Boosting nitrogen reduction to ammonia on Fe–N3S sites by introduction S into defect graphene

Single-atom catalysts have demonstrated their superiorities over other forms of catalysts for various reactions. Herein, we successfully implant Fe-isolated single atoms into N, S-co-doped defective graphene architecture (Fe–SAs/NSDG) as a highly efficient catalyst for N2 reduction. X-ray photoelectron spectra, X-ray absorption fine structure characterizations and density functional theory calculation revealed that Fe atoms are anchored to the carrier via the Fe–N3S coordination configuration. The density functional theory calculations identify that Fe–N3S as the active site can promote nitrogen reduction reaction (NRR). It is worth noting that the introduction of S can greatly increase catalyst NRR activity. The obtained catalyst exhibits a strong activity for NRR with the highest ammonia yield rate of 28.89 μg/h·mg/cat at −0.4 V and the highest Faradaic efficiency of 23.7% at −0.1 V, respectively. These results demonstrate that the Fe–SAs/NSDG can be a promising cathode material for NRR.