High-yielding low-cost vanadium oxide nanotubes were prepared by the hydrothermal self-assembling process from vanadium pentoxide and organic molecules as structure-directing templates.Moreover,a new method was discov...High-yielding low-cost vanadium oxide nanotubes were prepared by the hydrothermal self-assembling process from vanadium pentoxide and organic molecules as structure-directing templates.Moreover,a new method was discovered for determining the content of V (IV) in vanadium oxide nanotubes by thermogravimetric analysis (TGA).This method is simple,precise and feasible and can be extended to determine the content of low oxidation state in the other transition metal oxide nanomaterials.展开更多
In-situ growing carbon nanotubes （CNTs） directly on carbon fibers （CFs） always lead to a degraded tensile strength of CFs and then a poor fiber-dominated mechanical property of carbon/carbon composites （C/ Cs）. ...In-situ growing carbon nanotubes （CNTs） directly on carbon fibers （CFs） always lead to a degraded tensile strength of CFs and then a poor fiber-dominated mechanical property of carbon/carbon composites （C/ Cs）. To solve this issue, here, a novel carbon fiber-based multiscale reinforcement is reported. To synthesize it, carbon fibers （CFs） have been first grafted by graphene oxide （GO）, and then carbon nanotubes （CNTs） have been in-situ grown on GO-grafted CFs by catalytic chemical vapor deposition. Characterizations on this novel reinforcement show that GO grafting cannot only nondestructively improve the surface chemical activity of CFs but also protect CFs against the high-temperature corrosion of metal catalyst during CNT growth, which maintains their tensile properties. Tensile property tests for unidirectional C/Cs with different preforms show that this novel reinforcement can endow C/C with improved tensile properties, 32% and 87% higher than that of pure C/C and C/C only doped with in-situ grown CNTs. This work would open up a possibility to fabricate multiscale C/Cs with excellent global performance.展开更多
Oxide nanotubes with different diameters and lengths were fabricated on the biomedical Ti2448 alloy by anodic oxidation in neutral electrolyte. Similar to oxide nanotubes fabricated on pure titanium and its alloys, th...Oxide nanotubes with different diameters and lengths were fabricated on the biomedical Ti2448 alloy by anodic oxidation in neutral electrolyte. Similar to oxide nanotubes fabricated on pure titanium and its alloys, the as-grown nanotubes on Ti2448 also exhibit gradually changing chemical distribution along the direction of tube growth. Furthermore, several kinds of oxides with different valence states （MxOy） are formed simultaneously for each alloying element M, while their volume fractions vary gradually along the tube-growth direction. The findings of this study would provide insight into the effect of valence states on the desired nanotube properties and help develop ways to enhance the properties of the preferred oxide.展开更多
Developing efficient supported Pd catalysts and understanding their catalytic mechanism in CO oxidation are challenging research topics in recent years.This paper describes the synthesis of Pd nanoparticles supported ...Developing efficient supported Pd catalysts and understanding their catalytic mechanism in CO oxidation are challenging research topics in recent years.This paper describes the synthesis of Pd nanoparticles supported on CeO2 nanotubes via an alcohol reduction method.The effect of the support morphology on the catalytic reaction was explored.Subsequently,the performance of the prepared catalysts was investigated toward CO oxidation reaction and characterized by Nitrogen sorption,X-ray diffraction,X-ray photoelectron spectroscopy,transmission electron microscopy,and CO-temperature-programmed desorption techniques.The results indicated that the catalyst of Pd on CeO2 nanotubes exhibits excellent activity in CO oxidation at low temperatures,due to its large surface area,the high dispersion of Pd species,the mesoporous and tubular structure of the CeO2-nanotube support,the abundant Ce3＋,formation of Pd–O–Ce bonding,and enhanced metal–support interaction on the catalyst surface.展开更多
