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Bimetallic core/shell nanoparticle-decorated 3D urchin-like hierarchical TiO2 nanostructures with magneto-responsive and decolorization characteristics.

Xiang L, Liu S, Yin J, Zhao X - Nanoscale Res Lett (2015)

Bottom Line: The morphology and structure are characterized by scanning electron microscopy, transmission electron microscopy, energy-dispersive spectroscopy, and a surface area analyzer.It demonstrates that Co@Au and Co@Ag nanoparticles are uniformly decorated on urchin-like TiO2 nanostructures.The composite nanostructures show not only surface plasmon absorption band from Au or Ag but also a magneto-responsive characteristic from Co.

View Article: PubMed Central - PubMed

Affiliation: Department of Applied Physics, Smart Materials Laboratory, Northwestern Polytechnical University, Xi'an, 710072 China.

ABSTRACT
The semiconductors decorated with noble metals or magnetic metals have attracted increasing attention due to multifunctional properties. In this article, we prepare novel bimetallic core/shell nanoparticle (Co@Au and Co@Ag)-decorated 3D urchin-like hierarchical TiO2 nanostructures through combining electroless plating and in situ replacement processes. The morphology and structure are characterized by scanning electron microscopy, transmission electron microscopy, energy-dispersive spectroscopy, and a surface area analyzer. It demonstrates that Co@Au and Co@Ag nanoparticles are uniformly decorated on urchin-like TiO2 nanostructures. The composite nanostructures show not only surface plasmon absorption band from Au or Ag but also a magneto-responsive characteristic from Co. This allows composite nanostructures to exhibit advantages including enhanced decolorization efficiency compared to pure TiO2 nanostructures and facile separation from a solution by magnetic field.

No MeSH data available.


Related in: MedlinePlus

UV-visible absorption spectra of MB after interaction with hierarchical TiO2, Co@Au/TiO2, and Co@Ag/TiO2nanostructures. The spectra were measured after daylight lamp irradiation for 15 min.
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Fig6: UV-visible absorption spectra of MB after interaction with hierarchical TiO2, Co@Au/TiO2, and Co@Ag/TiO2nanostructures. The spectra were measured after daylight lamp irradiation for 15 min.

Mentions: Finally, the Co@Au/TiO2 and Co@Ag/TiO2 nanostructures are also evaluated for decolorization of methyl blue (MB) solution, a model dye in wastewater of the dyeing industry. The removal of MB molecules from the aqueous solution using Co@Au/TiO2 and Co@Ag/TiO2 nanostructures is monitored by UV–vis spectroscopy as shown in Figure 6. It is found that the intensity of the characteristic absorption peak of MB at 590 nm significantly decreases in the presence of Co@Au/TiO2 or Co@Ag/TiO2 nanostructures, indicating the rapid decolorization of MB. In particular, compared to urchin-like TiO2 nanostructures, the Co@Au/TiO2 or Co@Ag/TiO2 nanostructures show faster decolorization rate. For example, after daylight lamp irradiation for 15 min, the decrease of peak intensity of MB at 590 nm exceeds 90% in the presence of Co@Au/TiO2 nanostructures and exceeds 95% in the presence of Co@Ag/TiO2 nanostructures, which is distinctly faster than 19% of decolorization by pure urchin-like TiO2. According to the N2 adsorption-desorption isotherm, the special surface area of pure TiO2, Co@Au/TiO2, and Co@Ag/TiO2 nanostructures is 35, 31, and 34 m2/g, respectively. The difference in the surface area of three samples is not significant. Therefore, the faster decolorization of MB solution in the presence of Co@Au/TiO2 and Co@Ag/TiO2 nanostructures can be mainly attributed to Co@Au and Co@Ag nanoparticles decorated on TiO2, which have enhanced light-harvesting ability and improved the photocatalytical efficiency. The Co@Au/TiO2 and Co@Ag/TiO2 nanostructures can also retain their activity in repeated decolorization cycles. For example, after cycling decolorization for five times, the typical Co@Au/TiO2 nanostructures still maintain 85% of decolorization after irradiation for 15 min, while Co@Ag/TiO2 nanostructures maintain 90% of decolorization. In addition, it should be noted that the Co@Au/TiO2 or Co@Ag/TiO2 is also suitable for decolorization of other dyes, such as methyl orange (MO), etc., but the decolorization rate for MO is much slower compared to that for MB. The similar phenomenon has also been reported in other references, which can be attributed to the difference of molecular structure between MO and MB [16].Figure 6


Bimetallic core/shell nanoparticle-decorated 3D urchin-like hierarchical TiO2 nanostructures with magneto-responsive and decolorization characteristics.

