Ambient N₂ fixation to NH₃ at ambient conditions: Using Nb₂O₅ nanofiber as a high-performance electrocatalyst

Electrochemical reduction has emerged as an environmentally-benign and sustainable approach alternative to the Haber–Bosch process for artificial N₂ fixation at ambient conditions, while the challenge associated with N₂ activation underlines the demand of efficient electrocatalysts for the N₂ reduction reaction (NRR). In this work, Nb₂O₅ nanofiber is experimentally proved to act as a non-noble-metal NRR electrocatalyst for N₂ conversion to NH₃ with high activity and selectivity. When tested in 0.1 M HCl, such Nb₂O₅ nanofiber achieves a high average NH₃ yield (43.6 µg h⁻¹ mg⁻¹ _cat.) and a high Faradaic efficiency (9.26%) at − 0.55 V vs. reversible hydrogen electrode, rivaling the performances of most reported aqueous-based NRR electrocatalysts under ambient conditions and even comparable with those under high temperature and pressure. Notably, it also shows high stability during electrolysis and recycling test. The catalytic mechanism of NRR on Nb₂O₅ (181) surface is further discussed by density functional theory calculations.