The LiFePO4 nanotubes were successfully fabricated by a sol-gel method with porous anodic aluminum oxide as the template. Transmission electron microscopy and scanning electron microscopy showed that the synthesized L...The LiFePO4 nanotubes were successfully fabricated by a sol-gel method with porous anodic aluminum oxide as the template. Transmission electron microscopy and scanning electron microscopy showed that the synthesized LiFeP04 nanotubes were monodispersed and parallel to one another. Selected area electron diffraction pattern, X-ray diffraction and X-ray photoelectron spectroscopy investigations jointly demonstrated that the synthesized LiFePO4 nanotubes were pure olivine structure. This approach offered a potentially way for fabricating ordered LiFePO4 nanotubes at room temperature and ambient conditions, which might be expected to find promising application as a new cathode material in lithium ion battery,展开更多
In this communication,we report a synthetic approach to fabricate Y-junction Co nanowires and Y-junction Cu nanowires by AC electrodeposition using a hierarchically designed anodized aluminum oxide template.Morphology...In this communication,we report a synthetic approach to fabricate Y-junction Co nanowires and Y-junction Cu nanowires by AC electrodeposition using a hierarchically designed anodized aluminum oxide template.Morphology study showe that diameters of the stems and branches of the Y-junction nanowires were about 40 nm and 20 nm respectively.Structural analysis indicates that Co nanowires had a mixture of face-center-cubic and hexagonal-close-packed structures,whereas Cu nanowires had a face-center-cubic structure with a <110> texture.The Y-junction Co nanowires exhibited a longitudinal coercivity of 1300 Oe and remnant magnetization of 56%,which was affected by the growth direction and microstructure.The present method can be extended to other metallic systems and thus provides a simple and efficient way to fabricate Y-junction metal nanowires.展开更多
La-Co alloy nanowires can be made in pulse reversal current(PRC) and direct current(DC) electrodepositions under nonaqueous system, with the porous anodic aluminum oxide(AAO) as template. This membrane is subject to t...La-Co alloy nanowires can be made in pulse reversal current(PRC) and direct current(DC) electrodepositions under nonaqueous system, with the porous anodic aluminum oxide(AAO) as template. This membrane is subject to the dual-oxidation (two-step) anodizing. Scanning electron microscope(SEM) examination shows that all of the nanowires have uniform diameter about 200 nm, and their diameters are determined by the pore diameter of applied AAO template. X-ray energy dispersion analysis indicates that the chemical composition of La and Co elements is very close to 1-2 in stoichiometry. X-ray diffraction pattern investigation demonstrates that La-Co nanowire is the face-centered cubic(FCC) LaCo13.展开更多
One-dimensional Ni nanowires arrays were fabricated successfully by the electrochemical deposit in porous anodic alumina oxide(AAO)templates.The microstructure of nanoarrays was respectively observed by scanning elect...One-dimensional Ni nanowires arrays were fabricated successfully by the electrochemical deposit in porous anodic alumina oxide(AAO)templates.The microstructure of nanoarrays was respectively observed by scanning electron microscope s(SEM)and transmission electron microscopes(TEM).The results show that the obtained Ni nanowires are arranged orderly and the diameter is about 200nm.Crystallization way was observed by X-ray diffraction(XRD).The results show that Ni nanowire is face-centered cubic展开更多
The highly ordered CuO nanowire arrays of composite-oxides were synthesized within a porous anodic aluminum oxide(AAO) template by a citrate-based sol-gel route. A vacuum system was applied to draw the gel into the te...The highly ordered CuO nanowire arrays of composite-oxides were synthesized within a porous anodic aluminum oxide(AAO) template by a citrate-based sol-gel route. A vacuum system was applied to draw the gel into the template pores, which conquers the only driving force of this technique—capillary action, then the gel was thermally treated to prepare desired CuO nanowires. The results of scanning electron microscopy(SEM) indicate that the CuO nanowires are very uniformly assembled and parallel to each other in the pores of the anodic aluminum oxide(AAO) template membranes. The results of X-ray diffraction(XRD) and the selected-area electron diffraction(SAED) indicate that the CuO nanowires are monoclinic-type crystalline structure. Furthermore, X-ray photoelectron spectroscopy (XPS) demonstrates that the stoichiometric CuO is formed.展开更多
