Electrocatalytic nitrate reduction reaction is regarded as the promising method to mitigate nitrate pollution and produce ammonia, but cost-effective and efficient electrocatalysts are lacking. In this study, a low-cost Feanchored N-doped biochar (Fe-NBC) was synthesized from the N-rich wetland plant and used for electrocatalytic nitrate reduction reaction. At optimal conditions, Fe-NBC could achieve a maximum nitrate removal capacity of 1065 mg N/g Cat, a NH3 yield rate of 78.6 umol mg(cat)(-1) h(-1), a Faradaic efficiency of 75.3 %, and an energy consumption of 0.2073 kWh/g. The kinetics results showed that the reaction rate of Fe-NBC was 1.5 times of Feembedded biochar, and 3.5 times of bare N-doped biochar. Experimental results and characterizations demonstrated the pyridinic-N in the form of FeNx in Fe-NBCs enhance the electrocatalytic nitrate reduction performance by modulating the electronic properties of the Fe-NBCs surface. Furthermore, the Fe-NBC cathode exhibited an excellent stability due to the coverage of Fe species by deposited carbon during the pyrolysis process. This study deepens our understanding of the role of N species on electrocatalytic nitrate reduction and provides a green strategy for fabricating efficient electrocatalyst through waste biomass.
