Preparation of a High Performance Electrocatalyst for Oxygen Reduction Reaction by Suppressing the Agglomeration of the Carbon Material with RbCl

Abstract Replacing platinum (Pt) electrocatalysts with metal‐free or non‐precious metal electrocatalysts for the oxygen reduction reaction (ORR) remains an enormous challenge. Herein, a new highly active spheroidal nanocarbon ORR electrocatalyst is synthesized by annealing a rubidium‐phytic acid gel. The catalyst is composed of N, P‐doped spheroidal nanocarbon modified by PO 4 − groups on the surface and with an ultralow content of Rb (0.005 wt%) (PON/C‐“Rb”). The agglomeration caused by annealing in the presence of phytic acid alone is completely suppressed by the addition of RbCl. Because more edges, defects and PO 4 − groups are present on the PON/C‐“Rb”, the as‐prepared PON/C‐“Rb” electrocatalyst exhibits an outstanding ORR activity with a half‐wave potential that is 40 mV more positive than that of the commercial Pt/C catalyst and a similar onset potential of 1.00 V in a 0.1 M KOH solution. More importantly, the primary zinc‐air battery with PON/C‐“Rb” as a cathode catalyst shows a specific capacity and an energy density of 705 mAh g Zn −1 and 860 Wh Kg Zn −1 , respectively, which are comparable to most of the best reported metal‐free and non‐precious metal catalysts.