Cu–Bi Bimetallic Sulfides Loaded on Two-Dimensional Ti₃C₂T_<i>x</i> MXene for Efficient Electrocatalytic Nitrogen Reduction under Ambient Conditions

In this paper, Ti₃C₂T_<i>x</i> MXene/Cu-Bi bimetallic sulfide (Ti₃C₂T_<i>x</i>/BiCuS_2.5) composites were prepared by a simple <i>in situ</i> deposition method for electrocatalytic nitrogen reduction reaction (eNRR). Compared to Ti₃C₂T_<i>x</i>/Bi₂S₃ and Ti₃C₂T_<i>x</i>/CuS, the eNRR performance of Ti₃C₂T_<i>x</i>/BiCuS_2.5 is significantly improved. The results show that Ti₃C₂T_<i>x</i>/BiCuS_2.5 exhibits a NH₃ yield of 62.57 μg h^-1 mg^-1_cat. in 0.1 M Na₂SO₄ at -0.6 V vs reversible hydrogen electrode, and the Faradaic efficiency (FE) reaches 67.69%, which is better than that of Ti₃C₂T_<i>x</i>/CuS (NH₃ yield: 52.26 μg h^-1 mg^-1_cat., FE: 34.15%) and Ti₃C₂T_<i>x</i>/Bi₂S₃ (NH₃ yield: 54.04 μg h^-1 mg^-1_cat., FE: 37.38%). According to density functional theory calculations, the eNRR at the Ti₃C₂T_<i>x</i>/BiCuS_2.5 surface is the alternating pathway. The ¹H NMR experiment of ¹⁵N proves that the N of NH₃ generated in the experiment originates from N₂ passed during the experiment.