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1.
《Electroanalysis》2017,29(8):1934-1940
Nanoparticles have already found numerous applications and their global production is still increasing. Therefore, the engineered nanoobjects of uncertain toxicity become ubiquitous in the environment and a continuous monitoring of their presence is highly desirable. Here, we demonstrate a continuous electrochemical detection of gold nanoparticles (AuNPs) based on synchronous processes of their electrodissolution and electrocatalysis. This approach is realized by the injection of nanoparticles suspension into the Flow Injection Analysis (FIA) system. The modular structure of FIA system is particularly applicable for carrying out of sequential operations: AuNPs passivation, oxidation of aqueous SO2 and gold. It enables continuous, fast and reproducible gold nanoparticles determination in a wide concentration range: 10−10– 10−7 mol nanoobjects L−1. 相似文献
2.
Jude Lakbub Antibe Pouliwe Alexander Kamasah Cheng Yang Peng Sun 《Electroanalysis》2011,23(10):2270-2274
In this paper, the electrochemical behaviors of a single gold nanoparticle attached on a nanometer sized electrode have been studied. The single nanoparticle was characterized by using electrochemical methods. Since there is only one nanoparticle on the electrode, unarguable information for that sized particle could be obtained. Our preliminary results show that it becomes more difficult to oxidize gold nanoparticle or reduce gold nanoparticle oxide as the radius of the particle becomes smaller. Also, the peak potential of the reduction of gold nanoparticle oxide is proportional to the reciprocal of the radius of the particle. 相似文献
3.
Ahmed I. Abdelrahman Ahmad M. Mohammad Mohamed S. El-Deab Takeyoshi Okajima Takeo Ohsaka 《Macromolecular Symposia》2008,270(1):74-81
The layer-by-layer (LBL) approach has been utilized to self-assemble multilayers films of citrate-stabilized gold nanoparticles (AuNPs) on polycrystalline gold (poly-Au) substrates. 1,4-benzenedimethanethiol (BDMT) was used as a cross linker to bind every two successive AuNPs layers. The transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS) techniques were employed to confirm the existence of the alternative layers of AuNPs and BDMT in the self-assembled multilayers film. The AuNPs modified poly-Au electrode showed a significant electrocatalysis towards the reduction of oxygen (a positive potential shift of about 100 mV was observed in the reduction peak potential compared to that obtained at the bare poly-Au electrode). The AuNPs tend to aggregate during their assembling to different extent which markedly depends on the substrate geometry and roughness. An effort was dedicated to understand and control the aggregation phenomenon. 相似文献
4.
纳米材料特有的尺寸效应、量子效应和表面效应使其具有许多异于常规材料的性质 ,在催化、生物传感器、微电子器件和磁性材料等诸多领域都有广泛的应用前景 [1] .已有专家预言 ,与纳米材料相关的技术将在新世纪经济发展中起主导作用 ,对其研究是目前科学研究中的热点 .金纳米颗粒是目前研究得最多的金属纳米材料体系 .传统的金纳米颗粒的制备方法以溶胶 -凝胶法为主 [2~ 4 ] ,所制备的金纳米颗粒的粒径较大 (一般大于 1 0 nm) ,粒径分布不均匀 ,易于团聚 ,因而限制了其应用 .为了解决上述问题 ,Brust等 [5]将硫醇化合物在金属表面的自组装… 相似文献
5.
Size‐Dependent Electrocatalytic Activity of Free Gold Nanoparticles for the Glucose Oxidation Reaction 下载免费PDF全文
Dr. Seydou Hebié Dr. Teko W. Napporn Dr. Cláudia Morais Prof. Dr. K. Boniface Kokoh 《Chemphyschem》2016,17(10):1454-1462
Understanding the fundamental relationship between the size and the structure of electrode materials is essential to design catalysts and enhance their activity. Therefore, spherical gold nanoparticles (GNSs) with a mean diameter from 4 to 15 nm were synthesized. UV/Vis spectroscopy, transmission electron microscopy, and under‐potential deposition of lead (UPDPb) were used to determine the morphology, size, and surface crystallographic structure of the GNSs. The UPDPb revealed that their crystallographic facets are affected by their size and the growth process. The catalytic properties of these GNSs toward glucose electrooxidation were studied by cyclic voltammetry, taking into account the scan rate and temperature effects. The results clearly show the size‐dependent electrocatalytic activity for glucose oxidation reactions that are controlled by diffusion. Small GNSs with an average size of 4.2 nm exhibited high catalytic activity. This drastic increase in activity results from the high specific area and reactivity of the surface electrons induced by their small size. The reaction mechanism was investigated by in situ Fourier transform infrared reflectance spectroscopy. Gluconolactone and gluconate were identified as the intermediate and the final reaction product, respectively, of the glucose electrooxidation. 相似文献
6.
