▎ 摘　　要

Electrocatalytic nitrate-to-ammonia conversion (NO3RR) represents a promising approach for achieving both sustainable NH3 synthesis and wastewater treatment. Herein, we first demonstrate the great feasibility of using pyrite FeS2 as an effective and durable NO3RR catalyst. The developed FeS2 nanoparticles supported on reduced graphene oxide (FeS2/RGO) deliver the maximum NH3-Faradaic efficiency of 83.7% with a corresponding NH3 yield of 2.32 mg h(-1) cm(-2) at -0.6 V (RHE). FeS2/RGO also exhibits excellent stability during the cycling and long-term electrolysis tests. DFT calculations reveal that NO3- can be efficiently activated on surface Fe sites, which can drive the NO3RR process through an NHO pathway with a low energy barrier.