共查询到20条相似文献,搜索用时 15 毫秒
1.
Wang Ni Yao Mengqi Zhao Peng Zhang Qian Hu Wencheng 《Journal of Solid State Electrochemistry》2016,20(5):1429-1434
Journal of Solid State Electrochemistry - Highly mesoporous structure nickel cobalt oxides with an ultra-high specific surface area are synthesized through a sol–gel method by using silica... 相似文献
2.
A series of porous carbon materials with wide range of specific surface areas and different heteroatom contents had been prepared using polyaniline as carbon precursor and KOH as an activating agent. Effect of surface area and heteroatom of porous carbon materials on specific capacitance was investigated thoroughly in two typical aqueous KOH and organic 1-butyl-3- methylimidazolium tetrafluoroborate/acetonitirle electrolytes. The different trends of capacitance performance were observed in these two electrolytes. Electrochemical analyses suggested that the presence of faradaic interactions on heteroatom-enriched carbon materials in organic environment is less significant than that observed in aqueous electrolytes. Thus, in aqueous electrolyte, a balance between surface area and heteroatom content of activated porous carbon would be found to develop a supercapacitor with high energy density. In organic electrolyte, the capacitance performance of porous carbon is strongly dependent on the surface area. The results may be useful for the design of porous carbon-based supercapacitor with the desired capacitive performance in aqueous and organic electrolytes. 相似文献
3.
N. B. Kondrashova O. G. Vasil’eva V. A. Val’tsifer S. A. Astaf’eva V. N. Strel’nikov 《Russian Journal of Applied Chemistry》2009,82(1):1-5
The influence of the reactant ratio on the specific surface area, total pore volume, and mean pore diameter of mesoporous silicon dioxide prepared by the sol-gel method was examined. The optimal reactant ratio for preparing the material with a high specific surface area was determimed. 相似文献
4.
《Solid State Sciences》2012,14(7):833-839
Mesoporous maghemite (γ-Fe2O3) with high surface area was prepared by the thermal decomposition of Fe–urea complex ([Fe(CON2H4)6](NO3)3) with the aid of cetyltrimethyl ammonium bromide (CTAB), and its adsorption ability for the removal of fluoride was investigated. X-ray diffraction (XRD), nitrogen adsorption–desorption measurements, transmission electron micrograph (TEM) observations, and magnetic measurements show that the γ-Fe2O3 has a mesoporous structure and its crystallite size, specific surface area, and magnetic properties can be controlled by varying the content of CTAB in [Fe(CON2H4)6](NO3)3. The maximum adsorption capacity of the mesoporous γ-Fe2O3 for fluoride is estimated to be 7.9 mg/g, which suggests that the mesoporous γ-Fe2O3 is an excellent adsorbent for fluoride. 相似文献
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6.
The retention of polar compounds, the separation of structural isomers and thermal stability make carbonaceous materials very attractive stationary phases for liquid chromatography (LC). Carbon clad zirconia (C/ZrO2), one of the most interesting, exhibits unparalleled chemical and thermal stability, but its characteristically low surface area (20–30 m2/g) limits broader application as a second dimension separation in two-dimensional liquid chromatography (2DLC) where high retentivity and therefore high stationary phase surface area are required. In this work, we used a high surface area commercial HPLC alumina (153 m2/g) as a support material to develop a carbon phase by chemical vapor deposition (CVD) at elevated temperature using hexane vapor as the carbon source. The loading of carbon was varied by changing the CVD time and temperature, and the carbon coated alumina (C/Al2O3) was characterized both physically and chromatographically. The resulting carbon phases behaved as a reversed phase similar to C/ZrO2. At all carbon loadings, C/Al2O3 closely matched the unique chromatographic selectivity of carbon phases, and as expected the retentivity was increased over C/ZrO2. Excess carbon – the amount equivalent to 5 monolayers – was required to fully cover the oxide support in C/Al2O3, but this was less excess than needed with C/ZrO2. Plate counts were 60,000–76,000/m for 5 μm particles. Spectroscopic studies (XPS and FT-IR) were also conducted; they showed that the two materials were chemically very similar. 相似文献
7.
