Zr-doped α-FeOOH with high faradaic efficiency for electrochemical nitrogen reduction reaction

Highlights: • The moderated Zr/α-FeOOH shows excellent NRR activity with high selectivity. • The doping Zr promotes the activity and selectivity of α-FeOOH for NRR. • ATR-SEIRAS reveals the associative mechanism on Zr/α-FeOOH surface towards NRR. Electrochemical nitrogen reduction reaction (NRR) is regarded as a promising route for ammonia synthesis, which still faces several challenges including NH₃ yield and low selectivity. Herein, Zr-doped α-FeOOH (Zr/α-FeOOH) was developed as NRR electrocatalyst, which shows a high NH₃ yield of 1.39 × 10⁻¹⁰ mol s⁻¹ cm⁻² and a significantly increased Faradaic efficiency (FE) of 35.63%. The Zr doping is found to induce more O vacancies as NRR active sites, which results in the increased NH₃ yield. Besides, Zr species can suppress the competing side reaction effectively and have a positive effect on the high FE. Furthermore, the electrochemical in situ attenuated total reflection surface-enhanced infrared reflection absorption spectroscopy was conducted to investigate the NRR mechanism on Zr/α-FeOOH surface, which was revealed to follow an associative reaction pathway.