Graphdiyne Enabled Nitrogen Vacancy Formation in Copper Nitride for Efficient Ammonia Synthesis

The electrocatalytic reduction of nitrate is promising for sustainable ammonia synthesis but suffers from slow reduction kinetics and multiple competing reactions. Here, we report a catalyst featuring copper nitride (Cu 3 N) anchored on a novel graphdiyne support (termed Cu 3 N/GDY), which is used for electrocatalytic reduction of nitrate to produce ammonia. The GDY absorbed hydrogen and enabled nitrogen (N) vacancy formation in Cu 3 N for the fast nitrate reduction reaction (NO 3 RR). Further, the distinct absorption sites formed by GDY and N vacancy enabled the excellent selectivity and stability of NO 3 RR. Notably, the Cu 3 N/GDY catalyst achieved a high ammonia yield ( Y NH3 ) up to 35280 μg h –1 mg cat. –1 and a high Faradaic efficiency (FE) of 98.1% using 0.1 M NO 3 – at −0.9 V versus a reversible hydrogen electrode (RHE). Using electron paramagnetic resonance (EPR) technology and in situ X-ray absorption fine structure (XAFS) spectroscopy measurement, we visualized the N vacancy formation in Cu 3 N and electrocatalytic NO 3 RR enabled by GDY. These findings show the promise of GDY in sustainable ammonia synthesis and highlight the efficacy of Cu 3 N/GDY as a catalyst.