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
Through improving the aging process during synthesis of the support, γ-Al2O3 with large pore volume and high surface area was synthesized by a facile secondary reforming method. The synthesis parameters, such as the ...Through improving the aging process during synthesis of the support, γ-Al2O3 with large pore volume and high surface area was synthesized by a facile secondary reforming method. The synthesis parameters, such as the reaction temperature, the first aging temperature and the second aging temperature, were investigated. The textural properties of γ-Al2O3 were characterized by means of N2 adsorption-desorption isotherms, X-ray powder diffractometry （XRD）, scanning electron microscopy （SEM）, Fourier transform infrared （FTIR） spectroscopy and thermogravimetry （TG）. The experimental results indicated that AACH and amorphous A1OOH were the precursors of alumina, which were formed via precipitation from solutions after reaction of aluminum sulphate with ammonium hydrogen carbonate. The precursor nanocrystallites grew and re-assembled during the secondary reforming process, which resulted in an increased pore size and pore volume and a decreased bulk density. The as-synthesized γ-Al2O3 materials featured meso/macroporosity, large pore volume （2.175 cm^3/g）, high surface area （237.8 m^2/g）, and low bulk density （0.284 g/mL）.展开更多
A novel salt-assisted combustion process with ethylene glycol as a fuel and nitrate as an oxidant to synthesize high surface area celia nanopowders was reported. The effects of various tunable conditions, such as fuel...A novel salt-assisted combustion process with ethylene glycol as a fuel and nitrate as an oxidant to synthesize high surface area celia nanopowders was reported. The effects of various tunable conditions, such as fuel-to-oxidant ratio, type of salts, and amount of added salts, on the characteristics of the as-prepared powders were investigated by X-ray diffraction, transmission electron microscopy and BET surface area measurement. A mechanism scheme was proposed to illustrate the possible formation processes of well-dispersed ceria nanoparticles in the salt-assisted combustion synthesis. It was verified that the simple introduction of leachable inert inorganic salts as an excellent agglomeration inhibitor into the redox mixture precursor leads to the formation of well-dispersed ceria particles with particle size in the range of 4 ～6 nm and a drastic increase in the surface area. The presence of KCl results in an over ten-fold increment in specific surface area from 14.10 m^2·g^-1 for the produced ceria powders via the conventional combustion synthesis process to 156.74 m^2·g^-1 for the product by the salt-assisted combustion synthesis process at the same molar ratio of ethylene glycol-nitrate.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
A TiO2 heterostructure modified with carbon nitride nanosheets （CN-NSs） has been synthesized via a direct interfacial assembly strategy. The CN-NSs, which have a unique two-dimensional structure, were favorable for ...A TiO2 heterostructure modified with carbon nitride nanosheets （CN-NSs） has been synthesized via a direct interfacial assembly strategy. The CN-NSs, which have a unique two-dimensional structure, were favorable for supporting TiOa nanoparticles （NPs）. The uniform dispersion of TiO2 NPs on the surface of the CN-NSs creates sufficient interfacial contact at their nanojunctions, as was confirmed by electron microscopy analyses. In comparison with other reported metal oxide/CN composites, the strong interactions of the ultrathin CN-NSs layers with the TiO2 nanoparticles restrain their re-stacking, which results in a large specific surface area of 234.0 m2.g-1. The results indicate that the optimized TiOJCN-NSs hybrid exhibits remarkably enhanced photocatalytic efficiency for dye degradation （with k of 0.167 min-1 under full spectrum） and Ha production （with apparent quantum yield -- 38.4% for A = 400 ＋ 15 nm monochromatic light）. This can be ascribed to the improved surface area and quantum efficiency of the hybrid, with a controlled ratio that reaches the appropriate balance between producing sufficient nanojunctions and absorbing enough photons. Furthermore, based on the identification of the main active species for photodegradation, and the confirmation of active sites for H2 evolution, the charge transfer pathway across the TiO2/CN-NSs interface under simulated solar light is proposed.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
