Anchoring Au nanoparticles on Bi ultrathin nanosheets as an efficient heterogeneous catalyst for ambient-condition electrochemical ammonia synthesis

Electrochemical nitrogen reduction reaction (NRR) represents an emerging alternative to realize 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 yield NH3 rate of 20.39 µg h-1 mg-1cat. and a Faradaic efficiency of 15.53 % at -0.3 V (vs 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.