Well-aligned open-ended multi-walled carbon nanotube （MWCNT） arrays were prepared via chemical vapor deposition （CVD） method in porous anodic aluminum oxide （AAO） templates without depositing any transition meta...Well-aligned open-ended multi-walled carbon nanotube （MWCNT） arrays were prepared via chemical vapor deposition （CVD） method in porous anodic aluminum oxide （AAO） templates without depositing any transition metals as catalyst. Effects of the CVD temperature and heat treatment were studied in detail. Well-aligned open-ended MWCNT arrays were obtained at the CVD temperature above 600℃; when CVD temperature is reduced to around 550℃, CNTs, CNFs and other structures existed at the same time; no CNTs or carbon nanofibres （CNFs） could be fouad as the CVD temperature is below 500℃, and only amorphous carbon in the porous AAO template was found. Experimental results showed that the AAO template is catalytic during the CVD process, and it has the following two effects： to catalyze thermal decomposition of acetylene and to catalyze conversion of carbon decomposed from acetylene into CNTs or CNFs. Heat treatment could improve the graphitization degree, but it might also introduce new defects.展开更多
The progress of membrane technology with the development of membranes with controlled parameters led to porous membranes.These membranes can be formed using different methods and have numerous applications in science ...The progress of membrane technology with the development of membranes with controlled parameters led to porous membranes.These membranes can be formed using different methods and have numerous applications in science and technology.Anodization of aluminum in this aspect is an electro-synthetic process that changes the surface of the metal through oxidation to deliver an anodic oxide layer.This process results in a self-coordinated,exceptional cluster of round and hollow formed pores with controllable pore widths,periodicity,and thickness.Categorization in barrier type and porous type films,and different methods for the preparation of membranes,have been discussed.After the initial introduction,the paper proceeds with a brief overview of anodizing process.That engages anodic aluminum oxide(AAO)layers to be used as formats in various nanotechnology applications without the necessity for expensive lithographical systems.This review article surveys the current status of the investigation on AAO membranes.A comprehensive analysis is performed on AAO membranes in applications;filtration,sensors,drug delivery,template-assisted growth of various nanostructures.Their multiple usages in nanotechnology have also been discussed to gather nanomaterials and devices or unite theminto specific applications,such as nano-electronic gadgets,channel layers,and clinical platforms tissue designing.From this review,the fact that the specified enhancement of properties of AAO can be done by varying geometric parameters of AAO has been highlighted.No review paper focused on a detailed discussion of multiple applications of AAO with prospects and challenges.Also,it is a challenge for the research community to compare results reported in the literature.This paper provides tables for easy comparison of reported applications with membrane parameters.This review paper represents the formation,properties,applications with objective consideration of the prospects and challenges of AAO applications.The prospects may appeal to researchers to promote the development of unique membranes with functionalization and controlled geometric parameters and check the feasibility of the AAO membranes in nanotechnology and devices.展开更多
Nanostructures have drawn great attentions for functional device applications. Among the various techniques developed for fabricating arrayed nanostructures of functional materials, nanostructuring technique with poro...Nanostructures have drawn great attentions for functional device applications. Among the various techniques developed for fabricating arrayed nanostructures of functional materials, nanostructuring technique with porous anodic aluminum oxide （AAO） membrane as templates becomes more attractive owing to the superior geometrical characteristics and low-cost preparation process. In this mini review, progress about functional we summarize our recent nanostructuring based on perfectly-ordered AAO membrane to prepare perfectly- ordered nanostructure arrays of functional materials toward constructing high-performance energy conversion and storage devices. By employing the perfectly-ordered AAO membrane as templates, arrayed nanostructures in the form ofnanodot, nanorod, nanotube and nanopore have been synthesized over a large area. These as-obtained nanostructure arrays have large specific surface area, high regularity, large-scale implementation, and tunable nanos- cale features. All these advanced features enable them to be of great advantage for the performance improvement of energy conversion and storage devices, including photo- electrochemical water splitting cells, supercapacitors, and batteries, etc.展开更多
基金supported by tile National Natural Science Foundation of China(No.50375151,No.50323007 and No.50572107)863 Program(No.2002AA302609)"Hundreds Talent Program"of Chinese Academy of Sciences for financial Support.
