MXene,a transition metal carbide/nitride,has been prominent as an ideal electrochemical active material for supercapacitors.However,the low MXene load limits its practical applications.As environmental concerns and su...MXene,a transition metal carbide/nitride,has been prominent as an ideal electrochemical active material for supercapacitors.However,the low MXene load limits its practical applications.As environmental concerns and sustainable development become more widely recognized,it is necessary to explore a greener and cleaner technology to recycle textile by-products such as cotton.The present study proposes an effective 3D fabrication method that uses MXene to fabricate waste denim felt into ultralight and flexible supercapacitors through needling and carbonization.The 3D structure provided more sites for loading MXene onto Z-directional fiber bundles,resulting in more efficient ion exchange between the electrolyte and electrodes.Furthermore,the carbonization process removed the specific adverse groups in MXenes,further improving the specific capacitance,energy density,power density and electrical conductivity of supercapacitors.The electrodes achieve a maximum specific capacitance of 1748.5 mF cm-2 and demonstrate remarkable cycling stability maintaining more than 94%after 15,000 galvanostatic charge/discharge cycles.Besides,the obtained supercapacitors present a maximum specific capacitance of 577.5 mF cm^(-2),energy density of 80.2μWh cm^(-2)and power density of 3 mW cm^(-2),respectively.The resulting supercapacitors can be used to develop smart wearable power devices such as smartwatches,laying the foundation for a novel strategy of utilizing waste cotton in a high-quality manner.展开更多
The scarcity of wettability,insufficient active sites,and low surface area of graphite felt(GF)have long been suppressing the performance of vanadium redox flow batteries(VRFBs).Herein,an ultra-homogeneous multipledim...The scarcity of wettability,insufficient active sites,and low surface area of graphite felt(GF)have long been suppressing the performance of vanadium redox flow batteries(VRFBs).Herein,an ultra-homogeneous multipledimensioned defect,including nano-scale etching and atomic-scale N,O codoping,was used to modify GF by the molten salt system.NH_(4)Cl and KClO_(3) were added simultaneously to the system to obtain porous N/O co-doped electrode(GF/ON),where KClO_(3) was used to ultra-homogeneously etch,and O-functionalize electrode,and NH4Cl was used as N dopant,respectively.GF/ON presents better electrochemical catalysis for VO_(2)+/VO_(2)+ and V3+/V2+ reactions than only O-functionalized electrodes(GF/O)and GF.The enhanced electrochemical properties are attributed to an increase in active sites,surface area,and wettability,as well as the synergistic effect of N and O,which is also supported by the density functional theory calculations.Further,the cell using GF/ON shows higher discharge capacity,energy efficiency,and stability for cycling performance than the pristine cell at 140 mA cm^(−2) for 200 cycles.Moreover,the energy efficiency of the modified cell is increased by 9.7% from 55.2% for the pristine cell at 260 mA cm^(−2).Such an ultra-homogeneous etching with N and O co-doping through“boiling”molten salt medium provides an effective and practical application potential way to prepare superior electrodes for VRFB.展开更多
Hydrogen peroxide synthesis by electro-reduction of O_(2) to substitute the current anthraquinone process has attracted a great deal of attention. Low oxygen utilization rate and low hydrogen peroxide production remai...Hydrogen peroxide synthesis by electro-reduction of O_(2) to substitute the current anthraquinone process has attracted a great deal of attention. Low oxygen utilization rate and low hydrogen peroxide production remain obstacles to electro-Fenton application. In situ H_(2)O_(2) generated by electrochemical reaction depends on the electrochemical performance of the cathode and the structure of the reactor. Here, novel graphite felt(GF) modified by La-doped CeO_(2)(La-CeO_(2)) was developed as a cathode. A new double chamber electro-Fenton reactor was proposed, where an organic ultrafiltration membrane was used to prevent H_(2)O_(2) from spreading to the anode. The effects of hydrothermal temperature, time and urea concentration on the electrochemical properties of graphite felt were investigated. The accumulated concentration of H_(2)O_(2) on the modified cathode reached 218.4 mg·L^(-1)in 1 h when the optimal conditions of hydrothermal temperature 120 ℃ and urea concentration 0.55%(mass) in 24 h. The degradation rate of methyl orange reached 98.29%. The new electro-Fenton reactor can efficiently produce hydrogen peroxide to degrade various organic substances and has a high potential for treating wastewater in the chemical industry.展开更多
Fabrication, characterization and performance of a porous metal-fiber sintered felt （PMFSF） based on multi-tooth cutting and solid-phase sintering were studied. The PMFSF was used as the anodic methanol barrier in a...Fabrication, characterization and performance of a porous metal-fiber sintered felt （PMFSF） based on multi-tooth cutting and solid-phase sintering were studied. The PMFSF was used as the anodic methanol barrier in a passive air-breathing direct methanol fuel cell to mitigate the effects of methanol crossover. Compared with the commercial SUS316L felt made of bundle-drawn fibers, this self-made PMFSF has larger pore diameter, polarized pore distribution, irregular fiber shape, rougher surface, lower mass flow resistance and evident hydrophobicity. The results reveal that the use of a PMFSF significantly enhances the cell performance since it helps to maintain a balance between the reactant and product management while depressing methanol crossover. The PMFSF with a porosity of 70% yields the highest cell performance at a methanol concentration of 4 mol/L.展开更多
