Porous graphene oxide/chitosan （PGOC） materials were prepared by a unidirectional freeze-drying method. Their porous structure, mechanical property and adsorption for metal ions were investigated. The results show t...Porous graphene oxide/chitosan （PGOC） materials were prepared by a unidirectional freeze-drying method. Their porous structure, mechanical property and adsorption for metal ions were investigated. The results show that the incorporation of graphene oxide （GO） significantly increased the compressive strength of the PGOC materials. The saturated adsorption capacity of Pb^2＋ increased about 31%, up to 99 mg/g when 5 wt% GO was incorporated These biodegradable, nontoxic, efficient PGOC materials will be a potential adsorbent for metal ions in aqueous solution.展开更多
Three-dimensional porous nitrogen-doped graphene aerogels （NGAs） were synthesized by using graphene oxide （GO） and chitosan （CS） via a self-assembly process by one-pot hydrothermal method. The morphology and str...Three-dimensional porous nitrogen-doped graphene aerogels （NGAs） were synthesized by using graphene oxide （GO） and chitosan （CS） via a self-assembly process by one-pot hydrothermal method. The morphology and struc- ture of the as-prepared materials were characterized by means of scanning electron microscopy, transmission elec- tron microscopy, X-ray diffraction, XPS spectroscopy, Raman spectroscopy, nitrogen adsorption/desorption meas- urement and Fourier transform infrared spectroscopy. The electrochemical performance of NGAs was studied by cyclic voltammetry, galvanostatic charge/discharge and impedance spectroscopy measurements. The microstructure, surface area and capacitance of NGAs could be facilely controlled by adding different amounts of chitosan. The prepared NGA-4 showed a specific capacitance of 148.0 F/g at the discharge current density of 0.5 A/g and also re- tained 95.3% of the initial capacitance after 5000 cycles at the scan rate of 10 mV/s. It provided a possible way to obtain graphene based materials with high surface area and capacitance.展开更多
Nitrogen dioxide(NO_(2))is a representative toxicant in air pollution that mostly arises from the exhaust gas released by automobiles.It is related to various respiratory diseases such as pneumonia and sudden infant d...Nitrogen dioxide(NO_(2))is a representative toxicant in air pollution that mostly arises from the exhaust gas released by automobiles.It is related to various respiratory diseases such as pneumonia and sudden infant death syndrome.Additionally,because the toxicity of nitrogen dioxide is high in overpopulated areas(i.e.,a capital or metropolis),the development of simple,practical,and facile sensors is highly needed.This work presents a flexible and disposable paper-based NO_(2)sensor based on a reduced graphene oxide/chitosan(r GO/CS)composite.The synthesized r GO/CS composite can be easily flexed and deformed into various shapes,which are attributed to chitosan molecules that function as a dispersion and reduction agent and support material.In addition,this composite can be attached to paper owing to its adhesive property;hence it can be utilized in versatile applications in a disposable manner.By analyzing the conductive change of the r GO/CS composite when it reacts with NO_(2),we can detect nitrogen dioxide in a concentration range of 0–100 ppm with a detection limit of 1 ppm.Moreover,we performed NO_(2)detection in the exhaust gas released by automobiles using the r GO/CS composite for practical application.The results indicated that the r GO/CS composite has the potential to be used in feasible gas sensing as a facile and disposable sensor under various conditions.展开更多
以天然鳞片石墨为原料,采用改良的Hummers方法,制备了高纯度的薄层或单层氧化石墨(GO);并以抗坏血酸为还原剂,通过自组装还原的方式成功制备了具有三维多孔独巨石结构的还原氧化石墨烯(r GO)气凝胶,其形貌和结构经FT-IR,SEM,TEM,XRD和XP...以天然鳞片石墨为原料,采用改良的Hummers方法,制备了高纯度的薄层或单层氧化石墨(GO);并以抗坏血酸为还原剂,通过自组装还原的方式成功制备了具有三维多孔独巨石结构的还原氧化石墨烯(r GO)气凝胶,其形貌和结构经FT-IR,SEM,TEM,XRD和XPS表征。并对其作为锂离子电池负极材料的电化学性能进行了测试。结果表明:r GO气凝胶独特的形貌和结构提高了其比容量和循环性能,在100 m A·g-1电流密度下首周放电比容量可达1 700 m Ah·g-1,首周充电比容量达710 m Ah·g-1,经过100周循环后放电比容量仍可保持在450 m Ah·g-1,库伦效率保持在98%。展开更多
基金supported by the National Science Foundation of China(No.50873075)Tianjin Municipal Science and Technology Commission,PR China(No.09JCZDJC23300)
文摘Porous graphene oxide/chitosan （PGOC） materials were prepared by a unidirectional freeze-drying method. Their porous structure, mechanical property and adsorption for metal ions were investigated. The results show that the incorporation of graphene oxide （GO） significantly increased the compressive strength of the PGOC materials. The saturated adsorption capacity of Pb^2＋ increased about 31%, up to 99 mg/g when 5 wt% GO was incorporated These biodegradable, nontoxic, efficient PGOC materials will be a potential adsorbent for metal ions in aqueous solution.