A novel electrochemical aptasensor incorporating a signal enhancement for the determination of cocaine was designed. Gold nanoparticles were self‐assembled onto the surface of a gold electrode through 1,6‐hexanedithiol. A bifunctional derivative of the 32‐base cocaine‐binding aptamer with a redox‐active ferrocene moiety and a thiol linker group at the termini of the strand was self‐assembled onto the surface of gold nanoparticles. The oxidation peak current is linearly related to the concentration of cocaine from 1.0 to 15.0 μM with a detection limit of 0.5 μM. It was found that the sensitivity of the aptasensor with gold nanoparticles modification was ca. 10‐fold higher than that of the aptasensor without gold nanoparticles modification. This work demonstrates that gold nanoparticles‐assembled gold electrode provides a promising platform for immobilizing aptamer and enhancing the sensitivity. 相似文献
7.
Yanrong Zhao Ying Wu Yu Zhang Zeguan Chen Xia Cao Junwei Di Jianping Yang 《Electroanalysis》2009,21(8):939-943
A gold nanoparticles (AuNPs) modified indium tin oxide (ITO) film coated glass electrode was prepared via a novel electrochemical deposition technique. The UV‐visible spectrum and SEM indicated that the AuNPs on ITO electrode surface were spherical shape and quite symmetric distributed. The modified electrode exhibited excellent catalytic activity for the oxidation of morphine (MO). At optimal experimental condition, the oxidation current was responsive with the MO concentrations ranging from 8.0×10?7 to 1.6×10?5 M, the detection limit was 2.1×10 –7 M. The modified electrode also exhibited high stability and reproducibility. The average recoveries of detection MO in human urine were ranged between 91.95% and 92.23%, and the RSD was less than 3.68% (n=5). 相似文献
8.
在不引入其它还原剂和稳定剂的情况下, 加热天然生物多聚糖——壳聚糖(CHIT)和氯金酸的混合溶液, 一步反应制备高稳定性的金纳米粒子(GNPs). 采用紫外光谱、红外光谱、热重分析和透射电镜对产品进行了表征. 结果表明: 改变CHIT的浓度能够调控GNPs的光学和结构性质; 老化-时效处理可以作为粒子增长过程中的一个调控手段. 动力学数据证明GNPs的时效处理过程是一个CHIT诱导的自催化生长过程; 红外谱中1713.3 cm-1左右出现的新的吸收带, 可能是作为还原剂参加反应的壳聚糖或者它的水解产物分子中的部分羟基被氧化为羰基引起的. 本文工作也为进一步阐明目前还处于探索阶段的纳米粒子的形成机制以及实现其工业化绿色生产提供了可能性. 相似文献
9.
We investigate the preparation of nearly monodisperse gold nanoparticles by heat treatment in different conditions. The effects of various solvents, heating temperature, and heating time length on the monodispersity of gold nanoparticles were studied systematically and a general route to generate gold nanoparticles with uniform size was determined. The first step was to prepare gold nanoparticles with less than 3 nm and the following operation was to heat the gold nanoparticles in the present of thiolated solvents where monodispersed gold nanoparticles could be obtained easily. Our approach has enriched synthesis of monodisperse gold nanoparticles, and may provide some valuable experimental data about how the heating process affects the size evolution of gold nanoparticles. 相似文献
10.
Amplified Electrochemical DNA Sensor Based on Polyaniline Film and Gold Nanoparticles 总被引:1,自引:0,他引:1
In this work, an electrochemical DNA biosensor, based on a dual signal amplified strategy by employing a polyaniline film and gold nanoparticles as a sensor platform and enzyme‐linked as a label, for sensitive detection is presented. Firstly, polyaniline film and gold nanoparticles were progressively grown on graphite screen‐printed electrode surface via electropolymerization and electrochemical deposition, respectively. The sensor was characterized by scanning electron microscopy (SEM), cyclic voltammetry and impedance measurements. The polyaniline‐gold nanocomposite modified electrodes were firstly modified with a mixed monolayer of a 17‐mer thiol‐tethered DNA probe and a spacer thiol, 6‐mercapto‐1‐hexanol (MCH). An enzyme‐amplified detection scheme, based on the coupling of a streptavidin‐alkaline phosphatase conjugate and biotinylated target sequences was then applied. The enzyme catalyzed the hydrolysis of the electroinactive α‐naphthyl phosphate to α‐naphthol; this product is electroactive and has been detected by means of differential pulse voltammetry. In this way, the sensor coupled the unique electrical properties of polyaniline and gold nanoparticles (high surface area, fast heterogeneous electron transfer, chemical stability, and ease of miniaturisation) and enzymatic amplification. A linear response was obtained over a concentration range (0.2–10 nM). A detection limit of 0.1 nM was achieved. 相似文献
11.
