The electrochemical nitrogen reduction reaction (NRR) represents an emerging alternative for realizing ammonia (NH₃) synthesis from earth-abundant N₂ under ambient conditions. In this work, we describe the fabrication of a two-component heterogeneous composite composed of Au nanoparticles anchored on Bi nanosheets (denoted as Au/Bi NSs) and demonstrate their efficient performance for NRR electrocatalysis. The Au/Bi NSs are readily obtained by in situ electrochemical conversion of the pre-synthesized composite precursors composed of Au nanoparticles anchored on BiOCl nanoplates. Benefitting from the synergistic effect of Bi and Au components, the resultant Au/Bi NSs exhibit efficient NRR electrocatalytic activity in N₂-saturated 0.1 M HCl solution, achieving a NH₃ yield rate of 20.39 μg h⁻¹ mg_cat.⁻¹ and a faradaic efficiency of 15.53% at −0.3 V (vs. the reversible hydrogen electrode). This research may motivate further study of electrocatalytic N₂-to-NH₃ conversion and open up new opportunities for the synthesis of other heterogeneous catalysts.