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（英文）

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(5.7×10~8 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。     

双极电极-电致化学发光技术在生物分析中的应用

在微管道两端施加一定的电压时,置于这个电场中的金属或半导体带与溶液的界面电势差达到一定的数值后,就会引起溶液电活性物质在其两端发生氧化还原反应,该金属或半导体带即称为双极电极（BPE）. BPE与电致化学发光（ECL）技术的完美结合有诸多优点,如浓度富集、灵敏度高、成本低、装置轻便且不需要外加光源等,极适合生物分析检测. 本文综述了双极电极-电致化学发光技术在生物分析中的应用,并展望相关发展趋势.     

核黄素在镀铂铅笔芯热电极上的电致化学发光检测

利用电沉积方法制作了镀铂铅笔芯热电极(Pt/HPGE),用循环伏安法(CV)及扫描电镜(SEM)对其性质进行了表征.此电极具有价廉易得、重现性好及温度响应灵敏等特点.在此电极上研究了核黄素(RF)对Ru(bpy)32+-C2 O42-电致化学发光体系的猝灭作用,并推测了可能的机理,据此建立了灵敏检测RF的新方法.电极温...     

基于花状铂纳米颗粒构建的电致化学发光免疫传感器用于检测载脂蛋白A1

采用一锅合成法制备了新型的具有大比表面积的花状铂纳米颗粒（PtNFs）,并构建了一个高灵敏电致化学发光（ECL）免疫传感器用于检测载脂蛋白A1（Apo-A1）. 该PtNFs用于吸附二抗（anti-Apo-A1）,并用葡糖糖氧化酶（GOD）封闭其表面的非特异性位点,最终制备了PtNFs@anti-Apo-A1@GOD信号探针. 当Apo-A1存在时,通过夹心免疫反应将制备的信号探针捕获于电极表面,并将所制得的电极置于含有葡萄糖的过硫酸根底液中检测. GOD催化葡萄糖产生H₂O₂,H₂O₂在PtNFs的催化下分解并在电极表面原位产生O₂,所产生的O₂能够催化过硫酸根-氧气体系的电致化学发光反应,放大发光信号,提高检测灵敏度. 该传感器在0.1ng•mL^-1 ~ 100 ng•mL^-1范围内对Apo-A1有良好的线性响应,检测下限达到0.03ng•mL^-1,有望应用于临床分析诊断.     

氢气在贮氢合金电极上析出反应机理的研究

贮氢合金电极上氢气的析出反应分为水分子的放电和吸附氢原子复合脱附两个步骤，即反应按Ｖｏｌｍｅｒ－Ｔａｆｅｌ机理进行，反应的超电势η可以区分为η１和η２两个组成部分，反映了Ｖｏｌｍｅｒ和Ｔａｆｅｌ反应的极化特征。析氢反应的速度由二者混合控制，在高超电势区，主要则由Ｖｏｌｍｅｒ反应所控制。     

纳米阵列铂电极的样模法制备与应用

双多孔氧化铝为样模,利用直流沉积法自组装纳米阵列Ｐｔ电极。该电极在Ｆｅ（ＣＮ）＾４－６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,以该电极作为表现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,检测出中间产物单端吸附的ＣＯ。     

罗丹明B的电致化学发光行为研究

研究发现罗丹明B在碱性溶液中铂电极上有较强的电致化学发光行为.通过对不同NaOH浓度,以及对不同支持电解质的考察,确定最佳电致化学发光条件.在最优条件下,在1.2×10-7~1.1×10-6mol/L浓度范围内,罗丹明B的电致化学发光强度与其浓度成线性关系,最低检测限为9.0×10-8mol/L(S/N=3).将罗丹明B同一些生物活性物质相配合,然后通过罗丹明B的ECL技术对生物活性物质进行检测.     

磁性纳米粒子固定葡萄糖氧化酶修饰电极电致化学发光葡萄糖传感器

通过交联剂将葡萄糖氧化酶(GOD)固定在Fe3O4磁性纳米粒子上,在磁力作用下将该磁性复合粒子修饰在石蜡碳糊电极(SPCE)表面,制成易更新酶电极.GOD催化氧化葡萄糖生成过氧化氢,并使鲁米诺产生电致化学发光(ECL),据此首次构建了易更新型电致化学发光葡萄糖传感器.其电致发光强度与葡萄糖浓度在1×10-5～1.0×10-2 mol/L范围内呈线性关系,线性回归方程I＝65.4374C+23.9017(r=0.9987); 检出限为1.0 μmol/L.此传感器响应快, 稳定性高, 表面易更新,已用于测定人血清中葡萄糖的含量.     

