Herein,non-carbonized wood-based electrodes and separators with well-aligned channels and excellent mechanical properties are developed for supercapacitors.To enhance the conductivity and boost the capacitance,Ti_(3)C...Herein,non-carbonized wood-based electrodes and separators with well-aligned channels and excellent mechanical properties are developed for supercapacitors.To enhance the conductivity and boost the capacitance,Ti_(3)C_(2)(MXene)nanosheets with high electrical conductivity and excellent electrochemical activity are loaded into the wood cells via self-assembly triggered by fast evaporating water in Ti_(3)C_(2)suspension.By the assistance of positive charged polydopamine microspheres with large surface area,the self-restacking of Ti_(3)C_(2)nanosheets can be avoided and the high mass loading(50 wt%)can be achieved due to the extra driving force for Ti_(3)C_(2)absorption.Benefiting from the conductive Ti_(3)C_(2)nanosheets with massive active sites and the multiple well-aligned channels in wood with efficient transportation pathways for charge carriers,the as-designed free-standing electrode shows a large areal capacitance of 1060 mF cm^(-2)at 0.5 mA cm^(-2)and high capacitance retention of 67%at 10 mA cm^(-2).Also,this electrode is highly size-customizable,showing a good ability to be industrially processed into various shapes and dimensions.Furthermore,an all-wood based supercapacitor with Ti_(3)C_(2)/wood composites as two layers of electrodes and a wood slice as the separator is fabricated,presenting a high energy density of 10.5μW h cm^(-2)at 389.9μW cm^(-2).展开更多
Vertically aligned ZnO nanorods were synthesized on a-plane sapphire via a metal catalyzed vapor phase transport and condensation process in a two-zone vacuum furnace. Planar-tip and tapered-tip ZnO nanorods were succ...Vertically aligned ZnO nanorods were synthesized on a-plane sapphire via a metal catalyzed vapor phase transport and condensation process in a two-zone vacuum furnace. Planar-tip and tapered-tip ZnO nanorods were successfully synthesized by utilizing different source materials under the same growth conditions. The growth mechanisms were proposed to be vapor-liquid-solid （VLS） process for planar-tip ZnO nanorods and a combination of VLS and self-catalyzed processes for tapered-tip ZnO nanorods, From cathodoluminescence （CL） measurements, tapered-tip ZnO nanorods have more intense green emission than planar-tip ZnO nanorods, and therefore possess higher oxygen vacancy concentration than planar-tip ZnO nanorods. From CL characteristics, well-aligned planar-tip ZnO nanorods shall serve effectively as laser source, while well-aligned tapered-tip ZnO nanorods are suitable for direction-related optical applications.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
Well-aligned carbon nanotubes coated with titania (TiO2) were prepared by atmospheric pressure chemical vapor deposition (APCVD),and the sequential experiments including carbon nano- tubes preparation,air-oxidation pu...Well-aligned carbon nanotubes coated with titania (TiO2) were prepared by atmospheric pressure chemical vapor deposition (APCVD),and the sequential experiments including carbon nano- tubes preparation,air-oxidation purification and tita- nia nanoparticles coating were performed at different temperatures in the same reactor. Scanning electron microscopy (SEM),transmission electron microscope (TEM),X-ray diffraction patterns (XRD),and energy- dispersive X-ray spectra (EDX) demonstrated the well-aligned nanotubes and TiO2 nanoparticles in close proximity and the average diameter of TiO2 nanoparticles was 11.5 nm.展开更多
Well oriented ZnO nanorod array films were prepared by a low cost and low temperature hydrothermal approach. The wettability of the films were studied. The films treated with octadecanethiol(ODT) possess super hydroph...Well oriented ZnO nanorod array films were prepared by a low cost and low temperature hydrothermal approach. The wettability of the films were studied. The films treated with octadecanethiol(ODT) possess super hydrophobic properties. The static contact angle for water of the ODT modified films is 155.3°±2.3°, and the advancing and receding angles are 156.5°±1.9° and 150.3°±2.8°, respectively. It is believed that the super hydrophobic property of the ZnO nanorod array films is mainly caused by the nanostructures of the films and the modification of ODT adsorption layer on ZnO surfaces.展开更多
基金the Natural Science Foundation of the Jiangsu Higher Education Institutions of China(20KJB220008)Start-up Funds for Scientific Research at the Nanjing Forestry University(163020126).
