Harmonizing Cobalt Atom‐Cluster Moieties with Selective Oxygen Functional Groups for Augmented Electrocatalytic H2O2 Production

Abstract The cooperation between metal single atom (SA) and atomic cluster (AC) within an electrocatalyst has showcased enormous potential in 2e− oxygen reduction reaction (ORR) for hydrogen peroxide (H2O2) production. Nevertheless, developing an SA‐AC catalyst with the synergy of optimized functional groups to afford advanced catalytic capability has been challenging. Herein, a new and highly effective catalyst with tandem cobalt SA‐AC moieties and C─O─C functional group decorations anchored over carbon nanotubes is presented, which is denoted as Co SA‐AC(C─O─C). As an electrocatalyst, Co SA‐AC(C─O─C) demonstrates favorable activity, selectivity, and stability for 2e− ORR, delivering an onset potential of 0.72 V (vs RHE) and an H2O2 selectivity of 97.6% in 0.5 m H2SO4. In a flow‐cell reactor, the Co SA‐AC(C─O─C) realizes an H2O2 production rate of 3.88 mol gcat−1 h−1 at 300 mA cm−2 targeting on‐site pollutant treatment by integrating a Fenton‐like process. The theoretical computations guide the selection of C─O─C among the functional group decorations and reveal the actual active sites to locate at Co SAs, while the synergistic effect of Co ACs and C─O─C groups helps optimize the *OOH binding and modulate the electronic structure.