NEWS——基于CdS纳米晶的电致化学发光生物传感器（Ⅰ）

南京大学化学化工学院朱俊杰研究组最近研制了一种基于CdS纳米晶的电致化学发光（ECL）生物传感器（Analytical Chemistry,2007,79,5574-5581）。通过自组装与金纳米颗粒放大技术研制成一种新型的纳米晶体非标记型电化学发光生物传感器,并将其运用于LDL的检测。该传感器具有重现性好,响应速度快,稳定性好等优点。半导体纳米晶通过电化学反应产生氧化态或还原态,     

联吡啶钌修饰电极固相电致化学发光

由于电致化学发光(ECL)的连续可测性、高灵敏度、稳定和方法简单,被广泛应用于分子生物学、药学、化学和环保等领域.而将可电化学再生的ECL试剂固定于电极表面,可获得ECL传感器,从而减少分析过程中试剂的消耗并简化实验装置.联吡啶钌及其衍生物在电极表面的固定化研究成为ECL研究的重要方向.本文综述了2004年以来联吡啶钌及其衍生物修饰电极的固相ECL的研究进展,并简要介绍了各种固定方法及其相关的应用情况.     

Label-Free Electrochemiluminescence Imaging of Single-Cell Adhesions by Using Bipolar Nanoelectrode Array

A label-free and fast approach for positive electrochemiluminescence (ECL) imaging of single cells by bipolar nanoelectrode array is proposed. The reduction of oxygen at a platinized gold nanoelectrode array in a closed bipolar electrochemical system is coupled with an oxidative ECL process at the anodic side. For elevating the ECL imaging contrast of single cells, a driving voltage of −2.0 V is applied to in situ generate oxygen confined beneath cells that is subsequently used for ECL imaging at 1.1 V. High oxygen concentration in the confined space resulting from steric hindrance generates prominent oxygen reduction current at the cathodic side and higher ECL intensity at the anodic side, allowing positive ECL imaging of the cells adhesion region with excellent contrast. Cell morphology and adhesion strength can be successfully imaged with high image acquisition rate. This approach opens a new avenue for label-free imaging of single cells.     

Electrochemical Dynamics of a Single Platinum Nanoparticle Collision Event for the Hydrogen Evolution Reaction

Chronoamperometry was used to study the dynamics of Pt nanoparticle (NP) collision with an inert ultramicroelectrode via electrocatalytic amplification (ECA) in the hydrogen evolution reaction. ECA and dynamic light scattering (DLS) results reveal that the NP colloid remains stable only at low proton concentrations (1.0 mm ) under a helium (He) atmosphere, ensuring that the collision events occur at genuinely single NP level. Amperometry of single NP collisions under a He atmosphere shows that each discrete current profile of the collision event evolves from spike to staircase at more negative potentials, while a staircase response is observed at all of the applied potentials under hydrogen‐containing atmospheres. The particle size distribution estimated from the diffusion‐controlled current in He agrees well with electron microscopy and DLS observations. These results shed light on the interfacial dynamics of the single nanoparticle collision electrochemistry.     

Intracellular Wireless Analysis of Single Cells by Bipolar Electrochemiluminescence Confined in a Nanopipette

The inside walls of a nanopipette tip are decorated by a Pt deposit that is used as an open bipolar electrochemiluminescence (ECL) device to achieve intracellular wireless electroanalysis. The synergetic actions of nanopipette and of bipolar ECL lead to the spatial confinement of the voltage drop at the level of the Pt deposit, which generates ECL emission from luminol. The porous structure of Pt deposit permits the electrochemical transport of intracellular molecules into the nanopipette that is coupled with enzymatic reactions. Thus, the intracellular concentrations of hydrogen peroxide or glucose are measured in vivo as well as the intracellular sphingomyelinase activity. In comparison with the classic bipolar ECL, the remarkably low potential applied in our approach is restricted inside the nanopipette and it minimizes the potential bias of the voltage on the cellular activity. Accordingly, this wireless ECL approach provides a new direction for analysis of single living cells.     

Tracking the Electrocatalytic Activity of a Single Palladium Nanoparticle for the Hydrogen Evolution Reaction

The nanoparticle-based electrocatalysts’ performance is directly related to their working conditions. In general, a number of nanoparticles are uncontrollably fixed on a millimetre-sized electrode for electrochemical measurements. However, it is hard to reveal the maximum electrocatalytic activity owing to the aggregation and detachment of nanoparticles on the electrode surface. To solve this problem, here, we take the hydrogen evolution reaction (HER) catalyzed by palladium nanoparticles (Pd NPs) as a model system to track the electrocatalytic activity of single Pd NPs by stochastic collision electrochemistry and ensemble electrochemistry, respectively. Compared with the nanoparticle fixed working condition, Pd NPs in the nanoparticle diffused working condition results in a 2–5 orders magnitude enhancement of electrocatalytic activity for HER at various bias potential. Stochastic collision electrochemistry with high temporal resolution gives further insights into the accurate study of NPs’ electrocatalytic performance, enabling to dramatically enhance electrocatalytic efficiency.     

