Pyrolytic graphite (PG) with highly aligned graphene layers,present anisotropic electrical and thermal transport behavior,which is attractive in electronic,electrocatalyst and energy storage.Such pristine PG could mee...Pyrolytic graphite (PG) with highly aligned graphene layers,present anisotropic electrical and thermal transport behavior,which is attractive in electronic,electrocatalyst and energy storage.Such pristine PG could meeting the limit of electrical conductivity (~2.5×10^(4) S·cm^(−1)),although efforts have been made for achieving high-purity sp^(2) hybridized carbon.For manipulating the electrical conductivity of PG,a facile and efficient electrochemical strategy is demonstrated to enhance electrical transport ability via reversible intercalation/de-intercalation of AlCl_(4)^(-)into the graphitic interlayers.With the stage evolution at different voltages,variable electrical and thermal transport behaviors could be achieved via controlling AlCl_(4)^(-)concentrations in the PG because of substantial variation in the electronic density of states.Such evolution leads to decoupled electrical and thermal transport (opposite variation trend) in the in-plane and out-of-plane directions,and the in-plane electrical conductivity of the pristine PG (1.25×10^(4) S·cm^(−1)) could be massively promoted to 4.09×10^(4) S·cm(AlCl_(4)^(-)intercalated PG),much better than the pristine bulk graphitic papers used for the electrical transport and electromagnetic shielding.The fundamental mechanism of decoupled transport feature and electrochemical strategy here could be extended into other anisotropic conductive bulks for achieving unusual behaviors.展开更多
BACKGROUND Intercalated duct lesions(IDLs)are considered relatively benign and rare tumors of salivary glands,that were only described recently.Their histopathological appearance may range from ductal hyperplasia to e...BACKGROUND Intercalated duct lesions(IDLs)are considered relatively benign and rare tumors of salivary glands,that were only described recently.Their histopathological appearance may range from ductal hyperplasia to encapsulated adenoma with hybrid patterns of both variants.It is thought that IDLs may be the precursor for malignant proliferations,therefore their correct diagnosis remains crucial for proper lesion management.It is the first reported IDL case arising from the accessory parotid gland(APG),which stands for less frequent but higher malignancy rate tumor developmental area.CASE SUMMARY A 24-years-old male with no accompanying diseases was referred to the hospital with a painless nodule on the right cheek.On physical examination,the stiff,immobile,and painless mass was palpable in the anterior portion of the right parotideomasseteric region,just superior to the parotid duct.Ultrasound examination demonstrated 1.5 cm×1.0 cm hypoechogenic mass on the anterior part of the right parotid gland.Ultrasound-guided fine needle aspiration cytology,followed by liquid-based fine needle aspiration biopsy were performed.However,the results were uninformative.A contrast-enhanced magnetic res-onance imaging(MRI)of the parotid was obtained,demonstrating a 1.5 cm×1.0 cm×0.5 cm tumor with high intensity capsule together with low intensity core in the very anterior part of right superficial lobe,situated in the APG.An MRI features were uncharacteristic to common parotid tumors,therefore surgical resection followed up.After histopathological examination,the final diagnosis of hybrid IDL was confirmed.CONCLUSION Fine needle aspiration biopsy might not always be diagnostic,and given the malignant potential,the surgical resection of such lesion remains the treatment of choice.展开更多
Cost-effective,safe,and highly performing energy storage devices require rechargeable batteries,and among various options,aqueous zinc-ion batteries(ZIBs)have shown high promise in this regard.As a cathode material fo...Cost-effective,safe,and highly performing energy storage devices require rechargeable batteries,and among various options,aqueous zinc-ion batteries(ZIBs)have shown high promise in this regard.As a cathode material for the aqueous ZIBs,manganese dioxide(MnO_(2))has been found to be promising,but certain drawbacks of this cathode material are slow charge-transfer capability and poor cycling performance.Herein,a novel design of graphene quantum dots(GQDs)integrated with Zn-intercalated MnO_(2)nanosheets is put forward to construct a 3D nanoflower-like GQDs@ZnxMnO_(2)composite cathode for aqueous ZIBs.The synergistic coupling of GQDs modification with Zn intercalation provides abundant active sites and conductive medium to facilitate the ion/electron transmission,as well as ensure the GQDs@ZnxMnO_(2)composite cathode with enhanced charge-transfer capability and high electrochemical reversibility,which are elucidated by experiment results and in-situ Raman investigation.These impressive properties endow the GQDs@ZnxMnO_(2)composite cathode with superior aqueous Zn^(2+) storage capacity(~403.6 mAh·g^(−1)),excellent electrochemical kinetics,and good structural stability.For actual applications,the fabricated aqueous ZIBs can deliver a substantial energy density(226.8 W·h·kg^(−1)),a remarkable power density(650 W·kg^(−1)),and long-term cycle performance,further stimulating their potential application as efficient electrochemical storage devices for various energy-related fields.展开更多