Gold Nanoparticles Confined in Vertically Aligned Silica Nanochannels and Their Electrocatalytic Activity Toward Ascorbic Acid 下载免费PDF全文
Longhua Ding Wanzhen Li Qinqin Sun Yayun He Prof. Bin Su 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(40):12777-12780
A facile method of confining gold nanoparticles (AuNPs) in silica nanochannels aligned perpendicularly to an underlying electrode surface is reported. The nanochannel surface carrying a layer of (3‐aminopropyl)triethoxy silane (APTS) displays a strong electrostatic interaction with AuCl4?, eventually resulting in the confinement of AuNPs inside the nanochannels after chemical reduction. As‐prepared AuNPs in APTS‐modified mesoporous silica film (APTS‐MSF) are highly dispersed with a narrow size distribution. Furthermore, these AuNPs are free of protecting ligands and exhibit a good electrochemical catalytic activity toward the oxidation of ascorbic acid. 相似文献
12.
纳米尺度的金由于常表现出有趣的尺寸效应和物理化学特性而被大量应用于催化反应中,但是其在电催化反应中的应用却十分有限. 本文以水为溶剂、HAuCl4为前驱体、十二烷基聚乙二醇醚(Brij 35)等为软模板剂、NaBH4为还原剂、活性炭或石墨烯为载体,在温和反应条件下获得担载型金纳米电催化剂. 本文考察并优化了关键制备参数和样品纯化方法,最终确定NaBH4的最佳浓度区间为5 ~ 10mmol•L-1,Brij 35的最佳浓度约为1 mmol•L-1,在3 ~ 16 oC下金纳米颗粒的尺寸容易控制,石墨烯和活性炭(EC600)是金纳米颗粒的良好载体. 在优化的反应条件下,金纳米颗粒的粒径可以被控制在1 ~ 4 nm. 热处理法可以有效去除表面活性剂,纯化后的担载型纳米金电催化剂在醇类小分子的氧化反应中表现出良好的性能. 相似文献
13.
Raffaello Mazzaro Alessandro Boni Dr. Giovanni Valenti Prof. Massimo Marcaccio Prof. Francesco Paolucci Dr. Luca Ortolani Dr. Vittorio Morandi Prof. Paola Ceroni Dr. Giacomo Bergamini 《ChemistryOpen》2015,4(3):268-273
Graphene–metal composites have potential as novel catalysts due to their unique electrical properties. Here, we report the synthesis of a composite material comprised of monodispersed platinum nanoparticles on high-quality graphene obtained by using two different exfoliation techniques. The material, prepared via an easy, low-cost and reproducible procedure, was evaluated as an electrocatalyst for the hydrogen evolution reaction. The turnover frequency at zero overpotential (TOF0 in 0.1 m phosphate buffer, pH 6.8) was determined to be approximately 4600 h−1. This remarkably high value is likely due to the optimal dispersion of the platinum nanoparticles on the graphene substrate, which enables the material to be loaded with only very small amounts of the noble metal (i.e., Pt) despite the very highly active surface. This study provides a new outlook on the design of novel materials for the development of robust and scalable water-splitting devices. 相似文献
14.
近年来,贵金属纳米材料由于其具有独特的光学性质、稳定性、生物相容性和自身的结构特性等优点,被广泛用于重金属检测领域。总结了近年来金纳米粒子在重金属离子检测方面的研究现状,最后对贵金属纳米材料在重金属离子检测中的发展前景进行了展望。 相似文献
15.
