Synergetic Contribution of Boron and Fe-N-x Species in Porous Carbons toward Efficient Electrocatalysts for Oxygen Reduction Reaction

The development of porous carbon materials as highly efficient, durable, and economic electrocatalysts for oxygen reduction reaction (ORR) is of great importance for realizing practical applications of many significant energy conversion and storage devices. Herein, we demonstrate a general approach to porous carbons decorated with boron centers and atomically dispersed Fe-N-x species (denoted as FeBNC). The as-prepared FeBNC can serve as efficient electrocatalysts for ORR in an alkaline medium with a half-wave potential of 0.838 V vs RHE, comparable to that of the state-of-the-art porous carbon catalysts and the benchmark system Pt/C. Theoretical calculation reveals that incorporation of boron dopant into traditional Fe-N-x species-enriched porous carbons significantly lowers the energy barrier for oxygen reduction and therefore boosts the overall performance. This work not only provides an easy method to synthesize B-doped Fe-N-x centers-enriched porous carbons as highly efficient electrocatalysts for ORR and Zn-air batteries but also proves the origin of the catalytic performance from both B dopants and Fe-N-x sites.