Abstract
Abstract Optimal conditions for producing ultrafine iron powder by combining the processes of electrolysis and high-voltage discharge have been determined. It has been established that the maximum current efficiency q = 97.88% is achieved at a current density of D = 10000 A/m2, an iron sulfate concentration of C(FeSO4⋅7H2О) = 50 g/L, a process duration of τ = 60 min, an ammonium sulfate concentration of C((NH4)2SO4) = 40 g/L, and a voltage of U = 8000 V. Using electron microscopy, it has been found that the obtained iron powder contains nanosized particles having the BET specific surface area of 31.5 ± 0.3 m2/g as determined using low-temperature nitrogen adsorption. Analysis by Mössbauer spectroscopy showed the presence of magnetically ordered phases α-Fe and γ-Fe2O3, a phase close to α-FeOOH hydroxide (goethite), and possibly a mixture of β-FeOOH (acoghanite) and γ-FeOOH (lepidocrocite). It has been found that the conversion of phenanthrene during hydrogenation for 60 min in the presence of this iron powder is higher than in the presence of the industrial iron–chromium catalyst STK-1 and reaches 32.99%.