Carbon materials are effective substitutes for Pt counter electrodes(CEs) in dye-sensitized solar cells(DSSCs). However, many of these materials, such as carbon nanotubes and graphene, are expensive and require comple...Carbon materials are effective substitutes for Pt counter electrodes(CEs) in dye-sensitized solar cells(DSSCs). However, many of these materials, such as carbon nanotubes and graphene, are expensive and require complex preparation process. Herein, waste lignin, recycled from hazardous black liquors,is used to create oxygen-nitrogen-sulfur codoped carbon microspheres for use in DSSC CEs through the facile process of low-temperature preoxidation and high-temperature self-activation. The large number of ester bonds formed by preoxidation increase the degree of cross-linking of the lignin chains, leading to the formation of highly disordered carbon with ample defect sites during pyrolysis. The presence of organic O/N/S components in the waste lignin results in high O/N/S doping of the pyrolysed carbon,which increases the electrolyte ion adsorption and accelerates the electron transfer at the CE/electrolyte interface, as confirmed by density functional theory(DFT) calculations. The presence of inorganic impurities enables the construction of a hierarchical micropore-rich carbon structure through the etching effect during self-activation, which can provide abundant catalytically active sites for the reversible adsorption/desorption of electrolyte ions. Under these synergistic effects, the DSSCs that use this novel carbon CE achieve a quite high power-conversion efficiency of 9.22%. To the best of our knowledge, the value is a new record reported so far for biomass-carbon-based DSSCs.展开更多
With the advantages of high energy/power density,long cycling life and low cost,dual-carbon potassium ion hybrid capacitors(PIHCs)have great potential in the field of energy storage.Here,a novel bilayer-shelled N,O-do...With the advantages of high energy/power density,long cycling life and low cost,dual-carbon potassium ion hybrid capacitors(PIHCs)have great potential in the field of energy storage.Here,a novel bilayer-shelled N,O-doped hollow porous carbon microspheres(NOHPC)anode has been prepared by a self-template method,which is consisted of a dense thin shell and a hollow porous spherical core.Excitingly,the NOHPC anode possesses a high K-storage capacity of 325.9 mA h g^(−1)at 0.1 A g^(−1)and a capacity of 201.1 mAh g^(−1)at 5 A g^(−1)after 6000 cycles.In combination with ex situ characterizations and density functional theory calculations,the high reversible capacity has been demonstrated to be attributed to the co-doping of N/O heteroatoms and porous structure improved K+adsorption and intercalation capabilities,and the stable long-cycling performance originating from the bilayer-shelled hollow porous carbon sphere structure.Meanwhile,the hollow porous activated carbon microspheres(HPAC)cathode with a high specific surface area(1472.65 m^(2)g^(−1))deriving from etching NOHPC with KOH,contributing to a high electrochemical adsorption capacity of 71.2 mAh g^(−1)at 1 A g^(−1).Notably,the NOHPC//HPAC PIHC delivers a high energy density of 90.1 Wh kg^(−1)at a power density of 939.6 W kg^(−1)after 6000 consecutive charge-discharge cycles.展开更多
Starch,as a typical polysaccharide with natural spherical morphology,is not only a preferred precursor for preparing carbon materials but also a model polymer for investigating thermochemical evolution mechanisms.Howe...Starch,as a typical polysaccharide with natural spherical morphology,is not only a preferred precursor for preparing carbon materials but also a model polymer for investigating thermochemical evolution mechanisms.However,starch usually suffers from severe foaming and low carbon yield during direct pyrolysis.Herein,we report a simple and eco-friendly dry strategy,by maleic anhydride initiating the esterification of starch,to design carbon microspheres against the starch foaming.Moreover,the infuence of ester grafting on the pyrolytic behavior of starch is also focused.The formation of ester groups in precursor guarantees the structural stability of starch-based intermediate because it can promote the accumulation of unsaturated species and accelerate the water elimination during pyrolysis.Meanwhile,the esterification and dehydration reactions greatly deplete the primary hydroxyl groups in the starch molecules and thus the rapid levoglucosan release is inhibited,which well keeps the spherical morphology of starch and ensures the high carbon yield.In further exploration as anode materials for Lithium-ion batteries,the obtained carbon microspheres exhibit good cyclability and rate performance with a reversible capacity of 444 m Ah g^(-1)at 50 m A g^(-1).This work provides theoretical fundamentals for the controllable thermal transformation of biomass towards wide applications.展开更多
This article reported the electrochemical behaviors of a novel hollow carbon microspheres/manganese dioxide nanosheets(micro-HC/nano-MnO2) composite prepared by an in situ self-limiting deposition method under hydroth...This article reported the electrochemical behaviors of a novel hollow carbon microspheres/manganese dioxide nanosheets(micro-HC/nano-MnO2) composite prepared by an in situ self-limiting deposition method under hydrothermal condition. The results of scanning electron microscopy reveal that MnO2 nanosheets homogeneously grow onto the surface of micro-HC to form a loose-packed microstructure. The quantity of MnO2 required in the electrode layer has thereby been reduced significantly, and higher specific capacitances have been achieved. The micro-HC/nano-MnO2 electrode presents a high capacitance of 239.0 F g-1 at a current density of 5 m A cm-2, which is a strong promise for high-rate electrochemical capacitive energy storage applications.展开更多
As one of the low-cost energy storage systems,Na-ion batteries(NIBs)have received tremendous attention.However,the performance of current anode materials still cannot meet the requirements of NIBs.In our work,we obtai...As one of the low-cost energy storage systems,Na-ion batteries(NIBs)have received tremendous attention.However,the performance of current anode materials still cannot meet the requirements of NIBs.In our work,we obtain sulfur-doped interconnected carbon microspheres(S-CSs)via a simple hydrothermal method and subsequent sulfurizing treatment.Our S-CSs exhibit an ultrahigh reversible capacity of 520 mAh g^(-1) at 100 mA g^(-1) after 50 cycles and an excellent rate capability of 257 mAh g^(-1),even at a high current density of 2 A g^(-1).The density functional theory calculations demonstrate that sulfur doping in carbon favors the adsorption of Na atom during the sodiation process,which is accountable for the performance enhancement.Furthermore,we also utilize operando Raman spectroscopy to analyze the electrochemical reaction of our S-CSs,which further highlights the sulfur doping in improving Na-ion storage performance.展开更多
Nitrogen-doped lignin-based carbon microspheres are synthesized using 3-aminophenol as a nitrogen source by the hydrothermal method.The structural change and the effect on the electrochemical properties are systematic...Nitrogen-doped lignin-based carbon microspheres are synthesized using 3-aminophenol as a nitrogen source by the hydrothermal method.The structural change and the effect on the electrochemical properties are systematically investigated. Nitrogen-doped lignin-based carbon microspheres represent well-developed spherical morphology with many active sites, ultramicroporous(< 0.7 nm) structure, and large interlayer spacing. Consistent with the obtained physical structures and properties, the nitrogen-doped carbon microspheres exhibit fast sodium ion adsorption/intercalation kinetic process and excellent electrochemical performance. For example, a reversible specific capacity of 374 m Ah g^(-1) at 25 m A g^(-1) with high initial coulombic efficiency of 85% and high capacitance retention of 90% after 300 cycles at 100 m A g^(-1) and stable charge/discharge behavior at different current density is obtained. The additional defects and abundant ultramicroporous structure can enhance sloping capacity, and large interlayer spacing is considered to be the reason for improving plateau capacity.展开更多
