Porous carbon nitride(CN)spheres with partially crystalline frameworks have been successfully synthesized via a nanocasting approach by using spherical mesoporous cellular silica foams(MCFs)as a hard template,and ethy...Porous carbon nitride(CN)spheres with partially crystalline frameworks have been successfully synthesized via a nanocasting approach by using spherical mesoporous cellular silica foams(MCFs)as a hard template,and ethylenediamine and carbon tetrachloride as precursors.The resulting spherical CN materials have uniform diameters of ca.4μm,hierarchical three-dimensional(3-D)mesostructures with small and large mesopores with pore diameters centered at ca.4.0 and 43 nm,respectively,a relatively high BET surface area of~550 m^(2)/g,and a pore volume of 0.90 cm^(3)/g.High-resolution transmission electron microscope(HRTEM)images,wide-angle X-ray diffraction(XRD)patterns,and Raman spectra demonstrate that the porous CN material has a partly graphitized structure.In addition,elemental analyses,X-ray photoelectron spectra(XPS),Fourier transform infrared spectra(FT-IR),and CO_(2) temperature-programmed desorption(CO_(2)-TPD)show that the material has a high nitrogen content(17.8 wt%)with nitrogen-containing groups and abundant basic sites.The hierarchical porous CN spheres have excellent CO_(2) capture properties with a capacity of 2.90 mmol/g at 25℃and 0.97 mmol/g at 75℃,superior to those of the pure carbon materials with analogous mesostructures.This can be mainly attributed to the abundant nitrogen-containing basic groups,hierarchical mesostructure,relatively high BET surface area and stable framework.Furthermore,the presence of a large number of micropores and small mesopores also enhance the CO_(2) capture performance,owing to the capillary condensation effect.展开更多
Carbon materials are considered to be one of the most promising anode materials for sodium-ion batteries(SIBs),but the well-ordered graphitic structure limits the intercalation of sodium ions.Besides,the sluggish inte...Carbon materials are considered to be one of the most promising anode materials for sodium-ion batteries(SIBs),but the well-ordered graphitic structure limits the intercalation of sodium ions.Besides,the sluggish intercalation kinetics of sodium ions impedes the rate performance.Thus,the precise structure control of carbon materials is important to improve the battery performance.Herein,a 3D porous hard-soft composite carbon(3DHSC)was prepared using the NaCl as the template and phenolic resin and pitch as carbon precursors.The NaCl template restrains the growth of the graphite crystallite during the carbonization process,resulting in small graphitic domains with expanded interlayer spacing which is favorable for the sodium storage.Moreover,the Na Cl templates help to create abundant mesopores and macropores for fast sodium ion diffusion.The porous structure and the graphite crystalline structure can be precisely controlled by simply adjusting the mass ratio of Na Cl,and thus,the suitable structure can be prepared to reach high capacity and rate performance while keeping a relatively high Coulombic efficiency.Typically,a high reversible capacity(215 mA h g^(-1)at 0.05 A g^(-1)),an excellent rate capability(97 mA h g^(-1)at 5 A g^(-1)),and a high initial Coulombic efficiency(60%)are achieved.展开更多
Sodium-ion batteries(SIBs)have garnered significant interest in energy storage due to their similar working mechanism to lithium ion batteries and abundant reserves of sodium resource.Exploring facile synthesis of a c...Sodium-ion batteries(SIBs)have garnered significant interest in energy storage due to their similar working mechanism to lithium ion batteries and abundant reserves of sodium resource.Exploring facile synthesis of a carbon-based anode materials with capable electrochemical performance is key to promoting the practical application of SIBs.In this work,a combination of petroleum pitch and recyclable sodium chloride is selected as the carbon source and template to obtain hard carbon(HC)anode for SIBs.Carbonization times and temperatures are optimized by assessing the sodium ion storage behavior of different HC materials.The optimized HC exhibits a remarkable capacity of over 430 mAh·g^(-1) after undergoing full activation through 500 cycles at a density of current of 0.1 A·g^(-1).Furthermore,it demonstrates an initial discharge capacity of 276 mAh·g^(-1) at a density of current of 0.5 A·g^(-1).Meanwhile,the optimized HC shows a good capacity retention(170 mAh·g^(-1) after 750 cycles)and a remarkable rate ability(166 mAh·g^(-1) at 2 A·g^(-1)).The enhanced capacity is attributed to the suitable degree of graphitization and surface area,which improve the sodium ion transport and storage.展开更多
