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

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 mgcat.-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.