Fabrication of Fe3O4 nanoparticles by using cathode glow discharge electrolysis plasma and its electrochemical properties

In this work, Fe3O4 nanoparticles (NPs) were fabricated by one-step method using cathode glow discharge electrolysis (CGDE) plasma technique in 2.0 g L−1 Na2SO4 solution at 600, 650 and 700 V applied voltage, in which Pt needle point and scrap iron wire were served as cathode and anode, respectively. The fabricated products were characterized by FT-IR, XRD, SEM and TEM. A possible fabrication mechanism of Fe3O4 NPs under CGDE was proposed. In addition, electrochemical performance of Fe3O4 NPs as an electrode material for supercapacitors was investigated by cyclic voltammetry, galvanostatic charge–discharge, and electrochemical impedance spectroscopy in 1 mol L−1 Na2SO3 electrolyte. The results showed that the particle sizes of the fabricated products are below 20 nm, Fe3O4 NPs as the electrode material have good reversibility which can reach 247 F g−1 specific capacitance at current density of 0.5 A g−1, and still keep 41.1% capacity retention after 5000 cycles. Fe3O4 NPs can be regarded as a promising and favorable candidate of electrode materials for supercapacitor. Compared with other methods, CGDE has the advantages of simple experimental equipment, no gas supply, mild reaction conditions and no secondary pollution. It is a green synthesis technique without adding alkali, surfactant and ferric salt containing both Fe2+ and Fe3+.