Fe loaded and S, N co-doped carbon catalyst for oxygen reduction reaction with enhanced electrocatalytic activity and durability

Heteroatom-doped carbon is expected to be a replacement for commercial Pt/C as an efficient catalyst for oxygen reduction reaction (ORR). Here, we present synthesis of iron loaded and sulfur and nitrogen co-doped Fe/NC (Fe/SNC) through in-situ introduction of 2-aminothiazole molecules into ZIF-8 via the coordination of metal ions with organic ligands. Sulfur and nitrogen-doping in carbon supports effectively modulate the electronic structure of catalysts, increase the Brunauer-Emmett-Teller surface area, and expose a larger number of Fe-Nx activity centers. With increasing the doping amount of sulfur, the catalytic activity of Fe/SNC shows a volcano-type curve. The half-wave potential of the synthesized Fe/SNC-10 catalyst reaches 0.902 V. After 5,000 cycles of cyclic voltammetry, the half-wave potential of Fe/SNC-10 decreases by only 20 mV, demonstrating excellent stability. Due to the lower electronegativity of sulfur, the electronic structure of the Fe-Nx active center is modulated. Moreover, the larger atomic radius of sulfur cause defects on the carbon supports. Therefore, Fe/SNC-10 shows superior oxygen reduction activity and stability in alkaline solution compared with those of the Fe/NC catalyst. In addition, the zinc-air battery (ZAB) assembled with Fe/SNC-10 catalyst exhibits superior performance compared to those assembled with Fe/NC and Pt/C catalysts. This work provides a novel design strategy for advanced energy storage and conversion applications.