The mechanical behavior of the joints inside a loess layer is greatly important in weak intercalation studies owing to its involvement in a wide range of landslides in the loess region in China.The shear behavior of t...The mechanical behavior of the joints inside a loess layer is greatly important in weak intercalation studies owing to its involvement in a wide range of landslides in the loess region in China.The shear behavior of the joints in the loess stratum during direct shear and cyclic loadings was investigated using the PFC2D discrete element software.Loess mudstone and mudstone with weak intercalated layer materials were subjected to direct testing,and cyclic shear tests were conducted with consideration to the influence of normal stress and shear velocity.The macroscopic properties and damage patterns were obtained for six numerical configurations;namely,loess-weathered mudstone with 0°,10°,and-10°joints and weathered mudstone with 0°,10°,and-10°weak intercalated layers.The numerical test results revealed that,in the direct shear tests,the shear stress and shear displacement of the samples increased with the normal stress.In the cyclic shear tests with a total cycle number N=20,the shear stress-shear strain curve of the six different configurations exhibited a hysteresis loop.The numerical tests also revealed that,under cyclic shear,the normal stress and shear velocity affected the shear strength.The degree of damage increased as the shear velocity decreased from 0.1 mm/s to 0.005 mm/s for all six numerical configurations.Compared with the damage pattern of the direct shear tests,the damage of the cyclic shear tests mainly comprised shear cracks and fractures,some shaking consolidation settlement and fewer shear strain occurred around the joints.In the direct shear tests,more compression cracks and fractures occurred in the samples.The damage mainly developed along the joints,and shearing-off damage occurred.The results obtained by this study further elucidate the failure mechanism and microscopic damage response of the joints in the loess stratum in Northwest China.展开更多
The adsorption of CO_(2) on MgAl layered double hydroxides(MgAl-LDHs) based adsorbents has been an effective way to capture CO_(2),however the adsorption capacity was hampered due to the pore structure and the dispers...The adsorption of CO_(2) on MgAl layered double hydroxides(MgAl-LDHs) based adsorbents has been an effective way to capture CO_(2),however the adsorption capacity was hampered due to the pore structure and the dispersibility of adsorption active sites.To address the problem,we investigate the effect of intercalated anion and alkaline etching time on the structure,morphology and CO_(2) uptake performances of MgAl-LDHs.MgAl-LDHs are synthesized by the onepot hydrothermal method,followed by alkaline etching of NaOH,and characterized by x-ray diffraction,N_(2) adsorption,scanning electron microscopy and Fourier transform infrared spectroscopy.The CO_(2) adsorption tests of the samples are performed on a thermogravimetric analyzer,and the adsorption data are fitted by the first-order,pseudo-second-order and Elovich models,respectively.The results demonstrate that among the three intercalated samples,MgAl(Cl) using chloride salts as precursors possesses the highest adsorption capacity of CO_(2),owing to high crystallinity and porous structure,while MgAl(Ac) employing acetate salts as precursors displays the lowest CO_(2) uptake because of poor crystallinity,disorderly stacked structure and unsatisfactory pore structure.With regard to alkaline etching,the surface of the treated MgAl(Cl) is partly corroded,thus the specific surface area and pore volume increase,which is conducive to the exposure of adsorption active sites.Correspondingly,the adsorption performance of the alkaline-etched adsorbents is significantly improved,and MgAl(Cl)-6 has the highest CO_(2) uptake.With the alkaline etching time further increasing,the CO_(2) adsorption capacity of MgAl(Cl)-9 sharply decreases,mainly due to the collapse of pore structure and the fragmentized sheet-structure.Hence,the CO_(2) adsorption performance is greatly influenced by alkaline etching time,and appropriate alkaline etching time can facilitate the contact between CO_(2) molecules and the adsorbent.展开更多
Aqueous zinc-ion batteries have broad application prospects due to the eco-friendliness,cost-economy and high safety.However,the scarcity of high-performance cathodes with outstanding rate capability and long lifespan...Aqueous zinc-ion batteries have broad application prospects due to the eco-friendliness,cost-economy and high safety.However,the scarcity of high-performance cathodes with outstanding rate capability and long lifespan has affected their development.Herein,we report a metallic vanadium trioxide material intercalated with phase transformation as cathode applied in aqueous zinc-ion batteries.It offers satisfactory electrochemical performances with a high specific capacity(435 mAh g^(-1) at 0.5 A g^(-1)),decent power density(5.23 kW kg^(-1))and desired energy density(331 Wh kg^(-1)),as well as good cyclability.The superior performance originates from the stable structure and fast Zn^(2+)diffusion,enabled by the pre-intercalation of Zn^(2+)and water molecules.展开更多
Composites based on ultradispersed polytetrafluoroethylene and intercalated graphite oxide compounds with dodecahydro-closo-dodecaborates and methods of their fabrication have been developed. The fabricated composites...Composites based on ultradispersed polytetrafluoroethylene and intercalated graphite oxide compounds with dodecahydro-closo-dodecaborates and methods of their fabrication have been developed. The fabricated composites have been characterized using XRD analysis, and optical microscopy. These composites are distinguished with completeness of their combustion, since the combustion products comprise gaseous boron fluorine-containing compounds of boron, boron trifluoride (BF3), and boron oxyfluoride ((BOF)3). Besides, these composites are characterized with increased energy capacity as compared to purely oxygen-containing compounds, since the heat of formation of boron fluorine-containing compounds is higher than that of boron oxide. Introduction of ultradispersed polytetrafluoroethylene imparts composites with hydrophobicity, thus improving their functioning properties.展开更多