Carbon microspheres were prepared from waste cotton fibers by hydrothermal carbonization(HTC)with the addition of copper sulphate in this work.The important influence factors,temperature,concentration of copper sulpha...Carbon microspheres were prepared from waste cotton fibers by hydrothermal carbonization(HTC)with the addition of copper sulphate in this work.The important influence factors,temperature,concentration of copper sulphate,resident time were explored here.The smooth and regular carbon microspheres could be formed at 330°C with 0.15 wt%copper sulphate after 6 h from waste cotton fibers.The crystal structures of cotton fibers were destructed in a short resident time with 0.15 wt%copper sulphate from SEM images and XRD patterns of solid products.This strategy provides a new,mild and efficient method to prepare carbon microspheres from waste cotton fibers by HTC.FTIR spectra verified that the abundant functional groups existed on the surface of synthesized carbon microspheres.From XPS and element analysis results,the copper sulphate participated in the forming process of carbon microspheres indeed.The presence of copper sulphate in the carbon microspheres provided a possibility for the application in antibacterial field.Besides,the catalytic mechanism of copper sulphate on the hydrolysis and carbonization of waste cotton fibers were also discussed.In conclusion,the copper sulphate is an efficient agent for preparing carbon microspheres by HTC from waste cotton fibers.展开更多
The colloidal carbon microspheres(CMS)were prepared by the hydrothermal method.The nickel catalysts supported on carbon microspheres(Ni/CMS)were further prepared and were characterized by the Fourier transform infrare...The colloidal carbon microspheres(CMS)were prepared by the hydrothermal method.The nickel catalysts supported on carbon microspheres(Ni/CMS)were further prepared and were characterized by the Fourier transform infrared spectroscopy(FTIR),the X-ray diffraction(XRD),the scanning electron microscopy(SEM),the transmission electron microscopy(TEM),and the N_(2)adsorption technique.The selective hydrogenation of maleic anhydride(MA)to succinic anhydride(SA)over the Ni/CMS catalysts was investigated.The results indicated that the Ni/CMS catalyst,which was prepared with glucose as carbon source and calcined at 500℃,exhibited the best performance.The hydrogen pressure,reaction temperature,and reaction time could significantly affect the conversion of maleic anhydride during the hydrogenation reaction.A 98.4%conversion of MA and an 100%selectivity to SA were achieved over the Ni/CMS catalyst in acetic anhydride solvent under mild conditions covering a temperature of 90℃,a H2 pressure of 1.0 MPa,and a reaction time of 3 h.展开更多
Carbon-based anode materials are widely used in various battery energy storage systems due to their low cost,wide source,high conductivity and easy morphology control.However,current commercially available anode mater...Carbon-based anode materials are widely used in various battery energy storage systems due to their low cost,wide source,high conductivity and easy morphology control.However,current commercially available anode materials as active materials for lithium-/sodium-ion batteries generally suffer from large volume changes and poor rate performance.In response,we synthesized defect-rich N,S co-doped two dimensional(2D)nanosheet-assembled porous carbon microspheres(N,S-PCS)via simple hydrothermal,carbonization and etching process based on the principle of Schiff base reaction.The N,S-PCS structure is thus constructed by removing Fe7S8 nanoparticles from the carbon skeleton to form porous microspheres with N,S doping.Therefore,the micromorphology characteristic,pore structure and electroconductivity of carbon materials are effectively optimized via heteroatom doping and surface engineering.As expected,the prepared N,S-PCS electrodes exhibit excellent electrochemical performance in both lithium-ion and sodium-ion batteries.For lithium-ion batteries,it achieves reversible capacities of 1045 and 237 mAh g^(-1) at 0.1 and 20 A g^(-1),respectively.For sodium-ion batteries,it shows good cycling stability with a capacity of 157 mAh g^(-1) after 500 cycles at 1 A g^(-1).Experimental and theoretical calculation results confirm that the N,S co-doping strategies help to improve the structural stability,shorten the ion diffusion paths,and promote the reaction kinetics,thus achieving excellent electrochemical performance.This work is instructive for the practical application of nonmetal doping functionalized porous carbon structures for metal-ion batteries.展开更多
The basic structure of aromatic compounds that are abundant in coal is the carbonaceous precursor derived from carbon microspheres.However,it remains to be a huge challenge to prepare carbon microspheres using coal du...The basic structure of aromatic compounds that are abundant in coal is the carbonaceous precursor derived from carbon microspheres.However,it remains to be a huge challenge to prepare carbon microspheres using coal due to the complex construction and composition of coal.Herein,a simple and viable way to obtain coal-based microporous carbon microspheres was developed by means of ethanol pyrolysis and a sequential extraction strategy.The as-prepared carbon microsphere featured aspherical micron particles of a uniform size(0.6-1.6㎛),abundant O-functional groups,excellent thermal stability,high SBET(415.5-983.2 m^(2)/g),and plentiful ultra-micropores(63.15-72.72%).The coal-based carbon microsphere exhibited a noteworthy CO_(2)uptake(3.19-4.97 mmol/g at 273 K and 1.0 bar),acceptable CO_(2)/N_(2)selectivity(IAST:23-46)and moderate isosteric heats(20-32 kJ/mol).This synthetic strategy is important for the preparation of ultramicroporous carbon microspheres using coal,and the synthetic carbon microspheres have promising prospects for highly efficient CO_(2)capture.展开更多
Lightweight and high-performance are two determining factors for metal-organic-frameworks(MOFs)derived microwave absorbers.However,most of the reported MOFs derived absorbers usually possess high filler loading.Herein...Lightweight and high-performance are two determining factors for metal-organic-frameworks(MOFs)derived microwave absorbers.However,most of the reported MOFs derived absorbers usually possess high filler loading.Herein,a series of MOFs derived magnetic porous carbon microspheres with tunable diameter and high specific surface area have been synthesized via a pyrolysis process.The synthesized magnetic porous carbon microspheres,constructed by uniformly distributed core-shell Ni@C,exhibit high-performance microwave absorption with a low filler loading of 10 wt%.Considering the mciro-mesoporous structures,matched impedance,strong conductive loss,enhanced dipolar/interfacial polarization as well as strong magnetic coupling network,a minimum reflection loss of-60 dB and an absorption bandwidth of 7.0 GHz can be achieved at 2.6 mm.Moreover,the bandwidth reaches as wide as 10.2 GHz when the thickness is 4 mm.In addition,compared with other MOFs derived absorbers,this work provides us a simple strategy for the synthesis of porous carbon microspheres with lightweight and high-performance microwave absorption for practical applications.展开更多