文摘The LiFePO4 nanotubes were successfully fabricated by a sol-gel method with porous anodic aluminum oxide as the template. Transmission electron microscopy and scanning electron microscopy showed that the synthesized LiFeP04 nanotubes were monodispersed and parallel to one another. Selected area electron diffraction pattern, X-ray diffraction and X-ray photoelectron spectroscopy investigations jointly demonstrated that the synthesized LiFePO4 nanotubes were pure olivine structure. This approach offered a potentially way for fabricating ordered LiFePO4 nanotubes at room temperature and ambient conditions, which might be expected to find promising application as a new cathode material in lithium ion battery,
基金The authors are grateful for the financial support of this work from National Natural Science Foundation of China(No.20021002,29925310,29833090)Ministry of Science and Technology(2001CB610506).
基金financially supported partially by a NSF award CMMI-0825990
文摘In this communication,we report a synthetic approach to fabricate Y-junction Co nanowires and Y-junction Cu nanowires by AC electrodeposition using a hierarchically designed anodized aluminum oxide template.Morphology study showe that diameters of the stems and branches of the Y-junction nanowires were about 40 nm and 20 nm respectively.Structural analysis indicates that Co nanowires had a mixture of face-center-cubic and hexagonal-close-packed structures,whereas Cu nanowires had a face-center-cubic structure with a <110> texture.The Y-junction Co nanowires exhibited a longitudinal coercivity of 1300 Oe and remnant magnetization of 56%,which was affected by the growth direction and microstructure.The present method can be extended to other metallic systems and thus provides a simple and efficient way to fabricate Y-junction metal nanowires.
基金Project(04011311) supported by the Natural Science Foundation of Guangdong Province, ChinaProject(2006B14001001) supported by the Science and Technology Plan of Guangdong Province, ChinaProject(50471108) supported by the National Natural Science Foundation of China
文摘La-Co alloy nanowires can be made in pulse reversal current(PRC) and direct current(DC) electrodepositions under nonaqueous system, with the porous anodic aluminum oxide(AAO) as template. This membrane is subject to the dual-oxidation (two-step) anodizing. Scanning electron microscope(SEM) examination shows that all of the nanowires have uniform diameter about 200 nm, and their diameters are determined by the pore diameter of applied AAO template. X-ray energy dispersion analysis indicates that the chemical composition of La and Co elements is very close to 1-2 in stoichiometry. X-ray diffraction pattern investigation demonstrates that La-Co nanowire is the face-centered cubic(FCC) LaCo13.
文摘One-dimensional Ni nanowires arrays were fabricated successfully by the electrochemical deposit in porous anodic alumina oxide(AAO)templates.The microstructure of nanoarrays was respectively observed by scanning electron microscope s(SEM)and transmission electron microscopes(TEM).The results show that the obtained Ni nanowires are arranged orderly and the diameter is about 200nm.Crystallization way was observed by X-ray diffraction(XRD).The results show that Ni nanowire is face-centered cubic
基金Project(200623) supported by the Science Foundation of Shenzhen University, China
文摘The highly ordered CuO nanowire arrays of composite-oxides were synthesized within a porous anodic aluminum oxide(AAO) template by a citrate-based sol-gel route. A vacuum system was applied to draw the gel into the template pores, which conquers the only driving force of this technique—capillary action, then the gel was thermally treated to prepare desired CuO nanowires. The results of scanning electron microscopy(SEM) indicate that the CuO nanowires are very uniformly assembled and parallel to each other in the pores of the anodic aluminum oxide(AAO) template membranes. The results of X-ray diffraction(XRD) and the selected-area electron diffraction(SAED) indicate that the CuO nanowires are monoclinic-type crystalline structure. Furthermore, X-ray photoelectron spectroscopy (XPS) demonstrates that the stoichiometric CuO is formed.
