Electrochemical production of extremely high concentrations of hydrogen peroxide in discontinuous processes

This work reports the development and application of a gas diffusion electrode based on Printex L6 carbon for the production of high concentrations of hydrogen peroxide (H2O2) using a flow-by electrochemical reactor in discontinuous operation mode. With the application of current densities ranging between 75 and 200 mA cm(-2), the use of Printex L6 carbon-based GDE generated H2O2 concentrations in the range of 4,000-5,000 mg/L, despite the formation of scavengers. The proposed technique also promoted the production of ozone and persulfate species though at low concentrations. The application of the Printex L6 carbon-based GDE led to a roughly 3.4-3.9-fold increase in H2O2 concentrations compared to Vulcan XC-72R carbon-based GDE which was used for comparison purposes (Vulcan XC-72R carbon is currently-one of the most widely employed carbon materials in electrochemical processes). In addition, the Printex L6 carbon-based GDE exhibited high stability with a lifetime of 36 Ah (7,5 days) of uninterrupted use at 200 mA cm(-2). The improvements observed in the Printex L6 carbon-based GDE can be attributed to the presence of higher amounts of carboxyl oxygenated functional groups in the material and its greater electrochemically active surface area compared to the Vulcan XC-72R-based GDE.