Well‐aligned zinc oxide(ZnO)nanotube arrays loaded with tungsten trioxide(WO3)nanoparticles were synthesized by a process involving chemical bath deposition in combination with pyrolysis.The prepared ZnO–WO3composit...Well‐aligned zinc oxide(ZnO)nanotube arrays loaded with tungsten trioxide(WO3)nanoparticles were synthesized by a process involving chemical bath deposition in combination with pyrolysis.The prepared ZnO–WO3composites were characterized by X‐ray diffraction,energy dispersive spectrometer,field emission scanning electron microscopy,X‐ray photoelectron spectroscopy,photoluminescence spectroscopy,Fourier transform infrared spectroscopy and UV–vis diffuse reflectance spectroscopy.The photocatalytic activities of the ZnO–WO3composite photocatalysts with different WO3contents for the degradation of the herbicide chlorinated phenoxyacetic acid(MCPA‐Na)under simulated sunlight irradiation were systematically evaluated.It was found that the WO3content had a great effect on the photocatalytic activity of the ZnO–WO3composites.The composite with3%WO3showed the highest photocatalytic activity,with a degradation rate of chlorinated phenoxyacetic acid of98.5%after200min with20mg of photocatalyst.This photodegradation rate was about twice that of the pristine ZnO nanotube array.The recombination of photogenerated electrons and holes was increasingly suppressed with the addition of WO3to ZnO.The high relative content of defects on the surface of the ZnO–WO3composites was beneficial to their photocatalytic activity in the degradation of chlorinated phenoxyacetic acid.?2018,Dalian Institute of Chemical Physics,Chinese Academy of Sciences.Published by Elsevier B.V.All rights reserved.展开更多
Nitrous oxide adsorption on the pristine （6,0） magnesium oxide nanotube was studied by using density functional theory calculations. We present the nature of the N2O interaction in selected sites of the nanotube. Ad...Nitrous oxide adsorption on the pristine （6,0） magnesium oxide nanotube was studied by using density functional theory calculations. We present the nature of the N2O interaction in selected sites of the nanotube. Adsorption energies corresponding to adsorption of the N2O on the nanotube were calculated to be in the range - 11.67 to -22.21 kJ mol- 1. Our results indicate that the N2O molecule has a weak physical adsorption on the pristine models due to weak Van der Waals interaction between the nanotubes and N2O molecule. The important results can be useful in production of the N2O sensors.展开更多
Graphene oxide （GO）-multiwalled carbon nanotube （MWCNT） composite was synthesized and characterized by X-ray diffraction, atomic force microscopy, scanning electron microscopy, micro Raman, Fourier transform infra...Graphene oxide （GO）-multiwalled carbon nanotube （MWCNT） composite was synthesized and characterized by X-ray diffraction, atomic force microscopy, scanning electron microscopy, micro Raman, Fourier transform infrared and ultraviolet-visible near infrared spectroscopy techniques. Spectral characteris- tics of cladding modified fiber optic gas sensors were studied for various concentrations of ammonia, ethanol and methanol at 27 ℃. Thickness of the gas sensing layer was controlled by varying the concentration of composite in ethanol medium （0.5 and 1 mg/mL） for three times dipping process. The O.S mg/ mL concentrated GO-MWCNT coated sensor showed 1.20, 1.40 and 1.15 times higher sensitivity than the GO coated sensor for ammonia, ethanol and methanol vapors, respectively. Furthermore, it exhibited 1.50, 1.80 and 1.80 times better sensitivity than 1 mg/mL concentrated GO-MWCNT coated sensor for ammonia, ethanol and methanol vapors, respectively. The presence of functional groups in GO increased the sen- sitivity. This is mainly attributed to the effective electron charge transfer between the composite materials and analytes.展开更多
The functionalization of multi-walled carbon nanotubes （MWCNTs） by ozone treatment has been sys- tematically investigated by using Raman spectroscopy, transmission electron microscopy （TEM）, Fourier transform inha...The functionalization of multi-walled carbon nanotubes （MWCNTs） by ozone treatment has been sys- tematically investigated by using Raman spectroscopy, transmission electron microscopy （TEM）, Fourier transform inhared spectroscopy （FTIR）, X-ray photoelectron spectroscopy （XPS）, organic elemental anal- ysis （OEA） and Boehm titration. The results showed that the functionalization process occurred at defective sites （opened mouths, tube caps, debris, etc.） before opening caps and truncating walls, and finally the graphitic structure was deteriorated. The surface oxygen content first increased with the treatment time but kept at around 8.0 wt% after 5 h. The analysis of the distribution of oxygen-containing groups re- vealed that phenolic hydroxyl was gradually converted to carboxyl and lactone, The carboxyl was found to play a pivotal role to reduce the over-potentials when we used the functionalized MWCNTs as the cat- alyst for oxygen reduction reaction （ORR）.展开更多
