Highly efficient H2O2 electrogeneration from O2 reduction by pulsed current: Facilitated release of H2O2 from porous cathode to bulk

H2O2 production is the decisive factor of Electro-Fenton performance on contaminants degradation. Herein, a novel but simple strategy was proposed for drastically enhanced H2O2 production from anodic O-2 electroreduction. H2O2 concentration at steady-state is 99.5% higher under pulsed current of 2sON-2sOFF than under constant current when using reticulated vitreous carbon foam (RVC foam) cathode. This was caused by the facilitated H2O2 diffusion from the porous cathode to bulk as H2O2 electroreduction pathway was weakened. Additionally, the enhancement effect is more significant for RVC foam with low PPI. This strategy is also applicable to graphite felt (GF) cathode, in which a 56.0% higher H2O2 concentration was observed at steady-state under pulsed current of 2sON+ 2sOFF. Investigation on pulse frequency shows there exists an optimal frequency that achieves both effective H2O2 electro-generation and decreased H2O2 electroreduction. (C) 2017 Taiwan Institute of Chemical Engineers. Published by Elsevier B.V. All rights reserved.