Investigation on the Catalytic Performance of Reduced-Graphene-Oxide-Interpolated FeS2 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 FeS2 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 FeS2@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 similar to 98mV/decade and high durability are also observed for the FeS2@rGO composite for ORR. The reaction kinetics study shows that the rGO-interpolated FeS2 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 FeS2 play the major role for the happening of ORR through 4-electron pathway.