Cobalt oxide doped titanate nanotubes are synthesized with a simple hydrothermal treatment of mixed Co3O4 and TiO2 powders. The formed tubular nanostructure, chemical composition,and the elemental distribution are ana...Cobalt oxide doped titanate nanotubes are synthesized with a simple hydrothermal treatment of mixed Co3O4 and TiO2 powders. The formed tubular nanostructure, chemical composition,and the elemental distribution are analyzed using TEM, BET, FTIR, XRD, and XPS. The electrocatalytic activity towards oxygen evolution reactions and photodegradation against Rhodamine B are investigated. It has been found out that the oxygen evolutions starts at 0.8 V and reaches 0.98 mA ·cm^-1 at 1.4 V vs. SCE. For photodegradation of Rhodamine B, the concentration decreased to 24% after 1 h irradiation using the sample with a mass percentage of 5% cobalt. The results demonstrate that the cobalt oxide doped titanate nanotubes are good candidates as electrocatalysts and photocatalytic materials.展开更多
We have designed and prepared β-cyclodextrin （β-CD）-functionalized multi-walled nanotubes （MWCNTs-g-CD） for the oxidation of cinnamon oil to natural benzaldehyde under aqueous condi- tions. The synergistic effec...We have designed and prepared β-cyclodextrin （β-CD）-functionalized multi-walled nanotubes （MWCNTs-g-CD） for the oxidation of cinnamon oil to natural benzaldehyde under aqueous condi- tions. The synergistic effect of combining MWCNTs with β-CD led to a remarkable increase in the performance of the MWCNTs-g-CD for the catalytic oxidation of cinnamaldehyde, which exhibited 95% cinnamaldehyde conversion and 85% selectivity to natural benzaldehyde with a short reaction time of 10 rain. The MWCNTs-g-CD also exhibited outstanding recyclability with good stability, showing no discernible decrease in their catalytic activity over five reaction cycles.展开更多
Membrane technology for oil/water separation has received increasing attention in recent years. In this study, the hydrophilic/underwater superoleophobic membrane with enhanced water permeability and antifouling abili...Membrane technology for oil/water separation has received increasing attention in recent years. In this study, the hydrophilic/underwater superoleophobic membrane with enhanced water permeability and antifouling ability were fabricated by synergistically assembling graphene oxide （GO） nanosheets and titanium dioxide （TiO2） nanotubes for oil/water separation. GO/TiO2 membrane exhibits hydrophilic and underwater superoleophobic properties with water contact angle of 62° and under water oil contact angle of 162.8°. GO/TiO2 membrane shows greater water permeability with the water flux up to 531 L/ （m^2·h·bar）, which was more than 5 times that of the pristine GO membrane. Moreover, GO/TiO2 membrane had excellent oil/water separation efficiency and anti-oil-fouling capability, as oil residual in filtrate after separation was below 5 mg/L and flux recovery ratios were over 80%.The results indicate that the intercalation of TiO2 nanotubes into adjacent GO nanosheets enlarged the channel structure and modified surface topography of the obtained GO/TiO2 membranes, which improved the hydrophilicity, permeability and anti-oil-fouling ability of the membranes, enlightening the great prospects of GO/TiO2 membrane in oil-water treatment.展开更多