Electrochemical Preparation of N‐Doped Cobalt Oxide Nanoparticles with High Electrocatalytic Activity for the Oxygen‐Reduction Reaction 下载免费PDF全文
Hongtao Yu Prof. Yunchao Li Prof. Xiaohong Li Prof. Louzhen Fan Prof. Shihe Yang 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(12):3457-3462
Nitrogen‐doped CoO (N‐CoO) nanoparticles with high electrocatalytic activity for the oxygen‐reduction reaction (ORR) were fabricated by electrochemical reduction of CoCl2 in acetonitrile solution at cathodic potentials. The initially generated, highly reactive nitrogen‐doped Co nanoparticles were readily oxidized to N‐CoO nanoparticles in air. In contrast to their N‐free counterparts (CoO or Co3O4), N‐CoO nanoparticles with a N content of about 4.6 % exhibit remarkable ORR electrocatalytic activity, stability, and immunity to methanol crossover in an alkaline medium. The Co?Nx active sites in the CoO nanoparticles are held responsible for the high ORR activity. This work opens a new path for the preparation of nitrogen‐doped transition metal oxide nanomaterials, which are promising electrocatalysts for fuel cells. 相似文献
16.
Yanli Zhang Yanpei Liu Jiemei He Pengfei Pang Yuntao Gao Qiufen Hu 《Electroanalysis》2013,25(5):1230-1236
A gold nanoparticle (AuNP) and graphene nanosheet (GN) modified glassy carbon electrode (GCE) is proposed as voltammetric sensor for caffeic acid assay. The sensor exhibits a surface‐confined and reversible process for oxidation of caffeic acid revealed by cyclic voltammetry. The results show more favorable electron transfer kinetics than the bare GCE. The linear response of the sensor is from 5×10?7 to 5×10?5 M with a detection limit of 5×10?8 M (S/N=3). The AuNP/GN nanocomposite shows more favorable electrochemical activity and should be a kind of more robust and advanced functional material, which provides a promising platform for electrochemical sensors and biosensors. The method was successfully applied to detect caffeic acid in pharmaceutical tablets with satisfactory results. 相似文献
17.
Laura M. H. Pascual Dr. Stéphanie Boudesocque Prof. Dr. Laurent Dupont Prof. Dr. Jean Michel Prof. Dr. Richard Plantier-Royon Dr. Sylvain Gatard 《欧洲无机化学杂志》2023,26(18):e202300076
Water-soluble and air-stable gold nanoparticles stabilized by a xyloside-based ligand containing a pyridine ring-functionalized 1,2,3-triazole backbone were prepared in the presence of a reducing agent. During their preparation, UV-vis and NMR spectroscopic techniques were used to study the interaction between the xyloside ligand and Au(III) ions. These AuNPs were characterized by UV-vis spectroscopy, TEM and DLS and showed a small size (average diameter<10 nm determined by TEM). Their catalytic activity was tested in the reduction of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP) in water. 相似文献
18.
近年来,贵金属纳米材料由于其具有独特的光学性质、稳定性、生物相容性和自身的结构特性等优点,被广泛用于重金属检测领域。总结了近年来金纳米粒子在重金属离子检测方面的研究现状,最后对贵金属纳米材料在重金属离子检测中的发展前景进行了展望。 相似文献
19.
Gold nanoparticles (AuNPs) were electrodeposited on the surface of pencil graphite (PG) by fast scan cyclic voltammetry without using any additives in acidic medium. The effect of deposition time on the size of electrodeposited AuNPs was investigated in sulfuric acid as a supporting electrolyte. The deposition time was varied by varying the scan rate, number of cycles and applied potential range. Scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X‐ray diffraction (XRD) were used for characterization of PG and electrodeposited AuNPs. The results confirmed that nanosized gold particles (20 ± 8 nm) were deposited on the PG substrate with almost spherical geometry. 相似文献
20.
Selective and Simultaneous Determination of Dihydroxybenzene Isomers Based on Green Synthesized Gold Nanoparticles Decorated Reduced Graphene Oxide 下载免费PDF全文
Selvakumar Palanisamy Chelladurai Karuppiah Shen‐Ming Chen K. Muthupandi R. Emmanuel P. Prakash Mohamed S. Elshikh M. Ajmal Ali Fahad M. A. Al‐Hemaid 《Electroanalysis》2015,27(5):1144-1151
In the present study, we report the simultaneous electrochemical determination of hydroquinone (HQ), catechol (CC) and resorcinol (RC) at gold nanoparticles (Au‐NPs) decorated reduced graphene oxide (RGO) modified electrode. An enhanced and well defined peak current response with a better peak separation of HQ, CC and RC is observed at RGO/Au‐NPs composite than that of RGO and Au‐NPs modified electrodes. The fabricated modified electrode shows a wide linear response in the concentration range of 3–90 µM, 3–300 µM and 15–150 µM for HQ, CC and RC, respectively. The detection limit of HQ, CC and RC is found as 0.15 µM, 0.12 µM and 0.78 µM, respectively. 相似文献