Rational design of FeS2 microspheres as high-performance catalyst for electrooxidation of hydrazine

• Published in: Journal of materials science & technology Vol. 110; pp. 161 - 166
• Main Authors: Sun, Jie, Liu, Chuangwei, Kong, Wenhan, Liu, Jie, Ma, Liangyu, Li, Song, Xu, Yuanhong
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 30-05-2022
• Subjects: Rational design: Hydrazine electrooxidation: FeS2 microspheres: Electrochemistry; Rational design: Hydrazine electrooxidation: FeS2 microspheres: Electrochemistry
• ISSN: 1005-0302; 1941-1162
• DOI: 10.1016/j.jmst.2021.08.063

•Hydrazine is one of the raw materials of direct fuel cells, which play an important role in the field of energy, the electrocatalysis of hydrazine oxidation is an important challenge,but most electrocatalysts still suffer from low efficiency and stability.•Inspired by the relatively recognized performance of transition metal sulfides in the oxidation of hydrazine oxidation, the catalytic properties of two relatively stable iron sulfides of FeS2 and Fe3S4 were firstly investigated and compared via the density functional theory (DFT) calculations. Therein, the Fe centres were identified as the catalytic sites of all possible active locations.•Due to the different coordination numbers of iron-sulfur, the free energies of the dehydrogenation steps on FeS2 were far less than those on Fe3S4, which led to the much better catalytic performance of FeS2. Accordingly, FeS2 and Fe3S4 were then prepared by a facile one-step hydrothermal strategy.•Following experimental results were in agreement with the DFT calculation ones: FeS2 microspheres exhibited promising electrocatalytic performance in the electrocatalytic decomposition of hydrazine with a starting potential of 0.22 V vs. reversible hydrogen electrode (RHE) and peak oxidation current of 16 mA cm−2 (0.5 V vs. RHE). Meanwhile, stability and high faradaic efficiency (3.5e−/N2H4) were obtained for hydrazine oxidation to N2.
Inspired by the relatively recognized performance of transition metal sulfides in the oxidation of hydrazine, the catalytic properties of FeS2 and Fe3S4 are compared via the density functional theory calculations. Due to the different coordination numbers of iron-sulfur, the free energies of the dehydrogenation steps on FeS2 are far less than those on Fe3S4, which led to the much better catalytic performance of FeS2. Accordingly, FeS2 microspheres are rationally proposed as a more efficient electrocatalyst for hydrazine oxidation, which is then prepared by a facile one-step hydrothermal strategy. Such FeS2 microspheres show great activity for hydrazine oxidation with an onset oxidation potential of 0.22 V vs. reversible hydrogen electrode, and a peak current density of 16 mA cm−2. Meanwhile, stability and high faradaic efficiency (3.5e−/N2H4) is obtained for hydrazine oxidation to N2.