Cu2O and Cul were supported on multiwalled carbon nanotubes （MWCNTs） using a wet impregna- tion method, and the resulting materials were fully characterized by powder X-ray diffraction, Fourier transform infrared sp...Cu2O and Cul were supported on multiwalled carbon nanotubes （MWCNTs） using a wet impregna- tion method, and the resulting materials were fully characterized by powder X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy with energy dispersive X-ray spectroscopy, transmission electron microscopy, and temperature-programmed desorption with ammonia analysis. The results of these experiments revealed that Cu2O and CuI were deposited on the MWCNTs in the cubic and γ phases, respectively. These results also showed that the Cu-containing MWCNTs exhibited weak to strong electron-accepting （Lewis acidic） properties. The catalytic activities of these materials were studied for the synthesis of biologically significant N-（pyridin-2-yl）benzamides via the oxidative amidation of aryl aldehydes with 2-aminopyridines. The yields of the products were in the range 50%-95% with 100% selectivity. Notably, the CuI/MWCNT catalyst was much more effective than the Cu2O/MWCNT catalyst with respect to the isolated yield of the product, although the latter of these two catalysts exhibited much better recyclability. A preferential interaction was observed between the polar nature of the acid-activated MWCNTs and the ionic Cu2O compared with covalent CuL The differences in these interactions had a significant impact on the rate of the nucleophilic attack of the amino group of 2-aminopyridine substrate on the carbonyl group of the aryl aldehyde.展开更多
To extend the absorption capability of TiO_2 into visible light region and inhibit the recombination of photogenerated electrons and holes,we put forward an effective strategy of the coupling of TiO_2 with a suitable ...To extend the absorption capability of TiO_2 into visible light region and inhibit the recombination of photogenerated electrons and holes,we put forward an effective strategy of the coupling of TiO_2 with a suitable semiconductor that possesses a narrow band gap.Meanwhile,Ag_3PO_4-TiO_2 heterostructuralnanotube arrays were prepared by the two-step anodic oxidation to obtain the TiO_2 nanotube arrays and then by a deposition-precipitation method to load Ag_3PO_4.The samples were characterized by field emission scanning electron microscopy（FESEM）,energy dispersive spectrometry（EDS）,X-ray diffraction（XRD）,and UV-vis diffuse reflectance spectroscopy（UV-vis DRS）.The experimentalresults showed that Ag_3PO_4 nanoparticles were uniformly dispersed on the highly ordered TiO_2 nanotube arrays,which increased the visible-light absorption of TiO_2 photocatalyst.The photocurrent density and photocatalytic degradation of methylorange indicated that the performance of Ag_3PO_4-TiO_2 heterostructuralnanotube arrays was better than that of the TiO_2 nanotube arrays,which could be attributed to the effective electron-hole separation and the improved utilization of visible light.展开更多
A sensitive and selective preconcentration method using solid-phase extraction （SPE） disk made from oxidized multiwalled carbon nanotubes （OMWCNTs）, has been developed for the determination of aniline derivatives,...A sensitive and selective preconcentration method using solid-phase extraction （SPE） disk made from oxidized multiwalled carbon nanotubes （OMWCNTs）, has been developed for the determination of aniline derivatives, such as 2-nitroaniline （2-NA）, 4- nitroaniline （4-NA）, and 2,4-dichloroaniline （2,4-DCA） in water samples. Anilines were extracted onto OMWCNT disk and then determined by high performance liquid chromatography （HPLC） with UV detector. Several parameters on the recovery of the analytes were investigated. The experimental results showed that it was possible to obtain quantitative analysis when the solution pH was 8 using 200 mL of validation solution containing 2 ug of anilines and 10 mL of acetonitrile/ethanol （8/2, v/v） as an eluent. Relative standard deviations for five determinations were 7.5% （2-NA）, 6.5% （4-NA） and 3.8% （2,4-DCA） under optimum conditions. The linear range of calibration curves were 0.5 ng.mL 1 to 15 ng.mL-1 for each analyte with good correlation coefficients. The detection limits （3S/N） of 2-NA, 4-NA and 31 pg.mL -1 and 26 pg.mL-1 was successfully applied to 2,4-DCA were 30pg.mL -1, respectively. Our method the determination of aniline compounds in fiver water sample with high precision and accuracy.展开更多
文摘High-yielding low-cost vanadium oxide nanotubes were prepared by the hydrothermal self-assembling process from vanadium pentoxide and organic molecules as structure-directing templates.Moreover,a new method was discovered for determining the content of V (IV) in vanadium oxide nanotubes by thermogravimetric analysis (TGA).This method is simple,precise and feasible and can be extended to determine the content of low oxidation state in the other transition metal oxide nanomaterials.
