Integrating Nanoflower Morphology into Cr-N-C Catalysts for High-Rate H2O2 Electrosynthesis

Abstract Electrochemical two-electron oxygen reduction reaction (2e− ORR) for hydrogen peroxide (H2O2) production in acidic media holds great practical promise but remains bottlenecked by the scarcity of non-precious metal catalysts and severe mass transport limitations. Building on our previous identification of the inherent ORR-active nature of Cr-Nx moieties, herein, we report a flower-like single-atom Cr-N-C catalyst (F-CrNC) through rational morphological engineering. The well-defined three-dimensional open architecture maximizes active site exposure and shortens mass-transfer distances, thereby accelerating O2 supply and, crucially, the outward diffusion of H2O2 to mitigate side reactions. Driven by this morphological superiority, F-CrNC exhibits impressive apparent activity and selectivity, achieving a H2O2 productivity of 7.45 mol gcat−1 h−1 (at 100 mA) with over 80% Faradaic efficiency in a flow cell. This work highlights the decisive role of nanoscale structure design in translating intrinsic catalytic potential into real-device performance for H2O2 electrosynthesis.