In this paper,a new resin called Resin M for imparting antifelting properties to wool fabricshas been studied.Resin M may be used by aqueous oxidative/polymer technique.It is provedthat Oxidant A/Resin M treatment can...In this paper,a new resin called Resin M for imparting antifelting properties to wool fabricshas been studied.Resin M may be used by aqueous oxidative/polymer technique.It is provedthat Oxidant A/Resin M treatment can satisfy the machine washable requirement formulated byI.W.S..Resin M is a good agent for antifelting treatment of wool fabrics with proper pretreatment.Oxidant A/Resin M treatment has little influence on dyeing and moisture adsorption properties ofwool fibers.The pilling resistance of the treated fabrics is higher than that of the untreated ones.The strength and the handle of the treated fabrics have little been changed.According to thescanning electron microscope observations,it is recommended that the polymer encapsulation ofindividual fiber also plays an important role in the felting resistance of the treated fabrics though itis well known that the shrink resistance of the treated fabrics is believed to be due to the binding offibers.展开更多
Electro-oxidation of Ce （ Ⅲ ） to Ce （ Ⅳ ） in parallel plate flow type electrolyzer divided with cation exchange membrane was carried out in nitric acid media at carbon felt anode under galvanostatic conditions. ...Electro-oxidation of Ce （ Ⅲ ） to Ce （ Ⅳ ） in parallel plate flow type electrolyzer divided with cation exchange membrane was carried out in nitric acid media at carbon felt anode under galvanostatic conditions. Carbon felt was used as an anode for its high specific surface area and high oxygen evolution overpotential. Pt coated Ti plates were used as cathode and anode current feeder. The oxidation of 1 mol· L^-1 Ce（ Ⅲ ） solution in 2 mol· L^- 1 HNO3 was proceeding with a high current efficiency （92%） until about 80% of Ce（ Ⅲ ） was oxidized. Then, oxygen evolution, accompanied by terminal voltage jump, took place, lowering current efficiency. Ce（ Ⅲ ） was oxidized up to 90% with current efficiency of 62%. In this mode, strong carbon felt anode oxidation was observed. The wear out of carbon felt was 46% in six consequent runs （6 h of operation）. After each run, carbon felt surface had to be renewed with slightly alkaline solution to remove carbon oxidation products and ensure regular operational conditions. When anode surface was blocked, oxygen evolution took place from the beginning of electrolysis due to higher actual current density. The wear out of carbon felt anode could be minimized by means of oxygen evolution prevention. In the case when electrolysis had been stopped before oxygen evolution started （at Ce（ Ⅳ ） conversion of about 80% ）, the wear out of anode was less than 2% during 6 consequent runs （4 h of operation）.展开更多
Surface electropositivity and low internal resistance are important factors to improve the anode performance in microbial fuel cells (MFCs). Nitrogen doping is an effective way for the modification of traditional carb...Surface electropositivity and low internal resistance are important factors to improve the anode performance in microbial fuel cells (MFCs). Nitrogen doping is an effective way for the modification of traditional carbon materials. In this work, heat treatment and melamine were used to modify carbon felts to enhance electrogenesis capacity of MFCs. The modified carbon felts were characterized using X-ray photoelectron spectroscopy (XPS), scanning electron microscope (SEM), atomic force microscopy (AFM) and malvern zeta potentiometer. Results show that the maximum power densities under heat treatment increase from 276.1 to 423.4 mW/m(2) (700 degrees C) and 461.5 mW/m(2) (1200 degrees C) and further increase to 472.5 mW/m(2) (700 degrees C) and 515.4 mW/m(2) (1200 degrees C) with the co-carbonization modification of melamine. The heat treatment reduces the material resistivity, improves the zeta potential which is beneficial to microbial adsorption and electron transfer. The addition of melamine leads to the higher content of surface pyridinic and quaternary nitrogen and higher zeta potential. It is related to higher MFCs performance. Generally, the melamine modification at high temperature increases the feasibility of carbon felt as MFCs's anode materials. (C) 2016 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier B.V. and Science Press. All rights reserved.展开更多
Vanadium redox flow batteries(VRFBs)are one of the most promising energy storage systems owing to their safety,efficiency,flexibility and scalability.However,the commercial viability of VRFBs is still hindered by the ...Vanadium redox flow batteries(VRFBs)are one of the most promising energy storage systems owing to their safety,efficiency,flexibility and scalability.However,the commercial viability of VRFBs is still hindered by the low electrochemical performance of the available carbon-based electrodes.Defect engineering is a powerful strategy to enhance the redox catalytic activity of carbon-based electrodes for VRFBs.In this paper,uniform carbon defects are introduced on the surfaces of carbon felt(CF)electrode by Ar plasma etching.Together with a higher specific surface area,the Ar plasma treated CF offers additional catalytic sites,allowing faster and more reversible oxidation/reduction reactions of vanadium ions.As a result,the VRFB using plasma treated electrode shows a power density of 1018.3 mW/cm^(2),an energy efficiency(EE)of 84.5%,and the EE remains stable over 1000 cycles.展开更多
The cerium-based redox flow battery(RFB)is regarded as a compelling gridscale energy storage technology to revolutionize the utilization of renewable energy by storing the energy in liquid electrolytes.However,its wid...The cerium-based redox flow battery(RFB)is regarded as a compelling gridscale energy storage technology to revolutionize the utilization of renewable energy by storing the energy in liquid electrolytes.However,its widespread implementation is impeded by the cerium redox reactions that exhibit slow kinetics on commercial graphite felt(GF)electrodes.Surface functionalization may be an available activation strategy to achieve a significant boost in the electrochemical performance of GFs.However,conventional chemical and/or electrochemical routes for the surface functionalization of GFs suffer from the issues of complication,and the deterioration of the resulting modified electrode surface over long-term cycle processes leads to catalytic activity decline.Here,we develop a facile and general strategy for introducing the functional groups to the electrode through the addition of L-cysteine into electrolytes.The-COOH,-NH_(2),and-SH groups in L-cysteine can induce oxygen/nitrogen/sulfur trifunctional doping on GF surfaces with lower deterioration rates,which enables the activated GFs to demonstrate a promising electrocatalytic activity toward cerium redox reactions and excellent durability when used as a cerium-based RFB electrode.This study proposes a rational strategy to overcome the intrinsic limitations of existing modification techniques for GFs and provides a potential pathway toward high-performance RFBs.展开更多
