Vanadium redox flow batteries(VRFBs)hold significant promise for large-scale energy storage applications.However,the sluggish reaction kinetics on the electrode surface considerably limit their performance.Implementat...Vanadium redox flow batteries(VRFBs)hold significant promise for large-scale energy storage applications.However,the sluggish reaction kinetics on the electrode surface considerably limit their performance.Implementation of efficient surface modification on carbon electrodes through an economically viable production method is crucial for the practical application of VRFBs.Herein,a nano-carbon layer with morphology of fine nanoparticles(<90 nm)and rich oxygen functional groups was constructed on carbon felts by unbalanced magnetron sputtering coupled with thermal treatment.This modified carbon felt served as both anode and cathode in cell,enabling an improved wettability of electrolyte and high reversibility of the active mass,and promoted kinetics of redox reactions.The optimized carbon felt,achieved through one hour of deposition(1C-CF),demonstrated outstanding electrochemical performance in a single cell.The cell exhibited a high energy efficiency of 82.4%at a current density of 100 m A cm^(-2)and maintained 71.8%at a high current density of 250 mA cm^(-2).Furthermore,the energy efficiency remained at 77.2%during long-term cycling(450 cycles)at a current density of 150 mA cm^(-2),indicating good electrode stability.Our results shed light on the surface design of carbon felt electrodes for the broad application interest of VRFB energy storage systems.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
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
Polysulfide/ferricyanide flow batteries(S/Fe RFBs),with the advantages of abundant earth reservation low cost,high safety,and environmental friendliness,have attracted significant interest and demonstrated noteworthy ...Polysulfide/ferricyanide flow batteries(S/Fe RFBs),with the advantages of abundant earth reservation low cost,high safety,and environmental friendliness,have attracted significant interest and demonstrated noteworthy potential for practical applications.However,the battery performance,including the energy efficiency(EE),voltage efficiency(VE),and power density of the S/Fe RFBs remains low owing to the slow redox kinetics of polysulfide ions.To address these concerns,WS_(2)was selected as the booster and deposited on a commercial carbon felt electrode(WS_(2)-CF)to stimulate the redox reactions of polysulfide ions.With better hydrophilicity and smaller charge-transfer resistance,WS_(2)-CF exhibits enhanced electrochemical activity toward polysulfide redox reactions.Consequently,the battery performance of S/Fe RFB with WS_(2)-CF as the anode has been improved,with EE of 84%,VE of 84%,and a peak power density of 175.7 mW·cm^(-2),which are all higher than the cell only with the bare carbon felt(CF)as electrodes(76%,77%and 155.8 mW·cm^(-2),respectively).Furthermore,the cycling life of the S/Fe RFB with WS_(2)-CF has been prolonged to 2200 cycles with a capacity retention of 96% a 40 mA·cm^(-2)because of the good stability of WS_(2)-CF as the anode.Contrarily,under the same conditions,the S/Fe RFB without WS_(2)-CF terminated after 1500 cycles with a fast capacity decay.The successful utilization of WS_(2)as a booster on an electrode provides an efficient strategy for obtaining advanced S/Fe RFBs for practical applications.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
Developing non-noble-metal oxygen evolution reaction(OER) electrocatalysts with high performance is critical to electrocatalytic water splitting. In this work, we fabricated Co Fe-layered double hydroxide(LDH) nanowir...Developing non-noble-metal oxygen evolution reaction(OER) electrocatalysts with high performance is critical to electrocatalytic water splitting. In this work, we fabricated Co Fe-layered double hydroxide(LDH) nanowire arrays on graphite felt(Co Fe-LDH/GF) via a hydrothermal method. The Co Fe-LDH/GF, as a robust integrated 3 D OER anode, exhibits excellent catalytic activity with the need of low overpotential of 252 and 285 mV to drive current densities of 10 and 100 mA/cm^(2) in 1.0 mol/L KOH, respectively. In addition, it also maintains electrochemical durability for at least 24 h. This work would open up avenues for the development of GF like attractive catalyst supports for oxygen evolution applications.展开更多
The recent development of portable electronics promotes the growing demand for flexible energy storage devices. Supercapacitors are promising candidates due to their high power density. Therefore, flexible supercapaci...The recent development of portable electronics promotes the growing demand for flexible energy storage devices. Supercapacitors are promising candidates due to their high power density. Therefore, flexible supercapacitors are desired. Here, the porous activated carbon felts(ACFs) with exfoliated graphene nanosheets and rich oxygen-containing groups were fabricated by a facile thermal treatment strategy.Such ACFs can act as the flexible electrodes of all-solid-state supercapacitors directly without the use of binder and conductive materials. They exhibit excellent electrochemical properties, such as high specific areal capacitance, superior rate ability and long-term cycling stability. Moreover, the fabricated flexible all-solid-state supercapacitors based on ACFs deliver stable electrochemical performance under different bending states.展开更多