基金We are grateful to Research Center of Laser Fusion, China Academy of Engineering Physics. This work was financially supported by the National Natural Science Foundation of China （No. 51502274）, the Research Fund for the Doctoral Program of Southwest University of Science and Technology （Nos. 13zx7124, 15zx7137, 16zx7142） and the Research Fund for Joint Laboratory for Extreme Conditions Matter Properties （Nos. 13zxjk04, 14tdjk03）.
文摘Three-dimensional porous nitrogen-doped graphene aerogels （NGAs） were synthesized by using graphene oxide （GO） and chitosan （CS） via a self-assembly process by one-pot hydrothermal method. The morphology and struc- ture of the as-prepared materials were characterized by means of scanning electron microscopy, transmission elec- tron microscopy, X-ray diffraction, XPS spectroscopy, Raman spectroscopy, nitrogen adsorption/desorption meas- urement and Fourier transform infrared spectroscopy. The electrochemical performance of NGAs was studied by cyclic voltammetry, galvanostatic charge/discharge and impedance spectroscopy measurements. The microstructure, surface area and capacitance of NGAs could be facilely controlled by adding different amounts of chitosan. The prepared NGA-4 showed a specific capacitance of 148.0 F/g at the discharge current density of 0.5 A/g and also re- tained 95.3% of the initial capacitance after 5000 cycles at the scan rate of 10 mV/s. It provided a possible way to obtain graphene based materials with high surface area and capacitance.
基金supported by the National Research Foundation of Korea(NRF)under Grant Nos.NRF-2017M3A9F1031229,NRF2017R1E1A1A01075439,and NRF-2019R1C1C1005668The Korea Environment Industry&Technology Institute(KEITI)through its Ecological Imitation-based Environmental Pollution Management Technology Development Project+1 种基金funded by the Korea Ministry of Environment(MOE)(2019002800009)And Korea University(Grant No.K2111511)。
文摘Nitrogen dioxide(NO_(2))is a representative toxicant in air pollution that mostly arises from the exhaust gas released by automobiles.It is related to various respiratory diseases such as pneumonia and sudden infant death syndrome.Additionally,because the toxicity of nitrogen dioxide is high in overpopulated areas(i.e.,a capital or metropolis),the development of simple,practical,and facile sensors is highly needed.This work presents a flexible and disposable paper-based NO_(2)sensor based on a reduced graphene oxide/chitosan(r GO/CS)composite.The synthesized r GO/CS composite can be easily flexed and deformed into various shapes,which are attributed to chitosan molecules that function as a dispersion and reduction agent and support material.In addition,this composite can be attached to paper owing to its adhesive property;hence it can be utilized in versatile applications in a disposable manner.By analyzing the conductive change of the r GO/CS composite when it reacts with NO_(2),we can detect nitrogen dioxide in a concentration range of 0–100 ppm with a detection limit of 1 ppm.Moreover,we performed NO_(2)detection in the exhaust gas released by automobiles using the r GO/CS composite for practical application.The results indicated that the r GO/CS composite has the potential to be used in feasible gas sensing as a facile and disposable sensor under various conditions.
文摘以天然鳞片石墨为原料,采用改良的Hummers方法,制备了高纯度的薄层或单层氧化石墨(GO);并以抗坏血酸为还原剂,通过自组装还原的方式成功制备了具有三维多孔独巨石结构的还原氧化石墨烯(r GO)气凝胶,其形貌和结构经FT-IR,SEM,TEM,XRD和XPS表征。并对其作为锂离子电池负极材料的电化学性能进行了测试。结果表明:r GO气凝胶独特的形貌和结构提高了其比容量和循环性能,在100 m A·g-1电流密度下首周放电比容量可达1 700 m Ah·g-1,首周充电比容量达710 m Ah·g-1,经过100周循环后放电比容量仍可保持在450 m Ah·g-1,库伦效率保持在98%。