The design of pore structure is the key factor for the performance of porous carbon spheres.In this wo rk,novel micron-sized colloidal crystal microspheres consisting of fibrous silica(F-SiO_(2)) nanoparticles are fir...The design of pore structure is the key factor for the performance of porous carbon spheres.In this wo rk,novel micron-sized colloidal crystal microspheres consisting of fibrous silica(F-SiO_(2)) nanoparticles are firstly prepared by water-evapo ration-induced self-assembly of F-SiO_(2) nanoparticles in the droplets of an inverse emulsion system to be used as sacrificial templates.Acrylonitrile(AN) was infiltrated in the voids of the F-SiO_(2) colloidal crystal microspheres,and in-situ induced by ^(60)Co γ-ray to polymerize into polyacrylonitrile(PAN).After the PAN-infiltrated F-SiO_(2) colloidal crystal microspheres were carbonized and etched with HF solution,novel micron-sized inverse-opal N-doped carbon(IO-NC) microspheres consisting of hollow carbon nanoparticles with a hierarchical macro/meso-porous inner surface were obtained.The IO-NC microspheres have a specific surface area as high as 266.4 m^(2)/g and a molar ratio of C/N of 5.They have a good dispersibility in water,and show a high adsorption capacity towards rhodamine B(RhB) up to 137.28 mg/(g microsphe re).This work offers a way to obtain novel micron-sized hierarchical macro/meso-porous N-doped carbon microspheres,which opens a new idea to prepare high-performance hierarchical porous carbon materials.展开更多
Metal-free heteroatom doped nanocarbons are promising alternatives to the metal-based materials in catalytic ozonation for destruction of aqueous organic contaminants. In this study, N, S co-doped hollow carbon micros...Metal-free heteroatom doped nanocarbons are promising alternatives to the metal-based materials in catalytic ozonation for destruction of aqueous organic contaminants. In this study, N, S co-doped hollow carbon microspheres (NSCs) were synthesized from the polymerization products during persulfate wet air oxidation of benzothiazole. The contents of doped N and S as well as the structural stability were maneuvered by adjusting the subsequent N_(2)-annealing temperature. Compared with the prevailing single-walled carbon nanotubes, the N_(2)-annealed NSCs demonstrated a higher catalytic ozonation activity for benzimidazole degradation. According to the quantitative structure-activity relationship (QSAR) analysis, the synergistic effect between the graphitic N and the thiophene-S which redistributed the charge distribution of the carbon basal plane contributed to the activity enhancement of the N_(2)-annealed NSCs. Additionally, the hollow structure within the microspheres served as the microreactor to boost the mass transfer and reaction kinetics via the nanoconfinement effects. Quenching and electron paramagnetic resonance (EPR) tests revealed that benzimidazole degradation was dominated by the produced singlet oxygen (^(1)O_(2)) species, while hydroxyl radicals (^(·)OH) were also generated and participated. This study puts forward a novel strategy for synthesis of heteroatom-doped nanocarbons and sheds a light on the relationship between the active sites on the doped nanocarbons and the catalytic performance.展开更多
A kind of novel pitch-based activated carbon microsphere（ACM） characterized by its controlled porous structure was developed in this study,the curative effect of this ACM on diabetes mellitus in rats was investigate...A kind of novel pitch-based activated carbon microsphere（ACM） characterized by its controlled porous structure was developed in this study,the curative effect of this ACM on diabetes mellitus in rats was investigated.ACM 0.2-0.3 mm in diameter was prepared by modified method.The optimal ACM was screened by its adsorption ability for glucose.Diabetes mellitus model was established by streptozotocin injection in male Sprague-Dawley rats.Two groups of rats were orally administrated with ACM twice a day for 30 d.Intestinal glucose transport was determined in vitro using everted rat intestinal sacs technique.Compared with the diabetic mellitus group,the ACM treated group showed significant lower blood glucose level and improved glucose tolerance after two-week treatment.If ACM was applied in the mucosal side,glucose permeation clearance in the ACM treated group was significantly higher than that of the control group,especially at high glucose concentration（10 mg/mL） on the serosal side.The selected ACM possessed a BET specific surface of 1566 m^2/g and high volume of micropores（0.478 cm^3/g） with fine spherical morphology,and showed more significant adsorption capacity for glucose.As oral microsphere preparations,ACM presented the curative effect on streptozotocin-induced diabetes mellitus in rats.展开更多
Porous Fe3Odcarbon microspheres （PFCMs） were successfully fabricated via a facile electrospray method and subsequent heat treatment, using ferrous acetylacetonate, carbon nanotubes （CNTs）, Ketjen black （KB）, pol...Porous Fe3Odcarbon microspheres （PFCMs） were successfully fabricated via a facile electrospray method and subsequent heat treatment, using ferrous acetylacetonate, carbon nanotubes （CNTs）, Ketjen black （KB）, polyvinylpyrrolidone （PVP）, and polystyrene （PS） as raw materials. The porous carbon sphere framework decorated with well-dispersed CNTs and KB exhibits excellent electronic conductivity and acts as a good host to confine the Fe304 nanoparticles. The abundant mesopores in the carbon matrix derived from polymer pyrolysis can effectively accommodate the volume changes of F%O4 during the charge/ discharge process, facilitate electrolyte penetration, and promote fast ion diffusion. Moreover, a thin amorphous carbon layer on the Fe304 nanoparticle formed during polymer carbonization can further alleviate the mechanical stress associated with volume changes, and preventing aggregation and exfoliation of F%O4 nanoparticles during cycling. Therefore, as anode materials for lithium-ion batteries, the PFCMs exhibited excellent cycling stability with high specific capacities, and outstanding rate performances. After 130 cycles at a small current density of 0.1 A-g-1, the reversible capacity of the PFCM electrode is maintained at almost 1,317 mAh-g-1. High capacities of 746 and 525 mAh-g-1 were still achieved after 300 cycles at the larger currents of I and 5 A-g-1, respectively. The optimized structure design and facile fabrication process provide a promising way for the utilization of energy storage materials, which have high capacities but whose performance is hindered by large volume changes and poor electrical conductivity in lithium or sodium ion batteries.展开更多
Heteroatom doping, especially dual-doped carbon materials have attracted much attention for the past few years, and have been regarded as one of the most efficient strategies to enhance the capacitance behavior of por...Heteroatom doping, especially dual-doped carbon materials have attracted much attention for the past few years, and have been regarded as one of the most efficient strategies to enhance the capacitance behavior of porous carbon materials. In this work, a facile two-step synthetic route was developed to fab- ricate nitrogen and sulfur co-doped carbon microsphere （NSCM） by using thiourea as dopant. The NJS doping content is controlled via varying the carbonization temperature. It has been proved that a suitable quantity of N and S groups could not only provide pseudo-capacitance but also promote the electron transfer for carbon materials, which ensures the further utilization of the exposed surfaces for charge storage. The optimized NSCM prepared at a carbonization temperature of 800 ℃ （NSCM-800） achieves a capacitance of 277.1 F g^-1 at a current density of 0.3 A g^-1 in 6.0 mol L^-1 KOH electrolyte, which is 71% higher than that of undoped carbon microsphere. Besides, NSCM-800 shows an excellent cycling stability, 98.2% of the initial capacitance is retained after 5,000 cvcles at a current densitv of 3.0 A g^-1.展开更多
