Abstract

Darya O. Perevezentseva¹, Elena A. Vaitulevich¹ and Vladimir I. Bimatov²

DOI : http://dx.doi.org/10.13005/ojc/340267

Was to study influence of silver nanoparticles (AgNPs) obtainment conditions on their electrochemical activity. They are as follows methods of initiation such as heating and irradiation, the stabilizer introduction order and the amount of reducing agent. Methods of spectrophotometry, cyclic voltammetry and transmission microscopy. It has been shown that in the absence of polyethylene glycol (PEG), a mixture of AgNPs of various shapes is formed: polyhedral, spherical, nanorods with an average particle size of up to 40 nm. In the presence of PEG, AgNPs of triangular shape of smaller size up to 20 nm predominate, which is caused by the reduction of silver ions on the surface of the nucleai. In the presence of PEG, the maximum of the absorption band of AgNPs is shifted to the short-wavelength region by 10 nm compared to the absorption bands of AgNPs obtained in the absence of PEG. It has been found that in the presence of PEG the height of the anode maximum of AgNPs obtained by irradiation is 3.7 times higher than that of AgNPs obtained by heating. The potential of this anodic maximum shifts to 100 mV to area of positive potential values, the one of the cathodic maximum shifts to 100 mV to area of negative potential values, which is associated with the formation of more stable AgNPs oxides obtained by irradiation. It has been shown that the order of introduction of the reagents determines parameters of electrochemical signals of the AgNPs. The electrochemical activity of AgNPs does not depend on the order of introduction of the reagents during their preparation. However, the potential of the anode maximum of AgNPs depend on it. It has been established that the amount of reducing agent affects their electrochemical activity. AgNPs obtained with PEG in a molar ratio [Ag]:[C₆H₅O₇^3-] = 1:5  have the most electrochemical activity compared to AgNPs obtained in the equimolar ratio of the reagents. The anode maximum of these AgNPs splits into two: the shoulder at E = 0.4 V and the maximum at E = 0.6 V. The appearance of the shoulder is associated with the oxidation of smaller AgNPs. Thus, the size and form of AgNPs determins their electrochemical activity. The synthesis conditions control their electrochemical behavior caused by a change in the state of their surface.

Silver Nanoparticles; Electrochemical Behavior; Polyethylene Glycol; Sol; Gel Synthesis

[ View HTML Full Text]