Facile Method to Synthesize a High-Activity S-Doped Fe/SNC Single-Atom Catalyst by Metal–Organic Frameworks for Oxygen Reduction Reaction in Acidic Medium

Fe/NC single-atom catalysts containing atomically dispersed FeN4 moieties have exhibited encouraging activity comparable to that of Pt in aqueous acids and outstanding performance in practical proton exchange membrane fuel cells (PEMFCs). However, it is still challenging to design dispersive exposed Fe single atoms against agglomeration and tune Fe–Nx coordination configuration to maximize the intrinsic activity of each active site. Introducing a heteroatom, such as S, could effectively improve the activity of the Fe/NC catalyst. In this work, we synthesized a novel catalyst (denoted as Fe/SNC) by pyrolyzing Fe(SCN)3 and ZIF-8 precursors under media conditions. This in situ S-doped catalyst showed better activity (half-wave potential positively shifted by 25 mV) and stability (improved 18%) compared to the Fe/NC catalyst in 0.5M H2SO4 solution.