A Highly Efficient Metal‐Free Electrocatalyst of F‐Doped Porous Carbon toward N2 Electroreduction

Abstract

N 2 electroreduction into NH 3 represents an attractive prospect for N 2 utilization. Nevertheless, this process suffers from low Faraday efficiency (FE) and yield rate for NH 3. In this work, a highly efficient metal‐free catalyst is developed by introducing F atoms into a 3D porous carbon framework (F‐doped carbon) toward N 2 electroreduction. At −0.2 V versus reversible hydrogen electrode (RHE), the F‐doped carbon achieves the highest FE of 54.8% for NH 3, which is 3.0 times as high as that (18.3%) of pristine carbon frameworks. Notably, at −0.3 V versus RHE, the yield rate of F‐doped carbon for NH 3 reaches 197.7 µg NH3 mg−1cat. h−1. Such a value is more than one order of magnitude higher than those of other metal‐free electrocatalysts under the near‐ambient conditions for NH 3 product to date. Mechanistic studies reveal that the improved performance in N 2 electroreduction for F‐doped carbon originates from the enhanced binding strength of N 2 and the facilitated dissociation of N 2 into *N 2 H. F bonding to C atom creates a Lewis acid site due to the different electronegativity between the F and C atoms. As such, the repulsive interaction between the Lewis acid site and proton H suppresses the activity of H 2 evolution reaction, thus enhancing the selectivity of N 2 electroreduction into NH 3.