基金supported by the National Natural Science Foundation of China (Nos.51432008,51502242,U1435202,and 51202194)the Research Fund for the Doctoral Program of Higher Education of China (No.20126102110013)the Key Grant Project of Chinese Ministry of Education (No.313047)
文摘In-situ growing carbon nanotubes （CNTs） directly on carbon fibers （CFs） always lead to a degraded tensile strength of CFs and then a poor fiber-dominated mechanical property of carbon/carbon composites （C/ Cs）. To solve this issue, here, a novel carbon fiber-based multiscale reinforcement is reported. To synthesize it, carbon fibers （CFs） have been first grafted by graphene oxide （GO）, and then carbon nanotubes （CNTs） have been in-situ grown on GO-grafted CFs by catalytic chemical vapor deposition. Characterizations on this novel reinforcement show that GO grafting cannot only nondestructively improve the surface chemical activity of CFs but also protect CFs against the high-temperature corrosion of metal catalyst during CNT growth, which maintains their tensile properties. Tensile property tests for unidirectional C/Cs with different preforms show that this novel reinforcement can endow C/C with improved tensile properties, 32% and 87% higher than that of pure C/C and C/C only doped with in-situ grown CNTs. This work would open up a possibility to fabricate multiscale C/Cs with excellent global performance.
基金supported in part by the National Natural Science Foundation of China (No. 51401048)the National Basic Research Program of China (No. 2012CB933902)+3 种基金the Specialized Research Fund for the Doctoral Program of Higher Education (No. 20130042120043)the Doctoral Scientific Research Foundation of Liaoning Province (No. 20141002)the Fundamental Research Funds for the Central Universities (No. N140204004, L1502044)the Scientific Research Foundation for the Returned Overseas Chinese Scholars, State Education Ministry (No. 47-7)
文摘Oxide nanotubes with different diameters and lengths were fabricated on the biomedical Ti2448 alloy by anodic oxidation in neutral electrolyte. Similar to oxide nanotubes fabricated on pure titanium and its alloys, the as-grown nanotubes on Ti2448 also exhibit gradually changing chemical distribution along the direction of tube growth. Furthermore, several kinds of oxides with different valence states （MxOy） are formed simultaneously for each alloying element M, while their volume fractions vary gradually along the tube-growth direction. The findings of this study would provide insight into the effect of valence states on the desired nanotube properties and help develop ways to enhance the properties of the preferred oxide.
基金supported by the National Natural Science Foundation of China(21376209,21376169)Zhejiang Provincial Natural Science Foundation(LZ13B060004)+1 种基金Program for Zhejiang Leading Team of S&T Innovation(2013TD07)Program of Introducing Talents of Discipline to Universities(B06006)~~
文摘Developing efficient supported Pd catalysts and understanding their catalytic mechanism in CO oxidation are challenging research topics in recent years.This paper describes the synthesis of Pd nanoparticles supported on CeO2 nanotubes via an alcohol reduction method.The effect of the support morphology on the catalytic reaction was explored.Subsequently,the performance of the prepared catalysts was investigated toward CO oxidation reaction and characterized by Nitrogen sorption,X-ray diffraction,X-ray photoelectron spectroscopy,transmission electron microscopy,and CO-temperature-programmed desorption techniques.The results indicated that the catalyst of Pd on CeO2 nanotubes exhibits excellent activity in CO oxidation at low temperatures,due to its large surface area,the high dispersion of Pd species,the mesoporous and tubular structure of the CeO2-nanotube support,the abundant Ce3＋,formation of Pd–O–Ce bonding,and enhanced metal–support interaction on the catalyst surface.
