Facile electrochemical fabrication of magnetic Fe3O4 for electrocatalytic synthesis of ammonia used for hydrogen storage application

Abstract Ammonia (NH3) offers extensive applications in industrial production; moreover, it is a potential carrier for hydrogen energy and an eco-friendly fuel. Electrocatalytic synthesis of NH3 has drawn increasing research attention, wherein an excellent electrocatalyst plays a vital role. Iron (Fe) oxide nanomaterials with their high activity and cost effectiveness of its raw material Fe, have received significant attention in electrocatalytic N2 reduction reaction (NRR) to synthesize NH3. This study reports a rapid and cost-effective electrochemical method for synthesizing magnetic Fe3O4 nanoparticles, achieving gram-level production under ambient conditions. The synthesized magnetic Fe3O4 nanoparticles as electrocatalyst for NRR, achieved excellent faradaic efficiency of 16.9% and an optimal NH3 yield of 12.09 μg h−1 mg−1cat. at −0.15 V (versus the reversible hydrogen electrode (RHE)) in 0.1 M Na2SO4. Besides, density functional theory (DFT) calculations indicate that the N≡N bond was fully activated, and the NRR proceeds mainly along the alternating hydrogenation pathway.