Highly efficient and selective electrocatalytic hydrogen peroxide production on Co-O-C active centers on graphene...

Electrochemical oxygen reduction provides an eco-friendly synthetic route to hydrogen peroxide (H₂O₂), a widely used green chemical. However, the kinetically sluggish and low-selectivity oxygen reduction reaction (ORR) is a key challenge to electrochemical production of H₂O₂ for practical applications. Herein, we demonstrate that single cobalt atoms anchored on oxygen functionalized graphene oxide form Co-O-C@GO active centres (abbreviated as Co₁@GO for simplicity) that act as an efficient and durable electrocatalyst for H₂O₂ production. This Co₁@GO electrocatalyst shows excellent electrochemical performance in O₂-saturated 0.1 M KOH, exhibiting high reactivity with an onset potential of 0.91 V and H₂O₂ production of 1.0 mg cm^-2 h^-1 while affording high selectivity of 81.4% for H₂O₂. Our combined experimental observations and theoretical calculations indicate that the high reactivity and selectivity of Co₁@GO for H₂O₂ electrogeneration arises from a synergistic effect between the O-bonded single Co atoms and adjacent oxygen functional groups (C-O bonds) of the GO present in the Co-O-C active centres.