A new MEEKC method assisted with pressure-driven mobile phase was presented for the separation of felted explosives. Microemulsion solution was composed of 80 mmol/L heptane -120 mmol/L SDS (sodium dodecyl sulphate) -...A new MEEKC method assisted with pressure-driven mobile phase was presented for the separation of felted explosives. Microemulsion solution was composed of 80 mmol/L heptane -120 mmol/L SDS (sodium dodecyl sulphate) - 900 mmol/L butanol - 10 mmol/L borate at pH 9.4 and a pressure-driven flow of 0.020 mL/min under 1.3 MPa was employed to manipulate the separation. Explosives HMX (1, 3, 5, 7-tetranitro-l, 3, 5, 7-tetrazacyclooctane) and TATB (triamino-trinitrobenzene), which were felted on fluorine rubber F2311 (polytrifluorochlorethylene and polyvinylidene fluoride 1/1 co-polymerization) and F2314 (polytrifluorochlorethylene and polyvinylidene fluoride 4/1 co-polymerization) were well separated with very good peak shapes.展开更多
In this research the effects of mordant and plasma sputtering treatments on the crystallinity and morphological properties of wool fabrics were investigated. The felting behavior of the treated samples was also studie...In this research the effects of mordant and plasma sputtering treatments on the crystallinity and morphological properties of wool fabrics were investigated. The felting behavior of the treated samples was also studied. We used madder as a natural dye and copper sulfate as a metal mordant. We also used copper as the electrode material in a DC magnetron plasma sputtering device. The anti-felting properties of the wool samples before and after dying was studied, and it was shown that the shrink resistance and anti-felting behavior of the wool had been significantly improved by the plasma sputtering treatment. In addition, the percentage of crystallinity and the size of the crystals were investigated using an X-ray diffractometer, and a scanning electron microscope was used for morphological analysis. The amount of copper particles on the surface of the mordanted and sputtered fabrics was studied using the energy dispersive X- ray （EDX） method, and the hydrophobic properties of the samples were examined using the water drop test. The results show that with plasma sputtering treatment, the hydrophobic properties of the surface of wool become super hydrophobic.展开更多
Prussian blue (PB) modified carbon felt electrodes were prepared. The electrochemical behavior was investigated by cyclic voltammetry, electrochemical impedance spectroscopy and charge-discharge experiments. In order ...Prussian blue (PB) modified carbon felt electrodes were prepared. The electrochemical behavior was investigated by cyclic voltammetry, electrochemical impedance spectroscopy and charge-discharge experiments. In order to distinguish the mechanism of the PB modified carbon felt electrode, the electrochemical quartz crystal microbalance (EQCM) was employed. The results of cyclic voltammetry show that the modification can improve the reversibility and the suitable PB deposition is the amount of 10 circles deposition. PB modified carbon felt electrode can effectively decrease the charge transfer resistance. The voltage efficiency of VRB employing PB modified carbon felt electrode can be increased by 12%. The mass change of the PB modified Pt crystal electrode in the process of the potential scan is obvious. The reaction of substitution of VO2+ for high-spin Fe ion in PB is probable to happen and the possible reaction equation is given. The preliminary exploration shows that PB modified carbon felt is electrochemically promising for redox flow battery.展开更多
Sound absorbers including porous materials are used widely for noise control. The most widely-exploited and acknowledged absorption mechanism in porous materials is viscous friction due to relative motion between soli...Sound absorbers including porous materials are used widely for noise control. The most widely-exploited and acknowledged absorption mechanism in porous materials is viscous friction due to relative motion between solid and fluid. Acoustical performance of woven (carpet) and nonwoven (felt) materials made of wool using a traditional technique was investigated. Absorption coefficient of felt was measured using standing wave tube method with and without an air cavity. Data were compared with predictions determined using the laws of Delany and Bazely. Very good agreement between data and predictions was observed. Sound absorption coefficients of both materials also were measured using an impedance gun technique over a wider frequency range. Absorption coefficient obtained using impedance gun method shows that the absorption coefficient of felt is higher than the absorption coefficient of carpet for mid and higher frequencies. Furthermore insertion loss (IL) of the felt was measured in a circular duct. It is found that felt can attenuate sound pressure level between 1 dB and 10 dB.展开更多
PAN-based graphite felt （PGF） treated in 98% sulphuric acid for 5 h and then kept at 450 ℃ for 2 h was evaluated for their electrochemical performance as electrodes of vanadium redox battery （VRB）. Structure and ...PAN-based graphite felt （PGF） treated in 98% sulphuric acid for 5 h and then kept at 450 ℃ for 2 h was evaluated for their electrochemical performance as electrodes of vanadium redox battery （VRB）. Structure and characteristic of treated PAN-based graphite felt （TPGF） were determined by means of Fourier Transform Infi-ared Spectroscopy, Scanning Electron Microscopy, Brunauer-Emmett-Teller surface area analysis and VRB test system. The results show that the acid and heat synergistic effect increase the number of --COOH functional groups on the PGF surface, and the PGF is eroded by sulphuric acid oxidation, resulting in the surface area increases from 0.31 m^2/g to 0.45 m^2/g. The V（ Ⅱ ）/V（Ⅲ） redox reaction is electrochemically reversible on the TPGF electrode, while the V（Ⅳ）/V（Ⅴ） couple is a quasi reversible process. The diffusion coefficients of the oxidation for V（Ⅳ）/V（Ⅴ） obtained from the scope of peak current Ip vs scan rate v^1/2 is 4.4×10^-5 cm^2/s. The improvement of electrochemical activity for the electrode is mainly ascribed to the increase of the number of ---COOH groups on the TPGF, which behaves as active sites catalyzing the vanadium species reactions and accelerating electron transfer reaction and oxygen transfer.展开更多
