Ambient N2 fixation to NH3 electrocatalyzed by a spinel Fe3O4 nanorod

Abstract

Industrially, NH₃ is mainly produced via the Haber–Bosch process which is not only energy-consuming but emits a large amount of CO₂. Electrochemical reduction is regarded as an environmentally-benign alternative for sustainable NH₃ synthesis, and its efficiency heavily depends on the identification of Earth-abundant catalysts with high activity for the N₂ reduction reaction (NRR). In this work, we report that a spinel Fe₃O₄ nanorod on a Ti mesh (Fe₃O₄/Ti) acts as an efficient and durable NRR electrocatalyst under ambient conditions. When tested in 0.1 M Na₂SO₄, such Fe₃O₄/Ti achieves a high faradaic efficiency of 2.6% and a NH₃ yield 5.6 × 10⁻¹¹ mol s⁻¹ cm⁻² and at −0.4 V vs. a reversible hydrogen electrode.