Regeneration of porous Fe3O4 nanosheets from deep eutectic solvent for high-performance electrocatalytic nitrogen reduction

The production of ammonia through electrocatalytic nitrogen reduction reaction (NRR) is environmentally friendly and energy-saving, but it still suffers from the low NH 3 yield rate and poor selectivity. Herein, enlightened by the unique solubility of Fe 3 O 4 in deep eutectic solvent (DES), we, for the first time, reported a DES-based regeneration strategy to fabricate porous Fe 3 O 4 nanosheets utilizing commercial Fe 3 O 4 powder as raw materials. The as-regenerated porous Fe 3 O 4 nanosheets exhibited satisfactory electrocatalytic performance toward NRR, affording a NH 3 yield rate of 12.09 μg h −1 mg −1 cat along with an outstanding Faradaic efficiency (FE) of 34.38% at −0.1 V versus reversible hydrogen electrode (RHE), in the 0.1 M Na 2 SO 4 electrolyte. The superior electrocatalytic activity of the as-regenerated Fe 3 O 4 nanosheets mainly resulted from their unique sheet-like morphology with large active surface area, high porosity, and abundant oxygen vacancies. Our proposed DES-based regeneration strategy opens a new avenue for the construction of high-performance electrocatalyst from commercial raw materials, holding great promise in NRR.