A highly active defect engineered Cl-doped carbon catalyst for the N₂ reduction reaction

eNRR is a promisingly environment-friendly strategy to obtain ammonia under ambient conditions. For metal-based catalysts, the competitive adsorption of H⁺ over N₂ remains the primary hurdle for high ammonia yield and faradaic efficiency. Carbon-based metal-free catalysts attract our attention for the potential of being promising NRR catalysts due to their natural low HER activity. In this study, we prepared a modified Zn-based metal-organic framework (Zn-BTC) decorated with Cl ions by simply adding NaCl in the synthetic process. The existence of Cl ions in the framework contributes to the generation of large pores during thermolysis. Moreover, -Cl and -COCl species were formed in situ and connected with carbon atoms in the defect area. Benefitting from such a structure, this catalyst achieves a high ammonia yield rate of 103.96 μg h⁻¹ mg_cat⁻¹ and a faradaic efficiency of 21.71% at room temperature. Theoretical results also proved that the newly produced -COCl and -Cl functional groups could attract more electrons from adjacent carbon atoms due to their stronger electronegativity, thus improving its affinity towards N₂ while lowering the HER activity as reactive sites.