Low-Coordinated Co-N-C on Oxygenated Graphene for Efficient Electrocatalytic H2O2 Production

Electrochemical H2O2 production through the 2-electron oxygen reduction reaction (ORR) is a promising alternative to the energy-intensive anthraquinone process. Herein, by simultaneously regulating the coordination number of the atomically dispersed cobalt sites and the nearby oxygen functional groups via a one-step microwave thermal shock, a highly selective and active Co-N-C electrocatalyst for H2O2 electrosynthesis that exhibits a high H2O2 selectivity (91.3%), outstanding mass activity (44.4 A g(-1) at 0.65 V), and large kinetic current density (11.3 mA cm(-2) at 0.65 V) in 0.1 m KOH is obtained. In strong contrast to the typical Co-N-4 moieties for the 4-electron ORR, the present Co-N-C catalyst possesses a low-coordinated Co-N-2 configuration and abundant epoxide groups, which work in synergy for promoting the 2-electron ORR, as demonstrated by a series of control experiments and theoretical simulations. This study may provide an effective avenue to modulating the composition and structure of electrocatalysts at the atomic scale, leading to the development of new electrocatalysts with unprecedented reactivity.