Dipole–Dipole Tuned Electronic Reconfiguration of Defective Carbon Sites for Efficient Oxygen Reduction into H2O2

Abstract

AbstractMetal‐free carbon‐based materials are one of the most promising electrocatalysts toward 2‐electron oxygen reduction reaction (2e‐ORR) for on‐site production of hydrogen peroxide (H2O2), which however suffer from uncontrollable carbonizations and inferior 2e‐ORR selectivity. To this end, a polydopamine (PDA)‐modified carbon catalyst with a dipole–dipole enhancement is developed via a calcination‐free method. The H2O2 yield rate outstandingly reaches 1.8 mol gcat−1 h−1 with high faradaic efficiency of above 95% under a wide potential range of 0.4–0.7 VRHE, overwhelming most of carbon electrocatalysts. Meanwhile, within a lab‐made flow cell, the synthesized ORR electrode features an exceptional stability for over 250 h, achieved a pure H2O2 production efficacy of 306 g kWh−1. By virtue of its industrial‐level capabilities, the established flow cell manages to perform a rapid pulp bleaching within 30 min. The superior performance and enhanced selectivity of 2e‐ORR is experimentally revealed and attributed to the electronic reconfiguration on defective carbon sites induced by non‐covalent dipole–dipole influence between PDA and carbon, thereby prohibiting the cleavage of O–O in OOH intermediates. This proposed strategy of dipole–dipole effects is universally applicable over 1D carbon nanotubes and 2D graphene, providing a practical route to design 2e‐ORR catalysts.