Highly ordered mesoporous carbon arrays are prepared by a facile carbonization of the natural bamboo and oak wood in argon atmosphere. The as-prepared oak mesoporous carbon arrays have good electrocatalytic activity and high conductivity, based on their well connected framework, highly ordered microtexture, wider mesopores and larger surface area. Consequentially, the photovoltaic performance of the DSSC with the oak mesoporous carbon array film as counter electrode is excellent and comparable to that of the DSSC with FTO/Pt counter electrode. In addition, it is a simple method for a mass production of mesoporous carbon arrays with natural wood materials. 相似文献
8.
A novel polyaniline/mesoporous carbon nano-composite electrode for asymmetric supercapacitor 总被引:1,自引:0,他引:1
<正>A novel nano-composite of polyaniline/mesoporous carbon(PANI/CMK-3) was prepared with mesoporous carbon(CMK-3) serving as the support.Electrochemical asymmetric capacitors have been successfully designed by using PANI/CMK-3 composite and CMK-3 as positive and negative electrode,respectively.The results showed that the discharge capacity of the asymmetric capacitor could reach 87.4 F/g under the current density of 5 mA/cm~2 and cell voltage of 1.4 V.The energy density of the asymmetric capacitor was up to 23.8 Wh/kg with a power density of 206 W/kg.Furthermore,PANI/CMK-3-CMK-3 asymmetric capacitor using this PANI/CMK-3 nano-composite could be activated quickly and possess high charge-discharge efficiency. 相似文献
9.
Norepinephrine (NE) is detected amperometrically using the enzyme Phenylethanolamine N-methyl transferase and cofactor S-(5′-Adenosyl)-l-methionine chloride dihydrochloride with disposable screen printed mesoporous carbon electrodes. The role of internal surface area and pore size of the mesoporous carbon is systematically examined using soft-templated, mesoporous silica–carbon powders with highly microporous walls obtained from etching of the silica to produce powders with surface areas ranging from 671–2339 m2 g−1. As the surface area increases, the sensitivity of the biosensor at very low NE concentrations (0–500 pg mL−1) in phosphate buffered saline (PBS) increases just as the current signal increases with respect to the NE concentration of 81–1581 μA mL ng−1 cm−2 for the mesoporous carbons. The best performing electrode provides similar sensitivity in whole rabbit blood in comparison to PBS despite no membrane layer to filter the non-desired reactants; the small (<5 nm) pore size and large internal surface area acts to minimize non-specific events that decrease sensitivity. 相似文献
10.
《Electrochemistry communications》2008,10(6):859-863
In this paper, the unique properties of highly ordered mesoporous carbons modified glassy carbon electrode (OMCs/GE) are illustrated from comparison with carbon nanotubes modified glassy carbon electrode (CNTs/GE) for the electrochemical sensing applications. Electrochemical behaviors of eight kinds of inorganic and organic electroactive compounds were studied at OMCs/GE, which shows more favorable electron transfer kinetics than that at CNTs/GE. Especially, OMCs/GE exhibits remarkably strong and stable electrocatalytic response toward NADH compared with CNTs/GE. The ability of OMCs to promote electron transfer not only provides a new platform for the development of dehydrogenase-based bioelectrochemical devices, but also indicates a potential of OMCs in a wide range of sensing applications. OMCs prepared are the novel carbon electrode materials, exhibiting more favorable electrochemical reactivity than CNTs for the wide electrochemical sensing applications without pretreatments, while purification or end-opening processing was usually required in case of CNTs. 相似文献
11.
Shunxi Li Ruoyu Xu Hui Wang Dan J. L. Brett Shan Ji Bruno G. Pollet Rongfang Wang 《Journal of Solid State Electrochemistry》2017,21(10):2947-2954
A nitrogen (N)-doped mesoporous carbon material exhibiting ultra-high surface area was successfully synthesized from sheep bones via a facile and low-cost method. The obtained carbon material had an ultra-high specific surface area of 1961 m2 g?1 and provided rich active sites for the oxygen reduction reaction (ORR), which in turn resulted in high electrocatalytic activity. It was found that the pore size distribution for the newly prepared carbonaceous material fell in the range of 1–4 nm. Benefiting from its high surface area and the presence of pyridine-N and quaternary-N species, the as-prepared carbon material exhibited excellent ORR activity in an oxygen-saturated 0.1 M KOH solution, compared to commercial Pt/C (10 wt%). Due to its high ORR catalytic activity, stability and low-cost, using sheep bone as C and N precursors to produce N-doped carbon provides an encouraging step toward the goal of replacing commercial Pt/C as fuel cell cathode electrocatalyst. 相似文献
12.