In this work, a series of carbon aerogel microspheres（CAMs） with tailored pore structures were successfully prepared via a sol-gel method and subsequent heat-treatment at various temperatures from 600 to 1600 ℃. Th...In this work, a series of carbon aerogel microspheres（CAMs） with tailored pore structures were successfully prepared via a sol-gel method and subsequent heat-treatment at various temperatures from 600 to 1600 ℃. The effects of heat-treatment temperature（HTT） on the CAM microstructure were systematically investigated by physical and chemical characterization. The electrical conductivity increased by up to 250 S/cm and mesopores with high electrolyte accessibility developed in the CAM with increasing HTT. However, the specific surface area（SSA） decreased for HTTs from 1000 to 1600 ℃. The results show that these two factors should be finely balanced for further applications in high power supercapacitors.The CAMs carbonized at 1000 ℃ had the highest SSA（1454 m^2/g）, large mesoporous content（20%） and favorable conductivity（71 S/cm）. They delivered a high energy density of 38.4 Wh/kg at a power density of 0.17 kW/kg. They retained an energy density of 25.5 Wh/kg even at a high power density of 10.2 kW/kg,and a good rate capability of 84% after 10,000 cycles. This performance is superior to, or at least comparable to, those of most reported carbon materials.展开更多
Supported polyamines are promising candidates for the chemical adsorption of CO_(2),the performance of which is highly dependent on the porous structure of supports.In this work,we synthesized a kind of fibrous carbon...Supported polyamines are promising candidates for the chemical adsorption of CO_(2),the performance of which is highly dependent on the porous structure of supports.In this work,we synthesized a kind of fibrous carbon microspheres(FCMs)from environmentally friendly and low-cost chitin.The synthesized FCMs have microspheric morphology and fibrous sub-architecture,and the carbon fibers interweave to form pores with large diameters.The flexibility of the pores formed by the interweaving of carbon fibers also enable the supporting of high quantity of polyamines.Given these features,pentaethylenehexamine(PEHA)was physically dispersed in the pores of FCMs to prepare PEHA/FCMs adsorbents,which were systematically characterized and investigated for CO_(2) capture performance.It is found that PEHA/FCMs adsorbents show excellent ability for CO_(2) adsorption,with the highest CO_(2) capacity of 3.90 mmol g^(-1) at 75℃ when using 10 vol%of CO_(2) for determinations.The reversibility of PEHA/FCMs adsorbents for CO_(2) adsorption is also fairly good,and PEHA/FCMs adsorbents have strong ability for the selective adsorption of low-content CO_(2) from N_(2).展开更多
Multi-walled carbon nanotubes（MWCNTs） reinforced hollow glass microspheres（HGMs）/epoxy syntactic foam was fabricated. The effects of ultrasonication on the density, compression strength, and water absorption prope...Multi-walled carbon nanotubes（MWCNTs） reinforced hollow glass microspheres（HGMs）/epoxy syntactic foam was fabricated. The effects of ultrasonication on the density, compression strength, and water absorption properties were studied. Better dispersed MWCNTs can be obtained after ultrasonication treatment, but an increasing viscosity will lead to a larger amount of voids during syntactic foam preparation especially when the content of HGMs is more than 70 vol%. The existing voids will decrease the density of epoxy syntactic foam. However, the ultrasonication does not change the compression strength much. Ultrasonication treatment will decrease the water absorption content due to the better dispersion and hydrophobic properties of MWCNTs. But a significant increase of water absorption content occurs when HGMs is more than 70 vol%, which is attributed to the higher viscosity and larger amount of voids.展开更多
Carbon-based materials have become a research hotspot in the field of energy storage devices in recent years due to their abundant resources,low cost,and environmental friendliness.However,the low capacity and poor hi...Carbon-based materials have become a research hotspot in the field of energy storage devices in recent years due to their abundant resources,low cost,and environmental friendliness.However,the low capacity and poor high rate performance still constitute great challenges.Metal organic framework-derived carbon has been widely researched because of its high porosity,tunable structure,and good conductivity.In this work,N/S codoped hierarchical porous carbon microspheres were prepared by a high-temperature heat treatment and atomic doping process using a zinc-based organic framework as the precursor.When used as a potassium-ion battery anode,it has a high reversible specific capacity(435.7 mAh g^(-1)),good rate performance(133.5 mAh g^(-1)at 10,000 m A g^(-1)),and long-term cycling stability(73.2%capacity retention after the 2500th cycle).The potassium storage mechanism of the derived carbon was explained by various electrochemical analysis methods and microstructure characterization techniques,and the relationship between the structural characteristics and electrochemical properties was researched.In a supercapacitor,the porous carbon material exhibits a specific capacitance of 307.2 F g^(-1)at a current density of 0.2 A g^(-1)in a KOH aqueous solution and achieves a retention rate of 99.88%after 10,000 cycles.The assembled symmetric supercapacitor device delivers a high energy density of 6.69 Wh kg^(-1),with a corresponding power density of 2500 W kg^(-1).In addition,density functional theory calculations further confirmed that N/S codoping can improve the adsorption capacities of potassium and hydroxyl ions in the derived carbon.展开更多
基金supported by the National Natural Science Foundation of China (31890771 and 31901249)the Young Elite Scientists Sponsorship Program by CAST (2019QNRC001)+3 种基金the Hunan Provincial Technical Innovation Platform and Talent Program in Science and Technology (2020RC3041)the Training Program for Excellent Young Innovators of Changsha (kq2106056)the Hunan Provincial Natural Science Foundation of China (2022JJ30079)the Postgraduate Technology Innovation Project of Central South University of Forestry and Technology (2022CX02017)。
文摘Carbon materials are effective substitutes for Pt counter electrodes(CEs) in dye-sensitized solar cells(DSSCs). However, many of these materials, such as carbon nanotubes and graphene, are expensive and require complex preparation process. Herein, waste lignin, recycled from hazardous black liquors,is used to create oxygen-nitrogen-sulfur codoped carbon microspheres for use in DSSC CEs through the facile process of low-temperature preoxidation and high-temperature self-activation. The large number of ester bonds formed by preoxidation increase the degree of cross-linking of the lignin chains, leading to the formation of highly disordered carbon with ample defect sites during pyrolysis. The presence of organic O/N/S components in the waste lignin results in high O/N/S doping of the pyrolysed carbon,which increases the electrolyte ion adsorption and accelerates the electron transfer at the CE/electrolyte interface, as confirmed by density functional theory(DFT) calculations. The presence of inorganic impurities enables the construction of a hierarchical micropore-rich carbon structure through the etching effect during self-activation, which can provide abundant catalytically active sites for the reversible adsorption/desorption of electrolyte ions. Under these synergistic effects, the DSSCs that use this novel carbon CE achieve a quite high power-conversion efficiency of 9.22%. To the best of our knowledge, the value is a new record reported so far for biomass-carbon-based DSSCs.
