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11.
Gold nanoparticles were deposited electrolessly on multiwalled carbon nanotubes (CNTs) via in situ reduction of HAuCl4 by NaBH4. The resulting gold covered nanotubes were immobilised onto the surface of a glassy carbon electrode via evaporation of a suspension in chloroform. Anodic stripping voltammetry was performed with the modified electrode in As(III) solutions. A limit of detection (LOD based on 3σ) of 0.1 μg L−1 was obtained but more importantly a sensitivity of 1985 μA μM−1 was obtained with square wave voltammetry (SWV) in an optimised system with a deposition time of 120 s. These values, particularly the high sensitivity compare favourably with previously reported methods in the area of electrochemical arsenic detection. 相似文献
12.
Kathryn E. Toghill Lei Xiao Gregory G. Wildgoose Richard G. Compton 《Electroanalysis》2009,21(10):1113-1118
We report the simultaneous electroanalytical determination of Pb2+ and Cd2+ by linear sweep anodic stripping voltammetry (LSASV) using an antimony nanoparticle modified boron doped diamond (Sb‐BDD) electrode. Sb deposition was performed in situ with the analytes, from a solution of 1 mg L?1 SbCl3 in 0.1 M HCl (pH 1). Pb2+ inhibited the detection of Cd2+ during simultaneous additions at the bare BDD electrode, whereas in the presence of antimony, both peaks were readily discernable and quantifiable over the linear range 50–500 μg L?1. 相似文献
13.
The electrocatalytic detection of the anaesthetic halothane on a multiwalled carbon nanotube modified glassy carbon electrode is reported with a low limit of detection of 4.6 microM. A thorough investigation of the underlying cause of this apparent catalytic effect is undertaken by comparing the response of various carbon electrodes including glassy carbon, basal- and edge-plane pyrolytic graphite electrodes (bppg and eppg respectively) to increasing additions of halothane. The reduction of halothane is shifted by 250-300 mV to more negative potentials at an eppg electrode than that observed at the GC-CNT electrode. Therefore the results of this investigation show that, surprisingly, the electrocatalysis is not solely due to the introduction of edge-plane-like defect sites on the carbon nanotubes as is commonly found for many other substrates showing favourable voltammetry at nanotube modified electrodes. Instead, we reveal that in this unusual case the electroactive sites for the reduction of halothane are due to the presence of copper nanoparticles occluded within the carbon nanotubes during their production, which are never completely removed by standard purification techniques such as acid washing. This is only the third known case where apparent electrocatalysis by carbon nanotube modified electrodes is due to occluded metal-related nanoparticles within the nanotube structure, rather than the active sites being the edge-plane-like defect sites on the nanotubes. Furthermore this is the first case where the active sites are nanoparticles of copper metal, rather than metal oxide nanoparticles (namely oxides of iron(II)/(III)) as was found to be the case in the previous examples. 相似文献
14.
In this study,the three dimensional nanoscale organization in the photoactive layers of poly(3-hexylthiophene) (P3HT) and a methanofullerene derivative (PCBM) is revealed by transmission electron tomography.After annealing treatment,either at elevated temperature or during slow solvent evaporation,nanoscale interpenetrating networks are formed with high crystalline order and favorable concentration gradients of both components through the thickness of the photoactive layer.Such a tailored morphology acco... 相似文献
15.
Electrocatalysis at graphite and carbon nanotube modified electrodes: edge-plane sites and tube ends are the reactive sites 总被引:3,自引:0,他引:3
Banks CE Davies TJ Wildgoose GG Compton RG 《Chemical communications (Cambridge, England)》2005,(7):829-841
Carbon, and particularly graphite in its various forms, is an attractive electrode material. Two areas of particular interest are modified carbon electrodes and carbon nanotube electrodes. In this article we focus on the relationship between surface structure and electrochemical and chemical reactivity of electrodes based on these materials. We overview recent work in this area which has led us to believe that much of the catalytic activity, electron transfer and chemical reactivity of graphitic carbon electrodes is at surface defect sites, and in particular edge-plane-like defect sites. We also question the claimed special "catalytic" properties of carbon nanotube modified electrodes. 相似文献
16.