Activated carbon (AC) was fabricated from corncob, which is cheap and abundant. Experimental parameters such as particle size of corncob, KOHlchar weight ratio, and activation temperature and time were optimized to generate AC, which shows high methane sorption capacity. AC has high specific surface area (3227 m^2/g), with pore volume and pore size distribution equal to 1.829 cm^3/g and ca. 1.7-2.2 nm, respectively. Under the condition of 2℃ and less than 7.8 MPa, methane sorption in the presence of water (Rw = 1.4) was as high as 43.7 wt% methane per unit mass of dry AC. The result is significantly higher than those of coconut-derived AC (32 wt%) and ordered mesoporous carbon (41.2 wt%, Rw = 4.07) under the same condition. The physical properties and amorphous chaotic structure of AC were characterized by N2 adsorption isotherms, XRD, SEM and HRTEM. Hence, the corncob-derived AC can be considered as a competitive methane-storage material for vehicles, which are run by natural gas.
Key words 相似文献
Key words 相似文献
13.
Mesoporous titania nanoparticles (denoted as MTN) with high surface area (e.g., 252 m2 g−1) were prepared using tetrapropyl orthotitanate (TPOT) as a titania precursor and 10–20 nm or 20–30 nm silica colloids as
templates. Co-assembly of TPOT and silica colloids in an aerosol-assisted process and immediate calcination at 450 °C resulted
in anatase/silica composite nanoparticles. Subsequent removal of the silica colloids from the composite by NaOH solution created
mesopores in the TiO2 nanoparticles with pore size corresponding to that of silica colloids. Effects of silica colloids’ contents on MTN porosity
and crystallites’ growth at a higher calcination temperature (e.g., 1000 °C) were investigated. Silica colloids suppressed
the growth of TiO2 crystallites during calcination at a higher calcination temperature and controllable contents of the silica colloids in precursor
solution resulted in various atomic ratios of anatase to rutile in the calcinated materials. The mesostructure and crystalline
structure of these titania materials were characterized by transmission electron microscope (TEM), scanning electron microscope
(SEM), X-ray diffraction (XRD), differential thermal analysis (DTA)-thermo-gravimetric analysis (TGA), and N2 sorption. 相似文献
14.
Xiaomei Ma Mingxian Liu Lihua Gan Yunhui Zhao Longwu Chen 《Journal of Solid State Electrochemistry》2013,17(8):2293-2301
Micro- and mesoporous carbon spheres (MMCSs) are synthesized by the polymerization of colloidal silica-entrapped resorcinol/formaldehyde in the presence of ammonia as catalyst, followed by carbonization, sodium hydroxide (NaOH) etching to remove silica template, and potassium hydroxide (KOH) activation. The morphology and microstructure are characterized by scanning electron microscopy, transmission electron microscopy, and nitrogen adsorption–desorption. The results show that a typical sample (denoted as MMCS-3) unites the characteristics of regular spherical shape (uniform diameters of 500 nm), high specific surface area (1,620 m2 g?1), large pore volume (1.037 cm3 g?1), and combined micropores and mesopores (11.0 nm), which endows MMCS-3 good electrochemical performance. MMCS-3 as supercapacitor electrode shows a specific capacitance of 314 F g?1 under a current density of 0.5 A g?1 and low internal resistance of 0.2 Ω in 6 M KOH aqueous solution. The electrochemical capacitance still retains 198 F g?1 at a high current density of 10 A g?1. After 500 cycle numbers of galvanostatic charge/discharge at 0.5 A g?1, MMCS-3 electrode still remains the specific capacitance of 301 F g?1 with the retention of 96 %. This study highlights the potential of well-designed MMCSs as electrodes for widespread supercapacitor applications. 相似文献
15.
This paper describes the fabrication and electrochemical behavior of hierarchical nanoporous gold film (HNPGF) electrode by multi-cyclic electrochemical co-alloying/dealloying of two sacrifice metals (Zn and Sn) with gold. Different from the nanoporous gold film (NPGF) formed in the electrolyte of ZnCl2 in benzyl alcohol, the HNPGF obtained possessed special hierarchical porous structure and extra high roughness factor of 1250. This study reveals that hierarchical porous gold film electrodes are promising for catalysis. 相似文献
16.
