Achieving High Activity and Selectivity of Nitrogen Reduction via Fe-N-3 Coordination on Iron Single-Atom Electrocatalysts at Ambient Conditions

摘要

Electrocatalytic nitrogen reduction reaction (NRR) represents a highly promising process to ammonia synthesis for artificial N-2 fixation. However, the yield rate for NH3 production and Faradaic efficiency (FE) are still low, which greatly hinder its widespread applications. Until now, although a variety of catalysts, including single-atom catalysts, have been developed for NRR in the pursuit of suppressing hydrogen evolution reaction (HER) and the corresponding d G higher FE, the limited NH3 yield rate makes them uncompetitive for the synthesis of ammonia. Herein, we report a Fe single-atom catalyst anchoring on a nitrogen-doped carbon substrate (Fe SAC/N-C) as a highly efficient NRR catalyst. The catalyst achieves a high FE of 39.6% in 0.1 M KOH under room temperature, particularly a dramatically enhanced NH3 yield rate of 53.12 mu g(NH3) h-1 mg(cat)(-1). The isotopic labeling (N-15(2)) experiment confirms that the NH3 production completely originates from N-2 reduction. Meanwhile, theoretical calculations and X-ray fine structure in a maximum activation of NRR intermediates to produce ammonia with a high yield rate.