Red-blood-cell like nitrogen-doped carbons with highly catalytic activity towards oxygen reduction reaction

A highly active nitrogen-doped catalyst with a unique red-blood-cell(RBC)like structure is reported for oxygen reduction reaction(ORR).The catalyst Fe,N-C@carbon-900 was prepared by pyrolysis of the polyaniline(PANI)and polystyrene(PS)composites with adsorption of ferric ion on the shell of sphere structure at 900 ℃.Fe,N-C@carbon-900 with a unique RBC-like structure provides plenty of catalytic sites combining the electrical conductivity of the carbon sphere with the catalytic activity of the nitrogen-doped layer.The four-electron reduction pathway is selected for the catalyst Fe,N-C@carbon-900.The catalyst exhibit the ORR E_onset at 0.87 V(potentials is versus to reversible hydrogen electrode (RHE)),E_1/2 at 0.78 V and high diffusion-limiting current density(5.20 mA/cm²).Furthermore,this work indicates that both N and Fe accounted for high activity of the catalyst Fe,N-C@carbon-900 toward the oxygen reduction process.It is concluded that Fe and N exhibit synergistically promotion in the ORR activity for the catalyst Fe,N-C@carbon-900.We also provide a rational design of electrocatalysts with high ORR activity to further clarify the essential ORR sites of heteroatom doped carbon materials for fuel cells and metal-air battery applications.