Poly（pheniothiazine） films were prepared on a porous carbon felt（CF） electrode surface by an electrooxidative polymerization of three phenothiazine derivatives（i.e.,Tthionine（TN）,Toluidine Blue（TB） and Methyl...Poly（pheniothiazine） films were prepared on a porous carbon felt（CF） electrode surface by an electrooxidative polymerization of three phenothiazine derivatives（i.e.,Tthionine（TN）,Toluidine Blue（TB） and Methylene Blue（MB）） from 0.1 mol/L phosphate buffer solution（pH 7.0）.Among the three phenothiazies,the poly（TB） film-modified CF exhibited an excellent electrocatalytic activity for the oxidation of nicotinamide adenine dinucleotide reduced form（NADH） at ＋0.2 V vs.Ag/AgCl.The poly（TB） film-modified CF was successfully used as working electrode unit of highly sensitive amperometric flow-through detector for NADH.The peak currents（peak heights） were almost unchanged,irrespective of a carrier flow rate ranging from 2.0 to 4.1 mL/min,resulting in the measurement of NADH（ca.30 samples/hr） at 4.1 mL/min.The peak current responses of NADH showed linear relationship over the concentration range from 1 to 30 μmol/L（sensitivity：0.318 μA/（μmol/L）;correlation coefficient：0.997）.The lower detection limit was found to be 0.3 μmol/L（S/N = 3）.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
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
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
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
Tyrosinase（TYR） was covalently immobilized onto amino-functionalized carbon felt surface via glutaraldehyde-coupling under ultrasonic treatment for 10 min.The resulting TYR-immobilized carbon felt was used as a work...Tyrosinase（TYR） was covalently immobilized onto amino-functionalized carbon felt surface via glutaraldehyde-coupling under ultrasonic treatment for 10 min.The resulting TYR-immobilized carbon felt was used as a working electrode unit of bioelectrocatalytic flow-through detector for TYR substrates（catechol,p-chlorophenol（p-CP）,p-cresol,phenol etc.）.Cathodic peak currents based on the electroreduction of enzymatically produced o-quinones were detected at-50 mV vs.Ag/AgCl.Compared with previous work in which TYR was immobilized onto amino-functionalized carbon felt for 16 hr without the ultrasonic treatment,we succeeded in（1） shortening the enzyme immobilization time from 16 hr to 10 min,（2） enhancing the sensitivity of p-CP,and（3） improving the operational stability of p-CP.The ultrasonic treatment during the TYR immobilization step would lead to certain changes in the structure of the immobilized TYR and the morphology of the immobilized TYR-layer on the carbon felt surface.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
基金supported by National Natural Science Foundation of China(U21B2057)。
文摘Vanadium redox flow batteries(VRFBs)hold significant promise for large-scale energy storage applications.However,the sluggish reaction kinetics on the electrode surface considerably limit their performance.Implementation of efficient surface modification on carbon electrodes through an economically viable production method is crucial for the practical application of VRFBs.Herein,a nano-carbon layer with morphology of fine nanoparticles(<90 nm)and rich oxygen functional groups was constructed on carbon felts by unbalanced magnetron sputtering coupled with thermal treatment.This modified carbon felt served as both anode and cathode in cell,enabling an improved wettability of electrolyte and high reversibility of the active mass,and promoted kinetics of redox reactions.The optimized carbon felt,achieved through one hour of deposition(1C-CF),demonstrated outstanding electrochemical performance in a single cell.The cell exhibited a high energy efficiency of 82.4%at a current density of 100 m A cm^(-2)and maintained 71.8%at a high current density of 250 mA cm^(-2).Furthermore,the energy efficiency remained at 77.2%during long-term cycling(450 cycles)at a current density of 150 mA cm^(-2),indicating good electrode stability.Our results shed light on the surface design of carbon felt electrodes for the broad application interest of VRFB energy storage systems.
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financially supported by the NationalNatural Science Foundation of China(No.22209015)Scientific Research Foundation of Hunan Provincial Education Department(Nos.21A0195 and 21C0215)100 Talented Team of Hunan Province(No.XiangZu[2016]91)。
文摘Polysulfide/ferricyanide flow batteries(S/Fe RFBs),with the advantages of abundant earth reservation low cost,high safety,and environmental friendliness,have attracted significant interest and demonstrated noteworthy potential for practical applications.However,the battery performance,including the energy efficiency(EE),voltage efficiency(VE),and power density of the S/Fe RFBs remains low owing to the slow redox kinetics of polysulfide ions.To address these concerns,WS_(2)was selected as the booster and deposited on a commercial carbon felt electrode(WS_(2)-CF)to stimulate the redox reactions of polysulfide ions.With better hydrophilicity and smaller charge-transfer resistance,WS_(2)-CF exhibits enhanced electrochemical activity toward polysulfide redox reactions.Consequently,the battery performance of S/Fe RFB with WS_(2)-CF as the anode has been improved,with EE of 84%,VE of 84%,and a peak power density of 175.7 mW·cm^(-2),which are all higher than the cell only with the bare carbon felt(CF)as electrodes(76%,77%and 155.8 mW·cm^(-2),respectively).Furthermore,the cycling life of the S/Fe RFB with WS_(2)-CF has been prolonged to 2200 cycles with a capacity retention of 96% a 40 mA·cm^(-2)because of the good stability of WS_(2)-CF as the anode.Contrarily,under the same conditions,the S/Fe RFB without WS_(2)-CF terminated after 1500 cycles with a fast capacity decay.The successful utilization of WS_(2)as a booster on an electrode provides an efficient strategy for obtaining advanced S/Fe RFBs for practical applications.