Background: Felt stigma is a major social and psychological problem in epilepsy and manifests the fear or expectations of such “reactions” from people. Understanding of the pattern and prevalence of felt stigma give...Background: Felt stigma is a major social and psychological problem in epilepsy and manifests the fear or expectations of such “reactions” from people. Understanding of the pattern and prevalence of felt stigma gives an insight into the burden of this “second illness” of epilepsy in southeast Nigeria. Methods: Consecutive consenting adult epilepsy patients attending a neurology outpatient in Enugu southeast Nigeria were interviewed. Data on felt stigma was also collected using a scale for collection of stigma data on stigma designed by Jacoby et al. Results: A total of 295 patients were interviewed during the study (165 (55.9%) males and 130 (44.1%) females). About 29.4% (88/295) felt stigmatized and 82.1% of them highly so. Correlates of felt stigma were age of onset (negatively), seizure frequency, duration of epilepsy, use of non-orthodox treatment, seizures occurring in public and the presence of physical injuries. Predictors of felt stigma were having seizures in public (R2 = 0.232, p Conclusions: Felt epilepsy stigma is common among patients attending urban tertiary hospital in southeast Nigeria. Several preventable factors are associated with this phenomenon hence efforts aimed at preventing epilepsy should also target felt stigma prevention.展开更多
Isothermal sintering experiments were performed on the 316 L stainless steel fiber felts with fiber diameters of 8 μm and20 μm. Surface morphologies of the sintered specimens were investigated by using scanning elec...Isothermal sintering experiments were performed on the 316 L stainless steel fiber felts with fiber diameters of 8 μm and20 μm. Surface morphologies of the sintered specimens were investigated by using scanning electron microscopy(SEM) and optical microscopy. The results show that the amount of the sintering necks and the relative densities of the fiber felt increase with the increasing of both the sintering temperature and the sintering time. And the activation energies estimated present a decline at high relative densities for both 8 μm and 20 μm fiber felts. Moreover, the sintering densification of the fiber felts is dominated by volume diffusion mechanism at low temperature and relative densities. As more grain boundaries are formed at higher temperature and relative density, grain boundary diffusion will also contribute to the densification of the specimen.展开更多
A LiBr/LiOH non-eutectic mixture shows a potentially outstanding heat energy density of 800 J/g at a constant temperature,which makes it a very promising candidate for heat storage applications around 300℃.However,sa...A LiBr/LiOH non-eutectic mixture shows a potentially outstanding heat energy density of 800 J/g at a constant temperature,which makes it a very promising candidate for heat storage applications around 300℃.However,salt-based phase change materials are known for their too low thermal conductivity which can question the thermal storage systems effective feasibility.The objective here is to infiltrate a carbon felt of high porosity(>93%)with the LiBr/LiOH mixture to anticipate this deficiency.The device has to be adapted according to the properties and the characteristics of the studied storage and host materials.The developed procedure for the carbon felt infiltration with the synthesized binary system is presented.The optimised working conditions allow(1)minimizing the interaction time duration between the quartz tube and the salt-based mixture and,(2)verifying the good chemical compatibility of the mixture with the host matrix after infiltration.展开更多
In the pouring rain and before a cheer ing crowd of nearly 80.000 spectators gathered in Moscow＇s Luzhniki Staditun. Hugo Lloris, goalkeeper and Captain ofFrance NationalFootball Team, lifted the FIFA World Cup troph...In the pouring rain and before a cheer ing crowd of nearly 80.000 spectators gathered in Moscow＇s Luzhniki Staditun. Hugo Lloris, goalkeeper and Captain ofFrance NationalFootball Team, lifted the FIFA World Cup trophy on July 15. After an exciting game. the Russian World Cup ended with a decisive victory for ＂Les Bleus,＂ to the great joy of French supporters worldwide.展开更多
The graphite felt was oxidized at a positive electrode potential in sulfuric acid solution.The electrochemical performance of the treated graphite felt served as electrode for vanadium redox battery was investigated w...The graphite felt was oxidized at a positive electrode potential in sulfuric acid solution.The electrochemical performance of the treated graphite felt served as electrode for vanadium redox battery was investigated with FT-IR,SEM,XPS,BET,cyclic voltammetry and testing VRB system,respectively.The results show that the molar ratio of O to C increases from 0.085 to 0.15 due to the increase of—COOH functional groups during electrochemical oxidation treatment,and the GF surface is eroded by electrochemical oxidation,resulting in the surface area increase from 0.33 m2/g to 0.49 m 2/g.The VRB with modified GF electrode exhibits excellent performance under a current density of 30 mA/cm 2 .The average current efficiency reaches 94%and average voltage efficiency reaches 85%.The improvement of electrochemical activity for the electrode is ascribed to the increase of the number of—COOH group and the special surface of GF.展开更多
基金The authors acknowledge the financial support from the National Natural Science Foundation of China(Nos.52073224,32201491)the Textile Vision Basic Research Program of China(No.J202110)+3 种基金the Scientific Research Project of Shaanxi Provincial Education Department,China(No.22JC035)the Advanced Manufacturing Technology Program of Xi’an Science and Technology Bureau,China(No.21XJZZ0019)the Research Fund for the Doctoral Program of Xi’an Polytechnic University(No.BS202053)the Youth Innovation Team of Shaanxi Universities and Institute of Flexible electronics and Intelligent Textile.
