An isolated bimetallic Fe–Ru single-atom catalyst for efficient electrochemical nitrogen reduction

Abstract

Electrochemical nitrogen reduction reaction (NRR) is considered a promising alternative for green and sustainable ammonia (NH₃) synthesis, which has, however, long suffered from low efficiency and poor selectivity. In this study, an isolated bimetallic Fe–Ru single atom catalyst was synthesized via anchoring the metal single atoms on nitrogen-doped carbon nanorod spheres. The catalyst exhibits an optimized faradaic efficiency of 29.3% along with an NH₃ yield rate of 43.9 μg h⁻¹ mg⁻¹ for the NRR under −0.2 V vs. RHE. Control experiments and isotopic labelling test confirm that the generated NH₃ originates from the nitrogen (N₂) feeding gas. Computational analysis indicates that Fe acts as the active sites for nitrogen reduction. Impressively, an obvious synergistic effect exists between spatially isolated single atoms, which could be overlooked previously. The electronic structure of Fe sites is effectively influenced by Ru atoms, which results in the d-band center shift and stronger N₂ adsorption, further improving NRR performance.