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Ferric Phosphate Hydroxide Microstructures Affect Their Magnetic Properties.

Zhao J, Zhang Y, Run Z, Li P, Guo Q, Pang H - ChemistryOpen (2015)

Bottom Line: Several ferric phosphate hydroxide (Fe4(OH)3(PO4)3) microstructures were successfully prepared under hydrothermal conditions.More importantly, the magnetic properties of these materials are directly correlated to their size and micro/nanostructure morphology.These crystals are good examples that prove that physical and chemical properties of nano/microstructured materials are related to their structures, and the precise control of the morphology of such functional materials could allow for the control of their performance.

View Article: PubMed Central - PubMed

Affiliation: College of Chemistry and Chemical Engineering, Anyang Normal University Anyang, Henan, 455002, P. R. China.

ABSTRACT
Uniformly sized and shape-controlled nanoparticles are important due to their applications in catalysis, electrochemistry, ion exchange, molecular adsorption, and electronics. Several ferric phosphate hydroxide (Fe4(OH)3(PO4)3) microstructures were successfully prepared under hydrothermal conditions. Using controlled variations in the reaction conditions, such as reaction time, temperature, and amount of hexadecyltrimethylammonium bromide (CTAB), the crystals can be grown as almost perfect hyperbranched microcrystals at 180 °C (without CTAB) or relatively monodisperse particles at 220 °C (with CTAB). The large hyperbranched structure of Fe4(OH)3(PO4)3 with a size of ∼19 μm forms with the "fractal growth rule" and shows many branches. More importantly, the magnetic properties of these materials are directly correlated to their size and micro/nanostructure morphology. Interestingly, the blocking temperature (T B) shows a dependence on size and shape, and a smaller size resulted in a lower T B. These crystals are good examples that prove that physical and chemical properties of nano/microstructured materials are related to their structures, and the precise control of the morphology of such functional materials could allow for the control of their performance.

No MeSH data available.


Related in: MedlinePlus

SEM images of as-prepared Fe4(OH)3(PO4)3 samples. a,b) N4 and c,d) N5.
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fig03: SEM images of as-prepared Fe4(OH)3(PO4)3 samples. a,b) N4 and c,d) N5.

Mentions: Figures 3 a, b show SEM images of the product N4 prepared under the same conditions as N3 (shown in Figures 2 e, f) except for the addition of CTAB (0.50 g) into the reaction. The morphology of as-prepared sample N4 changed into a corner-truncated octahedron with a size of ∼6.5 μm. From this, it is obvious that the CTAB affects the growth of the product.4 Using the reaction conditions for N4 but increasing the reaction time to 24 h, we get as-prepared sample N5, with a microstructure reminiscent of a three-dimensional Christian Latin cross, which has a short horizontal axis and slightly longer vertical axis, but with the ends blunted. The CTAB is also important to form the Christian-cross morphology. The transformation from the corner-truncated octahedron to the Christian-cross morphology strongly depends on the competition between the etching and capping of surface of crystals by CTAB. The long reaction time makes CTAB etch and cap the corner-truncated octahedron to a large extent.4 The etching tends to decompose the particles, whereas the adsorbed CTAB molecules stabilize the particle surface and prevent that specific crystal facet from being etched. Once a pit has formed on the surface, further corrosion would occur inside the pit preferentially. As etching continues, the concentration of phosphate ions sufficiently decreases. In other words, the concentration of protons decreases and thus leads to the weakening of etching. As the etching and capping proceeds, the Christian-cross morphology forms. We propose three possible reactions under these hydrothermal conditions:123


Ferric Phosphate Hydroxide Microstructures Affect Their Magnetic Properties.

Zhao J, Zhang Y, Run Z, Li P, Guo Q, Pang H - ChemistryOpen (2015)

SEM images of as-prepared Fe4(OH)3(PO4)3 samples. a,b) N4 and c,d) N5.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4522176&req=5

fig03: SEM images of as-prepared Fe4(OH)3(PO4)3 samples. a,b) N4 and c,d) N5.
Mentions: Figures 3 a, b show SEM images of the product N4 prepared under the same conditions as N3 (shown in Figures 2 e, f) except for the addition of CTAB (0.50 g) into the reaction. The morphology of as-prepared sample N4 changed into a corner-truncated octahedron with a size of ∼6.5 μm. From this, it is obvious that the CTAB affects the growth of the product.4 Using the reaction conditions for N4 but increasing the reaction time to 24 h, we get as-prepared sample N5, with a microstructure reminiscent of a three-dimensional Christian Latin cross, which has a short horizontal axis and slightly longer vertical axis, but with the ends blunted. The CTAB is also important to form the Christian-cross morphology. The transformation from the corner-truncated octahedron to the Christian-cross morphology strongly depends on the competition between the etching and capping of surface of crystals by CTAB. The long reaction time makes CTAB etch and cap the corner-truncated octahedron to a large extent.4 The etching tends to decompose the particles, whereas the adsorbed CTAB molecules stabilize the particle surface and prevent that specific crystal facet from being etched. Once a pit has formed on the surface, further corrosion would occur inside the pit preferentially. As etching continues, the concentration of phosphate ions sufficiently decreases. In other words, the concentration of protons decreases and thus leads to the weakening of etching. As the etching and capping proceeds, the Christian-cross morphology forms. We propose three possible reactions under these hydrothermal conditions:123

Bottom Line: Several ferric phosphate hydroxide (Fe4(OH)3(PO4)3) microstructures were successfully prepared under hydrothermal conditions.More importantly, the magnetic properties of these materials are directly correlated to their size and micro/nanostructure morphology.These crystals are good examples that prove that physical and chemical properties of nano/microstructured materials are related to their structures, and the precise control of the morphology of such functional materials could allow for the control of their performance.

View Article: PubMed Central - PubMed

Affiliation: College of Chemistry and Chemical Engineering, Anyang Normal University Anyang, Henan, 455002, P. R. China.

ABSTRACT
Uniformly sized and shape-controlled nanoparticles are important due to their applications in catalysis, electrochemistry, ion exchange, molecular adsorption, and electronics. Several ferric phosphate hydroxide (Fe4(OH)3(PO4)3) microstructures were successfully prepared under hydrothermal conditions. Using controlled variations in the reaction conditions, such as reaction time, temperature, and amount of hexadecyltrimethylammonium bromide (CTAB), the crystals can be grown as almost perfect hyperbranched microcrystals at 180 °C (without CTAB) or relatively monodisperse particles at 220 °C (with CTAB). The large hyperbranched structure of Fe4(OH)3(PO4)3 with a size of ∼19 μm forms with the "fractal growth rule" and shows many branches. More importantly, the magnetic properties of these materials are directly correlated to their size and micro/nanostructure morphology. Interestingly, the blocking temperature (T B) shows a dependence on size and shape, and a smaller size resulted in a lower T B. These crystals are good examples that prove that physical and chemical properties of nano/microstructured materials are related to their structures, and the precise control of the morphology of such functional materials could allow for the control of their performance.

No MeSH data available.


Related in: MedlinePlus