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Complete magnesiothermic reduction reaction of vertically aligned mesoporous silica channels to form pure silicon nanoparticles.

Kim KH, Lee DJ, Cho KM, Kim SJ, Park JK, Jung HT - Sci Rep (2015)

Bottom Line: The procedure involves magnesium promoted reduction of vertically oriented mesoporous silica channels on reduced graphene oxides (rGO) sheets.The mesopores play a significant role in effectively enabling magnesium gas to interact with silica through a large number of reaction sites.The new method for complete magnesiothermic reduction of mesoporous silica approach provides a foundation for the rational design of silicon structures.

View Article: PubMed Central - PubMed

Affiliation: Department of Chemical and Biomolecular Engineering (BK21+Program), Korea Advance Institute of Science and Technology (KAIST), Daejeon 305-701 (Korea).

ABSTRACT
Owing to its simplicity and low temperature conditions, magnesiothermic reduction of silica is one of the most powerful methods for producing silicon nanostructures. However, incomplete reduction takes place in this process leaving unconverted silica under the silicon layer. This phenomenon limits the use of this method for the rational design of silicon structures. In this effort, a technique that enables complete magnesiothermic reduction of silica to form silicon has been developed. The procedure involves magnesium promoted reduction of vertically oriented mesoporous silica channels on reduced graphene oxides (rGO) sheets. The mesopores play a significant role in effectively enabling magnesium gas to interact with silica through a large number of reaction sites. Utilizing this approach, highly uniform, ca. 10 nm sized silicon nanoparticles are generated without contamination by unreacted silica. The new method for complete magnesiothermic reduction of mesoporous silica approach provides a foundation for the rational design of silicon structures.

No MeSH data available.


Characterization of completely reduced silicon nanoparticles.(a) Wide-angle X-ray scattering (WAXS) patterns of completely reduced silicon nanoparticles (red line), and conventional silicon nanoparticles (black line). X-ray photoelectron spectroscopy (XPS) spectrum of Si2p of (b) conventional silicon nanoparticle, (c) completely reduced silicon nanoparticles (d) the survey spectrum of completely reduced silicon nanoparticles.
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f4: Characterization of completely reduced silicon nanoparticles.(a) Wide-angle X-ray scattering (WAXS) patterns of completely reduced silicon nanoparticles (red line), and conventional silicon nanoparticles (black line). X-ray photoelectron spectroscopy (XPS) spectrum of Si2p of (b) conventional silicon nanoparticle, (c) completely reduced silicon nanoparticles (d) the survey spectrum of completely reduced silicon nanoparticles.

Mentions: To verify that complete conversion of silica to silicon takes place in the magnesiothermic reduction carried out by using the new approach with vertically aligned mesoporous silica channels, analyses of wide angle X-ray diffraction (XRD) pattern and X-ray photoelectron spectroscopy (XPS) spectra were performed. For this purpose, XRD of silicon nanostructures were prepared by magnesiothermic reduction reactions of two different silica templates. First, silicon nanoparticles were generated by employing a conventional silica-GO composite as a control (black line). In this case, XRD analysis (Figure 4a) shows that the silica layer not having a porous structure is formed on the graphene oxide sheets by simply mixing of TEOS and GO12. Second, silicon nanoparticles were prepared by using the mesoporous silica structure (red line). Analysis of the XRD patterns of the silicon particles produced by reduction of the conventional silica composite show three prominent diffraction peaks for silicon at 2θ = 28.4°, 47.3° and 56.1° (JCPDS #.65-1060), along with a broad peak around 2θ ca. 23° corresponding to residual silica. In contrast, the XRD pattern for silicon nanoparticle derived from the mesoporous silica only contains diffraction peaks for silicon only.


Complete magnesiothermic reduction reaction of vertically aligned mesoporous silica channels to form pure silicon nanoparticles.

Kim KH, Lee DJ, Cho KM, Kim SJ, Park JK, Jung HT - Sci Rep (2015)

Characterization of completely reduced silicon nanoparticles.(a) Wide-angle X-ray scattering (WAXS) patterns of completely reduced silicon nanoparticles (red line), and conventional silicon nanoparticles (black line). X-ray photoelectron spectroscopy (XPS) spectrum of Si2p of (b) conventional silicon nanoparticle, (c) completely reduced silicon nanoparticles (d) the survey spectrum of completely reduced silicon nanoparticles.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4355679&req=5

f4: Characterization of completely reduced silicon nanoparticles.(a) Wide-angle X-ray scattering (WAXS) patterns of completely reduced silicon nanoparticles (red line), and conventional silicon nanoparticles (black line). X-ray photoelectron spectroscopy (XPS) spectrum of Si2p of (b) conventional silicon nanoparticle, (c) completely reduced silicon nanoparticles (d) the survey spectrum of completely reduced silicon nanoparticles.
Mentions: To verify that complete conversion of silica to silicon takes place in the magnesiothermic reduction carried out by using the new approach with vertically aligned mesoporous silica channels, analyses of wide angle X-ray diffraction (XRD) pattern and X-ray photoelectron spectroscopy (XPS) spectra were performed. For this purpose, XRD of silicon nanostructures were prepared by magnesiothermic reduction reactions of two different silica templates. First, silicon nanoparticles were generated by employing a conventional silica-GO composite as a control (black line). In this case, XRD analysis (Figure 4a) shows that the silica layer not having a porous structure is formed on the graphene oxide sheets by simply mixing of TEOS and GO12. Second, silicon nanoparticles were prepared by using the mesoporous silica structure (red line). Analysis of the XRD patterns of the silicon particles produced by reduction of the conventional silica composite show three prominent diffraction peaks for silicon at 2θ = 28.4°, 47.3° and 56.1° (JCPDS #.65-1060), along with a broad peak around 2θ ca. 23° corresponding to residual silica. In contrast, the XRD pattern for silicon nanoparticle derived from the mesoporous silica only contains diffraction peaks for silicon only.

Bottom Line: The procedure involves magnesium promoted reduction of vertically oriented mesoporous silica channels on reduced graphene oxides (rGO) sheets.The mesopores play a significant role in effectively enabling magnesium gas to interact with silica through a large number of reaction sites.The new method for complete magnesiothermic reduction of mesoporous silica approach provides a foundation for the rational design of silicon structures.

View Article: PubMed Central - PubMed

Affiliation: Department of Chemical and Biomolecular Engineering (BK21+Program), Korea Advance Institute of Science and Technology (KAIST), Daejeon 305-701 (Korea).

ABSTRACT
Owing to its simplicity and low temperature conditions, magnesiothermic reduction of silica is one of the most powerful methods for producing silicon nanostructures. However, incomplete reduction takes place in this process leaving unconverted silica under the silicon layer. This phenomenon limits the use of this method for the rational design of silicon structures. In this effort, a technique that enables complete magnesiothermic reduction of silica to form silicon has been developed. The procedure involves magnesium promoted reduction of vertically oriented mesoporous silica channels on reduced graphene oxides (rGO) sheets. The mesopores play a significant role in effectively enabling magnesium gas to interact with silica through a large number of reaction sites. Utilizing this approach, highly uniform, ca. 10 nm sized silicon nanoparticles are generated without contamination by unreacted silica. The new method for complete magnesiothermic reduction of mesoporous silica approach provides a foundation for the rational design of silicon structures.

No MeSH data available.