Synergistic performance of nitrogen and sulfur co-doped Ti3C2TX for electrohydrogenation of N2 to NH3

Highlights: • Nitrogen and sulfur co-doping strategy increases the N₂ fixation yield of Ti₃C₂T_x by five times. • Synergistic effect of co-doping regulates the electron configuration and accelerates the reaction kinetics. • NS-Ti₃C₂T_x achieves excellent recyclability and long-term stability in acidic electrolyte. • This work opens a new research approach for high-performance catalysts in energy storage applications. -- Abstract: High-polluting industrial ammonia synthesis runs counter to the intentions of a low-carbon society. In contrast, the electrocatalytic nitrogen reduction reaction (NRR) is expected to provide fascinating and broad prospects for green ammonia synthesis, which urgently requires efficient and low-cost catalysts. Although it has been proven that two-dimensional (2D) transition metal carbides and carbonitrides (MXenes) have great potential for NRR, there is still need to further improve their activity. In this work, a co-doping strategy was employed to design the electronic configuration and structural mechanic of Ti₃C₂T_x catalysts for efficient NRR. As expected, the synergistic effect of N and S dopants in Ti₃C₂T_x (NS-Ti₃C₂T_x) significantly improves the electron/ion transport capacity and increases the catalytic active sites. Specifically, the as-prepared NS-Ti₃C₂T_x nanosheets demonstrated an excellent electrocatalytic stability with NH₃ yield of 34.23 μg h⁻¹ mg⁻¹_cat at −0.55 V vs. RHE, and a Faraday efficiency of 6.6% in 0.05 M H₂SO₄. Therefore, this work opens up a new research approach for preparing high-performance catalysts for energy storage applications through efficient nitrogen fixation technology.