A direct phase separation approach synthesis of hierarchically porous functional carbon as an advanced electrocatalyst for oxygen reduction reaction

Heteroatom-doped hierarchically porous carbon materials have attracted great research interests for applications in both energy conversion and storage devices. Rational constructing the architecture, selecting heteroatoms and tuning their bonding structure are keys for the synthesis of high performance carbon based electrode. Here we develop a phase separation approach for the synthesis of a novel porous exfoliated carbon block. Our protocol allows for simultaneous formation of exfoliated porous structure and heteroatom doping through a simple pyrolysis process. The as obtained sample is composed of graphene-like carbon layers, which are enriched with nitrogen dopants in the basal plane and phosphorus functional groups at the carbon edge. The particular structure and surface chemistry of the sample endow the materials with high catalytic properties for oxygen reduction reaction (ORR). On the one hand, the opened-edge thin carbon layers form open channels for efficient mass and ion transportation; On the other hand, the heteroatom dopants and functional groups change the surface chemistry and thus the electronic structure and the surface wettability of the host materials, further enhancing the intrinsic electrochemical performance of the carbon material.