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 g_cat⁻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.