The porous cubic yttrium oxides with high specific surface area were prepared yttrium nitrate and its complex formed with methyl salicylate. The specific surface area by the explosive decomposition of and properties o...The porous cubic yttrium oxides with high specific surface area were prepared yttrium nitrate and its complex formed with methyl salicylate. The specific surface area by the explosive decomposition of and properties of powders synthesized at various temperatures were characterized using BET, X-ray diffraction （XRD）, infrared spectra （IR）, and scanning electron microscopy （SEM）. The results indicate that the highest specific surface area is found to be 65.37 m^2·g^-1 at the calcination temperature of 600 ℃, and then decreases to 20.33 m2· g^- 1 with the calcination temperature rising from 600 to 900 ℃. The powders show strong surface activity for adsorping water and carbon dioxide in air, which also decreases with the rising calcination temperature. The drop both on the surface area and surface activity of samples at higher temperatures may be due to pore-narrowing（sintering） effects.展开更多
Abstract Lagoon-based municipal wastewater treatment plants （WWTPs） are facing difficulties meeting the needs of rapid population growth as well as the more stringent requirements of discharge permits. Three municip...Abstract Lagoon-based municipal wastewater treatment plants （WWTPs） are facing difficulties meeting the needs of rapid population growth as well as the more stringent requirements of discharge permits. Three municipal WWTPs were modified using a high surface area media with upgraded fine-bubble aeration systems. Performance data collected showed very promising results in terms of five-day biochemical oxygen demand （BOD5）, ammonia （NH3） and total suspended solids （TSS） removal. Two-year average ammonia effluents were 4.1 mg. L-1 for Columbia WWTP, 4 mg. L-1 for Larchmont WWTP and 2.1 mg. L-1 for Laurelville WWTE respectively. Two- year average BOD5 effluents were 6.8, 4.9 and 2.7 mg.Ll, and TSS effluents were 15.0, 9.6 and 7.5 mg.L-L The systems also showed low fecal coliform （FC） levels in their effluents.展开更多
The electrochemical reduction of CO2(CO2 RR) can substantially contribute to the production of useful chemicals and reduction of global CO2 emissions. Herein, we presented N and S dual-doped high-surface-area carbon m...The electrochemical reduction of CO2(CO2 RR) can substantially contribute to the production of useful chemicals and reduction of global CO2 emissions. Herein, we presented N and S dual-doped high-surface-area carbon materials(SZ-HCN) as CO2 RR catalysts. N and S were doped by one-step pyrolysis of a N-containing polymer and S powder. ZnCl2 was applied as a volatile porogen to prepare porous SZ-HCN. SZ-HCN with a high specific surface area(1510 m2 g–1) exhibited efficient electrocatalytic activity and selectivity for CO2 RR. Electrochemical measurements demonstrated that SZ-HCN showed excellent catalytic performance for CO2-to-CO reduction with a high CO Faradaic efficiency(~93%) at-0.6 V. Furthermore, SZ-HCN offered a stable current density and high CO selectivity over at least 20 h continuous operation, revealing remarkable electrocatalytic durability. The experimental results and density functional theory calculations indicated that N and S dual-doped carbon materials required lower Gibbs free energy to form the COOH* intermediate than that for single-N-doped carbon for CO2-to-CO reduction, thereby enhancing CO2 RR activity.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
The CeO_2-ZrO_2 solid solutions were prepared by a reverse microemulsion method. The effect of preparation parameters on the surface area and crystalline form of the solid solutions were studied by the BET surface are...The CeO_2-ZrO_2 solid solutions were prepared by a reverse microemulsion method. The effect of preparation parameters on the surface area and crystalline form of the solid solutions were studied by the BET surface area and XRD analysis. The studies indicate that the separation of the microemulsion phase during the preparation procedure can decrease the specific surface area of sample, adding hydrogen peroxide in the matrix solution can increase the specific surface area and stability of sample. The surface area of sample calcined at 550 ℃ for 5 h is 149 m^2·g^(-1), and that calcined at 900 ℃ for 6 h is 88 m^2·g^(-1). The sample with tetragonal symmetry Ce_(0.5)Zr_(0.5)O_2 phase has a higher stability.展开更多
A novel class of powdery carbon aerogels（PCAs） has been developed by the union of microemulsion polymerization and hypercrosslinking, followed by carbonization. The resulting aerogels are in a microscale powdery for...A novel class of powdery carbon aerogels（PCAs） has been developed by the union of microemulsion polymerization and hypercrosslinking, followed by carbonization. The resulting aerogels are in a microscale powdery form, demonstrate a well-defined 3D interconnected nanonetwork with hierarchical pores derived from numerous interstitial nanopores and intraparticle micropores, and exhibit high surface area（up to 1969 m^2/g）. Benefiting from these structural features, PCAs show impressive capacitive performances when utilized as electrodes for organic electrolyte supercapacitors,including large capacitances of up to 152 F/g, high energy densities of 37-15 Wh/kg at power densities of 34–6750 W/kg, and robust cycling stability.展开更多
