Lack of nano size effect on electrochemistry of dopamine at a gold nanoparticle modified indium tin oxide electrode

Gold nanoparticles (AuNPs) have unique properties, making them attractive for electronic and energy‐conversion devices and as (electro)catalysts for electrochemical sensors. In addition to the size and shape of AuNPs, the electrocatalytic properties of AuNP‐sensors are also determined by the stabilizing agent used in their synthesis. Here, AuNPs were synthesized with citrate, alginate and quercetin, obtaining spherical and negatively charged nanoparticles. The AuNPs were used to modify glassy carbon electrodes (AuNPs/GCE), which were characterized by scanning electron microscopy and electrochemical techniques. The AuNPs/GCE showed aggregates of different sizes and degrees of dispersion on the electrode surface depending on the stabilizing agent. The AuNP's aggregates affect the homogeneity of the film, the reproducibility of the electrodes and their response in buffer solution. Finally, to evaluate the electrocatalytic ability of the AuNPs/GCE, we studied the oxidation of two analytes with opposite charges: (1) sunset yellow (negative) and (2) hydrazine (positive). Compared with GCE, the AuNPs/GCE showed good electrocatalytic properties for hydrazine, increasing the current up to 50 % and shifting the potential by almost 400 mV, depending on the AuNP used. For the negatively charged analyte, the current decreased up to 50 % and no shift in potential was observed. Thus, the electrocatalytic properties of the AuNPs showed to be highly dependent on the nature of the analyte.

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“…1) . This experiment is commonly used to confirm the electrodeposition or the attachment of AuNPs .

true {A u}^{0} + {3 H}_{2} O \leftrightarrow {A u}_{2} O_{3} + {6 H}^{+} + {6 e}^{-}

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Section: Resultsmentioning

confidence: 99%

Electrochemical Characterization and Electrocatalytic Application of Gold Nanoparticles Synthesized with Different Stabilizing Agents

et al. 2017

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“…This ITO nanoparticle-modified electrode was cut to 2.5 Â 0.5 cm 2 size for the following experiments. Gold film electrodes were prepared by sputtering gold on silanized ITO glass substrates according to the published procedure [19]. In brief, ITO electrodes were silanized in 5% (V/V) MPTES in dry toluene for 24 h. After carefully washing, about 40 nm thick gold film was deposited by sputtering.…”

Section: Methodsmentioning

confidence: 99%