Limits...
Template Route to Chemically Engineering Cavities at Nanoscale: A Case Study of Zn(OH)(2) Template.

Wu D, Jiang Y, Liu J, Yuan Y, Wu J, Jiang K, Xue D - Nanoscale Res Lett (2010)

Bottom Line: The rudimental Zn(OH)(2) core is eliminated with ammonia solution.In addition, ZnO-based heterostructures possessing better chemical or physical properties can also be prepared via this unique templating process.Room-temperature photoluminescence spectra of the heterostructures and hollow structures are also shown to study their optical properties.

View Article: PubMed Central - HTML - PubMed

ABSTRACT
A size-controlled Zn(OH)(2) template is used as a case study to explain the chemical strategy that can be executed to chemically engineering various nanoscale cavities. Zn(OH)(2) octahedron with 8 vertices and 14 edges is fabricated via a low temperature solution route. The size can be tuned from 1 to 30 μm by changing the reaction conditions. Two methods can be selected for the hollow process without loss of the original shape of Zn(OH)(2) template. Ion-replacement reaction is suitable for fabrication of hollow sulfides based on the solubility difference between Zn(OH)(2) and products. Controlled chemical deposition is utilized to coat an oxide layer on the surface of Zn(OH)(2) template. The abundant hydroxyl groups on Zn(OH)(2) afford strong coordination ability with cations and help to the coating of a shell layer. The rudimental Zn(OH)(2) core is eliminated with ammonia solution. In addition, ZnO-based heterostructures possessing better chemical or physical properties can also be prepared via this unique templating process. Room-temperature photoluminescence spectra of the heterostructures and hollow structures are also shown to study their optical properties.

No MeSH data available.


Related in: MedlinePlus

a SEM image and b XRD pattern (JCPDS Card No. 34-394) of the as-prepared CeO2 hollow structure. c PL spectrum of CeO2 shell structure obtained under an ultraviolet excitation at 310 nm
© Copyright Policy
Related In: Results  -  Collection


getmorefigures.php?uid=PMC2964472&req=5

Figure 8: a SEM image and b XRD pattern (JCPDS Card No. 34-394) of the as-prepared CeO2 hollow structure. c PL spectrum of CeO2 shell structure obtained under an ultraviolet excitation at 310 nm

Mentions: A controlled chemical deposition was also utilized to coat a layer of silica onto Zn(OH)2 template. The coating technique has been detailedly described in recent work [34]. Based on the coordination ability of the hydroxyl groups, the mineralization of the cations can occur on the template to form a layer of SiO2 without additional surface modification. After treated with diluted HCl, SiO2 hollow structure was generated. Figure 7a is the low-magnification SEM image of the as-prepared SiO2 product which is uniform and the diameter is 1–2 μm. The magnified SEM image (Fig. 7b) reveals the hollow interior of the octahedra. Moreover, there are broken parts on the hollow particles which may serve as the intake entrance for drug delivery or DNA storage. The thickness of the shell is measured to be about 30 nm. Figure 7c displays a TEM image of the products. The silica hollow structures are octahedral in shape and the thin shell can well support the hollow structure. ZnO/SiO2 core/shell architectures can also be obtained by facile heat treatment of corresponding Zn(OH)2/SiO2 precursors. ZnO and SiO2 nanomaterials have been of interest for construction of many gas- and biosensing devices because of their biocompatibility, high chemical stability, and low cost. Therefore, ZnO/SiO2 composite structures are of great significance toward the bio- or medical related fields. During the structural change from bared ZnO to ZnO/SiO2 core/shell, variation of optical properties can be observed with PL spectra shown in Fig. 7d. The intensity of visible emission peak at 433 nm increases sharply, suggesting important application of ZnO/SiO2 core/shell in photoelectric and biosensing devices. Detailed work is being carried out to tailor the thickness and the porosity of the silica shell for the potential applications in drug delivery and controlled release. In addition, taking advantage of the function groups located on the template surface, a similar route in an ethanol–water system could also be utilized to synthesize other inorganic hollow compounds [35]. For example, CeO2 hollow octahedra were also synthesized through a similar method (Fig. 8), indicating the generality of the chemical deposition route. SEM image in Fig. 8a shows that the product consists of uniform CeO2 hollow shells grown in a large scale. XRD pattern in Fig. 8b is consistent with the standard literature values (JCPDS Card No. 34-394). Under the stimulation of 310 nm laser, the PL spectrum of the CeO2 shells has a strong emission band with the center at about 410 nm (Fig. 8c), which is ascribed to hopping from different defect levels to O 2p band. It is believed that these CeO2 shells may have find potential applications in displays, sensors, and photosensitive devices.