基金This project was supported by the National High Technology Research and Development Program of China （863 Program, No. 2004AA302030） and Na- tional Natural Science Foundation of China （NSFC No. 60574095）. Tests and analysis are supported by the United Foundation for Testing ＆： Analysis in Hefei, Chi- nese Academy of Sciences.
文摘Well-aligned open-ended multi-walled carbon nanotube （MWCNT） arrays were prepared via chemical vapor deposition （CVD） method in porous anodic aluminum oxide （AAO） templates without depositing any transition metals as catalyst. Effects of the CVD temperature and heat treatment were studied in detail. Well-aligned open-ended MWCNT arrays were obtained at the CVD temperature above 600℃; when CVD temperature is reduced to around 550℃, CNTs, CNFs and other structures existed at the same time; no CNTs or carbon nanofibres （CNFs） could be fouad as the CVD temperature is below 500℃, and only amorphous carbon in the porous AAO template was found. Experimental results showed that the AAO template is catalytic during the CVD process, and it has the following two effects： to catalyze thermal decomposition of acetylene and to catalyze conversion of carbon decomposed from acetylene into CNTs or CNFs. Heat treatment could improve the graphitization degree, but it might also introduce new defects.
文摘The progress of membrane technology with the development of membranes with controlled parameters led to porous membranes.These membranes can be formed using different methods and have numerous applications in science and technology.Anodization of aluminum in this aspect is an electro-synthetic process that changes the surface of the metal through oxidation to deliver an anodic oxide layer.This process results in a self-coordinated,exceptional cluster of round and hollow formed pores with controllable pore widths,periodicity,and thickness.Categorization in barrier type and porous type films,and different methods for the preparation of membranes,have been discussed.After the initial introduction,the paper proceeds with a brief overview of anodizing process.That engages anodic aluminum oxide(AAO)layers to be used as formats in various nanotechnology applications without the necessity for expensive lithographical systems.This review article surveys the current status of the investigation on AAO membranes.A comprehensive analysis is performed on AAO membranes in applications;filtration,sensors,drug delivery,template-assisted growth of various nanostructures.Their multiple usages in nanotechnology have also been discussed to gather nanomaterials and devices or unite theminto specific applications,such as nano-electronic gadgets,channel layers,and clinical platforms tissue designing.From this review,the fact that the specified enhancement of properties of AAO can be done by varying geometric parameters of AAO has been highlighted.No review paper focused on a detailed discussion of multiple applications of AAO with prospects and challenges.Also,it is a challenge for the research community to compare results reported in the literature.This paper provides tables for easy comparison of reported applications with membrane parameters.This review paper represents the formation,properties,applications with objective consideration of the prospects and challenges of AAO applications.The prospects may appeal to researchers to promote the development of unique membranes with functionalization and controlled geometric parameters and check the feasibility of the AAO membranes in nanotechnology and devices.
文摘Nanostructures have drawn great attentions for functional device applications. Among the various techniques developed for fabricating arrayed nanostructures of functional materials, nanostructuring technique with porous anodic aluminum oxide （AAO） membrane as templates becomes more attractive owing to the superior geometrical characteristics and low-cost preparation process. In this mini review, progress about functional we summarize our recent nanostructuring based on perfectly-ordered AAO membrane to prepare perfectly- ordered nanostructure arrays of functional materials toward constructing high-performance energy conversion and storage devices. By employing the perfectly-ordered AAO membrane as templates, arrayed nanostructures in the form ofnanodot, nanorod, nanotube and nanopore have been synthesized over a large area. These as-obtained nanostructure arrays have large specific surface area, high regularity, large-scale implementation, and tunable nanos- cale features. All these advanced features enable them to be of great advantage for the performance improvement of energy conversion and storage devices, including photo- electrochemical water splitting cells, supercapacitors, and batteries, etc.
