Coupling Fe and Mo single atoms on hierarchical N-doped carbon nanotubes enhances electrochemical nitrogen reduction reaction performance

Electrochemical nitrogen reduction reaction (NRR) paves a new way to cost-efficient production of ammonia, but is still challenging in the sluggish kinetics caused by hydrogen evolution reaction competition and chemical inertness of N≡N bond. Herein, we report a “dual-site” strategy for boosting NRR performance. A high-performance catalyst is successfully constructed by anchoring isolated Fe and Mo atoms on hierarchical N doped carbon nanotubes through a facile self-sacrificing template route, which exhibits a remarkably improved NH3 yield rate of 26.8 $$\mu {\rm{g}} \cdot {{\rm{h}}^{ - 1}} \cdot {\rm{mg}}_{{\rm{cat}}}^{ - 1}$$ with 11.8% Faradaic efficiency, which is 2.5 and 1.6 times larger than those of Fe/NC and Mo/NC. The enhancement can be attributed to the unique hierarchical structure that profits from the contact of electrode and electrolyte, thus improving the mass and electron transport. More importantly, the in situ Fourier transform infrared spectroscopy (in situ FTIR) result firmly demonstrates the crucial role of the coupling of Fe and Mo atoms, which can efficiently boost the generation and transmission of *N2Hy intermediates, leading to an accelerated reaction rate.