Highly exposed active sites of Fe/N co-doped defect-rich graphene as an efficient electrocatalyst for oxygen reduction reaction.

A defect-rich interconnected hierarchical three-dimensional Fe and N co-doped graphene has been prepared by a facile synthesis with poly (2, 5-benzimidazole) (ABPBI) as nitrogen and carbon sources and CaCO 3 as the template. ABPBI possesses abundant nitrogen, and pyrolysis of ABPBI is helpful to form graphene structure. CaCO 3 and its decomposition products CO 2 can promote the formation of interconnected hierarchical porous three-dimensional graphene, which possesses more defects and exposed active sites. Benefiting from the defective catalysis mechanism, rich defects catalysts are applied as electrode materials to enhance the catalytic performance for oxygen reduction reaction (ORR). Electrochemically, the half-wave potential (E 1/2 ) of Fe-3D-NG#800 is 0.84 V (vs. RHE), and the accelerated durability tests shows the E 1/2 of Fe-3D-NG#800 shifted by a 21 mV drop after cyclic voltammetry scanning for 5000 cycles. Therefore, Fe-3D-NG#800 has excellent activity and durability than 20 wt % Pt/C.