An activated carbon with ash content less than 10% and specific surface area more than 1 600 m 2 /g was prepared from coal and the effect of K containing compounds in preparation of coal based activated carbon was inv...An activated carbon with ash content less than 10% and specific surface area more than 1 600 m 2 /g was prepared from coal and the effect of K containing compounds in preparation of coal based activated carbon was investigated in detail in this paper. KOH was used in co carbonization with coal, changes in graphitic crystallites in chars derived from carbonization of coal with and without KOH were analyzed by X ray diffraction (XRD) technique, activation rates of chars with different contents of K containing compounds were deduced, and resulting activated carbons were characterized by nitrogen adsorption isotherms at 77 K and iodine numbers. The results showed that the addition of KOH to the coal before carbonization can realize the intensive removal of inorganic matters from chars under mild conditions, especially the efficient removal of dispersive quartz, an extremely difficult separated mineral component in other processes else. Apart from this, KOH demonstrates a favorable effect in control over coal carbonization with the goal to form nongraphitizable isotropic carbon precursor, which is a necessary prerequisite for the formation and development of micro pores. However, the K containing compounds such as K 2 CO 3 and K 2 O remaining in chars after carbonization catalyze the reaction between carbon and steam in activation, which leads to the formation of macro pores. In the end an innovative method, in which KOH is added to coal before carbonization and K containing compounds are removed by acid washing after carbonization, was proposed for the synthesis of quality coal based activated carbon.展开更多
Zirconia-ceria mixed oxide powders were prepared by high temperature aging method.The effects of the temperature and the time of aging, cerium content and calcination on powder performance were studied.The result show...Zirconia-ceria mixed oxide powders were prepared by high temperature aging method.The effects of the temperature and the time of aging, cerium content and calcination on powder performance were studied.The result shows that high temperature aging is an efficient way of preparation of ZrO2-CeO2 mixed oxide powders with high specific surface area and good thermal stability, and that addition of a small amount of cerium to hydrous zirconia can promote the preparation of high specific surface area powders.展开更多
More than 500 datasets from the literature have been used to evaluate the relationships of specific surface area (SSA),cation exchange capacity (CEC) and activity versus the liquid limit (LL).The correlations gave R^2...More than 500 datasets from the literature have been used to evaluate the relationships of specific surface area (SSA),cation exchange capacity (CEC) and activity versus the liquid limit (LL).The correlations gave R^2 values ranging between 0.71 and 0.92.Independent data were also used to validate the correlations.Estimated SSA values slightly overestimate the measured SSA up to 100 m^2/g.Regarding the estimated CEC values,they overestimated the measured CEC values up to 20 meq/(100 g).A probabilistic approach was performed for the correlations of SSA,CEC and activity versus LL.The analysis shows that the relations of SSA,CEC and activity with LL are robust.Using the LL values,it is possible to assess other basic engineering properties of clays.展开更多
New energy sources that reduce the volume of harmful gases such as SO_(x)and NO_(x)released into the atmosphere are in constant development.Natural gas,primarily made up of methane,is being widely used as one reliable...New energy sources that reduce the volume of harmful gases such as SO_(x)and NO_(x)released into the atmosphere are in constant development.Natural gas,primarily made up of methane,is being widely used as one reliable energy source for heating and electricity generation due to its high combustion value.Currently,natural gas accounts for a large portion of electricity generation and chemical feedstock in manufacturing plastics and other commercially important organic chemicals.In the near future,natural gas will be widely used as a fuel for vehicles.Therefore,a practical storage device for its storage and transportation is very beneficial to the deployment of natural gas as an energy source for new technologies.In this tutorial review,biomaterials-based carbon monoliths(CMs),one kind of carbonaceous material,was reviewed as an adsorbent for natural gas(methane)adsorption and storage.展开更多
