Enhancing H₂O₂ Electrosynthesis at Industrial-Relevant Current in Acidic Media on Diatomic Cobalt Sites

Abstract

Electrocatalytic synthesis of hydrogen peroxide (H₂O₂) in acidic media is an efficient and eco-friendly approach to produce inherently stable H₂O₂, but limited by the lack of selective and stable catalysts under industrial-relevant current densities. Herein, we report a diatomic cobalt catalyst for two-electron oxygen reduction to efficiently produce H₂O₂ at 50-400 mA cm^-2 in acid. Electrode kinetics study shows a >95% selectivity for two-electron oxygen reduction on the diatomic cobalt sites. In a flow cell device, a record-high production rate of 11.72 mol g_cat^-1 h^-1 and exceptional long-term stability (100 h) are realized under high current densities. <i>In situ</i> spectroscopic studies and theoretical calculations reveal that introducing a second metal into the coordination sphere of the cobalt site can optimize the binding strength of key H₂O₂ intermediates due to the downshifted d-band center of cobalt. We also demonstrate the feasibility of processing municipal plastic wastes through decentralized H₂O₂ production.