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 O₂ 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 electrogeneration and decreased H₂O₂ electroreduction.