文摘MXene,a transition metal carbide/nitride,has been prominent as an ideal electrochemical active material for supercapacitors.However,the low MXene load limits its practical applications.As environmental concerns and sustainable development become more widely recognized,it is necessary to explore a greener and cleaner technology to recycle textile by-products such as cotton.The present study proposes an effective 3D fabrication method that uses MXene to fabricate waste denim felt into ultralight and flexible supercapacitors through needling and carbonization.The 3D structure provided more sites for loading MXene onto Z-directional fiber bundles,resulting in more efficient ion exchange between the electrolyte and electrodes.Furthermore,the carbonization process removed the specific adverse groups in MXenes,further improving the specific capacitance,energy density,power density and electrical conductivity of supercapacitors.The electrodes achieve a maximum specific capacitance of 1748.5 mF cm-2 and demonstrate remarkable cycling stability maintaining more than 94%after 15,000 galvanostatic charge/discharge cycles.Besides,the obtained supercapacitors present a maximum specific capacitance of 577.5 mF cm^(-2),energy density of 80.2μWh cm^(-2)and power density of 3 mW cm^(-2),respectively.The resulting supercapacitors can be used to develop smart wearable power devices such as smartwatches,laying the foundation for a novel strategy of utilizing waste cotton in a high-quality manner.
基金supported by the National Natural Science Foundation of China(No.51872090)Natural Science Foundation of Hebei Province(No.E2019209433,E2022209158)Colleges and Universities in Hebei Province Science and Technology Research Project(No.JZX2024026).
文摘The scarcity of wettability,insufficient active sites,and low surface area of graphite felt(GF)have long been suppressing the performance of vanadium redox flow batteries(VRFBs).Herein,an ultra-homogeneous multipledimensioned defect,including nano-scale etching and atomic-scale N,O codoping,was used to modify GF by the molten salt system.NH_(4)Cl and KClO_(3) were added simultaneously to the system to obtain porous N/O co-doped electrode(GF/ON),where KClO_(3) was used to ultra-homogeneously etch,and O-functionalize electrode,and NH4Cl was used as N dopant,respectively.GF/ON presents better electrochemical catalysis for VO_(2)+/VO_(2)+ and V3+/V2+ reactions than only O-functionalized electrodes(GF/O)and GF.The enhanced electrochemical properties are attributed to an increase in active sites,surface area,and wettability,as well as the synergistic effect of N and O,which is also supported by the density functional theory calculations.Further,the cell using GF/ON shows higher discharge capacity,energy efficiency,and stability for cycling performance than the pristine cell at 140 mA cm^(−2) for 200 cycles.Moreover,the energy efficiency of the modified cell is increased by 9.7% from 55.2% for the pristine cell at 260 mA cm^(−2).Such an ultra-homogeneous etching with N and O co-doping through“boiling”molten salt medium provides an effective and practical application potential way to prepare superior electrodes for VRFB.
基金supported by the Tianjin Synthetic Biotechnology Innovation Capacity Improvement Project (TSBICIP-KJGG003)Qinglan Plan of the Jiangsu Education Department。
文摘Hydrogen peroxide synthesis by electro-reduction of O_(2) to substitute the current anthraquinone process has attracted a great deal of attention. Low oxygen utilization rate and low hydrogen peroxide production remain obstacles to electro-Fenton application. In situ H_(2)O_(2) generated by electrochemical reaction depends on the electrochemical performance of the cathode and the structure of the reactor. Here, novel graphite felt(GF) modified by La-doped CeO_(2)(La-CeO_(2)) was developed as a cathode. A new double chamber electro-Fenton reactor was proposed, where an organic ultrafiltration membrane was used to prevent H_(2)O_(2) from spreading to the anode. The effects of hydrothermal temperature, time and urea concentration on the electrochemical properties of graphite felt were investigated. The accumulated concentration of H_(2)O_(2) on the modified cathode reached 218.4 mg·L^(-1)in 1 h when the optimal conditions of hydrothermal temperature 120 ℃ and urea concentration 0.55%(mass) in 24 h. The degradation rate of methyl orange reached 98.29%. The new electro-Fenton reactor can efficiently produce hydrogen peroxide to degrade various organic substances and has a high potential for treating wastewater in the chemical industry.