Recent research has underscored the critical need for high-level global products to support comprehensive environmental monitoring and management[1],aligning closely with the objectives of the United Nations'Susta...Recent research has underscored the critical need for high-level global products to support comprehensive environmental monitoring and management[1],aligning closely with the objectives of the United Nations'Sustainable Development Goals(SDGs),particularly SDG 11.This goal focuses on transforming cities into inclusive,safe,resilient,and sustainable spaces.Understanding the relationship between urban expansion and population growth is essential for advancing sustainable urban development.However,the SDG11.3.1 indicator,despite having a clear evaluation method(the Ratio of Land Consumption Rate to Population Growth Rate(LCRPGR)),currently faces a significant challenge because of the lack of available data[2].This data gap hinders the comprehensive and effective measurement of urban land use efficiency,impacting the sustainable management of urban expansion.Therefore,there is an urgent need to acquire precise global-scale information on urban spatial distributions to address the data shortfall for the SDG 11.3.1 indicator and to facilitate improvements in the methods for expanding and monitoring this indicator.This process will assist in comprehensively assessing and managing the economic,social,and environmental impacts of urbanization,thereby supporting the objectives involved in sustainable urban development[3].展开更多
Defect-rich,highly porous two-dimensional carbon nanosheets(CNS) have attracted tremendous research interests in catalysis and environmental purification and other fields,because of their unique micromorphology,chemic...Defect-rich,highly porous two-dimensional carbon nanosheets(CNS) have attracted tremendous research interests in catalysis and environmental purification and other fields,because of their unique micromorphology,chemical stability and high specific surface area.Herein,in this work,we report a new solution to synthesize an ultrathin two-dimensional CNS with rich defects and abundant pores via two-step etching the Ti_(3)AlC_(2)with the help of I2and NaOH.The CNS thickness,specific surface area and pore volume could be all tunable by adding the amount of I2.And the highest specific surface area and pore volume of the synthesized 2D CNS can be achieved 1134.4 m^(2)/g and 0.80 cm^(3)/g,with a thickness of only 0.64 nm and a yield of 35.9%.When employed as the anodes for lithium-ion batteries,the synthesized CNS anodes exhibit good cycling and rate capabilities.This work provides a novel and facile strategy for synthesizing highly porous and defective 2D carbon materials with good lithium storage properties.展开更多
Exfoliated graphite oxide was prepared by an improved Hummers method and was then reduced to graphene with hydrazine in the presence of ammonium hydroxide.N2adsorption–desorption measurement showed that graphene so o...Exfoliated graphite oxide was prepared by an improved Hummers method and was then reduced to graphene with hydrazine in the presence of ammonium hydroxide.N2adsorption–desorption measurement showed that graphene so obtained had a specific surface area as high as 818 m2/g.Galvanostatic charge/discharge curves demonstrated that the as-prepared graphene exhibited a specific capacitance of 186.9 F/g at a current density of 0.1 A/g and that about 96%of the specific capacitance was retained after 2000 cycles at a current density of 5 A/g.展开更多
The carbon dioxide reduction reaction(CO_(2)RR)for the synthesis of high-energy-density and high-value multi-carbon(C_(2+))products has demonstrated consider-able potential for practical applications.In this work,we d...The carbon dioxide reduction reaction(CO_(2)RR)for the synthesis of high-energy-density and high-value multi-carbon(C_(2+))products has demonstrated consider-able potential for practical applications.In this work,we design a novel copper oxide foam(OD-Cu foam)catalyst through a high-temperature calcination pro-cess,characterized by a substantial specific surface area.The distinctive three-dimensional structure of the OD-Cu foam catalyst and the metal oxide particles covered on its surface provide abundant active sites.The total Faradaic efficiency of 57.3%for C_(2+)products over the OD-Cu foam is achieved at-0.85 V versus reversible hydrogen electrode(RHE).Furthermore,the partial current density for C_(2+)products over the OD-Cu foam reaches 44.1 mA cm^(-2)at-0.95 V versus RHE,surpassing significantly that both of Cu foam(3.4 mA cm^(-2))and copper oxide foil(OD-Cu foil)(1.6 mA cm^(-2)).In addition,the integrated structure of the OD-Cu foam,which does not require complex preparation processes,facilitates its application in CO_(2)RR.These results underscore the significance of three-dimensional structure and high specific surface area,emphasizing the consider-able potential of this catalyst for effective and sustainable CO_(2)conversion.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
