An aqueous phase TEMPO mediated electrooxidation of 2-thiophenemethanol using MnO2–Pi dispersed nanocarbon spheres on a carbon fiber paper electrode

Abstract

An environmentally benign and economic method was developed for the electrocatalytic oxidation of 2-thiophenemethanol in an aqueous acidic medium. Nanocarbon spheres (NCS) coated on carbon fiber paper (CFP) were used as a host matrix to disperse manganese dioxide nanoparticles from phosphate buffer solution through electrochemical deposition. The developed electrode (MnO₂–Pi–NCS/CFP) was used as a working electrode for electrochemical oxidation of 2-thiophenemethanol in the presence of a mediator TEMPO in 0.01 M H₂SO₄ medium. Different analytical methods were used to characterize the modified electrodes. Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) were used to study the electrochemical properties of the modified electrodes. The electrochemically active surface area values calculated for bare CFP, NCS coated CFP and MnO₂–Pi–NCS/CFP electrodes were found to be 1.43 cm², 2.86 cm², and 6.72 cm² respectively for the geometric area of 0.7 cm² of the electrodes. Coating of NCS and MnO₂–Pi resulted in porosity and roughness of the CFP electrode which enhances the surface area. MnO₂–Pi–NCS/CFP demonstrated higher electrocatalytic activity for oxidation of 2-thiophenemethanol to 2-thiophenemethanal in aqueous acidic media with a TEMPO mediator compared to unmodified electrodes.