Potassium-ion hybrid capacitors(PIHCs)are widely regarded as highly promising energy storage devices,due to their exceptional energy density,impressive power density,and abundant potassium resources.Unfortunately,rest...Potassium-ion hybrid capacitors(PIHCs)are widely regarded as highly promising energy storage devices,due to their exceptional energy density,impressive power density,and abundant potassium resources.Unfortunately,restricted by the inherent capacitive storage mechanism,the carbon cathodes possess a much lower specific capacity than battery-type anodes.Therefore,designing high-performance carbon cathodes is extremely urgent for the development of PIHCs.Herein,N,O codoped porous carbon(NOPC)was fabricated through the NaCl hard template method and combined KOH/melamine chemical activation technique,displaying the characteristics of abundant N/O content(4.7 at%/16.9 at%),ultrahigh specific surface area(3092 m^(2)g^(-1))and hierarchical pore network.The designed NOPC cathode delivers a high specific capacity(164.4 mAh.g^(-1)at 0.05 A.g^(-1))and superior cyclability(95.1%retention ratio at 2 A·g^(-1)over 2500 cycles).Notably,the adjustable ratio of micropores to mesopores facilitates the achievement of the optimal bal-ance between capacity and rate capability.Moreover,the pseudocapacitance can be further augmented through the incorporation of N/O functional groups.As expected,the graphite//NOPC based PIHC possesses a high energy density of 113 Wh·kg-at 747 W·kg^(-1)and excellent capacity retention of 84.4% fter 400 cycles at 1.0 A·g^(-1).This work introduces a novel strategy for designing carbon cathodes that enhances the electrochemical performance of PIHCs.展开更多
The chemical compositions of the sludge after treatment are tested by fully chemical analysis techniques. Its crystalline phase structure changes of the sludge calcined at different temperature are characterized by XR...The chemical compositions of the sludge after treatment are tested by fully chemical analysis techniques. Its crystalline phase structure changes of the sludge calcined at different temperature are characterized by XRD method. Nitrogen gas isothermal adsorption method (77 K) is applied to measure the influences of ammonium bicarbonate on specific surface area and pore structure of activated alumina synthesized from waste aluminum sludge. The result shows that the amount of Al2O3 in the sludge accounts for more than 94%, and Na2Owt% in a 0.1-0.2% range. By calcining raw sludge at 600℃, monophase γ-Al2O3 is obtained. And this can satisfy the performance requirements of activated alumina adsorbent. The specific surface area of the specimen with NH4HCO3 added has expanded from 179 to 249 m^2/g and the pore volume from 0.25 to 1.11 cm^3/g as well as the average pore diameter from 5.6 to 17.8 nm. All these show that NH4HCO3 is an effective pore-expansion agent to remarkably improve the structure and performance of activated alumina synthesized from waste aluminum sludge.展开更多
The viscose rayon was pretreated with four different pre-treatment reagents respectively, and the preparation ofactivated carbon fibers (ACF) was performed undersame carbonizing and activating conditions. The poresize...The viscose rayon was pretreated with four different pre-treatment reagents respectively, and the preparation ofactivated carbon fibers (ACF) was performed undersame carbonizing and activating conditions. The poresize distribution, the specific surface area, and the porestructure parameter of these viscose - based ACF werestudied by using quartz spring balance BET- weightmethod. The experiment result indicates that the poresize distribution and the pore structure parameter ofACF is varied by using different pretreatment reagents.展开更多
Fe/C-based magnetically activated carbon(MAC) was obtained by carbonizing and activating its precursor, that was prepared by co-precipitation of anthracite coal impregnated in ferric chloride solution. The effect of t...Fe/C-based magnetically activated carbon(MAC) was obtained by carbonizing and activating its precursor, that was prepared by co-precipitation of anthracite coal impregnated in ferric chloride solution. The effect of the concentrations of FeCl3 and pH of solution on BET surface area, pore volume and magnetic properties of the MAC was studied by BET N2 adsorption and VSM method. The results indicated that the magnetization of MAC gradually increases with increasing concentration of FeCl3 and pH value of solution, and BET surface area was inclined to fluctuation. The largest BET surface area and magnetization of MAC were 1327.5 m2/g and 35.56 emu/g, respectively. The form of magnetic matter in the magnetically activated carbon was mainly Fe3C by X-ray powder diffraction(XRD) and magnetic attraction test.展开更多
