▎ 摘　　要

2D carbon nanosheet provides an attractive prospect in the field of electrochemical catalysis, and how to prepare atomic level 2D carbon nanosheet with good electrochemical performance by an easy and efficient method is still a big challenge. Herein, graphene-like N-doped carbon nanosheet with the thickness of 0.6-2 nm is prepared by one-step and solvent-free method of pyrolyzing dopamine (DA) confined by graphitic carbon nitride (g-C3N4). Pyrocondensation polymerization of DA within the interlayers of g-C3N4 to form N-doped benzene-fused ring structures at high temperature is reported, and DA-derived graphene-like carbon nanosheet at 1000 degrees C exhibits an excellent oxygen reduction reaction activity in alkaline environment and pronounced catalytic activity in acidic medium. It can further improve the practical application of DA-based carbon materials.