In Situ Electrochemical Generation of Hydrogen Peroxide in Alkaline Aqueous Solution by using an Unmodified Gas Diffusion Electrode

Hydrogen peroxide (H2O2) is an oxidizing agent commonly used for various applications and is available in aqueous solution in a wide range of concentrations. This work describes the H2O2 electrogeneration process in alkaline medium (KOH 1.0 mol L-1), using an unmodified gas diffusion electrode (GDE) manufactured with Printex 6L carbon. The experiments were performed in a single-compartment electrochemical cell equipped with a GDE as the working electrode, which was fed with N-2 or O-2 at a pressure of 0.2bar. Electrolysis experiments were performed at a constant potential (-0.5 <= E <=-1.4V) for 90min. The H2O2 concentration reached a maximum value of 3370mgL(-1) at -1.1V (vs. Ag/AgCl), and H2O2 electrogeneration followed pseudo-zero-order kinetics with an apparent rate constant k(app)=59.7mgL(-1) min(-1). A low energy consumption of 8.0 kWh kg(-1) was calculated for these electrogeneration conditions.