In this work,a facile"carbonization-activation"strategy is developed to synthesize N,P-codoped hierarchical porous carbon.Phosphoric acid is innovatively introduced during the hydrothermal process to achieve...In this work,a facile"carbonization-activation"strategy is developed to synthesize N,P-codoped hierarchical porous carbon.Phosphoric acid is innovatively introduced during the hydrothermal process to achieve in-situ P doping as well as create abundant pores,and the employment of sodamide is of vital importance to simultaneously serve as activating agent and N-source to succeed a high-level N doping.Thus,the obtained samples exhibit a unique three-dimensional hierarchical structure with an ultra-high specific surface area(3646 m^(2)g^(-1))and ultra-high N-doping level(9.81 at.%).Computational analyses confirm that N,P co-doping and higher N content can enhance active sites and widen potential differences of carbon materials to improve their capacitance.The as-prepared carbon materials demonstrate superior electrochemical performances,such as an ultra-high capacitance of 586 Fg^(-1)at 1 Ag^(-1),a superior rate capability of 409 Fg^(-1)at 20 Ag^(-1),and excellent long-term stability of 97%capacitance retention after10,000 cycles in 6 M KOH.Moreover,an assembled symmetric supercapacitor delivers a high energy density of 28.1 Wh kg^(-1)at the power density of 450 W kg^(-1)in 1 M Na_(2)SO_(4),demonstrating a great potential for applications in supercapacitors.展开更多
A facile synthesis procedure is proposed to prepare homogeneous Zr and Ti co-doped SBA-15(Zr-Ti-SBA-15)with high specific surface area of 876.0m2 g−1.Based on“masking mechanism”from tanning,lactic acid was used as m...A facile synthesis procedure is proposed to prepare homogeneous Zr and Ti co-doped SBA-15(Zr-Ti-SBA-15)with high specific surface area of 876.0m2 g−1.Based on“masking mechanism”from tanning,lactic acid was used as masking agent to obtain the uniform distribution of Zr and Ti species in the SBA-15 framework.The obtained materials were characterized by powder X-ray diffraction(XRD),nitrogen adsorption-desorption isotherms,scanning electron microscope(SEM),transmission electron microscope(TEM)and X-ray photoelectron(XPS).The results reveal that in mesoporous materials,the presence of lactic acid gives rise to the uniform distribution of Zr and Ti species.The adsorption equilibrium and kinetic studies of Zr-Ti-SBA-15 materials show that the adsorption process conforms to the Langmuir isotherm and pseudo-second-order kinetic model,respectively.Regenerational experiments show that the Zr-Ti-SBA-15 displays a significant adsorption ability for methylene blue(MB)(up to 291.6 mg/g),along with good reusability,indicating promising potentials of commercialization.Methodologically,this work provides a wide range of possibilities for further development of SBA-15 based on bimetallic and sewage disposal.展开更多
Effect of activated carbon and electrolyte on electrochemical properties of organic supercapacitor was investigated. The results show that specific surface area and mesoporosity of activated carbon influence specific ...Effect of activated carbon and electrolyte on electrochemical properties of organic supercapacitor was investigated. The results show that specific surface area and mesoporosity of activated carbon influence specific capacitance. If specific surface area is larger and mesoporosity is higher, the specific capacitance will become bigger. Specific surface area influences resistance of carbon electrode and consequently influences power property and pore size distribution. If specific surface area is smaller and mesoporosity is higher, the power property will become better. Ash influences leakage current and electrochemical cycling stability. If ash content is lower, the performance will become better. The properties of supercapacitor highly depend on the electrolyte. The compatibility of electrolyte and activated carbon is a determining factor of supercapacitor’s working voltage. LiPF6/(EC+EMC+DMC) is inappropriate for double layer capacitor. MeEt3NPF4/PC has higher specific capacitance than Et4NPF4/PC because methyl’s electronegativity value is lower than ethyl and MeEt3N+ has more positive charges and stronger polarizability than Et4N+ when an ethyl is substituted by methyl.展开更多
An improved biosorbent of thiourea modified chitosan microsphere(TMCM) with high specific surface,favorable mechanical strength and excellent adsorption performance had been synthesized via microfluidic technology. ...An improved biosorbent of thiourea modified chitosan microsphere(TMCM) with high specific surface,favorable mechanical strength and excellent adsorption performance had been synthesized via microfluidic technology. Polyethylene glycol was used as a significant component added in aqueous solution of chitosan to produce such microspheres through droplets forming, chemical crosslinking and pores creating. For the improvement of adsorption capacity, thiourea was considered as an excellent choice in increasing amino functional group by graft modification. The SEM, FTIR and EDS were employed to detect distinct features of TMCM. Copper(Ⅱ) was used to test the adsorption performance of TMCM. The experimental results indicated that TMCM exhibited higher adsorption capacity(q_e= 60.6 mg g_(-1)) and faster adsorption rate than that non-modified chitosan microsphere(NMCM).The adsorption kinetic was described well by the pseudo-second order kinetic model, which suggested that chemical adsorption along with electrons transferring was dominant in adsorption process.展开更多