Graphite oxide, a pseudo-two-dimensional solid in bulk form, was synthesized from natural graphite powder by oxidization with KMnO4 in concentrated H2SO4. The poly(vinyl acetate)-intercalated graphite oxide nano-compo...Graphite oxide, a pseudo-two-dimensional solid in bulk form, was synthesized from natural graphite powder by oxidization with KMnO4 in concentrated H2SO4. The poly(vinyl acetate)-intercalated graphite oxide nano-composite was prepared by an in situ intercalative polymerization reaction, in which n-octanol-graphite oxide intercalation compounds were first obtained, vinyl acetate monomer was then dispersed into the interlayer of modified graphite oxide, followed by thermal polymerization of the monomer. It was experimentally shown that the c-axis space of poly(vinyl acetate)-intercalated graphite oxide was increased to 0.115 nm, which suggested there existed a monolayer of poly(vinyl acetate) chain between the layers of graphite oxide. The nanocomposite was also characterized with thermal analysis and FT-IR spectrometry.展开更多
The problem in practice of determining the proper combination of Z<sub>i</sub> in a set of changegears may be abstracted to the problem of finding the proper combination and permutation ofthe elements a<...The problem in practice of determining the proper combination of Z<sub>i</sub> in a set of changegears may be abstracted to the problem of finding the proper combination and permutation ofthe elements a<sub>i,i+1</sub> of the set A<sub>1</sub> to give maximum M-d. Some results to find optimal combina-tions of the elements of the set A<sub>1</sub> have been reported in part I. In this part, some rules forpermuting these elements are introduced. By means of these rules, three kinds of intercalated setsof A<sub>1</sub> have been found, namely: (1) Sets with an even left wing, (2) Sets with coincidence of bothwings, and (3) Sets with circulated elements.展开更多
1 Introduction Magnesium salts are very important by-product of salt lake industry in West China.Nearly 200 million cubic meters of waste brine are released to the environment
In this paper, we report a simple and facile self-assembly method to successfully fabricate cationic metal porphyrin-MtTMPyP(Mt= Cobalt(Ⅱ), Manganese(Ⅲ), or Iron(Ⅲ); TMPyP = 5, 10, 15, 20-tetrakis(N-methylpyridiniu...In this paper, we report a simple and facile self-assembly method to successfully fabricate cationic metal porphyrin-MtTMPyP(Mt= Cobalt(Ⅱ), Manganese(Ⅲ), or Iron(Ⅲ); TMPyP = 5, 10, 15, 20-tetrakis(N-methylpyridinium-4-yl) porphyrin) intercalated into the layer of graphene oxide(GO) by the cooperative effects of electrostatic and π-π stacking interaction between positively charged metal porphyrin and negatively charged GO sheets. Followed by reduction with hydrazine vapor, a series of novel 2 D MtTMPyP/rGO_n were fabricated. The as-prepared 2 D hybrids were fully characterized and tested as non-noble metal catalysts for oxygen reduction reaction(ORR) in an alkaline medium. The MtTMPyP/rGO_n hybrids, especially CoTMPyP/rGO_5, demonstrated an improved electrocatalytic activity for ORR and a number of exchanged electrons close to 4-electron reaction, increased stability and excellent tolerance to methanol, showing a potential alternative catalyst for ORR in fuel cells and air batteries.展开更多
The ESR signal of lithium intercalated MCMB can be well simulated by combination of a Lorentz curve and a Gauss curve. The ESR intensity of the Lorentz component is essentially independent of temperature while the Gau...The ESR signal of lithium intercalated MCMB can be well simulated by combination of a Lorentz curve and a Gauss curve. The ESR intensity of the Lorentz component is essentially independent of temperature while the Gauss component shows a linear change with the reciprocal of temperature, indicative of Pauli spin and Curie spin, respectively. The former is probably associated with the ordered (graphitized) structures while the latter with the disordered structures in the sample.展开更多
The unprecedentedly growing demand for energy storage devices in recent years calls for diversified chemistries with unique advantages.When it comes to safety and cost,aqueous battery systems have attracted tremendous...The unprecedentedly growing demand for energy storage devices in recent years calls for diversified chemistries with unique advantages.When it comes to safety and cost,aqueous battery systems have attracted tremendous attention.Owing to its small size,high polarity,and hydrogen bonding,water in the electrode materials,either in the form of structural water or cointercalated hydrated cations,drastically change the electrochemical behavior through multiple aspects.This review discusses the roles of water in aqueous batteries from how water molecules coordinate with cations to examples of watermediated reactions in different types of host materials.展开更多
Electrochemical method has been used to insert K/Na into FeSe lattice to prepare alkali-intercalated iron selenides at room temperature. Magnetization measurement reveals that KxFe2Se2 and NaxFe2Se2 are superconductiv...Electrochemical method has been used to insert K/Na into FeSe lattice to prepare alkali-intercalated iron selenides at room temperature. Magnetization measurement reveals that KxFe2Se2 and NaxFe2Se2 are superconductive at 31 K and 46 K, respectively. This is the first successful report of obtaining metal-intercalated FeSe-based high-temperature superconductors using electrochemical method. It provides an effective route to synthesize metal-intercalated layered compounds for new superconductor exploration.展开更多