基金supported by the National Natural Science Foundation of China(Nos.21701163,21671181,21831006,and 22075268)the Fundamental Research Funds for the Central Universities(No.WK5290000003)Innovation Key Fund Project of University of Science and Technology of China(YD2060002023).
文摘With the advantages of high energy/power density,long cycling life and low cost,dual-carbon potassium ion hybrid capacitors(PIHCs)have great potential in the field of energy storage.Here,a novel bilayer-shelled N,O-doped hollow porous carbon microspheres(NOHPC)anode has been prepared by a self-template method,which is consisted of a dense thin shell and a hollow porous spherical core.Excitingly,the NOHPC anode possesses a high K-storage capacity of 325.9 mA h g^(−1)at 0.1 A g^(−1)and a capacity of 201.1 mAh g^(−1)at 5 A g^(−1)after 6000 cycles.In combination with ex situ characterizations and density functional theory calculations,the high reversible capacity has been demonstrated to be attributed to the co-doping of N/O heteroatoms and porous structure improved K+adsorption and intercalation capabilities,and the stable long-cycling performance originating from the bilayer-shelled hollow porous carbon sphere structure.Meanwhile,the hollow porous activated carbon microspheres(HPAC)cathode with a high specific surface area(1472.65 m^(2)g^(−1))deriving from etching NOHPC with KOH,contributing to a high electrochemical adsorption capacity of 71.2 mAh g^(−1)at 1 A g^(−1).Notably,the NOHPC//HPAC PIHC delivers a high energy density of 90.1 Wh kg^(−1)at a power density of 939.6 W kg^(−1)after 6000 consecutive charge-discharge cycles.
基金supported by the National Science Foundation for Excellent Young Scholars of China(21922815)the Key Research and Development(R&D)Projects of Shanxi Province(201903D121180)the National Key Research and Development(R&D)Program of China。
文摘Starch,as a typical polysaccharide with natural spherical morphology,is not only a preferred precursor for preparing carbon materials but also a model polymer for investigating thermochemical evolution mechanisms.However,starch usually suffers from severe foaming and low carbon yield during direct pyrolysis.Herein,we report a simple and eco-friendly dry strategy,by maleic anhydride initiating the esterification of starch,to design carbon microspheres against the starch foaming.Moreover,the infuence of ester grafting on the pyrolytic behavior of starch is also focused.The formation of ester groups in precursor guarantees the structural stability of starch-based intermediate because it can promote the accumulation of unsaturated species and accelerate the water elimination during pyrolysis.Meanwhile,the esterification and dehydration reactions greatly deplete the primary hydroxyl groups in the starch molecules and thus the rapid levoglucosan release is inhibited,which well keeps the spherical morphology of starch and ensures the high carbon yield.In further exploration as anode materials for Lithium-ion batteries,the obtained carbon microspheres exhibit good cyclability and rate performance with a reversible capacity of 444 m Ah g^(-1)at 50 m A g^(-1).This work provides theoretical fundamentals for the controllable thermal transformation of biomass towards wide applications.
基金supported by the National Natural Science Foundation of China (51203071, 51363014 and 51362018)China Postdoctoral Science Foundation (2014M552509)+1 种基金the Key Project of Chinese Ministry of Education (212183)the Natural Science Funds for Distinguished Young Scholars of Gansu Province (1111RJDA012)
文摘This article reported the electrochemical behaviors of a novel hollow carbon microspheres/manganese dioxide nanosheets(micro-HC/nano-MnO2) composite prepared by an in situ self-limiting deposition method under hydrothermal condition. The results of scanning electron microscopy reveal that MnO2 nanosheets homogeneously grow onto the surface of micro-HC to form a loose-packed microstructure. The quantity of MnO2 required in the electrode layer has thereby been reduced significantly, and higher specific capacitances have been achieved. The micro-HC/nano-MnO2 electrode presents a high capacitance of 239.0 F g-1 at a current density of 5 m A cm-2, which is a strong promise for high-rate electrochemical capacitive energy storage applications.
基金Fundamental Research Funds for the Central Universities,Grant/Award Number:21617330National Natural Science Foundation of China,Grant/Award Numbers:21703081,51702056,51772135Ministry of Education of the People's Republic of China,Grant/Award Number:6141A02022516。
文摘As one of the low-cost energy storage systems,Na-ion batteries(NIBs)have received tremendous attention.However,the performance of current anode materials still cannot meet the requirements of NIBs.In our work,we obtain sulfur-doped interconnected carbon microspheres(S-CSs)via a simple hydrothermal method and subsequent sulfurizing treatment.Our S-CSs exhibit an ultrahigh reversible capacity of 520 mAh g^(-1) at 100 mA g^(-1) after 50 cycles and an excellent rate capability of 257 mAh g^(-1),even at a high current density of 2 A g^(-1).The density functional theory calculations demonstrate that sulfur doping in carbon favors the adsorption of Na atom during the sodiation process,which is accountable for the performance enhancement.Furthermore,we also utilize operando Raman spectroscopy to analyze the electrochemical reaction of our S-CSs,which further highlights the sulfur doping in improving Na-ion storage performance.