基金supported by the National Natural Science Foundation of China(51574071)~~
文摘Well‐aligned zinc oxide(ZnO)nanotube arrays loaded with tungsten trioxide(WO3)nanoparticles were synthesized by a process involving chemical bath deposition in combination with pyrolysis.The prepared ZnO–WO3composites were characterized by X‐ray diffraction,energy dispersive spectrometer,field emission scanning electron microscopy,X‐ray photoelectron spectroscopy,photoluminescence spectroscopy,Fourier transform infrared spectroscopy and UV–vis diffuse reflectance spectroscopy.The photocatalytic activities of the ZnO–WO3composite photocatalysts with different WO3contents for the degradation of the herbicide chlorinated phenoxyacetic acid(MCPA‐Na)under simulated sunlight irradiation were systematically evaluated.It was found that the WO3content had a great effect on the photocatalytic activity of the ZnO–WO3composites.The composite with3%WO3showed the highest photocatalytic activity,with a degradation rate of chlorinated phenoxyacetic acid of98.5%after200min with20mg of photocatalyst.This photodegradation rate was about twice that of the pristine ZnO nanotube array.The recombination of photogenerated electrons and holes was increasingly suppressed with the addition of WO3to ZnO.The high relative content of defects on the surface of the ZnO–WO3composites was beneficial to their photocatalytic activity in the degradation of chlorinated phenoxyacetic acid.?2018,Dalian Institute of Chemical Physics,Chinese Academy of Sciences.Published by Elsevier B.V.All rights reserved.
文摘Nitrous oxide adsorption on the pristine （6,0） magnesium oxide nanotube was studied by using density functional theory calculations. We present the nature of the N2O interaction in selected sites of the nanotube. Adsorption energies corresponding to adsorption of the N2O on the nanotube were calculated to be in the range - 11.67 to -22.21 kJ mol- 1. Our results indicate that the N2O molecule has a weak physical adsorption on the pristine models due to weak Van der Waals interaction between the nanotubes and N2O molecule. The important results can be useful in production of the N2O sensors.
文摘Graphene oxide （GO）-multiwalled carbon nanotube （MWCNT） composite was synthesized and characterized by X-ray diffraction, atomic force microscopy, scanning electron microscopy, micro Raman, Fourier transform infrared and ultraviolet-visible near infrared spectroscopy techniques. Spectral characteris- tics of cladding modified fiber optic gas sensors were studied for various concentrations of ammonia, ethanol and methanol at 27 ℃. Thickness of the gas sensing layer was controlled by varying the concentration of composite in ethanol medium （0.5 and 1 mg/mL） for three times dipping process. The O.S mg/ mL concentrated GO-MWCNT coated sensor showed 1.20, 1.40 and 1.15 times higher sensitivity than the GO coated sensor for ammonia, ethanol and methanol vapors, respectively. Furthermore, it exhibited 1.50, 1.80 and 1.80 times better sensitivity than 1 mg/mL concentrated GO-MWCNT coated sensor for ammonia, ethanol and methanol vapors, respectively. The presence of functional groups in GO increased the sen- sitivity. This is mainly attributed to the effective electron charge transfer between the composite materials and analytes.