In the present work, selective methanation of carbon monoxide in hydrogen rich stream was investigated over Ni/CeO2 nanocatalysts. The obtained results revealed that increasing in nickel loading decreased the BET surf...In the present work, selective methanation of carbon monoxide in hydrogen rich stream was investigated over Ni/CeO2 nanocatalysts. The obtained results revealed that increasing in nickel loading decreased the BET surface area, pore vohune and nickel dispersion. The 25%Ni/CeO2 with a NiO crystal size of 12 nm exhibited the highest activity in CO methanation reaction and reached to maximum CO conversion and CH4 selectivity at temperatures above 230 ℃. The catalytic results revealed that CO selective methanation well progressed at lower temperatures while CO2 methanation was completely suppressed until CO conversion reached to maximum value.展开更多
A series of high surface area graphitic carbon materials （HSGCs） were prepared by ball-milling method. Effect of the graphitic degree of HSGCs on the catalytic performance of Ba-Ru-K/HSGC-x （x is the ball-milling t...A series of high surface area graphitic carbon materials （HSGCs） were prepared by ball-milling method. Effect of the graphitic degree of HSGCs on the catalytic performance of Ba-Ru-K/HSGC-x （x is the ball-milling time in hour） catalysts was studied using ammonia synthesis as a probe reaction. The graphitic degree and pore structure of HSGC-x supports could be successfully tuned via the variation of ball-milling time. Ru nanoparticles of different Ba-Ru-K/HSGC-x catalysts are homogeneously distributed on the supports with the particle sizes ranging from 1.6 to 2.0 nm. The graphitic degree of the support is closely related to its facile electron transfer capability and so plays an important role in improving the intrinsic catalytic performance of Ba-Ru-K/HSGC-x catalyst.展开更多
Mesoporous LaMnO3 perovskite catalysts with high surface area were synthesized by using the recently developed hard templating method designated as ＂nanocasting＂.Ordered mesoporous silica designated as SBA-15 was us...Mesoporous LaMnO3 perovskite catalysts with high surface area were synthesized by using the recently developed hard templating method designated as ＂nanocasting＂.Ordered mesoporous silica designated as SBA-15 was used as the hard template.It was found that the surface area of the nanocast perovskites can be tuned（80–190 m2/g）by varying the aging temperature of the SBA-15 template.Nanocast LaMnO3 catalysts showed high conversion efficiencies for the total oxidation of methanol under steady state conditions,the one with the highest value of surface area being the best catalysts,as expected.Kinetic studies were performed for all of the synthesized catalysts.Rate constants were found to vary in accordance with the specific surface area of the nanocast catalyst which depends on the aging temperature of the parent template.From the rate constants obtained from experimental conversions at various space velocities（19500 to 78200 h〈sup〉–1）,values of activation energy and pre-exponential factor for the three nanocast LaMnO3 catalysts were determined by the linear regression of the Arrhenius plot.It is observed that the activation energy for all the catalysts remain constant irrespective of the variation in specific surface area.Further,a linear relationship was found to exist between the pre-exponential factor and specific surface areas of the catalysts indicating that the rates per unit surface area remains the same for all the catalysts.展开更多
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the financial support by the Natural Science Foundation of Liaoning Province of China (Grant No. 2013020122)the National Natural Science Foundationof China (Grant No. 21076100 and 51308045)the financial support by the PetroChina Company Limited (Grant No. 10-01A-01-01-01)
文摘Through improving the aging process during synthesis of the support, γ-Al2O3 with large pore volume and high surface area was synthesized by a facile secondary reforming method. The synthesis parameters, such as the reaction temperature, the first aging temperature and the second aging temperature, were investigated. The textural properties of γ-Al2O3 were characterized by means of N2 adsorption-desorption isotherms, X-ray powder diffractometry （XRD）, scanning electron microscopy （SEM）, Fourier transform infrared （FTIR） spectroscopy and thermogravimetry （TG）. The experimental results indicated that AACH and amorphous A1OOH were the precursors of alumina, which were formed via precipitation from solutions after reaction of aluminum sulphate with ammonium hydrogen carbonate. The precursor nanocrystallites grew and re-assembled during the secondary reforming process, which resulted in an increased pore size and pore volume and a decreased bulk density. The as-synthesized γ-Al2O3 materials featured meso/macroporosity, large pore volume （2.175 cm^3/g）, high surface area （237.8 m^2/g）, and low bulk density （0.284 g/mL）.
