Boron nitride supported copper single atom catalyst for nitrate reduction reaction

Recently, the electrochemical nitrate reduction reaction (NO₃RR) has been interested to enable an artificial nitrogen cycle in ammonia (NH₃) production and decarbonize the current ammonia industry. In this study, a series of Cu supported on the porous boron nitride (BN) catalysts were successfully prepared using a simple pyrolysis method with various Cu loadings and B/N ratios for the NO₃RR. The electrocatalytic performance of CuBN was evaluated using a self-designed H-cell with different NO₃^- concentrations of electrolyte. It was demonstrated that the formation of Cu single atoms and the interaction between Cu and BN significantly influence NH₃ productivity in the NO₃RR. The 1 wt% CuBN catalyst with a B/N ratio of 1:36 exhibited superior NH₃ productivity of 3184.9 μg/mg_cat/h and a selectivity of above 95 %, along with outstanding stability. By utilizing X-ray absorption spectroscopy and other advanced techniques, this catalyst was found to possess the highest amount of active Cu single atoms, which had a strong interaction with the BN support. In addition, though a comparison with Cu/Al₂O₃, the impact of Lewis acidity on the NO₃RR was also elucidated.