Orderly mesoporous CuFe2O4spinel-type mixed oxide with high specific surface area was prepared successfully by a hard-template method in which KIT-6mesoporous silica was selected as the hard template.The KIT-6 hard te...Orderly mesoporous CuFe2O4spinel-type mixed oxide with high specific surface area was prepared successfully by a hard-template method in which KIT-6mesoporous silica was selected as the hard template.The KIT-6 hard template and CuFe2O4samples were characterized by X-ray diffraction,X-ray photoelectron spectroscopy,X-ray fluorescence,transmission electron microscopy,scanning electron microscopy,nitrogen physisorption,and hydrogen-temperature programmed reduction.The KIT-6 hard template had perfect crystallization and ordered mesoporous structure with a probable pore distribution of about 9.1 nm,large enough to be filled by the spinel precursor.The mesoporous CuFe2O4spinel oxide synthesized inside the KIT-6 mesopores had a relatively small pore size(4.3 nm),orderly arrangement,and high specific area(194 m2/g).The catalytic activity of the mesoporous CuFe2O4was tested for the selective oxidation of ammonia to nitrogen.The conversion of ammonia reached nearly 100%at 300°C with a nitrogen selectivity as high as 96%.The nitrogen selectivity remained high with increasing temperature and even maintained a value of80%at 600°C.展开更多
Activated carbon aerogels(ACAs) derived from sol-gel polycondensation of resorcinol (R) and formaldehyde (F) were pyrolyzed under Ar flow and activated in CO2 atmosphere. The morphology of ACAs was characterized...Activated carbon aerogels(ACAs) derived from sol-gel polycondensation of resorcinol (R) and formaldehyde (F) were pyrolyzed under Ar flow and activated in CO2 atmosphere. The morphology of ACAs was characterized by scanning electron microscopy (SEM) and the structural properties were determined by N2 adsorption at 77 K. The results show that ACAs have a typical three-dimensional nanonetwork structure composing of cross-linking of carbon nanoparticles. The specific surface area and the total pore volume remarkably increase with increasing activation time while the previous porous structure still remains. The specific capacitance of the 950-10-ACA electrode can reach up to 212.3 F/g in 6 mol/L KOH electrolyte. The results of constant-current charge-discharge testing indicate that the ACAs electrodes present fast charge- discharge rate and long cycle life (about 98% capacitance retained after 3000 charge-discharge cycles at 1.25 mA/cm2). Lower internal resistances can be achieved for 950-10-ACA electrode in KOH electrolyte. Our investigations are very important to improve the wettability and electrochemical performance of electrode for supercapacitors.展开更多
The catalytic pyrolyses of rayon have been studied respectively by thermo-gravimetric analysis (TGA) when rayon was treated with phosphoric acid (PA), three ammonium phosphate salts and ammonium sulfate (AS). The air ...The catalytic pyrolyses of rayon have been studied respectively by thermo-gravimetric analysis (TGA) when rayon was treated with phosphoric acid (PA), three ammonium phosphate salts and ammonium sulfate (AS). The air is favorable to the catalysis of dibasic ammonium phosphate (DAP), but not to those of ADP, PA, AP, and AS obviously. It is put forward that a peak’s shape character can be described with the ratio of height to half-height-width (H/W /2) of the peak on a differential thermo-gravimetric (DTG) curve. A flat cracking peak, presenting a more moderate dehydration reaction, has a smaller ratio and could lead to higher carbonization and activation yields. The experimental results prove this view. According to expectation, the order of catalysis is: DAP≥ADP>PA> APAS no catalyst.展开更多