Template Route to Chemically Engineering Cavities at Nanoscale: A Case Study of Zn(OH)(2) Template.

Wu D, Jiang Y, Liu J, Yuan Y, Wu J, Jiang K, Xue D - Nanoscale Res Lett (2010)

a SEM image and b XRD pattern (JCPDS Card No. 34-394) of the as-prepared CeO2 hollow structure. c PL spectrum of CeO2 shell structure obtained under an ultraviolet excitation at 310 nm
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2964472&req=5

Figure 8: a SEM image and b XRD pattern (JCPDS Card No. 34-394) of the as-prepared CeO2 hollow structure. c PL spectrum of CeO2 shell structure obtained under an ultraviolet excitation at 310 nm
Mentions: A controlled chemical deposition was also utilized to coat a layer of silica onto Zn(OH)2 template. The coating technique has been detailedly described in recent work [34]. Based on the coordination ability of the hydroxyl groups, the mineralization of the cations can occur on the template to form a layer of SiO2 without additional surface modification. After treated with diluted HCl, SiO2 hollow structure was generated. Figure 7a is the low-magnification SEM image of the as-prepared SiO2 product which is uniform and the diameter is 1–2 μm. The magnified SEM image (Fig. 7b) reveals the hollow interior of the octahedra. Moreover, there are broken parts on the hollow particles which may serve as the intake entrance for drug delivery or DNA storage. The thickness of the shell is measured to be about 30 nm. Figure 7c displays a TEM image of the products. The silica hollow structures are octahedral in shape and the thin shell can well support the hollow structure. ZnO/SiO2 core/shell architectures can also be obtained by facile heat treatment of corresponding Zn(OH)2/SiO2 precursors. ZnO and SiO2 nanomaterials have been of interest for construction of many gas- and biosensing devices because of their biocompatibility, high chemical stability, and low cost. Therefore, ZnO/SiO2 composite structures are of great significance toward the bio- or medical related fields. During the structural change from bared ZnO to ZnO/SiO2 core/shell, variation of optical properties can be observed with PL spectra shown in Fig. 7d. The intensity of visible emission peak at 433 nm increases sharply, suggesting important application of ZnO/SiO2 core/shell in photoelectric and biosensing devices. Detailed work is being carried out to tailor the thickness and the porosity of the silica shell for the potential applications in drug delivery and controlled release. In addition, taking advantage of the function groups located on the template surface, a similar route in an ethanol–water system could also be utilized to synthesize other inorganic hollow compounds [35]. For example, CeO2 hollow octahedra were also synthesized through a similar method (Fig. 8), indicating the generality of the chemical deposition route. SEM image in Fig. 8a shows that the product consists of uniform CeO2 hollow shells grown in a large scale. XRD pattern in Fig. 8b is consistent with the standard literature values (JCPDS Card No. 34-394). Under the stimulation of 310 nm laser, the PL spectrum of the CeO2 shells has a strong emission band with the center at about 410 nm (Fig. 8c), which is ascribed to hopping from different defect levels to O 2p band. It is believed that these CeO2 shells may have find potential applications in displays, sensors, and photosensitive devices.

Bottom Line: The rudimental Zn(OH)(2) core is eliminated with ammonia solution.In addition, ZnO-based heterostructures possessing better chemical or physical properties can also be prepared via this unique templating process.Room-temperature photoluminescence spectra of the heterostructures and hollow structures are also shown to study their optical properties.

View Article: PubMed Central - HTML - PubMed

ABSTRACT
A size-controlled Zn(OH)(2) template is used as a case study to explain the chemical strategy that can be executed to chemically engineering various nanoscale cavities. Zn(OH)(2) octahedron with 8 vertices and 14 edges is fabricated via a low temperature solution route. The size can be tuned from 1 to 30 μm by changing the reaction conditions. Two methods can be selected for the hollow process without loss of the original shape of Zn(OH)(2) template. Ion-replacement reaction is suitable for fabrication of hollow sulfides based on the solubility difference between Zn(OH)(2) and products. Controlled chemical deposition is utilized to coat an oxide layer on the surface of Zn(OH)(2) template. The abundant hydroxyl groups on Zn(OH)(2) afford strong coordination ability with cations and help to the coating of a shell layer. The rudimental Zn(OH)(2) core is eliminated with ammonia solution. In addition, ZnO-based heterostructures possessing better chemical or physical properties can also be prepared via this unique templating process. Room-temperature photoluminescence spectra of the heterostructures and hollow structures are also shown to study their optical properties.

No MeSH data available.


Related in: MedlinePlus