Improving the Efficiency of Carbon Cloth for the Electrogeneration of H₂O₂: Role of Polytetrafluoroethylene and Carbon Black Loading

Abstract

In this work, H2O2 is electro-generated in the cathodic compartment of a divided filter-press cell with a carbon cloth in the configuration of a gas diffusion electrode using air as oxygen source. The effect of Teflon® content was studied and it was found that the appropriate content is within the range of 10-20%. The production was greatly enhanced after the air-brushing deposition (and subsequent annealing) of simply 0.5 mg of carbon black. Higher additions clogged the pores and resulted counterproductive in terms of H2O2 generation. At a current density of 25 mA cm-2, the production rate was 15 mg H2O2 h-1 cm-2 with a current efficiency close to 100%. Production rate increased with current density up to more than 40 mg H2O2 h-1 cm-2 at 87.5 mA cm-2. The good performance and ease of preparation of this electrode make it an interesting alternative to generate hydrogen peroxide for Electro-Fenton processes.