Highly Defective Boron Carbon Nitride Nanosheets: A Robust Electro-Catalyst for Efficient Nitrogen Fixation

Metal-free carbon-based catalysts have received a lot of attention in electrochemical nitrogen reduction reaction (NRR), but their activity is still unsatisfactory. Designing advanced catalysts with highly defective structure is critical for improving the activity and selectivity toward NRR. We present a method for preparing homogeneous ternary boron carbon nitride (BCN) nanosheets using an organic–inorganic hybrid precursor pyrolysis. Raman spectra and electron paramagnetic resonance analysis reveal the abundant defective structure in the BCN catalyst. The homogeneous element distribution and abundant defective structure in BCN promote the formation of Lewis-acid sites (undercoordinated B sites) and Lewis-base sites (undercoordinated N sites) for N2 activation. Benefiting from the structural advantages of BCN, the optimal catalyst exhibits a high faradaic efficiency of 27.2% at −0.29 V (vs RHE), an ammonia yield of 5.21 μg h–1 mgcat–1 at −0.49 V (vs RHE), and an excellent long-term durability, surpassing most previous reports.