Chiral inorganic semiconductors with high dissymmetric factor are highly desirable,but it is generally difficult to induce chiral structure in inorganic semiconductors because of their structure rigidity and symmetry....Chiral inorganic semiconductors with high dissymmetric factor are highly desirable,but it is generally difficult to induce chiral structure in inorganic semiconductors because of their structure rigidity and symmetry.In this study,we introduced chiral ZnO film as hard template to transfer chirality to CsPbBr_(3) film and PbS quantum dots(QDs)for circularly polarized light(CPL)emission and detection,respectively.The prepared CsPbBr_(3)/ZnO thin film exhibited CPL emission at 520 nm and the PbS QDs/ZnO film realized CPL detection at 780 nm,featuring high dissymmetric factor up to around 0.4.The electron transition based mechanism is responsible for chirality transfer.展开更多
Silica-based anode material is the most concerned material at present,which has the advantages of good cycle stability,high theoretical specific capacity and abundant reserves.However,silica suffers from inherent low ...Silica-based anode material is the most concerned material at present,which has the advantages of good cycle stability,high theoretical specific capacity and abundant reserves.However,silica suffers from inherent low conductivity,severe volume expansion effect and low initial coulombic efficiency,which limits its application in lithium-ion batteries.Nanotubes structure can mitigate the volume expansion during lithiation/delithiation.In this article,silica nanotubes(SNTs)were prepared using carbon nanotubes(CNTs)as a template,and then the uniform carbon layer was coated on their surface by carbonization of citric acid.The hollow structure of nanotubes provides more sites for the insertion of Li+during lithiation and additional channels for Li+migration in the cycles,which improves the electrochemical performance.Conductivity can be enhanced by coating carbon layer.The specific capacity of the composite material is about 650 mAh g^(-1)at 0.1 A g^(-1)after 100 cycles.With a specific capacity of 400 mAh g^(-1)even at 1 A g^(-1)after 100 cycles.The silica-based material is a competitive anode material for lithium-ion batteries.展开更多
基金This work was supported by the National Natural Science Foundation of China(NSFC)(Nos.2089012,20721063,20821140537,20871030)State Key Basic Research Program of PRC(Nos.2006CB932302 and 2009AA033701)+3 种基金Shanghai Leading Academic Discipline Project(No.B108)Science&Technology Com-mission of Shanghai Municipality(No.08DZ2270500)C.S.Ha also thanks the National Research Foundation(NRF)of Korea for support through the Korea-China Joint Research Center Program on Mesoporous Thin Films(No.K20803001459-10B1200-00310)the Acceleration Research Program(No.2010-0000790).
文摘Porous carbon nitride(CN)spheres with partially crystalline frameworks have been successfully synthesized via a nanocasting approach by using spherical mesoporous cellular silica foams(MCFs)as a hard template,and ethylenediamine and carbon tetrachloride as precursors.The resulting spherical CN materials have uniform diameters of ca.4μm,hierarchical three-dimensional(3-D)mesostructures with small and large mesopores with pore diameters centered at ca.4.0 and 43 nm,respectively,a relatively high BET surface area of~550 m^(2)/g,and a pore volume of 0.90 cm^(3)/g.High-resolution transmission electron microscope(HRTEM)images,wide-angle X-ray diffraction(XRD)patterns,and Raman spectra demonstrate that the porous CN material has a partly graphitized structure.In addition,elemental analyses,X-ray photoelectron spectra(XPS),Fourier transform infrared spectra(FT-IR),and CO_(2) temperature-programmed desorption(CO_(2)-TPD)show that the material has a high nitrogen content(17.8 wt%)with nitrogen-containing groups and abundant basic sites.The hierarchical porous CN spheres have excellent CO_(2) capture properties with a capacity of 2.90 mmol/g at 25℃and 0.97 mmol/g at 75℃,superior to those of the pure carbon materials with analogous mesostructures.This can be mainly attributed to the abundant nitrogen-containing basic groups,hierarchical mesostructure,relatively high BET surface area and stable framework.Furthermore,the presence of a large number of micropores and small mesopores also enhance the CO_(2) capture performance,owing to the capillary condensation effect.
