Two-Dimensional Conjugated Aromatic Networks as High-Site-Density and Single-Atom Electrocatalysts for the Oxygen Reduction Reaction

Two-dimensional conjugated aromatic networks (CAN) with ultra-thin conjugated layers (ca. 3.5 nm) and high single-metal-atom-site density (mass content of 10.7 wt %, and 0.73 metal atoms per nm2 ) are prepared via a facile pyrolysis-free route involving a one-step ball milling of the solid-phase-synthesized polyphthalocyanine. These materials display outstanding oxygen reduction reaction (ORR) mass activity of 47 mA mgcat.-1 represents 1.3- and 6.4-fold enhancements compared to Pt and Pt/C in benchmark Pt/C, respectively. Moreover, the primary Zn-air batteries constructed with CAN as an air electrode demonstrate a mass/volume power density of 880 W gcat.-1 /615 W cmcat.-3 and stable long-term operation for 100 h. This strategy offers a new way to design high-performance electrocatalysts with atomic precision for use in other energy-storage and conversion applications.