Monoclinic BiVO_(4) is a widely researched semiconductor in solar water splitting owing to its suitable characteristics. However, BiVO_(4) faces limitations, such as the inefficient separation and transportation of ph...Monoclinic BiVO_(4) is a widely researched semiconductor in solar water splitting owing to its suitable characteristics. However, BiVO_(4) faces limitations, such as the inefficient separation and transportation of photogenerated charges in the bulk and poor catalytic water oxidation reactions at the surface that affect the water-splitting efficiency. In this work, the Cs intercalation strategy at the surface of BiVO_(4) is proposed for the enhanced water splitting to H_(2) and O_(2) productions via the effective separation and transportation photogenerated charges and improved surface catalytic water oxidation reactions. The Cs ions are found to intercalate at the surface of BiVO_(4) and regulate the oxygen vacancies to provide active O_(2) production sites and stability. The surface intercalation of Cs boosts the photocurrent to 1.89 mA cm^(-2)at 1.23 V vs.reference hydrogen electrode(RHE). A stoichiometric evolution of H_(2) and O_(2) is recorded with a faradaic efficiency of 92%. The open-circuit voltage measurements confirmed the increase in the carrier lifetime with the work function tuning upon Cs intercalation. The proposed Cs intercalation strategy suggests an effective route to suppress the charge recombination with an increase in carrier lifetime and charge separation in BiVO_(4) for the enhanced PEC application.展开更多
An efficient method based on atomic force microscopy(AFM) has been developed to characterize silicon intercalated graphene grown on single crystalline Ir(111) thin films. By combining analyses of the phase image, ...An efficient method based on atomic force microscopy(AFM) has been developed to characterize silicon intercalated graphene grown on single crystalline Ir(111) thin films. By combining analyses of the phase image, force curves,and friction–force mapping, acquired by AFM, the locations and coverages of graphene and silicon oxide can be well distinguished. We can also demonstrate that silicon atoms have been successfully intercalated between graphene and the substrate. Our method gives an efficient and simple way to characterize graphene samples with interacted atoms and is very helpful for future applications of graphene-based devices in the modern microelectronic industry, where AFM is already widely used.展开更多
High pressure method was ased for the first time to produce rectorite clay (REC)/phenolic resin (PF) and organic rectorite clay (OREC) /phenolic resin and montmorillonite( MMT)lphenolic resin (PF) nanocompos...High pressure method was ased for the first time to produce rectorite clay (REC)/phenolic resin (PF) and organic rectorite clay (OREC) /phenolic resin and montmorillonite( MMT)lphenolic resin (PF) nanocomposites. The structure of the material phase was studied by X-ray diffraction (XRD), transmission electron microscopy (TEM), Fourier transform infrared ( FT- IR ) spectroscopy, thermogravimetric analysis ( TGA ), and atomic force microscopg" (AFM). The experimental results show that intercalated clay/resin nanocomposites could form under normal temperature and high pressure conditions by the intercalation of polymeric molecules rather than interlayer polymerization.展开更多
An intercalative composite of graphite oxide (GO) as host intercalated by an object of TiO2 nanoparticles was obtained at low temperature by mixing GO with Ti(SO4)2 solution, and by another object of Ti2O3 while m...An intercalative composite of graphite oxide (GO) as host intercalated by an object of TiO2 nanoparticles was obtained at low temperature by mixing GO with Ti(SO4)2 solution, and by another object of Ti2O3 while mixing with TiCl4 ethanol solution. Microstructures of the GO and its intercalative composites at different C/Ti ratio were studied by XRD, SEM, AFM and FF-IR, and the evolution of these lamellar structures was studied based on the temperature change. The photocatalytic activity of the intercalative composites was characterized according to the degradation of methyl orange. The intercalative composite formed by Ti(SO4)2 solution presents an excellent photocatalytic reactivity, while that formed by TiCl4 presents no observablly photocatalytic reactivity. The electric conductivity variation of different composites was checked, in order to investigate the role of the possible electron transfer between the graphite layer and TiO2 nanocrystal during TiO2 excited by UV light irradiation.展开更多
A new intercalation compound, Fe0.85PS3(4,4-bipyH)0.30 (4,4-bipy = 4,4-bipyridine), is obtained by the intercalation of 4,4-bipyridine?HCl with lamellar FePS3, which is characterized by elemental analysis, powder X-r...A new intercalation compound, Fe0.85PS3(4,4-bipyH)0.30 (4,4-bipy = 4,4-bipyridine), is obtained by the intercalation of 4,4-bipyridine?HCl with lamellar FePS3, which is characterized by elemental analysis, powder X-ray diffraction, infrared spectroscopy. By comparison with the pure FePS3, the lattice spacing of Fe0.85PS3(4,4-bipyH)0.30 is expanded by ~ 5.7 , indicating that the ring plane of the guest is perpendicular to the layer of the host. The magnetic property of Fe0.85PS3(4,4-bipyH)0.30 is studied with SQUID. It exhibits an antiferromagnetic phase transition with TN of about 70 K.展开更多
