oxide (AAO) template by pulse electrodeposition. The cylindrical Ni nanoparticles with different lengths and diameters in these arrays were characterized by transmission electron microscope (TEM) and alternating-gradient magnetometer (AGM) measurements. Magnetization measurements revealed that an array of such nanowires with 20-nm diameters has an enhanced coercivity (ca. 1169 Oe) and a high remanence ratio (ca. 0.96).     

Dendritic nanowire ultraviolet laser array

Self-organized dendritic crystal growth is explored to assemble uniform semiconductor nanowires into highly ordered one-dimensional microscale arrays that resemble comb structures. The individual ZnO nanowires have uniform diameters ranging from 10 to 300 nm. They are evenly spaced on a stem with a regular periodicity of 0.1-2 micrometer. Under optical excitation, each individual ZnO nanowire serves as a Fabry-Perot optical cavity, and together they form a highly ordered nanowire ultraviolet laser array.     

Epitaxial Growth and Thermoelectric Measurement of Bi2Te3/Sb Superlattice Nanowires

Superlattice nanowires are expected to show further enhanced thermoelectric performance compared with conventional nanowires or superlattice thin films. We report the epitaxial growth of high density Bi₂Te₃/Sb superlattice nanowire arrays with a very small bilayer thickness by pulse electrodeposition. Transmission electron microscopy, selected area electron diffraction and high resolution transmission electron microscopy were used to characterize the superlattice nanowires, and Harman technique was employed to measure the figure of merit (ZT) of the superlattice nanowire array in high vacuum condition. The superlattice nanowire arrays exhibit a ZT of 0.15 at 330 K, and a temperature difference of about 6.6 K can be realized across the nanowire arrays.