Electrochemical nitrogen reduction is a significant alternative route for synthesizing ammonia, but constructing efficient catalysts for electrochemical nitrogen fixation still faces tough challenges. In this work, Cu3P@NC (NC: nitrogen-doped carbon) nanosheets were prepared via the low-temperature pyrolysis-phosphating of Cu-MOFs. When applied to the nitrogen reduction reaction, Cu3P@NC exhibited a high ammonia yield rate of 10.4 μg h-1 mg-1cat at -0.3 V (vs. RHE) and a faradaic efficiency (FE) of 6.3% at -0.1 V (vs. RHE). The outstanding performance was attributed to the large electrochemical surface area and the defects induced as a result of N doping, which helped enhance N2 adsorption. This work provides a novel strategy for preparing N-doped carbon materials for wide-ranging applications.