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Monodisperse α-Fe2O3 Mesoporous Microspheres: One-Step NaCl-Assisted Microwave-Solvothermal Preparation, Size Control and Photocatalytic Property.

Cao SW, Zhu YJ - Nanoscale Res Lett (2010)

Bottom Line: In this approach, Fe(NO3)3 · 9H2O is used as the iron source, and polyvinylpyrrolidone (PVP) acts as a surfactant in the presence of NaCl in mixed solvents of H2O and ethanol.One of the advantages of this method is that the size of α-Fe2O3 mesoporous microspheres can be adjusted in the range from ca. 170 to ca. 260 nm by changing the experimental parameters.High photocatalytic activities in the degradation of salicylic acid are observed for α-Fe2O3 mesoporous microspheres with different specific surface areas.

View Article: PubMed Central - HTML - PubMed

Affiliation: State Key Laboratory of High Performance Ceramics and Superfine Microstructure, Shanghai Institute of Ceramics, Chinese Academy of Sciences, 200050, Shanghai, People's Republic of China. y.j.zhu@mail.sic.ac.cn.

ABSTRACT
A simple one-step NaCl-assisted microwave-solvothermal method has been developed for the preparation of monodisperse α-Fe2O3 mesoporous microspheres. In this approach, Fe(NO3)3 · 9H2O is used as the iron source, and polyvinylpyrrolidone (PVP) acts as a surfactant in the presence of NaCl in mixed solvents of H2O and ethanol. Under the present experimental conditions, monodisperse α-Fe2O3 mesoporous microspheres can form via oriented attachment of α-Fe2O3 nanocrystals. One of the advantages of this method is that the size of α-Fe2O3 mesoporous microspheres can be adjusted in the range from ca. 170 to ca. 260 nm by changing the experimental parameters. High photocatalytic activities in the degradation of salicylic acid are observed for α-Fe2O3 mesoporous microspheres with different specific surface areas.

No MeSH data available.


Characterization of sample 6: a, b SEM micrographs; c–e TEM micrographs; f the SAED pattern of a single microsphere.
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Figure 4: Characterization of sample 6: a, b SEM micrographs; c–e TEM micrographs; f the SAED pattern of a single microsphere.

Mentions: Sample 6 was prepared at a higher microwave-solvothermal temperature of 140°C instead of 120°C, while the other conditions were kept unchanged. Figure 1b shows the XRD pattern of sample 6, from which one can see that the product is a single phase of α-Fe2O3 with a hexagonal structure (JCPDS No. 80–2377). The higher intensities of the XRD peaks of sample 6 compared with those of sample 1 (Figure 1a) indicate that the crystallinity of sample 6 is improved. Figure 4a–e shows the SEM and TEM micrographs of sample 6. One can see that almost exclusive α-Fe2O3 mesoporous microspheres assembled with nanocrystals are obtained and that dispersed nanocrystals are hardly observed compared with sample 1. However, the average diameter of α-Fe2O3 microspheres in sample 6 increases to ca. 260 nm, higher than that of sample 1 (170 nm), implying that higher microwave-hydrothermal temperature will produce α-Fe2O3 microspheres with larger size. Figure 4f shows the SAED pattern of a single microsphere, revealing the single-crystal-like feature of the mesoporous microsphere formed via an oriented aggregation of α-Fe2O3 nanocrystals. The above experimental results indicate that the size of α-Fe2O3 mesoporous microspheres can be controlled (in the range from ca. 170 to ca. 260 nm under the present experimental conditions used) by changing the experimental parameters such as the microwave-solvothermal time and concentration of PVP.


Monodisperse α-Fe2O3 Mesoporous Microspheres: One-Step NaCl-Assisted Microwave-Solvothermal Preparation, Size Control and Photocatalytic Property.

Cao SW, Zhu YJ - Nanoscale Res Lett (2010)

Characterization of sample 6: a, b SEM micrographs; c–e TEM micrographs; f the SAED pattern of a single microsphere.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3102339&req=5

Figure 4: Characterization of sample 6: a, b SEM micrographs; c–e TEM micrographs; f the SAED pattern of a single microsphere.
Mentions: Sample 6 was prepared at a higher microwave-solvothermal temperature of 140°C instead of 120°C, while the other conditions were kept unchanged. Figure 1b shows the XRD pattern of sample 6, from which one can see that the product is a single phase of α-Fe2O3 with a hexagonal structure (JCPDS No. 80–2377). The higher intensities of the XRD peaks of sample 6 compared with those of sample 1 (Figure 1a) indicate that the crystallinity of sample 6 is improved. Figure 4a–e shows the SEM and TEM micrographs of sample 6. One can see that almost exclusive α-Fe2O3 mesoporous microspheres assembled with nanocrystals are obtained and that dispersed nanocrystals are hardly observed compared with sample 1. However, the average diameter of α-Fe2O3 microspheres in sample 6 increases to ca. 260 nm, higher than that of sample 1 (170 nm), implying that higher microwave-hydrothermal temperature will produce α-Fe2O3 microspheres with larger size. Figure 4f shows the SAED pattern of a single microsphere, revealing the single-crystal-like feature of the mesoporous microsphere formed via an oriented aggregation of α-Fe2O3 nanocrystals. The above experimental results indicate that the size of α-Fe2O3 mesoporous microspheres can be controlled (in the range from ca. 170 to ca. 260 nm under the present experimental conditions used) by changing the experimental parameters such as the microwave-solvothermal time and concentration of PVP.

Bottom Line: In this approach, Fe(NO3)3 · 9H2O is used as the iron source, and polyvinylpyrrolidone (PVP) acts as a surfactant in the presence of NaCl in mixed solvents of H2O and ethanol.One of the advantages of this method is that the size of α-Fe2O3 mesoporous microspheres can be adjusted in the range from ca. 170 to ca. 260 nm by changing the experimental parameters.High photocatalytic activities in the degradation of salicylic acid are observed for α-Fe2O3 mesoporous microspheres with different specific surface areas.

View Article: PubMed Central - HTML - PubMed

Affiliation: State Key Laboratory of High Performance Ceramics and Superfine Microstructure, Shanghai Institute of Ceramics, Chinese Academy of Sciences, 200050, Shanghai, People's Republic of China. y.j.zhu@mail.sic.ac.cn.

ABSTRACT
A simple one-step NaCl-assisted microwave-solvothermal method has been developed for the preparation of monodisperse α-Fe2O3 mesoporous microspheres. In this approach, Fe(NO3)3 · 9H2O is used as the iron source, and polyvinylpyrrolidone (PVP) acts as a surfactant in the presence of NaCl in mixed solvents of H2O and ethanol. Under the present experimental conditions, monodisperse α-Fe2O3 mesoporous microspheres can form via oriented attachment of α-Fe2O3 nanocrystals. One of the advantages of this method is that the size of α-Fe2O3 mesoporous microspheres can be adjusted in the range from ca. 170 to ca. 260 nm by changing the experimental parameters. High photocatalytic activities in the degradation of salicylic acid are observed for α-Fe2O3 mesoporous microspheres with different specific surface areas.

No MeSH data available.