(B, N)‐Rich B−C−N Nanosheet‐assembled Microwires as Effective Electrocatalysts for Oxygen Reduction Reaction

Abstract Developing highly active and stable nanocarbon electrocatalysts for the oxygen reduction reaction (ORR) in alkaline medium has attracted much attention due to their potential as an alternative to traditional metal‐based or noble metal catalysts. Herein, a unique micro‐nano structure of (B, N)‐rich B−C−N nanosheet‐assembled microwires (BCNNAM) were synthesized and driven electrochemical oxide reduction reaction. The diameter of the microwires about 1 μm, while the nanosheets have an average thickness of less than 20 nm. The compact nanosheets are mostly separated with a bending, curling and crumpling morphology. All those constitutes a ternary system with large surface area and abundant activity sites facilitate fast mass/electron transport for ORR catalytic activity. Thus, the B, N‐rich B−C−N nanosheet‐assembled microwires show significantly improved electrocatalytic activity with an onset potential of 0.95 V and half‐wave potential of 0.83 V compared to BNNAM, nitride‐doped carbon, porous carbon and a commercial Pt/C electrocatalyst. Such high catalytic performance of B, N‐rich B−C−N micro‐nano structures is due to the enhanced activity by the coexistence of B, C and N and the mass transfer promoted by the unique hierarchical porous structure.