Enhanced Fe dispersion via “pinning” effect of thiocyanate ion on ferric ion in Fe-N-S-doped catalyst as an excellent oxygen reduction reaction electrode

In this study, by using thiocyanate as an iron ion dispersing agent, the pinning effect of thiocyanate ion (SCN⁻) enables the high dispersion of Fe³⁺ in a nitrogen-doped carbon polymer and significantly promotes ORR catalysis in both acidic and alkaline media. It shows 47.3 A g⁻¹ kinetic ORR current density in 0.1 M H₂SO₄ solution at 0.8 V vs. RHE. In addition, SCN⁻ can dope into the base material and modify the surface of catalysts, which generates strong cyanide N functional groups. Additionally, it also has a higher BET surface area and more uniform granularity, which accounts for the enhancement in mass transport.