A novel method for exfoliating graphite oxide(GrO)was implemented through the mass water absorption of a GrO–poly(ethylene glycol)(GrO–PEG)composite.The GrO–PEG composite was prepared by intercalating PEG into the ...A novel method for exfoliating graphite oxide(GrO)was implemented through the mass water absorption of a GrO–poly(ethylene glycol)(GrO–PEG)composite.The GrO–PEG composite was prepared by intercalating PEG into the lamellae of GrO,and the variation of the basal spacing was measured by X-ray diffraction analysis.The yield of graphene was measured with an ultraviolet–visible spectrophotometer,and the properties of graphene oxide(GO)were characterized by atomic force microscopy,transmission electron microscopy(TEM),Raman spectrometry,and Fourier transform infrared spectroscopy.Increasing intercalation time was found to improve the yield of GO,whereas increasing the PEG molecular weight had the opposite effect.The GO sheets produced from the intercalation–absorption–exfoliation process were found to be a four-layer structure.TEM and Raman analyses indicate that the graphitized structure and oxygen groups of GO were preserved during the exfoliation process.Most importantly,the results show that good-quality GO could be prepared via a mild method involving water absorption of a GrO–PEG composite.展开更多
基金financially supported by the National Key R&D Program of China (No. 2018YFB0104400)the National Natural Science Foundation of China (Nos. 52074036, 51725401, and 51874019)Beijing Municipal Science and Technology Commission (No. Z191100002719007)
文摘Pyrolytic graphite (PG) with highly aligned graphene layers,present anisotropic electrical and thermal transport behavior,which is attractive in electronic,electrocatalyst and energy storage.Such pristine PG could meeting the limit of electrical conductivity (~2.5×10^(4) S·cm^(−1)),although efforts have been made for achieving high-purity sp^(2) hybridized carbon.For manipulating the electrical conductivity of PG,a facile and efficient electrochemical strategy is demonstrated to enhance electrical transport ability via reversible intercalation/de-intercalation of AlCl_(4)^(-)into the graphitic interlayers.With the stage evolution at different voltages,variable electrical and thermal transport behaviors could be achieved via controlling AlCl_(4)^(-)concentrations in the PG because of substantial variation in the electronic density of states.Such evolution leads to decoupled electrical and thermal transport (opposite variation trend) in the in-plane and out-of-plane directions,and the in-plane electrical conductivity of the pristine PG (1.25×10^(4) S·cm^(−1)) could be massively promoted to 4.09×10^(4) S·cm(AlCl_(4)^(-)intercalated PG),much better than the pristine bulk graphitic papers used for the electrical transport and electromagnetic shielding.The fundamental mechanism of decoupled transport feature and electrochemical strategy here could be extended into other anisotropic conductive bulks for achieving unusual behaviors.
文摘BACKGROUND Intercalated duct lesions(IDLs)are considered relatively benign and rare tumors of salivary glands,that were only described recently.Their histopathological appearance may range from ductal hyperplasia to encapsulated adenoma with hybrid patterns of both variants.It is thought that IDLs may be the precursor for malignant proliferations,therefore their correct diagnosis remains crucial for proper lesion management.It is the first reported IDL case arising from the accessory parotid gland(APG),which stands for less frequent but higher malignancy rate tumor developmental area.CASE SUMMARY A 24-years-old male with no accompanying diseases was referred to the hospital with a painless nodule on the right cheek.On physical examination,the stiff,immobile,and painless mass was palpable in the anterior portion of the right parotideomasseteric region,just superior to the parotid duct.Ultrasound examination demonstrated 1.5 cm×1.0 cm hypoechogenic mass on the anterior part of the right parotid gland.Ultrasound-guided fine needle aspiration cytology,followed by liquid-based fine needle aspiration biopsy were performed.However,the results were uninformative.A contrast-enhanced magnetic res-onance imaging(MRI)of the parotid was obtained,demonstrating a 1.5 cm×1.0 cm×0.5 cm tumor with high intensity capsule together with low intensity core in the very anterior part of right superficial lobe,situated in the APG.An MRI features were uncharacteristic to common parotid tumors,therefore surgical resection followed up.After histopathological examination,the final diagnosis of hybrid IDL was confirmed.CONCLUSION Fine needle aspiration biopsy might not always be diagnostic,and given the malignant potential,the surgical resection of such lesion remains the treatment of choice.
基金financially supported by the National Nature Science Foundations of China (Nos. 52002157 and 51873083)the Nature Science Foundations of Jiangsu Province, China (No. BK20190976)
文摘Cost-effective,safe,and highly performing energy storage devices require rechargeable batteries,and among various options,aqueous zinc-ion batteries(ZIBs)have shown high promise in this regard.As a cathode material for the aqueous ZIBs,manganese dioxide(MnO_(2))has been found to be promising,but certain drawbacks of this cathode material are slow charge-transfer capability and poor cycling performance.Herein,a novel design of graphene quantum dots(GQDs)integrated with Zn-intercalated MnO_(2)nanosheets is put forward to construct a 3D nanoflower-like GQDs@ZnxMnO_(2)composite cathode for aqueous ZIBs.The synergistic coupling of GQDs modification with Zn intercalation provides abundant active sites and conductive medium to facilitate the ion/electron transmission,as well as ensure the GQDs@ZnxMnO_(2)composite cathode with enhanced charge-transfer capability and high electrochemical reversibility,which are elucidated by experiment results and in-situ Raman investigation.These impressive properties endow the GQDs@ZnxMnO_(2)composite cathode with superior aqueous Zn^(2+) storage capacity(~403.6 mAh·g^(−1)),excellent electrochemical kinetics,and good structural stability.For actual applications,the fabricated aqueous ZIBs can deliver a substantial energy density(226.8 W·h·kg^(−1)),a remarkable power density(650 W·kg^(−1)),and long-term cycle performance,further stimulating their potential application as efficient electrochemical storage devices for various energy-related fields.
