Abstract:

The electrocatalytic nitrogen reduction reaction (NRR) has emerged as a promising renewable energy source and a feasible strategy as an alternative to Haber-Bosch ammonia (NH₃) synthesis. However, finding an efficient and cost-effective robust catalyst to activate and cleave the extremely strong triple bond in nitrogen (N₂) for electrocatalytic NRR is still a challenge. Herein, a FeNi@CNS nanocomposite as an efficient catalyst for N₂ fixation under ambient conditions is designed. This FeNi@CNS nanocomposite was prepared by a simple water bath process and post-calcination. The FeNi@CNS is demonstrated to be a highly efficient NRR catalyst, which exhibits better NRR performance with exceptional Faradaic efficiency of 9.83% and an NH₃ yield of 16.52 μg h^-1 cm^-2 in 0.1 M Na₂SO₄ aqueous solution. Besides, high stability and reproducibility with consecutive 6 cycles for two hours are also demonstrated throughout the NRR electrocatalytic process for 12 h. Meanwhile, the FeNi@CNS catalyst encourages N₂ adsorption and activation as well as effectively suppressing competitive HER. Therefore, this earth-abundant FeNi@CNS catalyst with a subtle balance of activity and stability has excellent potential in NRR industrial applications.

Key words: Electrocatalytic nitrogen reduction, Transition-metal alloy, FeNi@CNS catalyst, N₂ fixation to NH₃