Enhanced Electrocatalytic Behaviour of Poy(aniline-co-2-hydroxyaniline) Coated Electrodes for Hydrogen Peroxide Electrooxidation
Polymer-coated electrodes are widely used for the detection and oxidation of hydrogen peroxide (H2O2). Conducting polyaniline (PANI), poly (2-hydroxyanilne) (PHA), and their copolymer poly(aniline-co-2-hydroxyaniline) (PACHA) were electrochemically synthesized on a gold substrate for H2O2 detection and analysis. Cyclic voltammetry (CV), square wave voltammetry (SWV), and differential pulse voltammetry (DPV) techniques were used for electroanalysis. Both PACHA and PANI greatly reduced the gold overpotential for H2O2 oxidation with enhanced current densities. The PACHA- and PANI-coated electrodes showed oxidative peaks at 0.30 and 0.50 V, respectively, in the presence of 1.4 × 10−6 M H2O2, while PHA-coated electrodes exhibited no response. The fabricated electrodes displayed a linear response towards H2O2 in range of 2 × 10−7 to 1.4 × 10−6 M, with very low detection limits (LODs) of 1 × 10−7 M (for PACHA) and 1.15 × 10−7 M (for PANI) evaluated from CV data. In case of SWV and DPV, the LODs were found to be 1.78 × 10−7 M (for PACHA) and 1 × 10−7 M (for PANI), respectively. The materials exhibit high sensitivity of 650 A/Mcm2 and show good stability. The PACHA-coated electrode shows better capacitance (1.84 × 10−3 F) than PHA- (2.52 × 10−4 F) and PANI-coated (1.17 × 10−3 F) electrodes.