Spinel LiMn₂O₄ Nanofiber: An Efficient Electrocatalyst for N₂ Reduction to NH₃ under Ambient Conditions

The production of ammonia (NH₃) in the industrial scale basically relies on the traditional technology of Haber-Bosch, which is operated under harsh conditions with high energy consumption and a huge number of greenhouse gas emissions. Electrochemical N₂ reduction reaction (NRR) is a promising route for artificial N₂-to-NH₃ fixation with less energy consumption. However, an effective electrocatalyst, as a prerequisite of the NRR, is of significance. Here, we report that a spinel LiMn₂O₄ nanofiber acts as a noble-metal-free electrocatalyst for NH₃ synthesis with excellent performance under ambient conditions. The electrocatalyst, which was tested in 0.1 M HCl, has an excellent Faradaic efficiency of 7.44% and a NH₃ yield of 15.83 μg h^-1 mg_cat.^-1 at -0.50 V versus reversible hydrogen electrode. Moreover, it also possesses excellent electrochemical and structure stability.