基金Projects(50930005,51075155)supported by the National Natural Science Foundation of ChinaProject(20100172110001)supported by PhD Programs Foundation of Ministry of Education of China
文摘Fabrication, characterization and performance of a porous metal-fiber sintered felt （PMFSF） based on multi-tooth cutting and solid-phase sintering were studied. The PMFSF was used as the anodic methanol barrier in a passive air-breathing direct methanol fuel cell to mitigate the effects of methanol crossover. Compared with the commercial SUS316L felt made of bundle-drawn fibers, this self-made PMFSF has larger pore diameter, polarized pore distribution, irregular fiber shape, rougher surface, lower mass flow resistance and evident hydrophobicity. The results reveal that the use of a PMFSF significantly enhances the cell performance since it helps to maintain a balance between the reactant and product management while depressing methanol crossover. The PMFSF with a porosity of 70% yields the highest cell performance at a methanol concentration of 4 mol/L.
文摘In this paper,a new resin called Resin M for imparting antifelting properties to wool fabricshas been studied.Resin M may be used by aqueous oxidative/polymer technique.It is provedthat Oxidant A/Resin M treatment can satisfy the machine washable requirement formulated byI.W.S..Resin M is a good agent for antifelting treatment of wool fabrics with proper pretreatment.Oxidant A/Resin M treatment has little influence on dyeing and moisture adsorption properties ofwool fibers.The pilling resistance of the treated fabrics is higher than that of the untreated ones.The strength and the handle of the treated fabrics have little been changed.According to thescanning electron microscope observations,it is recommended that the polymer encapsulation ofindividual fiber also plays an important role in the felting resistance of the treated fabrics though itis well known that the shrink resistance of the treated fabrics is believed to be due to the binding offibers.
文摘Electro-oxidation of Ce （ Ⅲ ） to Ce （ Ⅳ ） in parallel plate flow type electrolyzer divided with cation exchange membrane was carried out in nitric acid media at carbon felt anode under galvanostatic conditions. Carbon felt was used as an anode for its high specific surface area and high oxygen evolution overpotential. Pt coated Ti plates were used as cathode and anode current feeder. The oxidation of 1 mol· L^-1 Ce（ Ⅲ ） solution in 2 mol· L^- 1 HNO3 was proceeding with a high current efficiency （92%） until about 80% of Ce（ Ⅲ ） was oxidized. Then, oxygen evolution, accompanied by terminal voltage jump, took place, lowering current efficiency. Ce（ Ⅲ ） was oxidized up to 90% with current efficiency of 62%. In this mode, strong carbon felt anode oxidation was observed. The wear out of carbon felt was 46% in six consequent runs （6 h of operation）. After each run, carbon felt surface had to be renewed with slightly alkaline solution to remove carbon oxidation products and ensure regular operational conditions. When anode surface was blocked, oxygen evolution took place from the beginning of electrolysis due to higher actual current density. The wear out of carbon felt anode could be minimized by means of oxygen evolution prevention. In the case when electrolysis had been stopped before oxygen evolution started （at Ce（ Ⅳ ） conversion of about 80% ）, the wear out of anode was less than 2% during 6 consequent runs （4 h of operation）.
文摘Surface electropositivity and low internal resistance are important factors to improve the anode performance in microbial fuel cells (MFCs). Nitrogen doping is an effective way for the modification of traditional carbon materials. In this work, heat treatment and melamine were used to modify carbon felts to enhance electrogenesis capacity of MFCs. The modified carbon felts were characterized using X-ray photoelectron spectroscopy (XPS), scanning electron microscope (SEM), atomic force microscopy (AFM) and malvern zeta potentiometer. Results show that the maximum power densities under heat treatment increase from 276.1 to 423.4 mW/m(2) (700 degrees C) and 461.5 mW/m(2) (1200 degrees C) and further increase to 472.5 mW/m(2) (700 degrees C) and 515.4 mW/m(2) (1200 degrees C) with the co-carbonization modification of melamine. The heat treatment reduces the material resistivity, improves the zeta potential which is beneficial to microbial adsorption and electron transfer. The addition of melamine leads to the higher content of surface pyridinic and quaternary nitrogen and higher zeta potential. It is related to higher MFCs performance. Generally, the melamine modification at high temperature increases the feasibility of carbon felt as MFCs's anode materials. (C) 2016 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier B.V. and Science Press. All rights reserved.
基金Project(Xiang Zu [2016] 91) supported by the “100 Talented Teams” of Hunan Province,ChinaProject(2018RS3077) supported by the Huxiang High-level Talents Program,China+2 种基金Project(22002009) supported by the National Natural Science Foundation of ChinaProject(2021JJ40565) supported by the Natural Science Foundation of Hunan Province,ChinaProject(19C0054) supported by the Scientific Research Foundation of Hunan Provincial Education Department,China。
文摘Vanadium redox flow batteries(VRFBs)are one of the most promising energy storage systems owing to their safety,efficiency,flexibility and scalability.However,the commercial viability of VRFBs is still hindered by the low electrochemical performance of the available carbon-based electrodes.Defect engineering is a powerful strategy to enhance the redox catalytic activity of carbon-based electrodes for VRFBs.In this paper,uniform carbon defects are introduced on the surfaces of carbon felt(CF)electrode by Ar plasma etching.Together with a higher specific surface area,the Ar plasma treated CF offers additional catalytic sites,allowing faster and more reversible oxidation/reduction reactions of vanadium ions.As a result,the VRFB using plasma treated electrode shows a power density of 1018.3 mW/cm^(2),an energy efficiency(EE)of 84.5%,and the EE remains stable over 1000 cycles.
