Nitrogen‐Doped Carbon Nanosheets with Size‐Defined Mesopores as Highly Efficient Metal‐Free Catalyst for the Oxygen Reduction Reaction

Nitrogen-doped carbon nanosheets (NDCN) with size-defined mesopores are reported as highly efficient metal-free catalyst for the oxygen reduction reaction (ORR). A uniform and tunable mesoporous structure of NDCN is prepared using a templating approach. Such controlled mesoporous structure in the NDCN exerts an essential influence on the electrocatalytic performance in both alkaline and acidic media for the ORR. The NDCN catalyst with a pore diameter of 22 nm exhibits a more positive ORR onset potential than that of Pt/C (-0.01 V vs. -0.02 V) and a high diffusion-limited current approaching that of Pt/C (5.45 vs. 5.78 mA cm(-2) ) in alkaline medium. Moreover, the catalyst shows pronounced electrocatalytic…