Efficient electrohydrogenation of N2 to NH3 by oxidized carbon nanotubes under ambient conditions

Abstract

It is of great importance to search for efficient and stable metal-free catalysts toward electrochemical N₂-to-NH₃ conversion. In this communication, a chemically oxidized carbon nanotube material (O-CNT) is verified as an active electrocatalyst for the N₂ reduction reaction under ambient conditions. In 0.1 M LiClO₄, O-CNT achieves a large NH₃ yield of 32.33 μg h⁻¹ mg_cat.⁻¹ and a high faradaic efficiency of 12.50% at −0.4 V vs. the reversible hydrogen electrode. It also demonstrates superior stability. Density functional theory calculations suggest that C–O groups play a key role in the electrochemical N₂ fixation.