Ultra-small and highly dispersive iron oxide hydroxide as an efficient catalyst for oxidation reactions: a Swiss-army-knife catalyst

• Published in: Scientific reports Vol. 11; no. 1; pp. 6642 - 10
• Main Authors: Amini, Mojtaba, Mousazade, Younes, Zand, Zahra, Bagherzadeh, Mojtaba, Najafpour, Mohammad Mahdi
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 23-03-2021; Nature Publishing Group; Nature Portfolio
• Subjects: 639/638/263; 639/638/77/887; Aldehydes; Alkenes; Benzyl alcohol; Catalysts; Electrochemistry; Epoxidation; Humanities and Social Sciences; Hydrogen peroxide; Iron oxides; multidisciplinary; Oxidation; pH effects; Science; Science (multidisciplinary); Spectroscopy; Styrene; Sulfides
• ISSN: 2045-2322; 2045-2322
• DOI: 10.1038/s41598-021-85672-x

Ultra-small and highly dispersive (< 10 nm) iron oxide hydroxide is characterized by some methods. The compound is an efficient and stable catalyst for alcohol oxidation, organic sulfide oxidation, and epoxidation of alkenes in the presence of H
2
O
2
. The electrochemical oxygen-evolution reaction of the iron oxide hydroxide is also tested under acidic, neutral, and alkaline conditions. In the presence of the iron oxide hydroxide, excellent conversions (75–100%) and selectivities of substrates (92–97%), depending on the nature of the sulfide, were obtained. Benzylalcohols having electron-donating and-withdrawing substituents in the aromatic ring were oxidized to produce the corresponding aldehydes with excellent conversion (65–89%) and selectivity (96–100%) using this iron oxide hydroxide. The conversion of styrene and cyclooctene toward the epoxidation in the presence of this catalyst are 60 and 53%, respectively. Water oxidation for the catalysts was investigated at pH 2, 6.7, 12, and 14. The onset of OER at pH 14 is observed with a 475 mV overpotential. At 585 mV overpotential, a current density of more than 0.18 mA/cm
2
and a turnover frequency of 1.5/h is observed. Operando high-resolution visible spectroscopy at pH 14, similar to previously reported investigations, shows that Fe(IV)=O is an intermediate for water oxidation.