基金Project supported bythe National Natural Science Foundation of China (50306008) andthefundfromthe Preli minary ResearchProject of General Equipment Ministry (41328030507)
文摘A novel salt-assisted combustion process with ethylene glycol as a fuel and nitrate as an oxidant to synthesize high surface area celia nanopowders was reported. The effects of various tunable conditions, such as fuel-to-oxidant ratio, type of salts, and amount of added salts, on the characteristics of the as-prepared powders were investigated by X-ray diffraction, transmission electron microscopy and BET surface area measurement. A mechanism scheme was proposed to illustrate the possible formation processes of well-dispersed ceria nanoparticles in the salt-assisted combustion synthesis. It was verified that the simple introduction of leachable inert inorganic salts as an excellent agglomeration inhibitor into the redox mixture precursor leads to the formation of well-dispersed ceria particles with particle size in the range of 4 ～6 nm and a drastic increase in the surface area. The presence of KCl results in an over ten-fold increment in specific surface area from 14.10 m^2·g^-1 for the produced ceria powders via the conventional combustion synthesis process to 156.74 m^2·g^-1 for the product by the salt-assisted combustion synthesis process at the same molar ratio of ethylene glycol-nitrate.
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.
基金We thank the Analysis and Testing Center, Huazhong University of Science and Technology for their assistance in characterization of materials. This work is supported by the National Natural Science Foundation of China （No. 21571071）, Hubei Provincial Natural Science Foundation of China （No. 2015CFB313）, and the Fundamental Research Funds for the Central Universities （No. 2015QN183）.
文摘A TiO2 heterostructure modified with carbon nitride nanosheets （CN-NSs） has been synthesized via a direct interfacial assembly strategy. The CN-NSs, which have a unique two-dimensional structure, were favorable for supporting TiOa nanoparticles （NPs）. The uniform dispersion of TiO2 NPs on the surface of the CN-NSs creates sufficient interfacial contact at their nanojunctions, as was confirmed by electron microscopy analyses. In comparison with other reported metal oxide/CN composites, the strong interactions of the ultrathin CN-NSs layers with the TiO2 nanoparticles restrain their re-stacking, which results in a large specific surface area of 234.0 m2.g-1. The results indicate that the optimized TiOJCN-NSs hybrid exhibits remarkably enhanced photocatalytic efficiency for dye degradation （with k of 0.167 min-1 under full spectrum） and Ha production （with apparent quantum yield -- 38.4% for A = 400 ＋ 15 nm monochromatic light）. This can be ascribed to the improved surface area and quantum efficiency of the hybrid, with a controlled ratio that reaches the appropriate balance between producing sufficient nanojunctions and absorbing enough photons. Furthermore, based on the identification of the main active species for photodegradation, and the confirmation of active sites for H2 evolution, the charge transfer pathway across the TiO2/CN-NSs interface under simulated solar light is proposed.
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.
