Electrocatalytic Nitrate Reduction to Ammonia Using Metal-Free Nitrogen-Doped Carbon Catalysts Derived from Setaria viridis

Abstract

Electrocatalytic reduction of nitrate to ammonia is one potential strategy to remove nitrate and produce ammonia under ambient conditions. The use of carbonaceous materials as metal-free electrocatalysts is crucial for achieving high activity and precise product selectivity. Here, we propose a facile one-step calcination strategy to produce nitrogen-doped carbon (N–C-900–3) electrocatalysts derived from Setaria viridis (SV) for highly efficient nitrate-to-ammonia reduction (NO₃RR). Benefiting from the high concentration of defects and the high content of graphitic-N moiety, which play a crucial role in promoting the dissociation of water and the N–H bond formation, the resultant N–C-900–3 displays outstanding electrocatalytic performance with a maximum NH₃ yield rate of 6.23 mg h^–1 cm^–2 and a Faradaic efficiency (FE) of ca. 97.4%.