基金the support of the National Natural Science Foundation of China(51603147)Tianjin application foundation and advanced technology research plan project(15ZCZDGX00270 and 14RCHZGX00859)。
文摘Nitrogen-doped lignin-based carbon microspheres are synthesized using 3-aminophenol as a nitrogen source by the hydrothermal method.The structural change and the effect on the electrochemical properties are systematically investigated. Nitrogen-doped lignin-based carbon microspheres represent well-developed spherical morphology with many active sites, ultramicroporous(< 0.7 nm) structure, and large interlayer spacing. Consistent with the obtained physical structures and properties, the nitrogen-doped carbon microspheres exhibit fast sodium ion adsorption/intercalation kinetic process and excellent electrochemical performance. For example, a reversible specific capacity of 374 m Ah g^(-1) at 25 m A g^(-1) with high initial coulombic efficiency of 85% and high capacitance retention of 90% after 300 cycles at 100 m A g^(-1) and stable charge/discharge behavior at different current density is obtained. The additional defects and abundant ultramicroporous structure can enhance sloping capacity, and large interlayer spacing is considered to be the reason for improving plateau capacity.
基金by the National Nature Science Foundation of the People’s Republic of China(No.51703153).
文摘Carbon microspheres were prepared from waste cotton fibers by hydrothermal carbonization(HTC)with the addition of copper sulphate in this work.The important influence factors,temperature,concentration of copper sulphate,resident time were explored here.The smooth and regular carbon microspheres could be formed at 330°C with 0.15 wt%copper sulphate after 6 h from waste cotton fibers.The crystal structures of cotton fibers were destructed in a short resident time with 0.15 wt%copper sulphate from SEM images and XRD patterns of solid products.This strategy provides a new,mild and efficient method to prepare carbon microspheres from waste cotton fibers by HTC.FTIR spectra verified that the abundant functional groups existed on the surface of synthesized carbon microspheres.From XPS and element analysis results,the copper sulphate participated in the forming process of carbon microspheres indeed.The presence of copper sulphate in the carbon microspheres provided a possibility for the application in antibacterial field.Besides,the catalytic mechanism of copper sulphate on the hydrolysis and carbonization of waste cotton fibers were also discussed.In conclusion,the copper sulphate is an efficient agent for preparing carbon microspheres by HTC from waste cotton fibers.
基金The authors are grateful for the financial supports of the Project of Research and Development Fund of Nanchong City(19YFZJ0107,18YFZJ0041)the Meritocracy Research Funds of China West Normal University(17YC041)the Undergraduate Training Program for Innovation of China West Normal University.(cxcy2020186).
文摘The colloidal carbon microspheres(CMS)were prepared by the hydrothermal method.The nickel catalysts supported on carbon microspheres(Ni/CMS)were further prepared and were characterized by the Fourier transform infrared spectroscopy(FTIR),the X-ray diffraction(XRD),the scanning electron microscopy(SEM),the transmission electron microscopy(TEM),and the N_(2)adsorption technique.The selective hydrogenation of maleic anhydride(MA)to succinic anhydride(SA)over the Ni/CMS catalysts was investigated.The results indicated that the Ni/CMS catalyst,which was prepared with glucose as carbon source and calcined at 500℃,exhibited the best performance.The hydrogen pressure,reaction temperature,and reaction time could significantly affect the conversion of maleic anhydride during the hydrogenation reaction.A 98.4%conversion of MA and an 100%selectivity to SA were achieved over the Ni/CMS catalyst in acetic anhydride solvent under mild conditions covering a temperature of 90℃,a H2 pressure of 1.0 MPa,and a reaction time of 3 h.
基金supported by the National Natural Science Foundation of China(21905152 and 52302273)the Youth Innovation Team Project for Talent Introduction and Cultivation in Universities of Shandong Province+2 种基金the Taishan Scholar Project of Shandong Province of China(tsqn202211160 and tsqn202312199)the China Postdoctoral Science Foundation(2022M713249)the Shandong Provincial Natural Science Foundation of China(ZR2023QE176)。
文摘Carbon-based anode materials are widely used in various battery energy storage systems due to their low cost,wide source,high conductivity and easy morphology control.However,current commercially available anode materials as active materials for lithium-/sodium-ion batteries generally suffer from large volume changes and poor rate performance.In response,we synthesized defect-rich N,S co-doped two dimensional(2D)nanosheet-assembled porous carbon microspheres(N,S-PCS)via simple hydrothermal,carbonization and etching process based on the principle of Schiff base reaction.The N,S-PCS structure is thus constructed by removing Fe7S8 nanoparticles from the carbon skeleton to form porous microspheres with N,S doping.Therefore,the micromorphology characteristic,pore structure and electroconductivity of carbon materials are effectively optimized via heteroatom doping and surface engineering.As expected,the prepared N,S-PCS electrodes exhibit excellent electrochemical performance in both lithium-ion and sodium-ion batteries.For lithium-ion batteries,it achieves reversible capacities of 1045 and 237 mAh g^(-1) at 0.1 and 20 A g^(-1),respectively.For sodium-ion batteries,it shows good cycling stability with a capacity of 157 mAh g^(-1) after 500 cycles at 1 A g^(-1).Experimental and theoretical calculation results confirm that the N,S co-doping strategies help to improve the structural stability,shorten the ion diffusion paths,and promote the reaction kinetics,thus achieving excellent electrochemical performance.This work is instructive for the practical application of nonmetal doping functionalized porous carbon structures for metal-ion batteries.
基金supported financially by the Fundamental Research Funds for the Central Universities(Grant No.2021QN1044)the Natural Science Foundation Project of Ningxia(Grant No.2022AC03764)+1 种基金State Key Laboratory of High-efficiency Utilization of Coal and Green Chem-ical Engineering(Grant No.2021-K06)The key R&D projects of Ningxia(Talent special)(Grant No.2021BEB04083).
文摘The basic structure of aromatic compounds that are abundant in coal is the carbonaceous precursor derived from carbon microspheres.However,it remains to be a huge challenge to prepare carbon microspheres using coal due to the complex construction and composition of coal.Herein,a simple and viable way to obtain coal-based microporous carbon microspheres was developed by means of ethanol pyrolysis and a sequential extraction strategy.The as-prepared carbon microsphere featured aspherical micron particles of a uniform size(0.6-1.6㎛),abundant O-functional groups,excellent thermal stability,high SBET(415.5-983.2 m^(2)/g),and plentiful ultra-micropores(63.15-72.72%).The coal-based carbon microsphere exhibited a noteworthy CO_(2)uptake(3.19-4.97 mmol/g at 273 K and 1.0 bar),acceptable CO_(2)/N_(2)selectivity(IAST:23-46)and moderate isosteric heats(20-32 kJ/mol).This synthetic strategy is important for the preparation of ultramicroporous carbon microspheres using coal,and the synthetic carbon microspheres have promising prospects for highly efficient CO_(2)capture.