基金sponsored by National Natural Science Foundation of China(No.41902269)Chinese Universities Scientific Fund(2020TC095)。
文摘The mechanical behavior of the joints inside a loess layer is greatly important in weak intercalation studies owing to its involvement in a wide range of landslides in the loess region in China.The shear behavior of the joints in the loess stratum during direct shear and cyclic loadings was investigated using the PFC2D discrete element software.Loess mudstone and mudstone with weak intercalated layer materials were subjected to direct testing,and cyclic shear tests were conducted with consideration to the influence of normal stress and shear velocity.The macroscopic properties and damage patterns were obtained for six numerical configurations;namely,loess-weathered mudstone with 0°,10°,and-10°joints and weathered mudstone with 0°,10°,and-10°weak intercalated layers.The numerical test results revealed that,in the direct shear tests,the shear stress and shear displacement of the samples increased with the normal stress.In the cyclic shear tests with a total cycle number N=20,the shear stress-shear strain curve of the six different configurations exhibited a hysteresis loop.The numerical tests also revealed that,under cyclic shear,the normal stress and shear velocity affected the shear strength.The degree of damage increased as the shear velocity decreased from 0.1 mm/s to 0.005 mm/s for all six numerical configurations.Compared with the damage pattern of the direct shear tests,the damage of the cyclic shear tests mainly comprised shear cracks and fractures,some shaking consolidation settlement and fewer shear strain occurred around the joints.In the direct shear tests,more compression cracks and fractures occurred in the samples.The damage mainly developed along the joints,and shearing-off damage occurred.The results obtained by this study further elucidate the failure mechanism and microscopic damage response of the joints in the loess stratum in Northwest China.
基金Project supported by the National Natural Science Foundation of China(Grant No.21606058)the Natural Science Foundation of Guangxi,China(Grant Nos.2017GXNSFBA198193 and 2017GXNSFBA198124)the Startup Foundation for Doctors of Guilin University of Technology(Grant No.GLUTQD2015008)。
文摘The adsorption of CO_(2) on MgAl layered double hydroxides(MgAl-LDHs) based adsorbents has been an effective way to capture CO_(2),however the adsorption capacity was hampered due to the pore structure and the dispersibility of adsorption active sites.To address the problem,we investigate the effect of intercalated anion and alkaline etching time on the structure,morphology and CO_(2) uptake performances of MgAl-LDHs.MgAl-LDHs are synthesized by the onepot hydrothermal method,followed by alkaline etching of NaOH,and characterized by x-ray diffraction,N_(2) adsorption,scanning electron microscopy and Fourier transform infrared spectroscopy.The CO_(2) adsorption tests of the samples are performed on a thermogravimetric analyzer,and the adsorption data are fitted by the first-order,pseudo-second-order and Elovich models,respectively.The results demonstrate that among the three intercalated samples,MgAl(Cl) using chloride salts as precursors possesses the highest adsorption capacity of CO_(2),owing to high crystallinity and porous structure,while MgAl(Ac) employing acetate salts as precursors displays the lowest CO_(2) uptake because of poor crystallinity,disorderly stacked structure and unsatisfactory pore structure.With regard to alkaline etching,the surface of the treated MgAl(Cl) is partly corroded,thus the specific surface area and pore volume increase,which is conducive to the exposure of adsorption active sites.Correspondingly,the adsorption performance of the alkaline-etched adsorbents is significantly improved,and MgAl(Cl)-6 has the highest CO_(2) uptake.With the alkaline etching time further increasing,the CO_(2) adsorption capacity of MgAl(Cl)-9 sharply decreases,mainly due to the collapse of pore structure and the fragmentized sheet-structure.Hence,the CO_(2) adsorption performance is greatly influenced by alkaline etching time,and appropriate alkaline etching time can facilitate the contact between CO_(2) molecules and the adsorbent.
基金financially supported by the National Natural Science Foundation of China(51872139,51902158,and 51903121)the Recruitment Program of Global Experts(1211019)+2 种基金the“Six Talent Peak”Project of Jiangsu Province(XCL-043,XCL-021 and XCL-018)the Natural Science Foundation of Jiangsu Higher Education Institutions(19KJB430002 and 18KJB150016)the start-up fund from Nanjing Tech University(3983500197 and 3827401784)。
文摘Aqueous zinc-ion batteries have broad application prospects due to the eco-friendliness,cost-economy and high safety.However,the scarcity of high-performance cathodes with outstanding rate capability and long lifespan has affected their development.Herein,we report a metallic vanadium trioxide material intercalated with phase transformation as cathode applied in aqueous zinc-ion batteries.It offers satisfactory electrochemical performances with a high specific capacity(435 mAh g^(-1) at 0.5 A g^(-1)),decent power density(5.23 kW kg^(-1))and desired energy density(331 Wh kg^(-1)),as well as good cyclability.The superior performance originates from the stable structure and fast Zn^(2+)diffusion,enabled by the pre-intercalation of Zn^(2+)and water molecules.
文摘Composites based on ultradispersed polytetrafluoroethylene and intercalated graphite oxide compounds with dodecahydro-closo-dodecaborates and methods of their fabrication have been developed. The fabricated composites have been characterized using XRD analysis, and optical microscopy. These composites are distinguished with completeness of their combustion, since the combustion products comprise gaseous boron fluorine-containing compounds of boron, boron trifluoride (BF3), and boron oxyfluoride ((BOF)3). Besides, these composites are characterized with increased energy capacity as compared to purely oxygen-containing compounds, since the heat of formation of boron fluorine-containing compounds is higher than that of boron oxide. Introduction of ultradispersed polytetrafluoroethylene imparts composites with hydrophobicity, thus improving their functioning properties.
基金Financial support from Key Project of The National Natural Science Foundation of China (No. 59836230) is gratefully acknowledged.
