Fe, P, N- and FeP, N-doped carbon hollow nanospheres: A comparison study toward oxygen reduction reaction electrocatalysts.

[Display omitted] • FeP, N -Carbon and Fe, P, N -Carbon hollow nanospheres were prepared. • Fe, P, N -Carbon showed the onset potential of 1.03 V and half wave potential of 0.89 V when used as ORR electrocatalysts. • The ORR performance of Fe, P, N -Carbon was better than that of FeP, N -Carbon. • The unique nanostructure and favorable chemical components contributed to excellent ORR performance. In recent years, carbon materials co-doped with transition metals and heteroatoms have been widely used in the oxygen reduction reaction (ORR) as an alternative to platinum/carbon catalysts because of their high efficiency, low price, and appropriate sustainability. Herein, we report the synthesis of FeP, N -doped carbon (FeP, N -Carbon) hollow nanospheres (HNSs) and Fe, P, N -doped carbon (Fe, P, N -Carbon) HNSs. The FeP, N -Carbon was obtained via the pyrolysis of poly(o -phenylenediamine) (PoPD) HNSs in the presence of Fe(NO 3) 3 and phytic acid (PA), whereas Fe, P, N -Carbon was obtained by first pyrolyzing PoPD HNSs with Fe(NO 3) 3 , followed by another cycle of pyrolysis with PA. Fe, P, N -Carbon exhibited a better ORR performance than FeP, N -Carbon, with an onset potential of 1.03 V, a half-wave potential of 0.89 V and a limiting current density of 5.75 mA cm−2. The findings will provide insights into the controlled synthesis of transition-metal-heteroatom-codoped carbon nanomaterials for the development of advanced ORR electrocatalysts. [ABSTRACT FROM AUTHOR]