基金supported by the Guangdong Natural Science Funds for Distinguished Young Scholar (2017B030306006)the National Natural Science Foundation of China (Nos. 51772164, U1601206 and U1710256)+2 种基金the National Key Basic Research Program of China (2014CB932400)the Shenzhen Technical Plan Project (Nos. KQJSCX20160226191136, JCYJ20150529164918734 and JCYJ20170412171630020)the Shenzhen Environmental Science and New Energy Technology Engineering Laboratory (No. SDRC [2016]172)
文摘Carbon materials are considered to be one of the most promising anode materials for sodium-ion batteries(SIBs),but the well-ordered graphitic structure limits the intercalation of sodium ions.Besides,the sluggish intercalation kinetics of sodium ions impedes the rate performance.Thus,the precise structure control of carbon materials is important to improve the battery performance.Herein,a 3D porous hard-soft composite carbon(3DHSC)was prepared using the NaCl as the template and phenolic resin and pitch as carbon precursors.The NaCl template restrains the growth of the graphite crystallite during the carbonization process,resulting in small graphitic domains with expanded interlayer spacing which is favorable for the sodium storage.Moreover,the Na Cl templates help to create abundant mesopores and macropores for fast sodium ion diffusion.The porous structure and the graphite crystalline structure can be precisely controlled by simply adjusting the mass ratio of Na Cl,and thus,the suitable structure can be prepared to reach high capacity and rate performance while keeping a relatively high Coulombic efficiency.Typically,a high reversible capacity(215 mA h g^(-1)at 0.05 A g^(-1)),an excellent rate capability(97 mA h g^(-1)at 5 A g^(-1)),and a high initial Coulombic efficiency(60%)are achieved.
基金supported by Heilongjiang Province Key R&D Program(Grant No.GA22A014).
文摘Sodium-ion batteries(SIBs)have garnered significant interest in energy storage due to their similar working mechanism to lithium ion batteries and abundant reserves of sodium resource.Exploring facile synthesis of a carbon-based anode materials with capable electrochemical performance is key to promoting the practical application of SIBs.In this work,a combination of petroleum pitch and recyclable sodium chloride is selected as the carbon source and template to obtain hard carbon(HC)anode for SIBs.Carbonization times and temperatures are optimized by assessing the sodium ion storage behavior of different HC materials.The optimized HC exhibits a remarkable capacity of over 430 mAh·g^(-1) after undergoing full activation through 500 cycles at a density of current of 0.1 A·g^(-1).Furthermore,it demonstrates an initial discharge capacity of 276 mAh·g^(-1) at a density of current of 0.5 A·g^(-1).Meanwhile,the optimized HC shows a good capacity retention(170 mAh·g^(-1) after 750 cycles)and a remarkable rate ability(166 mAh·g^(-1) at 2 A·g^(-1)).The enhanced capacity is attributed to the suitable degree of graphitization and surface area,which improve the sodium ion transport and storage.
基金supported by the National Natural Science Foundation of China(Grant No.61904065)the National Key R&D Program of China(No.2016YFB070700702)the National Postdoctoral Program for Innovative Talent(No.BX20190127)。
文摘Chiral inorganic semiconductors with high dissymmetric factor are highly desirable,but it is generally difficult to induce chiral structure in inorganic semiconductors because of their structure rigidity and symmetry.In this study,we introduced chiral ZnO film as hard template to transfer chirality to CsPbBr_(3) film and PbS quantum dots(QDs)for circularly polarized light(CPL)emission and detection,respectively.The prepared CsPbBr_(3)/ZnO thin film exhibited CPL emission at 520 nm and the PbS QDs/ZnO film realized CPL detection at 780 nm,featuring high dissymmetric factor up to around 0.4.The electron transition based mechanism is responsible for chirality transfer.
基金This work was supported by the National Natural Science Foundation of China(grant Nos.51764008 and 21868010)the Natural Science Research Project of Education Department of Guizhou Province(grant No.QJJ[2022]001).
文摘Silica-based anode material is the most concerned material at present,which has the advantages of good cycle stability,high theoretical specific capacity and abundant reserves.However,silica suffers from inherent low conductivity,severe volume expansion effect and low initial coulombic efficiency,which limits its application in lithium-ion batteries.Nanotubes structure can mitigate the volume expansion during lithiation/delithiation.In this article,silica nanotubes(SNTs)were prepared using carbon nanotubes(CNTs)as a template,and then the uniform carbon layer was coated on their surface by carbonization of citric acid.The hollow structure of nanotubes provides more sites for the insertion of Li+during lithiation and additional channels for Li+migration in the cycles,which improves the electrochemical performance.Conductivity can be enhanced by coating carbon layer.The specific capacity of the composite material is about 650 mAh g^(-1)at 0.1 A g^(-1)after 100 cycles.With a specific capacity of 400 mAh g^(-1)even at 1 A g^(-1)after 100 cycles.The silica-based material is a competitive anode material for lithium-ion batteries.