Porous materials, developed by grafting functional groups through chemical surface modification with a surfactant, represent an innovative concept in energy storage. This work reports, in detail, the first practical realization of a novel carbon electrode based on grafting of vinyltrimethoxysilane (vtmos) functional group for energy storage in electric double layer capacitor (EDLC). Surface modification with surfactant vtmos enhances the hydrophobisation of activated carbon and the affinity toward propylene carbonate (PC) solvent, which improves the wettability of activated carbon in the electrolyte solution based on PC solvent, resulting in not only a lower resistance to the transport of electrolyte ions within micropores of activated carbon but also more usable surface area for the formation of electric double layer, and accordingly, higher specific capacitance, energy density, and power capability available from the capacitor based on modified carbon. Especially, the effects from surface modification become superior at higher discharge rate, at which much better EDLC performance (i.e., much higher energy density and power capability) has been achieved by the modified carbon, suggesting that the modified carbon is a novel and very promising electrode material of EDLC for large current applications where both high energy density and power capability are required. 相似文献
17.
S. Solís J. C. Martínez J. Paniagua M. Asomoza 《Journal of Sol-Gel Science and Technology》2006,37(2):121-123
The adsorption of a cysteine enzyme, on mesoporous silica with high specific surface area synthesized by the sol-gel method,
was studied in a heat flow calorimeter, to determine the energy involved in the adsorption process of the protein. The adsorption
was carried out at a constant temperature of 30°C to avoid the denaturation of the enzyme. The observed results indicate that
the obtained biomaterials (silica-enzyme) have possibilities for their application in several biotechnology processes.
The heat of papain adsorption and the solid-enzyme (SiO2-Papain) interactions at different pH are presented. 相似文献
18.
Shuangling Guo Fang Wang Hao Chen He Ren Rongshun Wang Xiumei Pan 《Journal of Solid State Electrochemistry》2012,16(10):3355-3362
Porous carbon materials with high surface area and different pore structure have been successfully prepared by phenolic resin combined with polyvinyl alcohol (PVA) and KOH as activation agents. The surface morphology, structure, and specific surface area of the carbon materials were studied by scanning electron microscopy, X-ray diffraction, and nitrogen sorption measurement, respectively. Furthermore, the effects of specific surface area, pore structure, and electrolyte on electrochemical properties were investigated by galvanostatic charge–discharge measurement. The results show that KOH–PVA-activated carbon materials display specific capacitance as high as 218 F?g?1 in 30 wt.% KOH aqueous electrolyte, 147 F?g?1 in 1 M LiPF6/(ethylene carbonate (EC) + dimethyl carbonate) (1:1?v/v), and 115 F?g?1 in 1 M Et3MeNBF4/propylene carbonate organic electrolyte, respectively. In addition, the carbon materials demonstrate long-term cycle stability, especially the AK3P-0.30 in aqueous electrolyte and the AK2P-0.30 with excellent rate capability in organic electrolyte. These reveal that the existence of a micro-mesoporous structure of activated carbon is beneficial to store energy in an aqueous supercapacitor and broad pore size distribution of activated carbon is favorable to energy storage in an organic supercapacitor. The carbon materials with pore size distribution in different ranges improve the electrochemical performance of supercapacitor in different electrolytes. A new pore-expand agent (PVA combining with KOH) was used to obtain porous carbons with enhanced properties for supercapacitor. 相似文献
19.
《Electrochemistry communications》2007,9(1):83-88
Electrode materials for supercapacitors are at present commonly evaluated and selected by their mass specific capacitance (CM, F g−1). However, using only this parameter may be a misleading practice because the electrode capacitance also depends on kinetics, and may not increase simply by increasing material mass. It is therefore important to complement CM by the practically accessible electrode specific capacitance (CE, F cm−2) in material selection. Poly[3,4-ethylene-dioxythiophene] (PEDOT) has a mass specific capacitance lower than other common conducting polymers, e.g. polyaniline. However, as demonstrated in this communication, this polymer can be potentiostatically grown to very thick films (up to 0.5 mm) that were porous at both micro- and nanometer scales. Measured by both cyclic voltammetry and electrochemical impedance spectrometry, these thick PEDOT films exhibited electrode specific capacitance (CE, F cm−2) increasing linearly with the film deposition charge, approaching 5 F cm−2, which is currently the highest amongst all reported materials. 相似文献
20.
A highly sensitive method for the rapid flow injection amperometric detection of hydrogen peroxide is reported, which is based on the excellent catalytic activity of carbon nanofiber coated simply on an electrode towards the reduction of H2O2 and has high throughput and interesting potential for the development of rapid and highly sensitive biosensors. 相似文献