A high-surface-area carbon (KC-1) was prepared from waste polystyrene-based ion exchange resin by KOH activation and used for naphthalene adsorption. The carbon exhibited a good hydrophobic nature with developed por...A high-surface-area carbon (KC-1) was prepared from waste polystyrene-based ion exchange resin by KOH activation and used for naphthalene adsorption. The carbon exhibited a good hydrophobic nature with developed porous structure, favoring the adsorption of organic compounds. The Brunauer-Emmett-Teller surface area and total pore volume of KC- 1 were 3442.2 and 1.68 cm3/g, respectively, which can be compared with those of KOH-activated carbons prepared from other precursors. Batch experiments were carded out to investigate the adsorption of naphthalene onto KC-1. The equilibrium data were analyzed by the Langmuir, Freundlich, and Polanyi- Manes isotherms and agreed with the Polanyi-Manes Model. The adsorption of naphthalene depended greatly on the porosity of the carbon, and the dispersive interactions between naphthalene and carbon could be relatively weak. The pH variation in aqueous solution had little effect on the adsorption process. The equilibrium time for 0.04 g/L of carbon dose was around 5 hr. Different models were used to evaluate the kinetic data and the pseudo second-order model was suitable to describe the kinetic process of naphthalene adsorption onto KC-1. Regeneration of spent carbon could be carded out effectively by alcohol treatment. The results indicated that KC-1 was a promising adsorbent for the removal of polycyclic aromatic hydrocarbons from aqueous solutions.展开更多
文摘An activated carbon with ash content less than 10% and specific surface area more than 1 600 m 2 /g was prepared from coal and the effect of K containing compounds in preparation of coal based activated carbon was investigated in detail in this paper. KOH was used in co carbonization with coal, changes in graphitic crystallites in chars derived from carbonization of coal with and without KOH were analyzed by X ray diffraction (XRD) technique, activation rates of chars with different contents of K containing compounds were deduced, and resulting activated carbons were characterized by nitrogen adsorption isotherms at 77 K and iodine numbers. The results showed that the addition of KOH to the coal before carbonization can realize the intensive removal of inorganic matters from chars under mild conditions, especially the efficient removal of dispersive quartz, an extremely difficult separated mineral component in other processes else. Apart from this, KOH demonstrates a favorable effect in control over coal carbonization with the goal to form nongraphitizable isotropic carbon precursor, which is a necessary prerequisite for the formation and development of micro pores. However, the K containing compounds such as K 2 CO 3 and K 2 O remaining in chars after carbonization catalyze the reaction between carbon and steam in activation, which leads to the formation of macro pores. In the end an innovative method, in which KOH is added to coal before carbonization and K containing compounds are removed by acid washing after carbonization, was proposed for the synthesis of quality coal based activated carbon.
文摘Zirconia-ceria mixed oxide powders were prepared by high temperature aging method.The effects of the temperature and the time of aging, cerium content and calcination on powder performance were studied.The result shows that high temperature aging is an efficient way of preparation of ZrO2-CeO2 mixed oxide powders with high specific surface area and good thermal stability, and that addition of a small amount of cerium to hydrous zirconia can promote the preparation of high specific surface area powders.
文摘More than 500 datasets from the literature have been used to evaluate the relationships of specific surface area (SSA),cation exchange capacity (CEC) and activity versus the liquid limit (LL).The correlations gave R^2 values ranging between 0.71 and 0.92.Independent data were also used to validate the correlations.Estimated SSA values slightly overestimate the measured SSA up to 100 m^2/g.Regarding the estimated CEC values,they overestimated the measured CEC values up to 20 meq/(100 g).A probabilistic approach was performed for the correlations of SSA,CEC and activity versus LL.The analysis shows that the relations of SSA,CEC and activity with LL are robust.Using the LL values,it is possible to assess other basic engineering properties of clays.
基金Acknowledgment is made to the Donors of the American Chemical Society Petroleum Research Fund for support of this research.
文摘New energy sources that reduce the volume of harmful gases such as SO_(x)and NO_(x)released into the atmosphere are in constant development.Natural gas,primarily made up of methane,is being widely used as one reliable energy source for heating and electricity generation due to its high combustion value.Currently,natural gas accounts for a large portion of electricity generation and chemical feedstock in manufacturing plastics and other commercially important organic chemicals.In the near future,natural gas will be widely used as a fuel for vehicles.Therefore,a practical storage device for its storage and transportation is very beneficial to the deployment of natural gas as an energy source for new technologies.In this tutorial review,biomaterials-based carbon monoliths(CMs),one kind of carbonaceous material,was reviewed as an adsorbent for natural gas(methane)adsorption and storage.