文摘Graphite oxide, a pseudo-two-dimensional solid in bulk form, was synthesized from natural graphite powder by oxidization with KMnO4 in concentrated H2SO4. The poly(vinyl acetate)-intercalated graphite oxide nano-composite was prepared by an in situ intercalative polymerization reaction, in which n-octanol-graphite oxide intercalation compounds were first obtained, vinyl acetate monomer was then dispersed into the interlayer of modified graphite oxide, followed by thermal polymerization of the monomer. It was experimentally shown that the c-axis space of poly(vinyl acetate)-intercalated graphite oxide was increased to 0.115 nm, which suggested there existed a monolayer of poly(vinyl acetate) chain between the layers of graphite oxide. The nanocomposite was also characterized with thermal analysis and FT-IR spectrometry.
文摘The problem in practice of determining the proper combination of Z<sub>i</sub> in a set of changegears may be abstracted to the problem of finding the proper combination and permutation ofthe elements a<sub>i,i+1</sub> of the set A<sub>1</sub> to give maximum M-d. Some results to find optimal combina-tions of the elements of the set A<sub>1</sub> have been reported in part I. In this part, some rules forpermuting these elements are introduced. By means of these rules, three kinds of intercalated setsof A<sub>1</sub> have been found, namely: (1) Sets with an even left wing, (2) Sets with coincidence of bothwings, and (3) Sets with circulated elements.
基金supported by the National Natural Science Foundationthe National Key Technologies R&D Program (2011BAE28B01)the 863 Program (2013AA032501)
文摘1 Introduction Magnesium salts are very important by-product of salt lake industry in West China.Nearly 200 million cubic meters of waste brine are released to the environment
基金supported by Natural Science Fund of Jiangsu Province (BK20141247, BK20140447)Exceptional Talent Project in Jiangsu Province (2015-XCL-035)+3 种基金University Science Research Project of Jiangsu Province (13KJB430005, 11KJA430008)funded by the Priority Academic Program development of Jiangsu Higher Education InstitutionsJiangsu Province universities' "blue and green blue project"financial support from the ARC (CE140100012, FT130100380, and DP170102267)
文摘In this paper, we report a simple and facile self-assembly method to successfully fabricate cationic metal porphyrin-MtTMPyP(Mt= Cobalt(Ⅱ), Manganese(Ⅲ), or Iron(Ⅲ); TMPyP = 5, 10, 15, 20-tetrakis(N-methylpyridinium-4-yl) porphyrin) intercalated into the layer of graphene oxide(GO) by the cooperative effects of electrostatic and π-π stacking interaction between positively charged metal porphyrin and negatively charged GO sheets. Followed by reduction with hydrazine vapor, a series of novel 2 D MtTMPyP/rGO_n were fabricated. The as-prepared 2 D hybrids were fully characterized and tested as non-noble metal catalysts for oxygen reduction reaction(ORR) in an alkaline medium. The MtTMPyP/rGO_n hybrids, especially CoTMPyP/rGO_5, demonstrated an improved electrocatalytic activity for ORR and a number of exchanged electrons close to 4-electron reaction, increased stability and excellent tolerance to methanol, showing a potential alternative catalyst for ORR in fuel cells and air batteries.
基金the National Natural Science Foundation of China (No. 29873034) is gratefully acknowledged. We thank Professor Han Xi YANG and
文摘The ESR signal of lithium intercalated MCMB can be well simulated by combination of a Lorentz curve and a Gauss curve. The ESR intensity of the Lorentz component is essentially independent of temperature while the Gauss component shows a linear change with the reciprocal of temperature, indicative of Pauli spin and Curie spin, respectively. The former is probably associated with the ordered (graphitized) structures while the latter with the disordered structures in the sample.
基金The author would like to acknowledge the financial support from the U.S.Department of Energy's Office of Electricity under Contract no.70247A.
文摘The unprecedentedly growing demand for energy storage devices in recent years calls for diversified chemistries with unique advantages.When it comes to safety and cost,aqueous battery systems have attracted tremendous attention.Owing to its small size,high polarity,and hydrogen bonding,water in the electrode materials,either in the form of structural water or cointercalated hydrated cations,drastically change the electrochemical behavior through multiple aspects.This review discusses the roles of water in aqueous batteries from how water molecules coordinate with cations to examples of watermediated reactions in different types of host materials.
基金supported by the National Natural Science Foundation of China(Grant Nos.51322211and 91422303)the Strategic Priority Research Program(B)of the Chinese Academy of Sciences(Grant No.XDB07020100)+1 种基金Beijing Nova Program of China(Grant No.2011096)K.C.Wong Education Foundation,Hong Kong,China
文摘Electrochemical method has been used to insert K/Na into FeSe lattice to prepare alkali-intercalated iron selenides at room temperature. Magnetization measurement reveals that KxFe2Se2 and NaxFe2Se2 are superconductive at 31 K and 46 K, respectively. This is the first successful report of obtaining metal-intercalated FeSe-based high-temperature superconductors using electrochemical method. It provides an effective route to synthesize metal-intercalated layered compounds for new superconductor exploration.