Xiang L, Liu S, Yin J, Zhao X - Nanoscale Res Lett (2015)

UV-visible absorption spectra of MB after interaction with hierarchical TiO2, Co@Au/TiO2, and Co@Ag/TiO2nanostructures. The spectra were measured after daylight lamp irradiation for 15 min.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4385119&req=5

Fig6: UV-visible absorption spectra of MB after interaction with hierarchical TiO2, Co@Au/TiO2, and Co@Ag/TiO2nanostructures. The spectra were measured after daylight lamp irradiation for 15 min.
Mentions: Finally, the Co@Au/TiO2 and Co@Ag/TiO2 nanostructures are also evaluated for decolorization of methyl blue (MB) solution, a model dye in wastewater of the dyeing industry. The removal of MB molecules from the aqueous solution using Co@Au/TiO2 and Co@Ag/TiO2 nanostructures is monitored by UV–vis spectroscopy as shown in Figure 6. It is found that the intensity of the characteristic absorption peak of MB at 590 nm significantly decreases in the presence of Co@Au/TiO2 or Co@Ag/TiO2 nanostructures, indicating the rapid decolorization of MB. In particular, compared to urchin-like TiO2 nanostructures, the Co@Au/TiO2 or Co@Ag/TiO2 nanostructures show faster decolorization rate. For example, after daylight lamp irradiation for 15 min, the decrease of peak intensity of MB at 590 nm exceeds 90% in the presence of Co@Au/TiO2 nanostructures and exceeds 95% in the presence of Co@Ag/TiO2 nanostructures, which is distinctly faster than 19% of decolorization by pure urchin-like TiO2. According to the N2 adsorption-desorption isotherm, the special surface area of pure TiO2, Co@Au/TiO2, and Co@Ag/TiO2 nanostructures is 35, 31, and 34 m2/g, respectively. The difference in the surface area of three samples is not significant. Therefore, the faster decolorization of MB solution in the presence of Co@Au/TiO2 and Co@Ag/TiO2 nanostructures can be mainly attributed to Co@Au and Co@Ag nanoparticles decorated on TiO2, which have enhanced light-harvesting ability and improved the photocatalytical efficiency. The Co@Au/TiO2 and Co@Ag/TiO2 nanostructures can also retain their activity in repeated decolorization cycles. For example, after cycling decolorization for five times, the typical Co@Au/TiO2 nanostructures still maintain 85% of decolorization after irradiation for 15 min, while Co@Ag/TiO2 nanostructures maintain 90% of decolorization. In addition, it should be noted that the Co@Au/TiO2 or Co@Ag/TiO2 is also suitable for decolorization of other dyes, such as methyl orange (MO), etc., but the decolorization rate for MO is much slower compared to that for MB. The similar phenomenon has also been reported in other references, which can be attributed to the difference of molecular structure between MO and MB [16].Figure 6

Bottom Line: The morphology and structure are characterized by scanning electron microscopy, transmission electron microscopy, energy-dispersive spectroscopy, and a surface area analyzer.It demonstrates that Co@Au and Co@Ag nanoparticles are uniformly decorated on urchin-like TiO2 nanostructures.The composite nanostructures show not only surface plasmon absorption band from Au or Ag but also a magneto-responsive characteristic from Co.

View Article: PubMed Central - PubMed

Affiliation: Department of Applied Physics, Smart Materials Laboratory, Northwestern Polytechnical University, Xi'an, 710072 China.

ABSTRACT
The semiconductors decorated with noble metals or magnetic metals have attracted increasing attention due to multifunctional properties. In this article, we prepare novel bimetallic core/shell nanoparticle (Co@Au and Co@Ag)-decorated 3D urchin-like hierarchical TiO2 nanostructures through combining electroless plating and in situ replacement processes. The morphology and structure are characterized by scanning electron microscopy, transmission electron microscopy, energy-dispersive spectroscopy, and a surface area analyzer. It demonstrates that Co@Au and Co@Ag nanoparticles are uniformly decorated on urchin-like TiO2 nanostructures. The composite nanostructures show not only surface plasmon absorption band from Au or Ag but also a magneto-responsive characteristic from Co. This allows composite nanostructures to exhibit advantages including enhanced decolorization efficiency compared to pure TiO2 nanostructures and facile separation from a solution by magnetic field.

No MeSH data available.


Related in: MedlinePlus