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Encapsulating spinel nancrystals in Laponite cages and applications in molecular oxidation of cyclohexane
Abstract The Co-based spinel nanocrystals were fabricated by thermal decomposition of clay cages comprised with Laponite (LP) that were assembled on ZIF-67 frameworks (LP@ZIF-67). Spinel phases included Co3O4, FeCo2O4 and MgCo2O4 were produced and encapsulated within the Laponite cages (LP@spinel). The prepared materials were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscope (SEM), transmission electron microscopy (TEM), N2 adsorption-desorption, Fourier transform infrared spectroscopy (FT-IR), and thermogravimetric analyses (TGA). It was indicated that the porous structure of Laponite and ZIF-67 was preserved after annealing at the temperature of ~400 °C. The XPS showed the binding energy of Co2P in sample of LP@spinel shifted to lower values compared to the Co3O4 which was obtained by annealing the pure phase of ZIF-67, and this demonstrates the catalytically active Co-centers were (220) facet-exposed in spinel nanocrystals. The material LP@spinel shares mesoporous structure with surface area of 135 m2·g− 1. The LP@spinel was found to exhibit brilliant performance on aerobic oxidation of cyclohexane to get cyclohexanone and cyclohexanol (KA oil). At a preset O2 pressure of 2.0 MPa, the catalysis showed an outstanding conversion at 17.2% and the selectivity was found to reach 95.3% of KA oil for a typical reaction t = 5.0 h at T = 150 °C.
Highlights Hard templates of clay sheets were assembled on ZIF-67 frameworks. Spinel nanocrystals were encapsulated in clay cages. Laponite reacts with ZIF-67 to form Fe- and Mg-spinel. The Fe- and Mg-spinel was active in the aerobic catalysis. The heterolytic or hemolytic character of catalysts was evaluated.
Encapsulating spinel nancrystals in Laponite cages and applications in molecular oxidation of cyclohexane
Abstract The Co-based spinel nanocrystals were fabricated by thermal decomposition of clay cages comprised with Laponite (LP) that were assembled on ZIF-67 frameworks (LP@ZIF-67). Spinel phases included Co3O4, FeCo2O4 and MgCo2O4 were produced and encapsulated within the Laponite cages (LP@spinel). The prepared materials were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscope (SEM), transmission electron microscopy (TEM), N2 adsorption-desorption, Fourier transform infrared spectroscopy (FT-IR), and thermogravimetric analyses (TGA). It was indicated that the porous structure of Laponite and ZIF-67 was preserved after annealing at the temperature of ~400 °C. The XPS showed the binding energy of Co2P in sample of LP@spinel shifted to lower values compared to the Co3O4 which was obtained by annealing the pure phase of ZIF-67, and this demonstrates the catalytically active Co-centers were (220) facet-exposed in spinel nanocrystals. The material LP@spinel shares mesoporous structure with surface area of 135 m2·g− 1. The LP@spinel was found to exhibit brilliant performance on aerobic oxidation of cyclohexane to get cyclohexanone and cyclohexanol (KA oil). At a preset O2 pressure of 2.0 MPa, the catalysis showed an outstanding conversion at 17.2% and the selectivity was found to reach 95.3% of KA oil for a typical reaction t = 5.0 h at T = 150 °C.
Highlights Hard templates of clay sheets were assembled on ZIF-67 frameworks. Spinel nanocrystals were encapsulated in clay cages. Laponite reacts with ZIF-67 to form Fe- and Mg-spinel. The Fe- and Mg-spinel was active in the aerobic catalysis. The heterolytic or hemolytic character of catalysts was evaluated.
Encapsulating spinel nancrystals in Laponite cages and applications in molecular oxidation of cyclohexane
Zhang, Peng (author) / Wang, Jian (author) / Jia, Yu (author) / Li, Wenqing (author) / Tan, Xiaoling (author) / Zhang, Dan (author) / Xu, Shaonan (author) / Zhang, Peiping (author) / Wei, Cundi (author) / Miao, Shiding (author)
Applied Clay Science ; 181
2019-07-13
Article (Journal)
Electronic Resource
English
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