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

Metal-freecarbon-based catalysts have received a lot of attentionin electrochemical nitrogen reduction reaction (NRR), but their activityis still unsatisfactory. Designing advanced catalysts with highlydefective structure is critical for improving the activity and selectivitytoward NRR. We present a method for preparing homogeneous ternaryboron carbon nitride (BCN) nanosheets using an organic-inorganichybrid precursor pyrolysis. Raman spectra and electron paramagneticresonance analysis reveal the abundant defective structure in theBCN catalyst. The homogeneous element distribution and abundant defectivestructure in BCN promote the formation of Lewis-acid sites (undercoordinatedB sites) and Lewis-base sites (undercoordinated N sites) for N-2 activation. Benefiting from the structural advantages ofBCN, the optimal catalyst exhibits a high faradaic efficiency of 27.2%at -0.29 V (vs RHE), an ammonia yield of 5.21 & mu;g h(-1) mg(cat) (-1) at -0.49V (vs RHE), and an excellent long-term durability, surpassing mostprevious reports.