Herein, we report a simple and effective preparation of ultrafine CNFs （u-CNFs） with high surface area via electrospinning of two immiscible polymers [polyacrylonitrile （PAN） and poly（methyl methacry- late） （P...Herein, we report a simple and effective preparation of ultrafine CNFs （u-CNFs） with high surface area via electrospinning of two immiscible polymers [polyacrylonitrile （PAN） and poly（methyl methacry- late） （PMMA）] followed by calcination at high temperature in an inert atmosphere. Various electrospinning conditions were optimized in detail. Four different kinds of PAN/PMMA ratios （10/0, 7：3, 5：5 and 3：7） were chosen and found that the PAN/PMMA ratio of 3：7 （PAN/PMMA-3：7） is the optimum one. BET anal- ysis showed the specific surface area of the u-CNFs-3：7 was 46Z57 m2/g with an excellent pore volume （1.15 cms g-l） and an average pore size （9.48 nm）： it is about 25 times higher than the conventional CNFs （c-CNFs）. TEM and FE-SEM images confirmed the ultrafine structure of the CNFs with a thinner fiber di- ameter of-50 nm. The graphitic nature and atomic arrangement of the u-CNFs were investigated by Raman and XPS analyses. For the supercapacitor application, unlike the common electrode preparation methods, the u-CNFs-3：7 was used without any activation, chemical or mechanical modifications. The u-CNFs- 3：7 showed a better specific capacitance of 86 Fig in 1 mol/L 1-12S04 when compared to pure CNFs. The excellent physicochemical properties make the u-CNFs-3：7 an alternative choice to the existing CNFs for the supercapacitors.展开更多
Herein, we report a new and simple method for the preparation of metallic copper nanospheres- decorated cellulose nanofiber composite （CuNSsJCNFs）. Initially, the cellulose acetate nanofibers （CANFs） were electros...Herein, we report a new and simple method for the preparation of metallic copper nanospheres- decorated cellulose nanofiber composite （CuNSsJCNFs）. Initially, the cellulose acetate nanofibers （CANFs） were electrospun followed by deacetylation and anionization to produce functional anionic cellulose nanofibers ff-CNFs）. The CuCl2 precursor was deposited on thef-CNFs （CuC12/CNFs） by a simple dipping method. Then the CuCIdCNFs were reduced under vacuum by using aluminum foil to produce the CuNSs/ CNFs. The resultant CuNSs/CNFs composite was characterized by various microscopic and spectroscopic methods. Fourier transform infrared spectroscopy （FT-IR） confirmed the successful functionalization of anionic groups with the CNFs. The field emission scanning electron microscopy （FE-SEM） and transmission electron microscope （TEM） results confirmed the formation of CuNSs on the surface of CNFs. From the scanning electron microscopy-energy dispersive spectroscopy （SEM-EDS） analysis, the weight percentage of Cu was found to be 23.5 wt%. The successful reduction of CuO to metallic Cu was confirmed by X-ray photoemission spectroscopy （XPS） and X-ray diffraction （XRD） analyses. Mechanism has been proposed for the formation of metallic Cu sphere on CNFs.展开更多
基金supported by a research fund of Chungnam National University in 2014
文摘Herein, we report a simple and effective preparation of ultrafine CNFs （u-CNFs） with high surface area via electrospinning of two immiscible polymers [polyacrylonitrile （PAN） and poly（methyl methacry- late） （PMMA）] followed by calcination at high temperature in an inert atmosphere. Various electrospinning conditions were optimized in detail. Four different kinds of PAN/PMMA ratios （10/0, 7：3, 5：5 and 3：7） were chosen and found that the PAN/PMMA ratio of 3：7 （PAN/PMMA-3：7） is the optimum one. BET anal- ysis showed the specific surface area of the u-CNFs-3：7 was 46Z57 m2/g with an excellent pore volume （1.15 cms g-l） and an average pore size （9.48 nm）： it is about 25 times higher than the conventional CNFs （c-CNFs）. TEM and FE-SEM images confirmed the ultrafine structure of the CNFs with a thinner fiber di- ameter of-50 nm. The graphitic nature and atomic arrangement of the u-CNFs were investigated by Raman and XPS analyses. For the supercapacitor application, unlike the common electrode preparation methods, the u-CNFs-3：7 was used without any activation, chemical or mechanical modifications. The u-CNFs- 3：7 showed a better specific capacitance of 86 Fig in 1 mol/L 1-12S04 when compared to pure CNFs. The excellent physicochemical properties make the u-CNFs-3：7 an alternative choice to the existing CNFs for the supercapacitors.
基金supported by the Basic Science Research Program through the National Research Foundation of Korea(NRF)funded by the Ministry of Science,ICT&Future Planning(2014R1A1A3A04049595)
文摘Herein, we report a new and simple method for the preparation of metallic copper nanospheres- decorated cellulose nanofiber composite （CuNSsJCNFs）. Initially, the cellulose acetate nanofibers （CANFs） were electrospun followed by deacetylation and anionization to produce functional anionic cellulose nanofibers ff-CNFs）. The CuCl2 precursor was deposited on thef-CNFs （CuC12/CNFs） by a simple dipping method. Then the CuCIdCNFs were reduced under vacuum by using aluminum foil to produce the CuNSs/ CNFs. The resultant CuNSs/CNFs composite was characterized by various microscopic and spectroscopic methods. Fourier transform infrared spectroscopy （FT-IR） confirmed the successful functionalization of anionic groups with the CNFs. The field emission scanning electron microscopy （FE-SEM） and transmission electron microscope （TEM） results confirmed the formation of CuNSs on the surface of CNFs. From the scanning electron microscopy-energy dispersive spectroscopy （SEM-EDS） analysis, the weight percentage of Cu was found to be 23.5 wt%. The successful reduction of CuO to metallic Cu was confirmed by X-ray photoemission spectroscopy （XPS） and X-ray diffraction （XRD） analyses. Mechanism has been proposed for the formation of metallic Cu sphere on CNFs.
