Self-supported iron-doped nickel sulfide as efficient catalyst for electrochemical urea and hydrazine oxidation reactions

The electrochemical oxidation of urea and hydrazine over self-supported Fe-doped Ni3S2/NF (Fe-Ni3S2/NF) nanostructured material is presented. Among the various reaction con-ditions Fe-Ni3S2/NF-2 prepared at 160 degrees C for 8 h using 0.03 mM Fe(NO3)(3) shows the best results for the hydrazine and urea oxidation reactions. The potential values of 0.36, 1.39, and 1.59 V are required to achieve the current density of the 100 mA cm(-2) in 1 M hydrazine (Hz), 0.33 M urea, and 1 M KOH electrolyte, respectively. The onset potential in 1 M KOH, 0.33 M Urea +1 M KOH, and 1 M Hz + 1 M KOH values are 1.528, 1.306, and 0.176 respec-tively. The Fe-Ni3S2/NF-2 shows stable performance at 10 mA cm-2 until 50 h and at 60 mA cm(-2) over the 25 h. A cell of PtC//Fe-Ni3S2/NF-2 requires the potential of 0.49, 1.46, and 1.59 V for the hydrogen production in 1 M Hz + 1 M KOH, 0.33 M Urea +1 M KOH, and 1 M KOH electrolyte, respectively, at a current density of 10 mA cm(-2), and almost 90% stable for the hydrogen production over the 80 h in all electrolytes. The improvement of the chemical kinetics of urea and hydrazine oxidation is due to the synergistic effect of the adsorption and fast electron transfer reaction on Fe-Ni3S2/NF-2. The doped Fe ion facili-tates the fast electron transfer and the surface of Ni3S2 support to the urea and hydrazine molecule adsorption.(C) 2022 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.

Automated summary

The electrochemical oxidation of urea and hydrazine over self-supported Fe-doped Ni3S2/NF nanostructured material is investigated. The Fe-Ni3S2/NF-2 prepared at specific conditions shows promising results in the oxidation reactions of hydrazine and urea. The improvement in the chemical kinetics of urea and hydrazine oxidation is attributed to the synergistic effect of adsorption and fast electron transfer on Fe-Ni3S2/NF-2. This study has implications for hydrogen energy applications.