基金financially supported by the National Natural Science Foundation of China(Nos.21307142 and 21403261)Ningbo Science and Technology Bureau(No.2014D10004)
文摘The functionalization of multi-walled carbon nanotubes （MWCNTs） by ozone treatment has been sys- tematically investigated by using Raman spectroscopy, transmission electron microscopy （TEM）, Fourier transform inhared spectroscopy （FTIR）, X-ray photoelectron spectroscopy （XPS）, organic elemental anal- ysis （OEA） and Boehm titration. The results showed that the functionalization process occurred at defective sites （opened mouths, tube caps, debris, etc.） before opening caps and truncating walls, and finally the graphitic structure was deteriorated. The surface oxygen content first increased with the treatment time but kept at around 8.0 wt% after 5 h. The analysis of the distribution of oxygen-containing groups re- vealed that phenolic hydroxyl was gradually converted to carboxyl and lactone, The carboxyl was found to play a pivotal role to reduce the over-potentials when we used the functionalized MWCNTs as the cat- alyst for oxygen reduction reaction （ORR）.
基金Supported by the National Natural Science Foundation of China(21576216,51372192)the Innovation Foundation from China Southern Power Grid(GDKJQQ20152050)
文摘Cobalt oxide doped titanate nanotubes are synthesized with a simple hydrothermal treatment of mixed Co3O4 and TiO2 powders. The formed tubular nanostructure, chemical composition,and the elemental distribution are analyzed using TEM, BET, FTIR, XRD, and XPS. The electrocatalytic activity towards oxygen evolution reactions and photodegradation against Rhodamine B are investigated. It has been found out that the oxygen evolutions starts at 0.8 V and reaches 0.98 mA ·cm^-1 at 1.4 V vs. SCE. For photodegradation of Rhodamine B, the concentration decreased to 24% after 1 h irradiation using the sample with a mass percentage of 5% cobalt. The results demonstrate that the cobalt oxide doped titanate nanotubes are good candidates as electrocatalysts and photocatalytic materials.
基金supported by the National Natural Science Foundation of China (21376279, 21276102, 21425627)Guangdong Technology Research Center for Synthesis and Separation of Thermosensitive Chemicals (2015B090903061)+1 种基金the Fundamental Research Funds for the Central Universities (14lgpy28)Guangzhou Science and Technology Plan Projects (2014J4100125)~~
文摘We have designed and prepared β-cyclodextrin （β-CD）-functionalized multi-walled nanotubes （MWCNTs-g-CD） for the oxidation of cinnamon oil to natural benzaldehyde under aqueous condi- tions. The synergistic effect of combining MWCNTs with β-CD led to a remarkable increase in the performance of the MWCNTs-g-CD for the catalytic oxidation of cinnamaldehyde, which exhibited 95% cinnamaldehyde conversion and 85% selectivity to natural benzaldehyde with a short reaction time of 10 rain. The MWCNTs-g-CD also exhibited outstanding recyclability with good stability, showing no discernible decrease in their catalytic activity over five reaction cycles.
文摘Membrane technology for oil/water separation has received increasing attention in recent years. In this study, the hydrophilic/underwater superoleophobic membrane with enhanced water permeability and antifouling ability were fabricated by synergistically assembling graphene oxide （GO） nanosheets and titanium dioxide （TiO2） nanotubes for oil/water separation. GO/TiO2 membrane exhibits hydrophilic and underwater superoleophobic properties with water contact angle of 62° and under water oil contact angle of 162.8°. GO/TiO2 membrane shows greater water permeability with the water flux up to 531 L/ （m^2·h·bar）, which was more than 5 times that of the pristine GO membrane. Moreover, GO/TiO2 membrane had excellent oil/water separation efficiency and anti-oil-fouling capability, as oil residual in filtrate after separation was below 5 mg/L and flux recovery ratios were over 80%.The results indicate that the intercalation of TiO2 nanotubes into adjacent GO nanosheets enlarged the channel structure and modified surface topography of the obtained GO/TiO2 membranes, which improved the hydrophilicity, permeability and anti-oil-fouling ability of the membranes, enlightening the great prospects of GO/TiO2 membrane in oil-water treatment.