文摘Herein,non-carbonized wood-based electrodes and separators with well-aligned channels and excellent mechanical properties are developed for supercapacitors.To enhance the conductivity and boost the capacitance,Ti_(3)C_(2)(MXene)nanosheets with high electrical conductivity and excellent electrochemical activity are loaded into the wood cells via self-assembly triggered by fast evaporating water in Ti_(3)C_(2)suspension.By the assistance of positive charged polydopamine microspheres with large surface area,the self-restacking of Ti_(3)C_(2)nanosheets can be avoided and the high mass loading(50 wt%)can be achieved due to the extra driving force for Ti_(3)C_(2)absorption.Benefiting from the conductive Ti_(3)C_(2)nanosheets with massive active sites and the multiple well-aligned channels in wood with efficient transportation pathways for charge carriers,the as-designed free-standing electrode shows a large areal capacitance of 1060 mF cm^(-2)at 0.5 mA cm^(-2)and high capacitance retention of 67%at 10 mA cm^(-2).Also,this electrode is highly size-customizable,showing a good ability to be industrially processed into various shapes and dimensions.Furthermore,an all-wood based supercapacitor with Ti_(3)C_(2)/wood composites as two layers of electrodes and a wood slice as the separator is fabricated,presenting a high energy density of 10.5μW h cm^(-2)at 389.9μW cm^(-2).
基金the National Science Council under Grant Nos.96-2221-E-007-151NSC 96-2120-M-007-006.
文摘Vertically aligned ZnO nanorods were synthesized on a-plane sapphire via a metal catalyzed vapor phase transport and condensation process in a two-zone vacuum furnace. Planar-tip and tapered-tip ZnO nanorods were successfully synthesized by utilizing different source materials under the same growth conditions. The growth mechanisms were proposed to be vapor-liquid-solid （VLS） process for planar-tip ZnO nanorods and a combination of VLS and self-catalyzed processes for tapered-tip ZnO nanorods, From cathodoluminescence （CL） measurements, tapered-tip ZnO nanorods have more intense green emission than planar-tip ZnO nanorods, and therefore possess higher oxygen vacancy concentration than planar-tip ZnO nanorods. From CL characteristics, well-aligned planar-tip ZnO nanorods shall serve effectively as laser source, while well-aligned tapered-tip ZnO nanorods are suitable for direction-related optical applications.
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.
基金This work was supported by the Hi-Tech Research and Development Program of China(Grant No.2004AA649290)the National Natural Science Foundation of China for Distinguished Young Scholars(Grant No.20525723).
文摘Well-aligned carbon nanotubes coated with titania (TiO2) were prepared by atmospheric pressure chemical vapor deposition (APCVD),and the sequential experiments including carbon nano- tubes preparation,air-oxidation purification and tita- nia nanoparticles coating were performed at different temperatures in the same reactor. Scanning electron microscopy (SEM),transmission electron microscope (TEM),X-ray diffraction patterns (XRD),and energy- dispersive X-ray spectra (EDX) demonstrated the well-aligned nanotubes and TiO2 nanoparticles in close proximity and the average diameter of TiO2 nanoparticles was 11.5 nm.
文摘Well oriented ZnO nanorod array films were prepared by a low cost and low temperature hydrothermal approach. The wettability of the films were studied. The films treated with octadecanethiol(ODT) possess super hydrophobic properties. The static contact angle for water of the ODT modified films is 155.3°±2.3°, and the advancing and receding angles are 156.5°±1.9° and 150.3°±2.8°, respectively. It is believed that the super hydrophobic property of the ZnO nanorod array films is mainly caused by the nanostructures of the films and the modification of ODT adsorption layer on ZnO surfaces.
