Energy efficient integrated H2O2 electrosynthesis via tailored bubble dynamics

Abstract

Integrating H₂O₂ electrosynthesis with anodic upgrading provides a pathway to spontaneous (electricity-free) operation.Here we investigate interfacial kinetic bottlenecks, especially on the anode, and identify factors that hinder the achievement of industrial-scale current densities. We use high-speed imaging in microelectrode systems and find that the organic substrate within the electrolyte acts as an interfacial bubble nucleation regulator. This substrate lowers the liquid-gas surface tension and significantly reduces the nucleation barrier for product gas bubbles. This reduction in the nucleation barrier leads to a higher frequency of microbubble formation and stagnant adhesion in anodic upgrading reactions compared to conventional water electrolysis. Guided by this mechanistic insight, we establish a fluidic strategy that enables efficient bubble removal in an MEA cell. Implementing an elevated electrolyte flow rate in an optimized MEA enables stable, biasfree co-electrosynthesis of H₂O₂, furoic acid, and H₂ at industrial-relevant current densities.