Polyvinylpyrrolidone-Coordinated Single-Site Platinum Catalyst Exhibits High Activity for Hydrogen Evolution Reaction

The essence of developing a Pt-based single-atom catalyst (SAC) for hydrogen evolution reaction (HER) is the preparation of well-defined and stable single Pt sites with desired electrocatalytic efficacy. Herein, we report a facile approach to generate uniformly dispersed Pt sites with outstanding HER performance via a photochemical reduction method using polyvinylpyrrolidone (PVP) molecules as the key additive to significantly simplify the synthesis and enhance the catalytic performance. The as-prepared catalyst displays remarkable kinetic activities (20 times higher current density than the commercially available Pt/C) with excellent stability (76.3 % of its initial activity after 5000 cycles) for HER. EXAFS measurements and DFT calculations demonstrate a synergetic effect, where the PVP ligands and the support together modulate the electronic structure of the Pt atoms, which optimize the hydrogen adsorption energy, resulting in a considerably improved HER activity.     

Selective Loading of Atomic Platinum on a RuCeOx Support Enables Stable Hydrogen Evolution at High Current Densities

High-performance electrocatalysts for the hydrogen evolution reaction (HER) have an important role to play in the development of renewable energy. Platinum remains the most efficient known HER electrocatalyst. Therefore, it is necessary to find ways to maximize Pt utilization in actual practical applications. Herein we demonstrate a facile strategy for synthesizing RuCeO_x-supported, selectively loaded, atomic Pt (0.49 wt. %) (denoted Pt/RuCeO_x-PA) by photoactivation at ambient temperature and pressure. Through the photoelectron transfer at the Mott-Schottky heterojunction in RuCeO_x, Pt atoms became embedded into the RuO₂ lattice. The resulting selectively loaded Pt-O-Ru moieties in Pt/RuCeO_x-PA give a stronger hydrogen spillover effect than Pt complexes randomly loaded by either chemical activation or thermal activation. As a result, Pt/RuCeO_x-PA shows superior HER performance to the materials prepared by random loading and is even better than a commercial Pt/C catalyst with much higher Pt loading (20 wt. %) at high current densities (from 50–600 mA cm⁻²).     

钼基析氢反应电催化剂的研究进展

电催化析氢反应作为一种绿色、可持续的制备氢气方法,受到了广泛关注. 近年来,非贵金属析氢催化剂以其低成本和相对高的催化活性取得了较快的研究进展,其中,钼基纳米催化剂目前已成为电催化析氢中最受关注的研究热点之一. 本文综述了钼基碳化物、磷化物、氮化物以及硫化物在电催化析氢反应中的催化机理和研究进展,分析了提高析氢催化活性的方法,并对钼基非贵金属催化剂的发展趋势进行了展望.     

Tunable Aryl Alkyl Ionic Liquid Supported Synthesis of Platinum Nanoparticles and Their Catalytic Activity in the Hydrogen Evolution Reaction and in Hydrosilylation

Tunable aryl alkyl ionic liquids (TAAILs) are ionic liquids (ILs) with a 1-aryl-3-alkylimidazolium cation having differently substituted aryl groups. Herein, nine TAAILs with the bis(trifluoromethylsulfonyl)imide anion are utilized in combination with and without ethylene glycol (EG) as reaction media for the rapid microwave synthesis of platinum nanoparticles (Pt-NPs). TAAILs allow the synthesis of small NPs and are efficient solvents for microwave absorption. Transmission electron microscopy (TEM) shows that small primary NPs with sizes of 2 nm to 5 nm are obtained in TAAILs and EG/TAAIL mixtures. The Pt-NPs feature excellent activity as electrocatalysts in the hydrogen evolution reaction (HER) under acidic conditions, with an overpotential at a current density of 10 mA cm⁻² as low as 32 mV vs the reversible hydrogen electrode (RHE), which is significantly lower than the standard Pt/C 20% with 42 mV. Pt-NPs obtained in TAAILs also achieved quantitative conversion in the hydrosilylation reaction of phenylacetylene with triethylsilane after just 5 min at 200 °C.     

Hierarchical Architectures Based on Ru Nanoparticles/Oxygen-Rich-Carbon Nanotubes for Efficient Hydrogen Evolution

Highly active and durable electrocatalysts are essential for producing hydrogen fuel through the hydrogen evolution reaction (HER). Here, a uniform deposition of Ru nanoparticles strongly interacting with oxygen-rich carbon nanotube architectures (Ru-OCNT) through ozonation and hydrothermal approaches has been designed. The hierarchical structure of Ru-OCNT is made by self-assembly of oxygen functionalities of OCNT. Ru nanoparticles interact strongly with OCNT at the Ru/OCNT interface to give excellent catalytic activity and stability of the Ru-OCNT, as further confirmed by density functional theory. Owing to the hierarchical structure and adjusted surface chemistry, Ru-OCNT has an overpotential of 34 mV at 10 mA cm⁻² with a Tafel slope of 27.8 mV dec⁻¹ in 1 M KOH, and an overpotential of 55 mV with Tafel slope of 33 mV dec⁻¹ in 0.5 M H₂SO₄. The smaller Tafel slope of Ru-OCNT than Ru-CNT and commercial Pt/C in both alkaline and acidic electrolytes indicates high catalytic activity and fast charge transfer kinetics. The as-proposed chemistry provides the rational design of hierarchically structured CNT/nanoparticle electrocatalysts for HER to produce hydrogen fuel.