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Electrochemical Behavior of Gold Nanoparticles Generated In Situ on 3‐(1‐Imidazolyl)propyl‐silsesquioxane
Author(s) -
Simon Ícaro A.,
Vacaro Bernardo B.,
Nunes Michael R.,
Benvenutti Edilson V.,
Dias Silvio L. P.,
Gushikem Yoshitaka,
Arguello Jacqueline
Publication year - 2013
Publication title -
electroanalysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.574
H-Index - 128
eISSN - 1521-4109
pISSN - 1040-0397
DOI - 10.1002/elan.201300130
Subject(s) - sodium borohydride , colloidal gold , silsesquioxane , cyclic voltammetry , borohydride , electrochemistry , inorganic chemistry , nanoparticle , potassium ferrocyanide , overpotential , detection limit , chemistry , catalysis , nuclear chemistry , materials science , electrode , nanotechnology , organic chemistry , chromatography , polymer
Gold nanoparticles of different morphologies have been synthesized on a silica‐based organic‐inorganic hybrid material for catalytic applications. The gold nanoparticles formations proceed through in situ chemical reduction of the AuCl 4 − anions previously adsorbed on 3‐(1‐imidazolyl)propyl‐silsesquioxane, which plays the role of substrate and stabilizer. Two distinct reducing agents, sodium citrate and sodium borohydride, were employed to generate gold nanoparticles of different sizes. UV‐vis diffuse reflectance as well as transmission electron microscopy were employed to evaluate the particle’s morphology. Modified carbon paste electrodes were prepared from these materials and their electrochemical behavior investigated using potassium ferrocyanide and 4‐nitrophenol as redox model compounds. Both AuNPs‐modified electrodes decreased the overpotential of 4‐nitrophenol reduction by around 90 mV compared to the unmodified electrode as evidenced by cyclic voltammetry experiment. However, the smaller diameter particles (borohydride‐reduced) produced more significant catalytic effect as a consequence of their large surface area. Regarding the sensing parameters, the sensitivity is higher for the borohydride‐reduced AuNPs while the values of limit of detection are of the same order of magnitude. Thus, the detection limit and sensitivity are 70.0±0.6 nM and 187 µA/mM for the citrate‐reduced AuNPs; and 75.0±2.2 nM and 238 µA/mM for the borohydride‐reduced AuNPs.