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排序方式: 共有157条查询结果,搜索用时 31 毫秒
1.
《Carbon》2015
In this work, three dimensional (3D) NixCo1−xS2/graphene composite hydrogels with different Ni contents (denoted as NixCo1−xS2/GH (x = 0, 0.31, 0.56, 0.66, 1)) have been synthesized by a simple one-step hydrothermal method and utilized as the active materials of supercapacitors. The as-prepared samples present a 3D interconnected porous network with the pore sizes in the range of several to tens micrometers. Interestingly, the NixCo1−xS2 particles are uniformly located on the graphene network and the particle size is evolved from ∼50 nm to ∼1.5 μm with the increase of Ni content. The electrochemical measurements revealed that the specific capacitance, rate capability and cyclability of different NixCo1−xS2/GH electrodes are strongly affected by their different Ni content. Among these, the 3D Ni0.31Co0.69S2/GH composite has the highest specific capacitance of 1166 F/g at a current density of 1 A/g. Furthermore, a specific capacitance of 559 F/g can be still maintained at high current density of 20 A/g. After 1000 charge–discharge cycles at 5 A/g, the specific capacitance remains a high value of 755 F/g. 相似文献
2.
Shilei Ding Zelong Jiang Jing Gu Hongliang Zhang Jiajia Cai Dongdong Wang 《Frontiers of Chemical Science and Engineering》2021,15(1):148-155
In this paper,two carbon-coated lithium titanate(LTO-C1 and LTO-C2)composites were synthesized using the ball-milling-assisted calcination method with different carbon precursor addition processes.The physical and electrochemical properties of the as-synthesized negative electrode materials were characterized to investigate the effects of two carbon-coated LTO synthesis processes on the electrochemical performance of LTO.The results show that the LTO-C2 synthesized by using Li2CO3 and TiO2 as the raw materials and sucrose as the carbon source in a one-pot method has less polarization during lithium insertion and extraction,minimal charge transfer impedance value and the best electrochemical performance among all samples.At the current density of 300 mA·h·g-1,the LTO-C2 composite delivers a charge capacity of 126.9 mA·h·g-1,and the reversible capacity after 300 cycles exceeds 121.3 mA·h·g-1 in the voltage range of 1.0–3.0 V.Furthermore,the electrochemical impedance spectra show that LTO-C2 has higher electronic conductivity and lithium diffusion coefficient,which indicates the advantages in electrode kinetics over LTO and LTO-C1.The results clarify the best electrochemical properties of the carbon-coated LTO-C2 composite prepared by the one-pot method. 相似文献
3.
新型纤维素基螯合纤维的制备与吸附性能 总被引:1,自引:0,他引:1
为了发展水处理的途径,制备了β-环糊精改性的新型纤维素基螯合纤维.运用原子吸收光谱和紫外光谱考察了其对模拟水样中重金属离子(Cu2+)和有机染料(中性红)的吸附性能.实验结果表明,螯合纤维对Cu2+吸附率达6.24 mg/g,符合Langmuir吸附模型;对中性红也具有较强的包结能力.该鏊合纤维水处理能力强,制备简单,操作简便,有潜在的应用价值. 相似文献
4.
Investigation on formaldehyde gas sensor with ZnO thick film prepared through microwave heating method 总被引:1,自引:0,他引:1
ZnO nanopowders were prepared through microwave heating method. ZnO thick film sensors were fabricated by using ZnO nanopowders as sensing materials. The phase composition and morphology of the material particles were characterized by means of X-ray diffraction (XRD) and transmission electron microscopy (TEM), respectively. The gas-sensing properties of the sensors based on ZnO nano-materials were investigated. It was found that the sensor based on ZnO nano-materials (low power, 10× 10 min) exhibited very high responses to benzene and toluene when operating at 440 and 370 °C, respectively; but the sensor based on ZnO (low power, 10× 10 min) showed very low responses to benzene and toluene when operating at 205–215 °C. The sensor based on ZnO (low power, 10× 10 min) showed high response and good selectivity to dilute formaldehyde when operating at 210 °C; especially, the response to 0.001 ppm HCHO attained 7.4 when operating at 210 °C. 相似文献
5.
《Journal of Industrial and Engineering Chemistry》2014,20(4):1650-1655
The performance of a highly cross-linked polyethylene catalyst supported on alumina for low temperature selective catalytic reduction of NOx by unburned hydrocarbons (HCs) existing in an exhaust gas was examined at different engine conditions with the addition of exhaust-gas recirculation. The HXPE catalyst was shown to exhibit good NOx reduction activity at low temperatures (100–250 °C) where the only reductant was the unburned HC, which was already present in the exhaust flow. The maximum NOx reduction of approximately 52% was achieved at a temperature of 150 °C. HXPE demonstrated very good selectivity toward N2 in the majority of tested conditions (∼80%). 相似文献
6.
To obtain the normal depth of parabolic section of open channels, multiple known parameters were incorporated into a comprehensive one by transforming basic equations, and a concept of the non-dimensional normal depth was introduced. The normal depth equations were simplified into a non-dimensional iterative formula that was proved to have a high velocity of convergence. By analyzing the comprehensive parameter and dimensionless normal depth under condition of usually adopted sizes of parabolic channels and through establishing their relationship, the iterative initial value of normal depth was obtained. The normal depth of parabolic channels was acquired by substituting the initial value into the iteration formula. The error analysis was made and a case study was provided as an application example. The case study showed that the iteration formula was very simple, convenient and precise for determining the normal depth of parabolic channels with the maximum relative error of normal depth being less than 0.34% when the ratio of width to depth was between 0.2 and 20. 相似文献
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9.
Poly(3,4-ethylenedioxythiophene) (PEDOT) hollow spheres with the size ranged from 210 to 850 nm and a conductivity of 6 × 10?2 S cm?1 have been prepared via electrochemical polymerization of 3,4-ethylenedioxythiophene in the presence of poly(vinyl pyrrolidone) as a soft template. Then, a novel Ag@PEDOT yolk/shell structure has been prepared simply and directly by a penetration and reduction approach. The morphology, formation, and the catalytic activity of the as-prepared Ag@PEDOT yolk/shell structure have been investigated. The experimental result shows that the as-prepared Ag@PEDOT yolk/shell structure exhibits excellent catalytic activity on reduction of p-nitrophenol. The employed approach may shed some light on preparing other noble metal@conductive polymer core/shell structure. 相似文献
10.
Hydrous ruthenium oxide/activated carbon black (RuOx/ACB) composite was synthesized for the first time for supercapacitors by a chemical impregnation method. The RuOx/ACB composite is characterized by thermogravimetric analysis (TGA), field emission scanning electron microscope (FE-SEM) and transmission electron microscope (TEM). The results of TGA and TEM characterization showed that the reaction temperature of composite moved to lower temperature due to the catalytic effect of RuOx. XRD characterization of RuOx/AC illustrated that amorphous hydrous RuOx structure maintained in the composite heated at 150 °C. The equivalent series resistance (ESR) of the composite almost increased with the increase of RuOx content in the composite. The specific capacitance (Csp) of the composite increased with increasing RuOx content in the composite while the Csp of RuOx decreased from 1255.8 to 533.7 F g?1. The above results showed that the utilization of RuOx decreased with higher loading RuOx on ACB. 相似文献