Electrosynthesis of Hydrogen Peroxide in a Novel Flow-through Electrochemical Reactor with in Situ generated Oxygen

Abstract

Most of electrochemical advanced oxidation processes (EAOP´s) such as the electroFenton (EF), photo electroFenton (PEF), solar photo electroFenton (SPEF) and electro-peroxone (E-peroxone) processes use hydrogen peroxide (H2O2) as its core reactant due to its possibility to react with some catalysts (Fe2+, O3) yielding high oxidant hydroxyl radicals to be used in the degradation of persistent organic pollutants [1]. Carbonaceous materials like carbon felt, carbon cloth and reticulated vitreous carbon (RVC) are the most used because of its capability to accumulate H2O2 [2,3]. The use of these materials is often in gas diffusion electrodes which are based in the injection of air from an external source to an air chamber located behind the electrode allowing the dispersion of the gas inside the electrode promoting the oxygen reduction [3]. This work deals with the in situ electrosynthesis of H2O2 in a flow through reactor using RVC as cathode material and Ti|Ir-Ta oxides expanded mesh as anode to improve the oxygen evolution reaction with subsequent reduction of O2 on the RVC to yield H2O2. The electrochemical cell consists of a flow channel where the electrodes are placed along its length, allowing the electrolyte to flow through them forcing the transport of oxygen bubbles inside the porous carbon material for its reduction to H2O2. [1] Sirés I., Brillas., E. Remediation of water pollution caused by pharmaceutical residues sed on electrochemical separation and degradation technologies: A review. Environmental International, 40 (2018) 212-229. [2] Coria G., Pérez T., Sirés I., Nava J.L., Mass transport studies during dissolved oxygen reduction to hydrogen peroxide in a filter-press electrolyzer using graphite felt, reticulated vitreous carbon and boron-doped diamond as cathodes. Journal of Electroanalytical Chemistry, 757 (2015) 225-229. [3] Pérez T., Coria G., Sirés I., Nava J.L., Uribe A.R., Electrosynthesis of hydrogen peroxide in a filter-press flow cell using graphite felt as air-diffusion cathode. Journal of Electroanalytical Chemistry, 812 (2018) 54-58.