N, S synergistic effect in hierarchical porous carbon for enhanced NRR performance

In this paper, a high-efficiency non-metallic catalyst for the electrocatalytic synthesis of NH3 was prepared by using a sulfur-modified N-doped MOF based on hierarchical porous carbon material. One-pot pyrolysis of metal azolate frameworks (MAF) resulted in the uniform doping of active N precursor. Moreover, the doping of sulfur atoms introduced the synergistic effect and improved the catalytic activity. Furthermore, the formed sulfur was hydrophobic, which hindered the occurrence of HER. Therefore, S/N-MPC achieved a high NH3 yield of 45.51 μgNH3 mgcat.−1 h−1 at −0.3 V and the best FE of 25.16% at −0.2 V, respectively. Moreover, it showed excellent durability in long time electrolysis reaction. Besides, DFT calculation results were used to elucidate the ammonia synthesis pathway of the catalyst, and it was proved that the ammonia synthesis reaction on the catalyst followed the alternate hydrogenation path of the association mechanism.