Electrocatalytic nitrate reduction using Fe0/Fe3O4 nanoparticles immobilized on nickel foam: Selectivity and energy consumption studies

The main objective of this study is to offer an effective electrocatalytic system with high selectivity to nitrogen and low energy consumption using Ni–Fe0@Fe3O4 nanocomposite. The Ni–Fe0@Fe3O4 nanocomposite electrode for electrocatalytic denitrification prepared via an electrodeposition method. Factors effective on nitrate electrocatalytic reduction such as current efficiency, nitrate removal, nitrite and ammonia generation, nitrogen selectivity, and energy consumption were studied using the Ni–Fe0@Fe3O4 nanocomposite electrode. The Ni–Fe0@Fe3O4 nanocomposite was characterized by BET, FE-SEM, EDX, and XRD techniques. The proposed electrocatalytic system reached 90.19% nitrate removal efficiency using 5 mA/cm2 current density within 240 min, pH of 6.2, and 10 mM NaCl compared to Ni foam (28.16%) and Ni–Fe0 (45.95%). The electrocatalytic system exhibited a high selectivity to nitrogen, desirable current efficiency, and low energy consumption, of about 4.42 KWh/n-nitrate-N under the optimum condition. The results showed that the ammonium and nitrite generation decreased in the electrocatalytic process.