文摘The porous cubic yttrium oxides with high specific surface area were prepared yttrium nitrate and its complex formed with methyl salicylate. The specific surface area by the explosive decomposition of and properties of powders synthesized at various temperatures were characterized using BET, X-ray diffraction （XRD）, infrared spectra （IR）, and scanning electron microscopy （SEM）. The results indicate that the highest specific surface area is found to be 65.37 m^2·g^-1 at the calcination temperature of 600 ℃, and then decreases to 20.33 m2· g^- 1 with the calcination temperature rising from 600 to 900 ℃. The powders show strong surface activity for adsorping water and carbon dioxide in air, which also decreases with the rising calcination temperature. The drop both on the surface area and surface activity of samples at higher temperatures may be due to pore-narrowing（sintering） effects.
文摘Abstract Lagoon-based municipal wastewater treatment plants （WWTPs） are facing difficulties meeting the needs of rapid population growth as well as the more stringent requirements of discharge permits. Three municipal WWTPs were modified using a high surface area media with upgraded fine-bubble aeration systems. Performance data collected showed very promising results in terms of five-day biochemical oxygen demand （BOD5）, ammonia （NH3） and total suspended solids （TSS） removal. Two-year average ammonia effluents were 4.1 mg. L-1 for Columbia WWTP, 4 mg. L-1 for Larchmont WWTP and 2.1 mg. L-1 for Laurelville WWTE respectively. Two- year average BOD5 effluents were 6.8, 4.9 and 2.7 mg.Ll, and TSS effluents were 15.0, 9.6 and 7.5 mg.L-L The systems also showed low fecal coliform （FC） levels in their effluents.
文摘The electrochemical reduction of CO2(CO2 RR) can substantially contribute to the production of useful chemicals and reduction of global CO2 emissions. Herein, we presented N and S dual-doped high-surface-area carbon materials(SZ-HCN) as CO2 RR catalysts. N and S were doped by one-step pyrolysis of a N-containing polymer and S powder. ZnCl2 was applied as a volatile porogen to prepare porous SZ-HCN. SZ-HCN with a high specific surface area(1510 m2 g–1) exhibited efficient electrocatalytic activity and selectivity for CO2 RR. Electrochemical measurements demonstrated that SZ-HCN showed excellent catalytic performance for CO2-to-CO reduction with a high CO Faradaic efficiency(~93%) at-0.6 V. Furthermore, SZ-HCN offered a stable current density and high CO selectivity over at least 20 h continuous operation, revealing remarkable electrocatalytic durability. The experimental results and density functional theory calculations indicated that N and S dual-doped carbon materials required lower Gibbs free energy to form the COOH* intermediate than that for single-N-doped carbon for CO2-to-CO reduction, thereby enhancing CO2 RR activity.
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.
文摘The CeO_2-ZrO_2 solid solutions were prepared by a reverse microemulsion method. The effect of preparation parameters on the surface area and crystalline form of the solid solutions were studied by the BET surface area and XRD analysis. The studies indicate that the separation of the microemulsion phase during the preparation procedure can decrease the specific surface area of sample, adding hydrogen peroxide in the matrix solution can increase the specific surface area and stability of sample. The surface area of sample calcined at 550 ℃ for 5 h is 149 m^2·g^(-1), and that calcined at 900 ℃ for 6 h is 88 m^2·g^(-1). The sample with tetragonal symmetry Ce_(0.5)Zr_(0.5)O_2 phase has a higher stability.
基金financial support from the National Natural Science Foundation of China (Nos 51372280,51422307, U1601206, 51702262)National Program for Support of Top-notch Young Professionals, Guangdong Natural Science Funds for Distinguished Young Scholar (No S2013050014408)+5 种基金Tip-top Scientific and Technical Innovative Youth Talents of Guangdong Special Support Program (No 2014TQ01C337)Fundamental Research Funds for the Central Universities (Nos. 15lgjc17, 3102017OQD057)the Key Laboratory of Polymeric Composite & Functional Materials of Ministry of Education (No. PCFM201602)the Project of the Natural Science Foundation of Shaanxi Province (No. 2017JQ5003)the Program of Introducing Talents of Discipline to Universities (No. B08040)National Key Basic Research Program of China (No. 2014CB932400)
文摘A novel class of powdery carbon aerogels（PCAs） has been developed by the union of microemulsion polymerization and hypercrosslinking, followed by carbonization. The resulting aerogels are in a microscale powdery form, demonstrate a well-defined 3D interconnected nanonetwork with hierarchical pores derived from numerous interstitial nanopores and intraparticle micropores, and exhibit high surface area（up to 1969 m^2/g）. Benefiting from these structural features, PCAs show impressive capacitive performances when utilized as electrodes for organic electrolyte supercapacitors,including large capacitances of up to 152 F/g, high energy densities of 37-15 Wh/kg at power densities of 34–6750 W/kg, and robust cycling stability.