基金financially supported by the National Natural Science Foundation of China(Nos.22179123 and52002138)Taishan Scholar Program of Shandong Province+1 种基金China(No.tsqn202211048)the Fundamental Research Funds for the Central Universities(Nos.202262010 and 862201013190)。
文摘Potassium-ion hybrid capacitors(PIHCs)are widely regarded as highly promising energy storage devices,due to their exceptional energy density,impressive power density,and abundant potassium resources.Unfortunately,restricted by the inherent capacitive storage mechanism,the carbon cathodes possess a much lower specific capacity than battery-type anodes.Therefore,designing high-performance carbon cathodes is extremely urgent for the development of PIHCs.Herein,N,O codoped porous carbon(NOPC)was fabricated through the NaCl hard template method and combined KOH/melamine chemical activation technique,displaying the characteristics of abundant N/O content(4.7 at%/16.9 at%),ultrahigh specific surface area(3092 m^(2)g^(-1))and hierarchical pore network.The designed NOPC cathode delivers a high specific capacity(164.4 mAh.g^(-1)at 0.05 A.g^(-1))and superior cyclability(95.1%retention ratio at 2 A·g^(-1)over 2500 cycles).Notably,the adjustable ratio of micropores to mesopores facilitates the achievement of the optimal bal-ance between capacity and rate capability.Moreover,the pseudocapacitance can be further augmented through the incorporation of N/O functional groups.As expected,the graphite//NOPC based PIHC possesses a high energy density of 113 Wh·kg-at 747 W·kg^(-1)and excellent capacity retention of 84.4% fter 400 cycles at 1.0 A·g^(-1).This work introduces a novel strategy for designing carbon cathodes that enhances the electrochemical performance of PIHCs.
文摘The chemical compositions of the sludge after treatment are tested by fully chemical analysis techniques. Its crystalline phase structure changes of the sludge calcined at different temperature are characterized by XRD method. Nitrogen gas isothermal adsorption method (77 K) is applied to measure the influences of ammonium bicarbonate on specific surface area and pore structure of activated alumina synthesized from waste aluminum sludge. The result shows that the amount of Al2O3 in the sludge accounts for more than 94%, and Na2Owt% in a 0.1-0.2% range. By calcining raw sludge at 600℃, monophase γ-Al2O3 is obtained. And this can satisfy the performance requirements of activated alumina adsorbent. The specific surface area of the specimen with NH4HCO3 added has expanded from 179 to 249 m^2/g and the pore volume from 0.25 to 1.11 cm^3/g as well as the average pore diameter from 5.6 to 17.8 nm. All these show that NH4HCO3 is an effective pore-expansion agent to remarkably improve the structure and performance of activated alumina synthesized from waste aluminum sludge.
文摘The viscose rayon was pretreated with four different pre-treatment reagents respectively, and the preparation ofactivated carbon fibers (ACF) was performed undersame carbonizing and activating conditions. The poresize distribution, the specific surface area, and the porestructure parameter of these viscose - based ACF werestudied by using quartz spring balance BET- weightmethod. The experiment result indicates that the poresize distribution and the pore structure parameter ofACF is varied by using different pretreatment reagents.
文摘Fe/C-based magnetically activated carbon(MAC) was obtained by carbonizing and activating its precursor, that was prepared by co-precipitation of anthracite coal impregnated in ferric chloride solution. The effect of the concentrations of FeCl3 and pH of solution on BET surface area, pore volume and magnetic properties of the MAC was studied by BET N2 adsorption and VSM method. The results indicated that the magnetization of MAC gradually increases with increasing concentration of FeCl3 and pH value of solution, and BET surface area was inclined to fluctuation. The largest BET surface area and magnetization of MAC were 1327.5 m2/g and 35.56 emu/g, respectively. The form of magnetic matter in the magnetically activated carbon was mainly Fe3C by X-ray powder diffraction(XRD) and magnetic attraction test.
基金financially supported by the National Natural Science Foundation of China(Nos.21776147,21606140,61604086,and 21905153)the Qingdao Municipal Science and Technology Bureau,China(19-6-1-91-nsh)+2 种基金the International Science&Technology Cooperation Program of China(No.2014DFA60150)the Department of Science and Technology of Shandong Province(Nos.ZR2018BB066 and 2016GGX104010)the Chemcloudcomputing of National Supercomputing Center in Shenzhen(Shenzhen CloudComputing Center)。
文摘In this work,a facile"carbonization-activation"strategy is developed to synthesize N,P-codoped hierarchical porous carbon.Phosphoric acid is innovatively introduced during the hydrothermal process to achieve in-situ P doping as well as create abundant pores,and the employment of sodamide is of vital importance to simultaneously serve as activating agent and N-source to succeed a high-level N doping.Thus,the obtained samples exhibit a unique three-dimensional hierarchical structure with an ultra-high specific surface area(3646 m^(2)g^(-1))and ultra-high N-doping level(9.81 at.%).Computational analyses confirm that N,P co-doping and higher N content can enhance active sites and widen potential differences of carbon materials to improve their capacitance.The as-prepared carbon materials demonstrate superior electrochemical performances,such as an ultra-high capacitance of 586 Fg^(-1)at 1 Ag^(-1),a superior rate capability of 409 Fg^(-1)at 20 Ag^(-1),and excellent long-term stability of 97%capacitance retention after10,000 cycles in 6 M KOH.Moreover,an assembled symmetric supercapacitor delivers a high energy density of 28.1 Wh kg^(-1)at the power density of 450 W kg^(-1)in 1 M Na_(2)SO_(4),demonstrating a great potential for applications in supercapacitors.