基金Natural Science Foundation of Liaoning Province,Grant/Award Number:2020-MZLH-40High-Level Talent Innovation Support Program of Dalian City,Grant/Award Number:2019RQ076National Natural Science Foundation of China,Grant/Award Numbers:21801034,51732007,51872033。
文摘The cerium-based redox flow battery(RFB)is regarded as a compelling gridscale energy storage technology to revolutionize the utilization of renewable energy by storing the energy in liquid electrolytes.However,its widespread implementation is impeded by the cerium redox reactions that exhibit slow kinetics on commercial graphite felt(GF)electrodes.Surface functionalization may be an available activation strategy to achieve a significant boost in the electrochemical performance of GFs.However,conventional chemical and/or electrochemical routes for the surface functionalization of GFs suffer from the issues of complication,and the deterioration of the resulting modified electrode surface over long-term cycle processes leads to catalytic activity decline.Here,we develop a facile and general strategy for introducing the functional groups to the electrode through the addition of L-cysteine into electrolytes.The-COOH,-NH_(2),and-SH groups in L-cysteine can induce oxygen/nitrogen/sulfur trifunctional doping on GF surfaces with lower deterioration rates,which enables the activated GFs to demonstrate a promising electrocatalytic activity toward cerium redox reactions and excellent durability when used as a cerium-based RFB electrode.This study proposes a rational strategy to overcome the intrinsic limitations of existing modification techniques for GFs and provides a potential pathway toward high-performance RFBs.
文摘A new MEEKC method assisted with pressure-driven mobile phase was presented for the separation of felted explosives. Microemulsion solution was composed of 80 mmol/L heptane -120 mmol/L SDS (sodium dodecyl sulphate) - 900 mmol/L butanol - 10 mmol/L borate at pH 9.4 and a pressure-driven flow of 0.020 mL/min under 1.3 MPa was employed to manipulate the separation. Explosives HMX (1, 3, 5, 7-tetranitro-l, 3, 5, 7-tetrazacyclooctane) and TATB (triamino-trinitrobenzene), which were felted on fluorine rubber F2311 (polytrifluorochlorethylene and polyvinylidene fluoride 1/1 co-polymerization) and F2314 (polytrifluorochlorethylene and polyvinylidene fluoride 4/1 co-polymerization) were well separated with very good peak shapes.
文摘In this research the effects of mordant and plasma sputtering treatments on the crystallinity and morphological properties of wool fabrics were investigated. The felting behavior of the treated samples was also studied. We used madder as a natural dye and copper sulfate as a metal mordant. We also used copper as the electrode material in a DC magnetron plasma sputtering device. The anti-felting properties of the wool samples before and after dying was studied, and it was shown that the shrink resistance and anti-felting behavior of the wool had been significantly improved by the plasma sputtering treatment. In addition, the percentage of crystallinity and the size of the crystals were investigated using an X-ray diffractometer, and a scanning electron microscope was used for morphological analysis. The amount of copper particles on the surface of the mordanted and sputtered fabrics was studied using the energy dispersive X- ray （EDX） method, and the hydrophobic properties of the samples were examined using the water drop test. The results show that with plasma sputtering treatment, the hydrophobic properties of the surface of wool become super hydrophobic.
基金Project (2008ZX07313-005) supported by the National Water Pollution Control and Management of Major Special Science and Technology Foundation
文摘Prussian blue (PB) modified carbon felt electrodes were prepared. The electrochemical behavior was investigated by cyclic voltammetry, electrochemical impedance spectroscopy and charge-discharge experiments. In order to distinguish the mechanism of the PB modified carbon felt electrode, the electrochemical quartz crystal microbalance (EQCM) was employed. The results of cyclic voltammetry show that the modification can improve the reversibility and the suitable PB deposition is the amount of 10 circles deposition. PB modified carbon felt electrode can effectively decrease the charge transfer resistance. The voltage efficiency of VRB employing PB modified carbon felt electrode can be increased by 12%. The mass change of the PB modified Pt crystal electrode in the process of the potential scan is obvious. The reaction of substitution of VO2+ for high-spin Fe ion in PB is probable to happen and the possible reaction equation is given. The preliminary exploration shows that PB modified carbon felt is electrochemically promising for redox flow battery.
文摘Sound absorbers including porous materials are used widely for noise control. The most widely-exploited and acknowledged absorption mechanism in porous materials is viscous friction due to relative motion between solid and fluid. Acoustical performance of woven (carpet) and nonwoven (felt) materials made of wool using a traditional technique was investigated. Absorption coefficient of felt was measured using standing wave tube method with and without an air cavity. Data were compared with predictions determined using the laws of Delany and Bazely. Very good agreement between data and predictions was observed. Sound absorption coefficients of both materials also were measured using an impedance gun technique over a wider frequency range. Absorption coefficient obtained using impedance gun method shows that the absorption coefficient of felt is higher than the absorption coefficient of carpet for mid and higher frequencies. Furthermore insertion loss (IL) of the felt was measured in a circular duct. It is found that felt can attenuate sound pressure level between 1 dB and 10 dB.