Chemically Modified Carbon Nanotubes for Use in Electroanalysis 总被引:6,自引:0,他引:6
Gregory G. Wildgoose Craig E. Banks Henry C. Leventis Richard G. Compton 《Mikrochimica acta》2006,152(3-4):187-214
The discovery of carbon nanotubes has had a profound impact on many areas of science and technology, not least that of electroanalysis.
The properties and applications of carbon nanotubes themselves have been well reviewed in the literature and a number of reviews
with an electrochemical emphasis have been published. However, the modification of carbon nanotubes has recently been the
focus of much research, primarily to improve their solubility in various solvents. Yet modified carbon nanotube electrodes
also allow the electrochemist to tailor the properties of the carbon nanotubes, or the electrode surface to impart desired
properties such as enhanced sensing capabilities. In this review we attempt to comprehensively cover the different chemical
and electrochemical modification strategies and research carried out using modified carbon nanotubes for electroanalytical
and bioanalytical applications. Furthermore we also discuss the use of modified carbon nanotubes in electrocatalysis and biocatalysis
from an analytical aspect, as well as seeking to dispel some of the myths surrounding the “electrocatalytic” properties of
carbon nanotubes. 相似文献
17.
Fran?ois G Chevallier Biljana Sljuki? Gregory G Wildgoose Li Jiang Timothy G J Jones Richard G Compton 《Chemphyschem》2006,7(3):697-703
A model for the adsorption process at spherical microparticles under transient diffusion conditions has been developed and solved using numerical simulation. This model allowed us to demonstrate that the system is controlled by two main dimensionless parameters: the adsorption rate constant ka' and the saturation parameter beta. Analytical models for the adsorption process at spherical microparticles under steady-state mass transport conditions have been derived. These models use previously developed empirical relationships for the calculation of the mass transfer coefficient (kc). The properties of the system were studied for both the case where mass transport is described by diffusion only and the case where it is the result of a coupled diffusion/convection process. These mathematical tools were then used to analyse the results obtained for the uptake of CuII by glassy carbon powder modified with the monomer L-cysteine methyl ester and to extract a minimum value for the adsorption rate constant which was found to be of the order of 10(-4) cm s(-1). 相似文献
18.
Wain AJ Wildgoose GG Heald CG Jiang L Jones TG Compton RG 《The journal of physical chemistry. B》2005,109(9):3971-3978
The influence of lithium ion pairing on the voltammetric reduction of anthraquinone in acetonitrile is reported. On gold electrodes, the single electron reduction generates a radical anion which forms a complex with lithium cations from the electrolyte. In situ ESR studies support this finding, and signal intensity measurements are used to estimate a value for the complexation equilibrium constant. Values calculated were of the of the order of 6000 mol(-1) dm3. Potential shift measurements and Digisim modeling are shown to be in support of a complexation mechanism in which a little of the complex precipitates on the electrode surface. The effect of lithium ion pairing is also demonstrated for the case in which 1-anthraquinonyl groups are covalently attached to multiwalled carbon nanotubes abrasively immobilized on a basal plane pyrolytic graphite electrode. 相似文献
19.
Nathan S. Lawrence Markus Pagels Simon F. J. Hackett Sean McCormack Andrew Meredith Timothy G. J. Jones Gregory G. Wildgoose Richard G. Compton Li Jiang 《Electroanalysis》2007,19(4):424-428
A pH probe based on a carbon‐epoxy electrode design is discussed. The electrode consists of three redox active components within a carbon epoxy matrix. These are the pH sensitive species anthraquinone and phenanthrenequinone, along with the pH insensitive ferrocene reference compound. The values of the peak potentials when combined are shown to shift by 120 mV/pH unit at 25 °C with respect to the ferrocene reference potential. 相似文献
20.
Christopher Batchelor-McAuley Gregory G. Wildgoose 《Electrochemistry communications》2008,10(8):1129-1131
The apparent electrocatalytic detection of aspirin and salicylic acid is compared using NiO nanoparticles and microparticles supported on graphitic electrodes using abrasive and non-abrasive (drop-dry) immobilisation. However control experiments revealed that, the observed voltammetry is not due to the immobilised NiO materials, but is instead due to the underlying graphitic substrates. Abrasive immobilisation of NiO microparticles on a graphite electrode abrades the underlying electrode surface, introducing more electroactive edge-plane defects. Even when drop-dry immobilisation is used (i.e. non-abrasive), appropriate control experiments are still required as other experimental methods employed may change the nature of the underlying substrate. 相似文献