Abstract: Electrocatalytic reduction of nitrogen (N₂) to ammonia (NH₃) by renewable energy-derived electricity provides a new route for sustainable development. But this process requires high-efficiency, high-selectivity and high-stability, inexpensive electrocatalysts. Owing to the unique electronic structure and catalytic mechanism, transition metal nitrides (TMNs) have been widely investigated as electrocatalysts for nitrogen reduction reaction (NRR) in recent years. However, to date, copper nitride-based materials are rarely reported for NRR. In this study, a three-dimensional self-supported copper nitride electrode (Cu₃N/CF) was prepared by a simple one-step high-temperature nitridation of copper foam (CF). The structure and morphology of Cu₃N/CF were systematically characterized and its NRR catalytic performance and stability were evaluated in neutral media. The results show that Cu₃N/CF electrode achieves high ammonia generation rate (1.12 × 10⁻¹⁰ mol/(s·cm²) and faradaic efficiency (1.5%) at −0.2 V vs RHE in 0.1 mol/L Na₂SO₄. In addition, it also exhibits excellent electrocatalytic cycle stability and structural stability.