基金supported by the Basic Research&Development Program (2020R1F1A105408412)the C1 Gas Refinery Program(2015M3D3A1A0106489931) through the National Research Foundation of Korea (NRF) funded by the Ministry of Science and ICT,Republic of Korea。
文摘Monoclinic BiVO_(4) is a widely researched semiconductor in solar water splitting owing to its suitable characteristics. However, BiVO_(4) faces limitations, such as the inefficient separation and transportation of photogenerated charges in the bulk and poor catalytic water oxidation reactions at the surface that affect the water-splitting efficiency. In this work, the Cs intercalation strategy at the surface of BiVO_(4) is proposed for the enhanced water splitting to H_(2) and O_(2) productions via the effective separation and transportation photogenerated charges and improved surface catalytic water oxidation reactions. The Cs ions are found to intercalate at the surface of BiVO_(4) and regulate the oxygen vacancies to provide active O_(2) production sites and stability. The surface intercalation of Cs boosts the photocurrent to 1.89 mA cm^(-2)at 1.23 V vs.reference hydrogen electrode(RHE). A stoichiometric evolution of H_(2) and O_(2) is recorded with a faradaic efficiency of 92%. The open-circuit voltage measurements confirmed the increase in the carrier lifetime with the work function tuning upon Cs intercalation. The proposed Cs intercalation strategy suggests an effective route to suppress the charge recombination with an increase in carrier lifetime and charge separation in BiVO_(4) for the enhanced PEC application.
基金supported by the National Basic Research Program of China(Grant Nos.2013CBA01600 and 2011CB932700)the National Natural Science Foundation of China(Grant Nos.61222112,61390501 and 51325204)Chinese Academy of Sciences(Grant Nos.1731300500015 and XDB07030100)
文摘An efficient method based on atomic force microscopy(AFM) has been developed to characterize silicon intercalated graphene grown on single crystalline Ir(111) thin films. By combining analyses of the phase image, force curves,and friction–force mapping, acquired by AFM, the locations and coverages of graphene and silicon oxide can be well distinguished. We can also demonstrate that silicon atoms have been successfully intercalated between graphene and the substrate. Our method gives an efficient and simple way to characterize graphene samples with interacted atoms and is very helpful for future applications of graphene-based devices in the modern microelectronic industry, where AFM is already widely used.
基金Funded by Key Scientific and Technological Research Project ofHubei Province (No.2004AA101C23) and Key Scientific and Tech-nological Research Project of Ministry of Education of China (No.02052)
文摘High pressure method was ased for the first time to produce rectorite clay (REC)/phenolic resin (PF) and organic rectorite clay (OREC) /phenolic resin and montmorillonite( MMT)lphenolic resin (PF) nanocomposites. The structure of the material phase was studied by X-ray diffraction (XRD), transmission electron microscopy (TEM), Fourier transform infrared ( FT- IR ) spectroscopy, thermogravimetric analysis ( TGA ), and atomic force microscopg" (AFM). The experimental results show that intercalated clay/resin nanocomposites could form under normal temperature and high pressure conditions by the intercalation of polymeric molecules rather than interlayer polymerization.
基金Funded by The National Natural Science Foundation of China(No.50572070 and No.50672066)
文摘An intercalative composite of graphite oxide (GO) as host intercalated by an object of TiO2 nanoparticles was obtained at low temperature by mixing GO with Ti(SO4)2 solution, and by another object of Ti2O3 while mixing with TiCl4 ethanol solution. Microstructures of the GO and its intercalative composites at different C/Ti ratio were studied by XRD, SEM, AFM and FF-IR, and the evolution of these lamellar structures was studied based on the temperature change. The photocatalytic activity of the intercalative composites was characterized according to the degradation of methyl orange. The intercalative composite formed by Ti(SO4)2 solution presents an excellent photocatalytic reactivity, while that formed by TiCl4 presents no observablly photocatalytic reactivity. The electric conductivity variation of different composites was checked, in order to investigate the role of the possible electron transfer between the graphite layer and TiO2 nanocrystal during TiO2 excited by UV light irradiation.
基金the National Natural Science Foundation of China for financial support.
文摘A new intercalation compound, Fe0.85PS3(4,4-bipyH)0.30 (4,4-bipy = 4,4-bipyridine), is obtained by the intercalation of 4,4-bipyridine?HCl with lamellar FePS3, which is characterized by elemental analysis, powder X-ray diffraction, infrared spectroscopy. By comparison with the pure FePS3, the lattice spacing of Fe0.85PS3(4,4-bipyH)0.30 is expanded by ~ 5.7 , indicating that the ring plane of the guest is perpendicular to the layer of the host. The magnetic property of Fe0.85PS3(4,4-bipyH)0.30 is studied with SQUID. It exhibits an antiferromagnetic phase transition with TN of about 70 K.
基金the National Natural Science Foundation of China(No.51804021)the China Postdoctoral Science Foundation(No.2018M640067)。
文摘A novel method for exfoliating graphite oxide(GrO)was implemented through the mass water absorption of a GrO–poly(ethylene glycol)(GrO–PEG)composite.The GrO–PEG composite was prepared by intercalating PEG into the lamellae of GrO,and the variation of the basal spacing was measured by X-ray diffraction analysis.The yield of graphene was measured with an ultraviolet–visible spectrophotometer,and the properties of graphene oxide(GO)were characterized by atomic force microscopy,transmission electron microscopy(TEM),Raman spectrometry,and Fourier transform infrared spectroscopy.Increasing intercalation time was found to improve the yield of GO,whereas increasing the PEG molecular weight had the opposite effect.The GO sheets produced from the intercalation–absorption–exfoliation process were found to be a four-layer structure.TEM and Raman analyses indicate that the graphitized structure and oxygen groups of GO were preserved during the exfoliation process.Most importantly,the results show that good-quality GO could be prepared via a mild method involving water absorption of a GrO–PEG composite.