Electro-synthesis of ammonia at ambient environment is a promising alternative of the industrial Haber-Bosch process operated under critical conditions. In this work, we have systematically investigated the electro-reduction of nitrate (NO₃⁻RR) to ammonia catalyzed by fluorine doped carbon (FC) synthesized from the pyrolysis of the discarded cigarette filter saturated with polytetrafluoroethylene (PTFE) solution. FC electrocatalyst shows an exceptional NO₃⁻RR catalytic performance with Faradaic efficiency of 20% associated with ammonia production rate of 23.8 mmol h⁻¹ g_cat⁻¹, 2 and 4-fold better than bare C electrocatalyst. Furthermore, a stable NO₃⁻RR activity is also achieved for FC electrocatalyst. Density functional theory (DFT) results suggest that F dopants efficiently reduce the energy barriers of NO₃⁻ hydrogenation and suppress the competitive hydrogen evolution reaction (HER). This observation will be beneficial for constructing a high-performance metal-free electrocatalyst to electro-synthesize ammonia from NO₃⁻RR.

在环境条件下电合成氨是在关键条件下运行的工业Haber-Bosch工艺的有希望的替代方法。在这项工作中，我们系统地研究了由废弃的香烟过滤嘴经聚四氟乙烯（PTFE）溶液饱和热解后合成的氟掺杂碳（FC）催化将硝酸根（NO ₃ ^- RR）电还原为氨。FC电催化剂显示出出色的NO ₃ ^- RR催化性能，其法拉第效率为20％，氨气产率为23.8 mmol h ^-1 g _cat ^-1，是裸C电催化剂的2倍和4倍。此外，稳定的NO ₃ ^-对于FC电催化剂，也实现了RR活性。密度泛函理论（DFT）的研究结果表明那个F掺杂剂有效地降低NO的能量壁垒₃ ^-氢化和抑制竞争析氢反应（HER）。该观察结果对于构建高性能的无金属电催化剂以从NO ₃ ^- RR电合成氨是有益的。