Gas/Liquid Hydrodynamics in Hydrogen Peroxide Electrosynthesis via the 2e ^– Oxygen Reduction Reaction: From Interface to Pore

Electrosynthesis has emerged as a novel in situ green H₂O₂ production technology, where enhancing two-electron oxygen reduction reaction (2e^- ORR) selectivity and optimizing mass transfer are critical to enhancing synthesis efficiency. Interface modulation and pore structure engineering have significantly improved the performance to yield promising experimental outcomes. Nevertheless, the physical mechanisms underlying these modifications have been poorly elucidated. This review systematically examines gas/liquid hydrodynamics across scales from triple-phase interfaces (microscopic) to porous electrode pores (mesoscopic). The flow patterns of single-phase diffusion and two-phase flow in porous structures are clarified. Besides, key structural parameters governing these processes are identified by a combined modeling approach. By elucidating the coupling mechanism between gas/liquid flow behaviors and 2e^- ORR electrocatalysis synthesis efficiency at multiscales, this work provides mechanistic foundations for advancing H₂O₂ electrosynthesis.