基金financially supported by the Fundamental Research Funds for the Central Universities(310201911cx037)the Shanghai Key Laboratory of R&D for Metallic Functional Materials(2021-01)the seed Foundation of Innovation and Creation for Graduate Students in Northwestern Polytechnical University(CX2020210)。
文摘Lightweight and high-performance are two determining factors for metal-organic-frameworks(MOFs)derived microwave absorbers.However,most of the reported MOFs derived absorbers usually possess high filler loading.Herein,a series of MOFs derived magnetic porous carbon microspheres with tunable diameter and high specific surface area have been synthesized via a pyrolysis process.The synthesized magnetic porous carbon microspheres,constructed by uniformly distributed core-shell Ni@C,exhibit high-performance microwave absorption with a low filler loading of 10 wt%.Considering the mciro-mesoporous structures,matched impedance,strong conductive loss,enhanced dipolar/interfacial polarization as well as strong magnetic coupling network,a minimum reflection loss of-60 dB and an absorption bandwidth of 7.0 GHz can be achieved at 2.6 mm.Moreover,the bandwidth reaches as wide as 10.2 GHz when the thickness is 4 mm.In addition,compared with other MOFs derived absorbers,this work provides us a simple strategy for the synthesis of porous carbon microspheres with lightweight and high-performance microwave absorption for practical applications.
基金supported by the National Natural Science Foundation of China (Nos.51573174,51773189 and 51973205)Science Challenge Project (No.TZ2018004)the Fundamental Research Funds for the Central Universities (No.WK3450000004)。
文摘The design of pore structure is the key factor for the performance of porous carbon spheres.In this wo rk,novel micron-sized colloidal crystal microspheres consisting of fibrous silica(F-SiO_(2)) nanoparticles are firstly prepared by water-evapo ration-induced self-assembly of F-SiO_(2) nanoparticles in the droplets of an inverse emulsion system to be used as sacrificial templates.Acrylonitrile(AN) was infiltrated in the voids of the F-SiO_(2) colloidal crystal microspheres,and in-situ induced by ^(60)Co γ-ray to polymerize into polyacrylonitrile(PAN).After the PAN-infiltrated F-SiO_(2) colloidal crystal microspheres were carbonized and etched with HF solution,novel micron-sized inverse-opal N-doped carbon(IO-NC) microspheres consisting of hollow carbon nanoparticles with a hierarchical macro/meso-porous inner surface were obtained.The IO-NC microspheres have a specific surface area as high as 266.4 m^(2)/g and a molar ratio of C/N of 5.They have a good dispersibility in water,and show a high adsorption capacity towards rhodamine B(RhB) up to 137.28 mg/(g microsphe re).This work offers a way to obtain novel micron-sized hierarchical macro/meso-porous N-doped carbon microspheres,which opens a new idea to prepare high-performance hierarchical porous carbon materials.
基金financial supports from the National Natural Science Foundation of China (No21978324)Tianjin Municipal Science and Technology Bureau (No.18YFYSZ00170)+1 种基金Beijing Natural Science Foundation (No. 8192039)Science Foundation of China University of Petroleum,Beijing(No. 2462020YXZZ034)。
文摘Metal-free heteroatom doped nanocarbons are promising alternatives to the metal-based materials in catalytic ozonation for destruction of aqueous organic contaminants. In this study, N, S co-doped hollow carbon microspheres (NSCs) were synthesized from the polymerization products during persulfate wet air oxidation of benzothiazole. The contents of doped N and S as well as the structural stability were maneuvered by adjusting the subsequent N_(2)-annealing temperature. Compared with the prevailing single-walled carbon nanotubes, the N_(2)-annealed NSCs demonstrated a higher catalytic ozonation activity for benzimidazole degradation. According to the quantitative structure-activity relationship (QSAR) analysis, the synergistic effect between the graphitic N and the thiophene-S which redistributed the charge distribution of the carbon basal plane contributed to the activity enhancement of the N_(2)-annealed NSCs. Additionally, the hollow structure within the microspheres served as the microreactor to boost the mass transfer and reaction kinetics via the nanoconfinement effects. Quenching and electron paramagnetic resonance (EPR) tests revealed that benzimidazole degradation was dominated by the produced singlet oxygen (^(1)O_(2)) species, while hydroxyl radicals (^(·)OH) were also generated and participated. This study puts forward a novel strategy for synthesis of heteroatom-doped nanocarbons and sheds a light on the relationship between the active sites on the doped nanocarbons and the catalytic performance.
基金The Ministry of Science and Technology of the People’s Republic of China (Contract No. 2010DFA44300)Shanghai Committee of Science and Technology (Grant No.10DZ2220500 and 11DZ2260600)
文摘A kind of novel pitch-based activated carbon microsphere（ACM） characterized by its controlled porous structure was developed in this study,the curative effect of this ACM on diabetes mellitus in rats was investigated.ACM 0.2-0.3 mm in diameter was prepared by modified method.The optimal ACM was screened by its adsorption ability for glucose.Diabetes mellitus model was established by streptozotocin injection in male Sprague-Dawley rats.Two groups of rats were orally administrated with ACM twice a day for 30 d.Intestinal glucose transport was determined in vitro using everted rat intestinal sacs technique.Compared with the diabetic mellitus group,the ACM treated group showed significant lower blood glucose level and improved glucose tolerance after two-week treatment.If ACM was applied in the mucosal side,glucose permeation clearance in the ACM treated group was significantly higher than that of the control group,especially at high glucose concentration（10 mg/mL） on the serosal side.The selected ACM possessed a BET specific surface of 1566 m^2/g and high volume of micropores（0.478 cm^3/g） with fine spherical morphology,and showed more significant adsorption capacity for glucose.As oral microsphere preparations,ACM presented the curative effect on streptozotocin-induced diabetes mellitus in rats.
文摘Porous Fe3Odcarbon microspheres （PFCMs） were successfully fabricated via a facile electrospray method and subsequent heat treatment, using ferrous acetylacetonate, carbon nanotubes （CNTs）, Ketjen black （KB）, polyvinylpyrrolidone （PVP）, and polystyrene （PS） as raw materials. The porous carbon sphere framework decorated with well-dispersed CNTs and KB exhibits excellent electronic conductivity and acts as a good host to confine the Fe304 nanoparticles. The abundant mesopores in the carbon matrix derived from polymer pyrolysis can effectively accommodate the volume changes of F%O4 during the charge/ discharge process, facilitate electrolyte penetration, and promote fast ion diffusion. Moreover, a thin amorphous carbon layer on the Fe304 nanoparticle formed during polymer carbonization can further alleviate the mechanical stress associated with volume changes, and preventing aggregation and exfoliation of F%O4 nanoparticles during cycling. Therefore, as anode materials for lithium-ion batteries, the PFCMs exhibited excellent cycling stability with high specific capacities, and outstanding rate performances. After 130 cycles at a small current density of 0.1 A-g-1, the reversible capacity of the PFCM electrode is maintained at almost 1,317 mAh-g-1. High capacities of 746 and 525 mAh-g-1 were still achieved after 300 cycles at the larger currents of I and 5 A-g-1, respectively. The optimized structure design and facile fabrication process provide a promising way for the utilization of energy storage materials, which have high capacities but whose performance is hindered by large volume changes and poor electrical conductivity in lithium or sodium ion batteries.
