Evolution of Pt and Ag nanoparticles composites with polyphenazines onto ITO electrodes during the oxidation of H2O2 with ascorbic acid

Abstract

Six polyphenazine electrodes modified with platinum and silver nanoparticles deposited over conducting polymers have been prepared using electrochemical techniques. Phenazine monomers were electropolymerized on Indium tin oxide (ITO) and their morphology was explored by SEM-EDX and Raman spectroscopy. The main findings indicated that the polymers are not homogenously electrodeposited, having pores where metal nanoparticles can be nested, which can play an important role in the ionic exchange with the electrolyte. At longer deposition times, formation of clusters is observed with a loss of electrocatalytic activity and at shorter deposition times the growth step is not yet started and catalysis does not occur. Platinum nanoparticles with sizes of 10-60 nm are formed on the polymer agglomerates. Electrochemical measurements of H2O2 and H2O2-ascorbic acid were carried out as a model system and the electrodes have been characterized by SEM-EDX. The size of the nanoparticles and their aggregates decreased with respect to those of the original size. After an electrochemical cleaning, the sizes of aggregates were recovered which justify the reproducibility of the sensor. For Ag/Polymer/ITO, in all of cases, formation of dendrites plus silver nanoparticles was observed by SEM-EDX.

Platinum Nanoparticles/Poly(isoleucine) Modified Glassy Carbon Electrode for the Simultaneous Determination of Hydroquinone and Catechol

“…Figure 2(c and d) indicates the distribution of the platinum nanoparticles on the surface of the Poly(Isoleucine) film with size range from 30 nm to 100 nm. Crystallite aggregation of platinum nanoparticles forming bright flower‐like structures increased the porosity and roughness of the electrode as well as the electrochemical surface area [34]. The SEM images indicated that the platinum nanoparticles are effectively modified on Poly(Isoleucine) films.…”