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supported by the National Natural Science Foundation of China (No.22072015)。
文摘Developing non-noble-metal oxygen evolution reaction(OER) electrocatalysts with high performance is critical to electrocatalytic water splitting. In this work, we fabricated Co Fe-layered double hydroxide(LDH) nanowire arrays on graphite felt(Co Fe-LDH/GF) via a hydrothermal method. The Co Fe-LDH/GF, as a robust integrated 3 D OER anode, exhibits excellent catalytic activity with the need of low overpotential of 252 and 285 mV to drive current densities of 10 and 100 mA/cm^(2) in 1.0 mol/L KOH, respectively. In addition, it also maintains electrochemical durability for at least 24 h. This work would open up avenues for the development of GF like attractive catalyst supports for oxygen evolution applications.
基金supported by National Natural Science Foundation of China (Nos. 21573116, 51822205 and 21875121)Ministry of Science and Technology of China (No. 2017YFA0206701)+1 种基金Ministry of Education of China (No. B12015)the Young Thousand Talents Program
文摘The recent development of portable electronics promotes the growing demand for flexible energy storage devices. Supercapacitors are promising candidates due to their high power density. Therefore, flexible supercapacitors are desired. Here, the porous activated carbon felts(ACFs) with exfoliated graphene nanosheets and rich oxygen-containing groups were fabricated by a facile thermal treatment strategy.Such ACFs can act as the flexible electrodes of all-solid-state supercapacitors directly without the use of binder and conductive materials. They exhibit excellent electrochemical properties, such as high specific areal capacitance, superior rate ability and long-term cycling stability. Moreover, the fabricated flexible all-solid-state supercapacitors based on ACFs deliver stable electrochemical performance under different bending states.
基金financially supported in part by the Open Research Center Project of the Ministry of Education,Science and Culture of Japan
文摘Poly（pheniothiazine） films were prepared on a porous carbon felt（CF） electrode surface by an electrooxidative polymerization of three phenothiazine derivatives（i.e.,Tthionine（TN）,Toluidine Blue（TB） and Methylene Blue（MB）） from 0.1 mol/L phosphate buffer solution（pH 7.0）.Among the three phenothiazies,the poly（TB） film-modified CF exhibited an excellent electrocatalytic activity for the oxidation of nicotinamide adenine dinucleotide reduced form（NADH） at ＋0.2 V vs.Ag/AgCl.The poly（TB） film-modified CF was successfully used as working electrode unit of highly sensitive amperometric flow-through detector for NADH.The peak currents（peak heights） were almost unchanged,irrespective of a carrier flow rate ranging from 2.0 to 4.1 mL/min,resulting in the measurement of NADH（ca.30 samples/hr） at 4.1 mL/min.The peak current responses of NADH showed linear relationship over the concentration range from 1 to 30 μmol/L（sensitivity：0.318 μA/（μmol/L）;correlation coefficient：0.997）.The lower detection limit was found to be 0.3 μmol/L（S/N = 3）.
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.
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supported in part by the Open Research Center Project of the Ministry of Education,Science and Culture of Japan
文摘Tyrosinase（TYR） was covalently immobilized onto amino-functionalized carbon felt surface via glutaraldehyde-coupling under ultrasonic treatment for 10 min.The resulting TYR-immobilized carbon felt was used as a working electrode unit of bioelectrocatalytic flow-through detector for TYR substrates（catechol,p-chlorophenol（p-CP）,p-cresol,phenol etc.）.Cathodic peak currents based on the electroreduction of enzymatically produced o-quinones were detected at-50 mV vs.Ag/AgCl.Compared with previous work in which TYR was immobilized onto amino-functionalized carbon felt for 16 hr without the ultrasonic treatment,we succeeded in（1） shortening the enzyme immobilization time from 16 hr to 10 min,（2） enhancing the sensitivity of p-CP,and（3） improving the operational stability of p-CP.The ultrasonic treatment during the TYR immobilization step would lead to certain changes in the structure of the immobilized TYR and the morphology of the immobilized TYR-layer on the carbon felt surface.
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.
