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Fast Cyclohexane Oxidation Under Mild Reaction Conditions Through a Controlled Creation of Redox‐Active Fe(II/III) Sites in a Metal−Organic Framework
Author(s) -
Kim AhReum,
Ahn Sol,
Yoon TaeUng,
Notestein Justin M.,
Farha Omar K.,
Bae YounSang
Publication year - 2019
Publication title -
chemcatchem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.497
H-Index - 106
eISSN - 1867-3899
pISSN - 1867-3880
DOI - 10.1002/cctc.201901050
Subject(s) - cyclohexane , redox , x ray photoelectron spectroscopy , chemistry , metal , oxide , inorganic chemistry , adsorption , desorption , metal organic framework , powder diffraction , scanning electron microscope , catalysis , materials science , crystallography , chemical engineering , organic chemistry , engineering , composite material
MIL‐100(Fe), a metal−organic framework containing coordinatively unsaturated iron sites, was prepared by a solvothermal method and utilized in cyclohexane oxidation. Interestingly, the composition and fraction of redox‐active Fe(II/III) sites in MIL‐100(Fe) could be tuned by using different pretreatment temperatures. The obtained materials were characterized by means of field‐emission scanning electron microscopy (FE‐SEM), powder X‐ray diffraction (PXRD), N 2 adsorption‐desorption isotherms, and X‐ray photoelectron spectroscopy (XPS). Due to the presence of redox‐active coordinatively unsaturated sites (CUS) at the iron atoms, MIL‐100(Fe) exhibited good performance for cyclohexane oxidation under mild reaction conditions. Oxidation rates were significantly enhanced when reduced Fe II sites were generated by high‐temperature pretreatments. In either high‐temperature or low‐temperature pretreatment, the isolated Fe(II/III) sites in MIL‐100 were far more reactive in cyclohexane oxidation than were bulk iron oxide materials. Finally, possible reaction pathways were proposed based on radical, Haber‐Weiss routes.