基金funded by National Natural Science Foundation of China grant number 51403210.
文摘A facile synthesis procedure is proposed to prepare homogeneous Zr and Ti co-doped SBA-15(Zr-Ti-SBA-15)with high specific surface area of 876.0m2 g−1.Based on“masking mechanism”from tanning,lactic acid was used as masking agent to obtain the uniform distribution of Zr and Ti species in the SBA-15 framework.The obtained materials were characterized by powder X-ray diffraction(XRD),nitrogen adsorption-desorption isotherms,scanning electron microscope(SEM),transmission electron microscope(TEM)and X-ray photoelectron(XPS).The results reveal that in mesoporous materials,the presence of lactic acid gives rise to the uniform distribution of Zr and Ti species.The adsorption equilibrium and kinetic studies of Zr-Ti-SBA-15 materials show that the adsorption process conforms to the Langmuir isotherm and pseudo-second-order kinetic model,respectively.Regenerational experiments show that the Zr-Ti-SBA-15 displays a significant adsorption ability for methylene blue(MB)(up to 291.6 mg/g),along with good reusability,indicating promising potentials of commercialization.Methodologically,this work provides a wide range of possibilities for further development of SBA-15 based on bimetallic and sewage disposal.
基金Project(2007CB613607) supported by the National Basic Research Program of China
文摘Effect of activated carbon and electrolyte on electrochemical properties of organic supercapacitor was investigated. The results show that specific surface area and mesoporosity of activated carbon influence specific capacitance. If specific surface area is larger and mesoporosity is higher, the specific capacitance will become bigger. Specific surface area influences resistance of carbon electrode and consequently influences power property and pore size distribution. If specific surface area is smaller and mesoporosity is higher, the power property will become better. Ash influences leakage current and electrochemical cycling stability. If ash content is lower, the performance will become better. The properties of supercapacitor highly depend on the electrolyte. The compatibility of electrolyte and activated carbon is a determining factor of supercapacitor’s working voltage. LiPF6/(EC+EMC+DMC) is inappropriate for double layer capacitor. MeEt3NPF4/PC has higher specific capacitance than Et4NPF4/PC because methyl’s electronegativity value is lower than ethyl and MeEt3N+ has more positive charges and stronger polarizability than Et4N+ when an ethyl is substituted by methyl.
基金support by National Basic Research Program of China(No.2014CB748500)National Natural Science Foundation of China(Nos.51578239,51322805)
文摘An improved biosorbent of thiourea modified chitosan microsphere(TMCM) with high specific surface,favorable mechanical strength and excellent adsorption performance had been synthesized via microfluidic technology. Polyethylene glycol was used as a significant component added in aqueous solution of chitosan to produce such microspheres through droplets forming, chemical crosslinking and pores creating. For the improvement of adsorption capacity, thiourea was considered as an excellent choice in increasing amino functional group by graft modification. The SEM, FTIR and EDS were employed to detect distinct features of TMCM. Copper(Ⅱ) was used to test the adsorption performance of TMCM. The experimental results indicated that TMCM exhibited higher adsorption capacity(q_e= 60.6 mg g_(-1)) and faster adsorption rate than that non-modified chitosan microsphere(NMCM).The adsorption kinetic was described well by the pseudo-second order kinetic model, which suggested that chemical adsorption along with electrons transferring was dominant in adsorption process.
