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 N-2 fixation at ambient conditions, while the challenge associated with N-2 activation underlines the demand of efficient electrocatalysts for the N-2 reduction reaction (NRR). In this work, Nb2O5 nanofiber is experimentally proved to act as a non-noble-metal NRR electrocatalyst for N-2 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 mu g h(-1) mg(cat.)(-1)) 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.