基金supported by the National Natural Science Foundation of China(42171291 and 42361144884)the Innovative Research Program of the International Research Center of Big Data for Sustainable Development Goals(CBAS2022IRP04)Joint HKU-CAS Laboratory for iEarth(313GJHZ2022074MI,E4F3050300)。
文摘Recent research has underscored the critical need for high-level global products to support comprehensive environmental monitoring and management[1],aligning closely with the objectives of the United Nations'Sustainable Development Goals(SDGs),particularly SDG 11.This goal focuses on transforming cities into inclusive,safe,resilient,and sustainable spaces.Understanding the relationship between urban expansion and population growth is essential for advancing sustainable urban development.However,the SDG11.3.1 indicator,despite having a clear evaluation method(the Ratio of Land Consumption Rate to Population Growth Rate(LCRPGR)),currently faces a significant challenge because of the lack of available data[2].This data gap hinders the comprehensive and effective measurement of urban land use efficiency,impacting the sustainable management of urban expansion.Therefore,there is an urgent need to acquire precise global-scale information on urban spatial distributions to address the data shortfall for the SDG 11.3.1 indicator and to facilitate improvements in the methods for expanding and monitoring this indicator.This process will assist in comprehensively assessing and managing the economic,social,and environmental impacts of urbanization,thereby supporting the objectives involved in sustainable urban development[3].
基金financially supported by the National Natural Science Foundation of China (No. 51902036)Natural Science Foundation of Chongqing Science & Technology Commission (No. cstc2019jcyj-msxm1407)+4 种基金Natural Science Foundation of Jiangsu Province (No. BK20200047)Natural Science Foundation of Chongqing Technology and Business University (No. 1952009)the Science and Technology Research Program of Chongqing Education Commission (Nos. KJQN201900826 and KJQN201800808)the Venture & Innovation Support Program for Chongqing Overseas Returnees (Nos. CX2021046 and CX2018129)the Innovation Group of New Technologies for Industrial Pollution Control of Chongqing Education Commission (No. CXQT19023)。
文摘Defect-rich,highly porous two-dimensional carbon nanosheets(CNS) have attracted tremendous research interests in catalysis and environmental purification and other fields,because of their unique micromorphology,chemical stability and high specific surface area.Herein,in this work,we report a new solution to synthesize an ultrathin two-dimensional CNS with rich defects and abundant pores via two-step etching the Ti_(3)AlC_(2)with the help of I2and NaOH.The CNS thickness,specific surface area and pore volume could be all tunable by adding the amount of I2.And the highest specific surface area and pore volume of the synthesized 2D CNS can be achieved 1134.4 m^(2)/g and 0.80 cm^(3)/g,with a thickness of only 0.64 nm and a yield of 35.9%.When employed as the anodes for lithium-ion batteries,the synthesized CNS anodes exhibit good cycling and rate capabilities.This work provides a novel and facile strategy for synthesizing highly porous and defective 2D carbon materials with good lithium storage properties.
基金supported by the National Natural Science Foundation of China(Grant Nos.51072047,21271067)the Program for Innovative Research Team in University(Grant No.IRT-1237)
文摘Exfoliated graphite oxide was prepared by an improved Hummers method and was then reduced to graphene with hydrazine in the presence of ammonium hydroxide.N2adsorption–desorption measurement showed that graphene so obtained had a specific surface area as high as 818 m2/g.Galvanostatic charge/discharge curves demonstrated that the as-prepared graphene exhibited a specific capacitance of 186.9 F/g at a current density of 0.1 A/g and that about 96%of the specific capacitance was retained after 2000 cycles at a current density of 5 A/g.
基金supported by the Jiangxi Gan Po Talent Support Program(20232BCJ22028).
