Mn₃O₄ Nanocube: An Efficient Electrocatalyst Toward Artificial N₂ Fixation to NH₃

Traditionally, ammonia (NH₃ ) is synthesized via the Haber-Bosch process, which is not only commanded by harsh conditions but causes serious environmental pollution. Electrochemical reduction is recognized as a mild and environmentally benign alternative approach for NH₃ synthesis, but an efficient electrocatalyst is a prerequisite for NH₃ production. In this communication, the first experimental demonstration that Mn₃ O₄ nanocubes can be used as an efficient non-noble-metal electrocatalyst for N₂ reduction reaction (NRR) at ambient conditions is reported. In 0.1 m Na₂ SO₄ aqueous solution, the catalyst delivers excellent NRR activity with an NH₃ yield of 11.6 µg h^-1 mg^-1 _cat. and Faradaic efficiency of 3.0% at -0.8 V versus reversible hydrogen electrode. Notably, this catalyst also possesses satisfactory durability during the electrolysis and recycling test.