Efficient nitrogen reduction to ammonia by fluorine vacancies with a multi-step promoting effect

Improving the performance of catalysts by adjusting the vacancy engineering is currently one of the main ways to design effective catalysts. However, there are no reports in the literature on the influence that fluorine vacancies (FVs) have on the electronic structures of materials. In this work, we report the generation of FVs for the first time and discuss in depth their regulation mechanism on materials and their role in the electrochemical N 2 reduction reaction (NRR). The catalyst optimized by FVs showed good NRR performance in Li 2 SO 4 solution. At 0 V vs. RHE, the faradaic efficiency (FE) reaches the highest value of 36.01%. When the potential is increased to −0.10 V vs. RHE, the highest ammonia yield is 7.99 μg h −1 cm −2 . The specific activity of the FV-optimized LaF 3 nanosheets (NSs) is 9.5 times higher than that of the defect-free LaF 3 NSs. It is currently reported as the most effective non-noble metal catalyst in the nitrogen reduction process under low overpotential. In addition, this catalyst also demonstrates long-term structural stability. In situ attenuated total reflectance surface-enhanced infrared absorption spectroscopy (ATR-SEIRAS) and density functional theory (DFT) show that the LaF 3 NSs with the optimal defects have a multi-step promoting effect. A new fluoride vacancy of tradition metal material (FV-LaF 3 - x nanosheets) is rationally designed and synthesized by sodium borohydride reduction at room temperature, which improves the nitrogen reduction performance due to multi-step promotion.