Investigation on the Catalytic Performance of Reduced‐Graphene‐Oxide‐Interpolated FeS 2 and FeS for Oxygen Reduction Reaction

The oxygen reduction reaction (ORR) plays a key role in many kinds of energy conversion and energy storage devices, especially in fuel cells. Developing low‐cost, easily prepared, and high‐efficiency catalysts is a crucial factor for the large‐scale applications of fuel cells. Herein, we report the reduced graphene oxide (rGO) interpolated FeS 2 and FeS as low cost and high performance electrocatalyst for ORR in the alkaline electrolyte. Cyclic voltammetry tests indicate that the onset potential of the ORR for FeS 2 @rGO is −0.142 V, which is close to the state‐of‐the‐art commercial Pt/C (‐0.114 V) catalyst. A low Tafel slope of ∼ 98 mV/decade and high durability are also observed for the FeS 2 @rGO composite for ORR. The reaction kinetics study shows that the rGO‐interpolated FeS 2 catalyzed ORR major happen through 4‐electron pathway, but the rGO‐interpolated FeS catalyzed ORR major happen through mixed 2‐electron and 4‐electron pathway. The S−S bond of FeS 2 play the major role for the happening of ORR through 4‐electron pathway.