Local-environment regulation engineering to boost acidic H2O2 electrosynthesis on cobalt porphyrin molecular electrocatalyst

Abstract Electrosynthesis of hydrogen peroxide (H 2 O 2 ) based on proton exchange membrane (PEM) reactor represents a promising route to industrial-level H 2 O 2 production, while it is hampered by the lack of high-efficiency electrocatalysts in acidic medium. Herein, we present a local-environment regulation engineering to promote the H 2 O 2 selectivity up to 92% on the structurally-defined cobalt porphyrin molecular catalyst through precisely-controlling specific oxygen functional group (OFG) on the reduced graphene oxide carrier. X-ray adsorption spectroscopy and Kelvin probe unravel that carboxyl and epoxy indirectly cause the charge-accumulation of Co center via delocalization of π-electrons on carbon plane, while hydroxyl directly induces the charge-depletion via axial coordination with Co center. Density functional theory illuminates the positive correlation between the electron density of Co center and H 2 O 2 selectivity. At an industrial current density of 200 mA cm − 2 , the optimized catalyst unprecedentedly achieves a steady H 2 O 2 productivity of ~ 20 mol h − 1 g cat −1 in a flow cell and the continuous production of high-concentration (ca. 11 wt%) pure H 2 O 2 in a PEM electrolyzer, suggesting a practical application potential in H 2 O 2 industry.