The Confined Interlayer Growth of Ultrathin Two-Dimensional Fe₃O₄ Nanosheets with Enriched Oxygen Vacancies for Peroxymonosulfate Activation

Abstract

Developing iron-based catalysts with superior activity and stability is a longterm goal for peroxymonosulfate (PMS) activation in advanced oxidation processes. Combining the confined interlayer growth strategy with melt infiltration under dry-chemical conditions, we successfully synthesized ultrathin 2D Fe 3 O 4 nanosheets with a monolayer thickness of about 1 nm. Atomic force microscopy, CS-corrected high-resolution transmission electron microscopy, X-ray photoelectron spectroscopy, X-ray absorption fine structure, etc. jointly revealed that the 2D Fe 3 O 4 nanosheets possessed special graphene-like morphology and enriched oxygen vacancies. As highly efficient AOP catalysts, a series of refractory organic pollutants, including phenolic compounds, antibiotics, and pharmaceuticals, were degraded and mineralized effectively via the activation of PMS. On the basis of radical quenching experiments, electrochemical analysis, and theory calculations, the radical generation (•OH and SO 4•− ) and mediated electron transfer were verified to be key mechanisms in the reaction. The oxygen vacancy-rich ultrathin 2D Fe 3 O 4 mediated the electron transfer between pollutions and oxidants, prompted the redox cycle of Fe 3 O 4 , and remarkably lowered the energy barrier for interfacial charge transfer. This work could generate 2D metal oxides nanosheets with sufficient oxygen vacancies in a large scale, leading the insight for boosting the activity of iron-based catalysts.

Fe2O3 Nanocatalysts Supported on Zeolite-Y for the Selective Synthesis of C2 Di-Indolyl Indolones and Isatins

“…Most of the reported studies found acetonitrile, MeCN, to be one of the suitable solvents for this cascade oxidative dearomatization of indoles. , Different oxidants such as molecular oxygen (O 2 ), H 2 O 2 , TBHP, and peroxymonosulfate were used for this type of oxidative dearomatization reaction. ,, For the current study, peroxymonosulfate as oxidant was preferred as H 2 O 2 hampers Fe chemistry, leading to tar formation. , Similarly, catalytic reactions mediated by a Fe-catalyst with O 2 and TBHP as oxidants are reported to have slow reaction kinetics . Recent studies showed that the peroxymonosulfate can be a suitable oxidant for the Fe-based catalytic oxidation reaction. , For further confirmation, reactions were performed with all the oxidants using 0.01 g of Fe 2 O 3 -Y, 3 mmol indole, and 1 mmol individual oxidants. No C2-trimerized product was obtained under this reaction conditions with H 2 O 2 , O 2 , and TBHP.…”

“…56 Recent studies showed that the peroxymonosulfate can be a suitable oxidant for the Fe-based catalytic oxidation reaction. 57,58 For further confirmation, reactions were performed with all the oxidants using 0.01 g of Fe 2 O 3 -Y, 3 mmol indole, and 1 mmol individual oxidants. No C2-trimerized product was obtained under this reaction conditions with H 2 O 2 , O 2 , and TBHP.…”

The interfacial effect induced by rare earth oxide in boosting the conversion of CO2 to formate

“…2(c)). 34,39 It is noted that even with different Ce : Bi ratios, the binding energy of Ce and Nb display barely any change (Fig. S11a-c, ESI †).…”

A potential link between the structure of iron catalysts and Fenton-like performance: from fundamental understanding to engineering design

“…75,76 For instance, Wang et al revealed that the Fe-O coordination number (3.4) in 2D Fe 3 O 4 containing ample oxygen vacancies was lower than that in commercial Fe 3 O 4 (4.6). 77 This will correspondingly affect Fenton-like catalytic performance since the coordination number of surface Fe sites is closely related to the H 2 O 2 adsorption and activation process. 30,51 Except for oxygen vacancies, the promoting effects of some other anion vacancies (i.e., sulfur vacancies in Fe sulde) on Fenton-like processes have also been reported with a similar mechanism to oxygen vacancies.…”