Chemical and electrochemical pre-treatment of polycrystalline platinum electrodes and interfering substances analysis

Abstract

Several methodologies are reported in the literature that aim to remove adsorbed substances from polycrystalline platinum electrode surfaces in order to obtain the real electroactive areas. However, those procedures often use highly toxic reagents for humans. Because of that, a methodology for the pretreatment of both the platinum electrode and the working glassware using less harmful solutions to humans and the environment was developed. All materials should be immersed in KMnO4 1 % for 12 h for the removal of interfering organic; then, rinse with ultrapure water and acidified H2O2 5 %. Subsequently, a 5 % HNO3 bath should be used to remove metallic contaminants and then performing a cyclic voltammetry in H2SO4 between H2 and O2 evolution potentials to obtain the voltammetric profile. The methodology is efficient since the real surface area of the working electrode increased by about 8 times compared to the untreated electrode. The paper also discusses the sources of interference and disturbances in the cyclic voltammogram arising from the methodology itself.