基金DST-SERB for the financial support for this research work(Project number:SERB/F/3690/2013-14)
文摘Cu2O and Cul were supported on multiwalled carbon nanotubes （MWCNTs） using a wet impregna- tion method, and the resulting materials were fully characterized by powder X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy with energy dispersive X-ray spectroscopy, transmission electron microscopy, and temperature-programmed desorption with ammonia analysis. The results of these experiments revealed that Cu2O and CuI were deposited on the MWCNTs in the cubic and γ phases, respectively. These results also showed that the Cu-containing MWCNTs exhibited weak to strong electron-accepting （Lewis acidic） properties. The catalytic activities of these materials were studied for the synthesis of biologically significant N-（pyridin-2-yl）benzamides via the oxidative amidation of aryl aldehydes with 2-aminopyridines. The yields of the products were in the range 50%-95% with 100% selectivity. Notably, the CuI/MWCNT catalyst was much more effective than the Cu2O/MWCNT catalyst with respect to the isolated yield of the product, although the latter of these two catalysts exhibited much better recyclability. A preferential interaction was observed between the polar nature of the acid-activated MWCNTs and the ionic Cu2O compared with covalent CuL The differences in these interactions had a significant impact on the rate of the nucleophilic attack of the amino group of 2-aminopyridine substrate on the carbonyl group of the aryl aldehyde.
基金Funded by the Natural Science Foundation of Hubei Province(2012FFB05105)
文摘To extend the absorption capability of TiO_2 into visible light region and inhibit the recombination of photogenerated electrons and holes,we put forward an effective strategy of the coupling of TiO_2 with a suitable semiconductor that possesses a narrow band gap.Meanwhile,Ag_3PO_4-TiO_2 heterostructuralnanotube arrays were prepared by the two-step anodic oxidation to obtain the TiO_2 nanotube arrays and then by a deposition-precipitation method to load Ag_3PO_4.The samples were characterized by field emission scanning electron microscopy（FESEM）,energy dispersive spectrometry（EDS）,X-ray diffraction（XRD）,and UV-vis diffuse reflectance spectroscopy（UV-vis DRS）.The experimentalresults showed that Ag_3PO_4 nanoparticles were uniformly dispersed on the highly ordered TiO_2 nanotube arrays,which increased the visible-light absorption of TiO_2 photocatalyst.The photocurrent density and photocatalytic degradation of methylorange indicated that the performance of Ag_3PO_4-TiO_2 heterostructuralnanotube arrays was better than that of the TiO_2 nanotube arrays,which could be attributed to the effective electron-hole separation and the improved utilization of visible light.
文摘A sensitive and selective preconcentration method using solid-phase extraction （SPE） disk made from oxidized multiwalled carbon nanotubes （OMWCNTs）, has been developed for the determination of aniline derivatives, such as 2-nitroaniline （2-NA）, 4- nitroaniline （4-NA）, and 2,4-dichloroaniline （2,4-DCA） in water samples. Anilines were extracted onto OMWCNT disk and then determined by high performance liquid chromatography （HPLC） with UV detector. Several parameters on the recovery of the analytes were investigated. The experimental results showed that it was possible to obtain quantitative analysis when the solution pH was 8 using 200 mL of validation solution containing 2 ug of anilines and 10 mL of acetonitrile/ethanol （8/2, v/v） as an eluent. Relative standard deviations for five determinations were 7.5% （2-NA）, 6.5% （4-NA） and 3.8% （2,4-DCA） under optimum conditions. The linear range of calibration curves were 0.5 ng.mL 1 to 15 ng.mL-1 for each analyte with good correlation coefficients. The detection limits （3S/N） of 2-NA, 4-NA and 31 pg.mL -1 and 26 pg.mL-1 was successfully applied to 2,4-DCA were 30pg.mL -1, respectively. Our method the determination of aniline compounds in fiver water sample with high precision and accuracy.