基金Project (03GKY3015) supported by the Foundation of Hunan Provincial Department of Science and Technology
文摘PAN-based graphite felt （PGF） treated in 98% sulphuric acid for 5 h and then kept at 450 ℃ for 2 h was evaluated for their electrochemical performance as electrodes of vanadium redox battery （VRB）. Structure and characteristic of treated PAN-based graphite felt （TPGF） were determined by means of Fourier Transform Infi-ared Spectroscopy, Scanning Electron Microscopy, Brunauer-Emmett-Teller surface area analysis and VRB test system. The results show that the acid and heat synergistic effect increase the number of --COOH functional groups on the PGF surface, and the PGF is eroded by sulphuric acid oxidation, resulting in the surface area increases from 0.31 m^2/g to 0.45 m^2/g. The V（ Ⅱ ）/V（Ⅲ） redox reaction is electrochemically reversible on the TPGF electrode, while the V（Ⅳ）/V（Ⅴ） couple is a quasi reversible process. The diffusion coefficients of the oxidation for V（Ⅳ）/V（Ⅴ） obtained from the scope of peak current Ip vs scan rate v^1/2 is 4.4×10^-5 cm^2/s. The improvement of electrochemical activity for the electrode is mainly ascribed to the increase of the number of ---COOH groups on the TPGF, which behaves as active sites catalyzing the vanadium species reactions and accelerating electron transfer reaction and oxygen transfer.
文摘Background: Felt stigma is a major social and psychological problem in epilepsy and manifests the fear or expectations of such “reactions” from people. Understanding of the pattern and prevalence of felt stigma gives an insight into the burden of this “second illness” of epilepsy in southeast Nigeria. Methods: Consecutive consenting adult epilepsy patients attending a neurology outpatient in Enugu southeast Nigeria were interviewed. Data on felt stigma was also collected using a scale for collection of stigma data on stigma designed by Jacoby et al. Results: A total of 295 patients were interviewed during the study (165 (55.9%) males and 130 (44.1%) females). About 29.4% (88/295) felt stigmatized and 82.1% of them highly so. Correlates of felt stigma were age of onset (negatively), seizure frequency, duration of epilepsy, use of non-orthodox treatment, seizures occurring in public and the presence of physical injuries. Predictors of felt stigma were having seizures in public (R2 = 0.232, p Conclusions: Felt epilepsy stigma is common among patients attending urban tertiary hospital in southeast Nigeria. Several preventable factors are associated with this phenomenon hence efforts aimed at preventing epilepsy should also target felt stigma prevention.
基金Project(51134003) supported by the National Natural Science Foundation of China
文摘Isothermal sintering experiments were performed on the 316 L stainless steel fiber felts with fiber diameters of 8 μm and20 μm. Surface morphologies of the sintered specimens were investigated by using scanning electron microscopy(SEM) and optical microscopy. The results show that the amount of the sintering necks and the relative densities of the fiber felt increase with the increasing of both the sintering temperature and the sintering time. And the activation energies estimated present a decline at high relative densities for both 8 μm and 20 μm fiber felts. Moreover, the sintering densification of the fiber felts is dominated by volume diffusion mechanism at low temperature and relative densities. As more grain boundaries are formed at higher temperature and relative density, grain boundary diffusion will also contribute to the densification of the specimen.
文摘A LiBr/LiOH non-eutectic mixture shows a potentially outstanding heat energy density of 800 J/g at a constant temperature,which makes it a very promising candidate for heat storage applications around 300℃.However,salt-based phase change materials are known for their too low thermal conductivity which can question the thermal storage systems effective feasibility.The objective here is to infiltrate a carbon felt of high porosity(>93%)with the LiBr/LiOH mixture to anticipate this deficiency.The device has to be adapted according to the properties and the characteristics of the studied storage and host materials.The developed procedure for the carbon felt infiltration with the synthesized binary system is presented.The optimised working conditions allow(1)minimizing the interaction time duration between the quartz tube and the salt-based mixture and,(2)verifying the good chemical compatibility of the mixture with the host matrix after infiltration.
文摘In the pouring rain and before a cheer ing crowd of nearly 80.000 spectators gathered in Moscow＇s Luzhniki Staditun. Hugo Lloris, goalkeeper and Captain ofFrance NationalFootball Team, lifted the FIFA World Cup trophy on July 15. After an exciting game. the Russian World Cup ended with a decisive victory for ＂Les Bleus,＂ to the great joy of French supporters worldwide.
基金Project(02-09-01)supported by Pangang Group Pangzhihua Iron and Steel Research Institute,China
文摘The graphite felt was oxidized at a positive electrode potential in sulfuric acid solution.The electrochemical performance of the treated graphite felt served as electrode for vanadium redox battery was investigated with FT-IR,SEM,XPS,BET,cyclic voltammetry and testing VRB system,respectively.The results show that the molar ratio of O to C increases from 0.085 to 0.15 due to the increase of—COOH functional groups during electrochemical oxidation treatment,and the GF surface is eroded by electrochemical oxidation,resulting in the surface area increase from 0.33 m2/g to 0.49 m 2/g.The VRB with modified GF electrode exhibits excellent performance under a current density of 30 mA/cm 2 .The average current efficiency reaches 94%and average voltage efficiency reaches 85%.The improvement of electrochemical activity for the electrode is ascribed to the increase of the number of—COOH group and the special surface of GF.
