Electrochemical nitrogen reduction (eNRR) is a promising strategy to replace the energy- and capital-intensive Haber-Bosch process. Unfortunately, the low selectivity of the eNRR process impedes the industrial application of this approach. In this work, a highly efficient and stable NRR electrocatalyst is obtained via coreduction of Cu and Ag precursors using the holly leaves as reducing agents. The as-obtained Cu3Ag bimetallic nanosheets exhibit excellent NRR performance with an NH3 production rate of 31.3 μg h-1 mg-1cat. and a Faradaic efficiency of 31.3% at -0.2 V vs RHE. According to density functional theory (DFT) calculation, the outstanding performance of Cu3Ag bimetallic nanosheets could be caused by the fact that Ag optimizes the 3d orbital occupation of Cu and synergistically enhances the charge transfer during the NRR process, resulting in a suitable adsorption strength of the intermediates.