基金supported by the National Natural Science Foundation of China(21306060,21573083)the Program for New Century Excellent Talents in Universities of China(NCET-13-0237)+3 种基金the Doctoral Fund of Ministry of Education of China(20130142120039)the Thousand Talents Plan,and the Initiatory Financial Support from Huazhong University of Science and Technology(HUST)Analytical and Testing Center of Huazhong University of Science and Technologythe support of the China Scholarship Council(CSC)
文摘Heteroatom doping, especially dual-doped carbon materials have attracted much attention for the past few years, and have been regarded as one of the most efficient strategies to enhance the capacitance behavior of porous carbon materials. In this work, a facile two-step synthetic route was developed to fab- ricate nitrogen and sulfur co-doped carbon microsphere （NSCM） by using thiourea as dopant. The NJS doping content is controlled via varying the carbonization temperature. It has been proved that a suitable quantity of N and S groups could not only provide pseudo-capacitance but also promote the electron transfer for carbon materials, which ensures the further utilization of the exposed surfaces for charge storage. The optimized NSCM prepared at a carbonization temperature of 800 ℃ （NSCM-800） achieves a capacitance of 277.1 F g^-1 at a current density of 0.3 A g^-1 in 6.0 mol L^-1 KOH electrolyte, which is 71% higher than that of undoped carbon microsphere. Besides, NSCM-800 shows an excellent cycling stability, 98.2% of the initial capacitance is retained after 5,000 cvcles at a current densitv of 3.0 A g^-1.
基金supported by the National Natural Science Foundation of China (51402324, 51002166 and 51402325)
文摘In this work, a series of carbon aerogel microspheres（CAMs） with tailored pore structures were successfully prepared via a sol-gel method and subsequent heat-treatment at various temperatures from 600 to 1600 ℃. The effects of heat-treatment temperature（HTT） on the CAM microstructure were systematically investigated by physical and chemical characterization. The electrical conductivity increased by up to 250 S/cm and mesopores with high electrolyte accessibility developed in the CAM with increasing HTT. However, the specific surface area（SSA） decreased for HTTs from 1000 to 1600 ℃. The results show that these two factors should be finely balanced for further applications in high power supercapacitors.The CAMs carbonized at 1000 ℃ had the highest SSA（1454 m^2/g）, large mesoporous content（20%） and favorable conductivity（71 S/cm）. They delivered a high energy density of 38.4 Wh/kg at a power density of 0.17 kW/kg. They retained an energy density of 25.5 Wh/kg even at a high power density of 10.2 kW/kg,and a good rate capability of 84% after 10,000 cycles. This performance is superior to, or at least comparable to, those of most reported carbon materials.
基金This work was supported by the National Natural Science Foundation of China(22008033 and 32060577)the Natural Science Foundation of Jiangxi Province(20192ACB21016).
文摘Supported polyamines are promising candidates for the chemical adsorption of CO_(2),the performance of which is highly dependent on the porous structure of supports.In this work,we synthesized a kind of fibrous carbon microspheres(FCMs)from environmentally friendly and low-cost chitin.The synthesized FCMs have microspheric morphology and fibrous sub-architecture,and the carbon fibers interweave to form pores with large diameters.The flexibility of the pores formed by the interweaving of carbon fibers also enable the supporting of high quantity of polyamines.Given these features,pentaethylenehexamine(PEHA)was physically dispersed in the pores of FCMs to prepare PEHA/FCMs adsorbents,which were systematically characterized and investigated for CO_(2) capture performance.It is found that PEHA/FCMs adsorbents show excellent ability for CO_(2) adsorption,with the highest CO_(2) capacity of 3.90 mmol g^(-1) at 75℃ when using 10 vol%of CO_(2) for determinations.The reversibility of PEHA/FCMs adsorbents for CO_(2) adsorption is also fairly good,and PEHA/FCMs adsorbents have strong ability for the selective adsorption of low-content CO_(2) from N_(2).
基金Funded by the National Natural Science Foundation of China(Nos.51301029 and 51375071)the Fundamental Research Funds for the Central Universities(No.DUT17RC(3)012)
文摘Multi-walled carbon nanotubes（MWCNTs） reinforced hollow glass microspheres（HGMs）/epoxy syntactic foam was fabricated. The effects of ultrasonication on the density, compression strength, and water absorption properties were studied. Better dispersed MWCNTs can be obtained after ultrasonication treatment, but an increasing viscosity will lead to a larger amount of voids during syntactic foam preparation especially when the content of HGMs is more than 70 vol%. The existing voids will decrease the density of epoxy syntactic foam. However, the ultrasonication does not change the compression strength much. Ultrasonication treatment will decrease the water absorption content due to the better dispersion and hydrophobic properties of MWCNTs. But a significant increase of water absorption content occurs when HGMs is more than 70 vol%, which is attributed to the higher viscosity and larger amount of voids.
基金supported by the National Natural Science Foundation of China (51764029, 52004116)the National Key Research and Development Program of China (2019YFC1803501)+1 种基金the Applied Basic Research Plan of Yunnan Province(202001AU070039, 2018FB087)the Science Research Foundation of Yunnan Provincial Department of Education (2020J0070)
文摘Carbon-based materials have become a research hotspot in the field of energy storage devices in recent years due to their abundant resources,low cost,and environmental friendliness.However,the low capacity and poor high rate performance still constitute great challenges.Metal organic framework-derived carbon has been widely researched because of its high porosity,tunable structure,and good conductivity.In this work,N/S codoped hierarchical porous carbon microspheres were prepared by a high-temperature heat treatment and atomic doping process using a zinc-based organic framework as the precursor.When used as a potassium-ion battery anode,it has a high reversible specific capacity(435.7 mAh g^(-1)),good rate performance(133.5 mAh g^(-1)at 10,000 m A g^(-1)),and long-term cycling stability(73.2%capacity retention after the 2500th cycle).The potassium storage mechanism of the derived carbon was explained by various electrochemical analysis methods and microstructure characterization techniques,and the relationship between the structural characteristics and electrochemical properties was researched.In a supercapacitor,the porous carbon material exhibits a specific capacitance of 307.2 F g^(-1)at a current density of 0.2 A g^(-1)in a KOH aqueous solution and achieves a retention rate of 99.88%after 10,000 cycles.The assembled symmetric supercapacitor device delivers a high energy density of 6.69 Wh kg^(-1),with a corresponding power density of 2500 W kg^(-1).In addition,density functional theory calculations further confirmed that N/S codoping can improve the adsorption capacities of potassium and hydroxyl ions in the derived carbon.