基金supported by the National High Technology Research and Development Program of China (2013AA065900)the National Natural Science Foundation of China (21177008,21121064)
文摘Orderly mesoporous CuFe2O4spinel-type mixed oxide with high specific surface area was prepared successfully by a hard-template method in which KIT-6mesoporous silica was selected as the hard template.The KIT-6 hard template and CuFe2O4samples were characterized by X-ray diffraction,X-ray photoelectron spectroscopy,X-ray fluorescence,transmission electron microscopy,scanning electron microscopy,nitrogen physisorption,and hydrogen-temperature programmed reduction.The KIT-6 hard template had perfect crystallization and ordered mesoporous structure with a probable pore distribution of about 9.1 nm,large enough to be filled by the spinel precursor.The mesoporous CuFe2O4spinel oxide synthesized inside the KIT-6 mesopores had a relatively small pore size(4.3 nm),orderly arrangement,and high specific area(194 m2/g).The catalytic activity of the mesoporous CuFe2O4was tested for the selective oxidation of ammonia to nitrogen.The conversion of ammonia reached nearly 100%at 300°C with a nitrogen selectivity as high as 96%.The nitrogen selectivity remained high with increasing temperature and even maintained a value of80%at 600°C.
基金Funded by the National Science Foundation of China(Nos.11074176 and 10976019)the Research Fund for the Doctoral Program of Higher Education of China(No.20100181110080)
文摘Activated carbon aerogels(ACAs) derived from sol-gel polycondensation of resorcinol (R) and formaldehyde (F) were pyrolyzed under Ar flow and activated in CO2 atmosphere. The morphology of ACAs was characterized by scanning electron microscopy (SEM) and the structural properties were determined by N2 adsorption at 77 K. The results show that ACAs have a typical three-dimensional nanonetwork structure composing of cross-linking of carbon nanoparticles. The specific surface area and the total pore volume remarkably increase with increasing activation time while the previous porous structure still remains. The specific capacitance of the 950-10-ACA electrode can reach up to 212.3 F/g in 6 mol/L KOH electrolyte. The results of constant-current charge-discharge testing indicate that the ACAs electrodes present fast charge- discharge rate and long cycle life (about 98% capacitance retained after 3000 charge-discharge cycles at 1.25 mA/cm2). Lower internal resistances can be achieved for 950-10-ACA electrode in KOH electrolyte. Our investigations are very important to improve the wettability and electrochemical performance of electrode for supercapacitors.
文摘The catalytic pyrolyses of rayon have been studied respectively by thermo-gravimetric analysis (TGA) when rayon was treated with phosphoric acid (PA), three ammonium phosphate salts and ammonium sulfate (AS). The air is favorable to the catalysis of dibasic ammonium phosphate (DAP), but not to those of ADP, PA, AP, and AS obviously. It is put forward that a peak’s shape character can be described with the ratio of height to half-height-width (H/W /2) of the peak on a differential thermo-gravimetric (DTG) curve. A flat cracking peak, presenting a more moderate dehydration reaction, has a smaller ratio and could lead to higher carbonization and activation yields. The experimental results prove this view. According to expectation, the order of catalysis is: DAP≥ADP>PA> APAS no catalyst.
基金supported by the Program for Changjiang Scholars Innovative Research Team in Universitythe National Natural Science Foundation of China (No.51178215)
文摘A high-surface-area carbon (KC-1) was prepared from waste polystyrene-based ion exchange resin by KOH activation and used for naphthalene adsorption. The carbon exhibited a good hydrophobic nature with developed porous structure, favoring the adsorption of organic compounds. The Brunauer-Emmett-Teller surface area and total pore volume of KC- 1 were 3442.2 and 1.68 cm3/g, respectively, which can be compared with those of KOH-activated carbons prepared from other precursors. Batch experiments were carded out to investigate the adsorption of naphthalene onto KC-1. The equilibrium data were analyzed by the Langmuir, Freundlich, and Polanyi- Manes isotherms and agreed with the Polanyi-Manes Model. The adsorption of naphthalene depended greatly on the porosity of the carbon, and the dispersive interactions between naphthalene and carbon could be relatively weak. The pH variation in aqueous solution had little effect on the adsorption process. The equilibrium time for 0.04 g/L of carbon dose was around 5 hr. Different models were used to evaluate the kinetic data and the pseudo second-order model was suitable to describe the kinetic process of naphthalene adsorption onto KC-1. Regeneration of spent carbon could be carded out effectively by alcohol treatment. The results indicated that KC-1 was a promising adsorbent for the removal of polycyclic aromatic hydrocarbons from aqueous solutions.