A facile iron-sulfur double-doping strategy to prepare high performance FeNx/S-NC electrocatalyst for oxygen reduction reaction in zinc-air battery

Herein, a facile iron-sulfur double-doping strategy is developed for the synthesis of highly active FeNx/S-NC catalyst by pyrolysis double-doped polypyrrole precursor, PPy-Fe3+-SCN-. The unique precursor firstly prepared coordinating SCN- with Fe3+ ions adsorbed in situ into matrixes (PPy-Fe3+) during an oxidative polymerization process. Subsequent PPy-Fe3+-SCN- produced containing sites Fe-Nx and thiophene-like sulfur structures. Furthermore, has larger specific area than FeNx-NC without precursor. Meanwhile, depending on presence structure, shows higher valence band (-7.27 eV) that (-7.76 eV), leading to smaller energy gap LUMO level O2. excellent initial potential 1.02 V half-wave 0.90 V, achieving one highest catalytic activities based Fe-N-C reported so far, ORR alkaline environment. For stability test, still maintains this 91% current density after 20000 s, which also better Pt/C. Finally, employed as cathode material zinc-air battery, greater maximum peak power capacity