Single‐atom Iron Catalyst with Biomimetic Active Center to Accelerate Proton Spillover for Medical‐level Electrosynthesis of H2O2Disinfectant

Abstract

AbstractElectrosynthesis of H2O2has great potential for directly converting O2into disinfectant, yet it is still a big challenge to develop effective electrocatalysts for medical‐level H2O2production. Herein, we report the design and fabrication of electrocatalysts with biomimetic active centers, consisting of single atomic iron asymmetrically coordinated with both nitrogen and sulfur, dispersed on hierarchically porous carbon (FeSA‐NS/C). The newly‐developed FeSA‐NS/C catalyst exhibited a high catalytic activity and selectivity for oxygen reduction to produce H2O2at a high current of 100 mA cm−2with a record high H2O2selectivity of 90 %. An accumulated H2O2concentration of 5.8 wt.% is obtained for the electrocatalysis process, which is sufficient for medical disinfection. Combined theoretical calculations and experimental characterizations verified the rationally‐designed catalytic active center with the atomic Fe site stabilized by three‐coordinated nitrogen atoms and one‐sulfur atom (Fe‐N3S‐C). It was further found that the replacement of one N atom with S atom in the classical Fe‐N4‐C active center could induce an asymmetric charge distribution over N atoms surrounding the Fe reactive center to accelerate proton spillover for a rapid formation of the OOH* intermediate, thus speeding up the whole reaction kinetics of oxygen reduction for H2O2electrosynthesis.