Cu–Bi\nBimetallic Sulfides Loaded on Two-Dimensional\nTi<sub>3</sub>C<sub>2</sub>T<sub><i>x</i></sub> MXene for\nEfficient Electrocatalytic Nitrogen Reduction under Ambient Conditions

In this paper, Ti<sub>3</sub>C<sub>2</sub>T<sub><i>x</i></sub> MXene/Cu–Bi bimetallic sulfide (Ti<sub>3</sub>C<sub>2</sub>T<sub><i>x</i></sub>/BiCuS<sub>2.5</sub>)\ncomposites\nwere prepared by a simple <i>in situ</i> deposition method\nfor electrocatalytic nitrogen reduction reaction (eNRR). Compared\nto Ti<sub>3</sub>C<sub>2</sub>T<sub><i>x</i></sub>/Bi<sub>2</sub>S<sub>3</sub> and Ti<sub>3</sub>C<sub>2</sub>T<sub><i>x</i></sub>/CuS, the eNRR performance of Ti<sub>3</sub>C<sub>2</sub>T<sub><i>x</i></sub>/BiCuS<sub>2.5</sub> is significantly\nimproved. The results show that Ti<sub>3</sub>C<sub>2</sub>T<sub><i>x</i></sub>/BiCuS<sub>2.5</sub> exhibits a NH<sub>3</sub> yield\nof 62.57 μg h<sup>–1</sup> mg<sup>–1</sup><sub>cat.</sub> in 0.1 M Na<sub>2</sub>SO<sub>4</sub> at −0.6 V\nvs reversible hydrogen electrode, and the Faradaic efficiency (FE)\nreaches 67.69%, which is better than that of Ti<sub>3</sub>C<sub>2</sub>T<sub><i>x</i></sub>/CuS (NH<sub>3</sub> yield: 52.26 μg\nh<sup>–1</sup> mg<sup>–1</sup><sub>cat.</sub>, FE: 34.15%)\nand Ti<sub>3</sub>C<sub>2</sub>T<sub><i>x</i></sub>/Bi<sub>2</sub>S<sub>3</sub> (NH<sub>3</sub> yield: 54.04 μg h<sup>–1</sup> mg<sup>–1</sup><sub>cat.</sub>, FE: 37.38%).\nAccording to density functional theory calculations, the eNRR at\nthe Ti<sub>3</sub>C<sub>2</sub>T<sub><i>x</i></sub>/BiCuS<sub>2.5</sub> surface is the alternating pathway. The <sup>1</sup>H NMR\nexperiment of <sup>15</sup>N proves that the N of NH<sub>3</sub> generated\nin the experiment originates from N<sub>2</sub> passed during the\nexperiment.