文摘The carbon dioxide reduction reaction(CO_(2)RR)for the synthesis of high-energy-density and high-value multi-carbon(C_(2+))products has demonstrated consider-able potential for practical applications.In this work,we design a novel copper oxide foam(OD-Cu foam)catalyst through a high-temperature calcination pro-cess,characterized by a substantial specific surface area.The distinctive three-dimensional structure of the OD-Cu foam catalyst and the metal oxide particles covered on its surface provide abundant active sites.The total Faradaic efficiency of 57.3%for C_(2+)products over the OD-Cu foam is achieved at-0.85 V versus reversible hydrogen electrode(RHE).Furthermore,the partial current density for C_(2+)products over the OD-Cu foam reaches 44.1 mA cm^(-2)at-0.95 V versus RHE,surpassing significantly that both of Cu foam(3.4 mA cm^(-2))and copper oxide foil(OD-Cu foil)(1.6 mA cm^(-2)).In addition,the integrated structure of the OD-Cu foam,which does not require complex preparation processes,facilitates its application in CO_(2)RR.These results underscore the significance of three-dimensional structure and high specific surface area,emphasizing the consider-able potential of this catalyst for effective and sustainable CO_(2)conversion.
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supported by the Iran National Science Foundation(INSF)(91052908)
文摘In the present work, selective methanation of carbon monoxide in hydrogen rich stream was investigated over Ni/CeO2 nanocatalysts. The obtained results revealed that increasing in nickel loading decreased the BET surface area, pore vohune and nickel dispersion. The 25%Ni/CeO2 with a NiO crystal size of 12 nm exhibited the highest activity in CO methanation reaction and reached to maximum CO conversion and CH4 selectivity at temperatures above 230 ℃. The catalytic results revealed that CO selective methanation well progressed at lower temperatures while CO2 methanation was completely suppressed until CO conversion reached to maximum value.
基金supported by the Natural Science Foundation of China(NSFC Grant No.20803064)the Natural Science Foundation of Zhejiang Provence(Y4090348 and LY12B03007)Qianjiang Talent Project in Zhejiang Province(2010R10039 and 2013R10056)
文摘A series of high surface area graphitic carbon materials （HSGCs） were prepared by ball-milling method. Effect of the graphitic degree of HSGCs on the catalytic performance of Ba-Ru-K/HSGC-x （x is the ball-milling time in hour） catalysts was studied using ammonia synthesis as a probe reaction. The graphitic degree and pore structure of HSGC-x supports could be successfully tuned via the variation of ball-milling time. Ru nanoparticles of different Ba-Ru-K/HSGC-x catalysts are homogeneously distributed on the supports with the particle sizes ranging from 1.6 to 2.0 nm. The graphitic degree of the support is closely related to its facile electron transfer capability and so plays an important role in improving the intrinsic catalytic performance of Ba-Ru-K/HSGC-x catalyst.
基金supported by the the National Science and Engineering Research Council(Canada)the Fonds Québécois de la Recherche sur la Nature et les Technologies(Province of Quebec)
文摘Mesoporous LaMnO3 perovskite catalysts with high surface area were synthesized by using the recently developed hard templating method designated as ＂nanocasting＂.Ordered mesoporous silica designated as SBA-15 was used as the hard template.It was found that the surface area of the nanocast perovskites can be tuned（80–190 m2/g）by varying the aging temperature of the SBA-15 template.Nanocast LaMnO3 catalysts showed high conversion efficiencies for the total oxidation of methanol under steady state conditions,the one with the highest value of surface area being the best catalysts,as expected.Kinetic studies were performed for all of the synthesized catalysts.Rate constants were found to vary in accordance with the specific surface area of the nanocast catalyst which depends on the aging temperature of the parent template.From the rate constants obtained from experimental conversions at various space velocities（19500 to 78200 h〈sup〉–1）,values of activation energy and pre-exponential factor for the three nanocast LaMnO3 catalysts were determined by the linear regression of the Arrhenius plot.It is observed that the activation energy for all the catalysts remain constant irrespective of the variation in specific surface area.Further,a linear relationship was found to exist between the pre-exponential factor and specific surface areas of the catalysts indicating that the rates per unit surface area remains the same for all the catalysts.
