Calcium-barium sulfo-ferritealuminate(C_3BA_(3-y)F_(y)$)was synthesized by doping Ba-bearing calcium sulphoaluminate(C_3BA_3$)with Fe^(3+).The effects of calcination temperature,holding time and Fe-doping concentratio...Calcium-barium sulfo-ferritealuminate(C_3BA_(3-y)F_(y)$)was synthesized by doping Ba-bearing calcium sulphoaluminate(C_3BA_3$)with Fe^(3+).The effects of calcination temperature,holding time and Fe-doping concentration on the solid-state reaction process of the C_(3)BA_(3-y)F_(y)$(y=0,0.2,0.25,0.4,and 0.6)were investigated by the Rietveld/XRD quantitative phase analysis.The experimental results show that Fe-doping not only significantly improvs the synthesis of C_(3)BA_(3-y)F_(y)$,but also reduces the solid-state reaction potential energy barrier and then promots mineral formation.Nevertheless,the mineral begins to decompose when the Fe/Al ratio exceeds 2/13 and the calcination temperature exceeds 1300℃.The Ginstling equation is found to be the most appropriate kinetic model for the statistical fitting of C_(3)BA_(3-y)F_(y)$formation process,based on the mathematical model.It is observed that the apparent activation energy of C_(3)BA_(3-y)F_(y)$decreases and then increases with increasing Fe-doping concentration.展开更多
Multiphase design is a promising approach to achieve superior ablation resistance of multicomponent ultra-high temperature ceramic,while understanding the ablation mechanism is the foundation.Here,through investigatin...Multiphase design is a promising approach to achieve superior ablation resistance of multicomponent ultra-high temperature ceramic,while understanding the ablation mechanism is the foundation.Here,through investigating a three-phase multicomponent ceramic consisting of Hf-rich carbide,Nb-rich carbide,and Zr-rich silicide phases,we report a newly discovered solid-state reaction process among multiphase multicomponent ceramic during ablation.It was found that this solid-state reaction occurred in the matrix/oxide scale interface region.In this process,metal cations are counter-diffused between the multicomponent phases,thereby resulting in their composition evolution,which allows the multicomponent phases to exist stably under a higher oxygen partial pressure,leading to the improvement of thermodynamic stability of three-phase multicomponent ceramic.Additionally,this solid-state reaction process appears synergistic with the preferential oxidation behavior among the oxide scale in enhancing the ablation performance.展开更多
The formation mechanism of calcium vanadate and manganese vanadate and the difference between calcium and manganese in the reaction with vanadium are basic issues in the calcification roasting and manganese roasting p...The formation mechanism of calcium vanadate and manganese vanadate and the difference between calcium and manganese in the reaction with vanadium are basic issues in the calcification roasting and manganese roasting process with vanadium slag.In this work,CaO–V_(2)O_(5) and MnO_(2)–V_(2)O_(5) diffusion couples were prepared and roasted for different time periods to illustrate and compare the diffusion reaction mechanisms.Then,the changes in the diffusion product and diffusion coefficient were investigated and calculated based on scanning electron microscopy (SEM) with energy dispersive X-ray spectroscopy (EDS) analysis.Results show that with the extension of the roasting time,the diffusion reaction gradually proceeds among the CaO–V_(2)O_(5) and MnO_(2)–V_(2)O_(5) diffusion couples.The regional boundaries of calcium and vanadium are easily identifiable for the CaO–V_(2)O_(5) diffusion couple.Meanwhile,for the MnO_(2)–V_(2)O_(5) diffusion couple,MnO_(2) gradually decomposes to form Mn_(2)O_(3),and vanadium diffuses into the interior of Mn_(2)O_(3).Only a part of vanadium combines with manganese to form the diffusion production layer.CaV_(2)O_(6) and MnV_(2)O_(6) are the interfacial reaction products of the CaO–V_(2)O_(5) and MnO_(2)–V_(2)O_(5) diffusion couples,respectively,whose thicknesses are 39.85 and 32.13μm when roasted for 16 h.After 16 h,both diffusion couples reach the reaction equilibrium due to the limitation of diffusion.The diffusion coefficient of the CaO–V_(2)O_(5) diffusion couple is higher than that of the MnO_(2)–V_(2)O_(5) diffusion couple for the same roasting time,and the diffusion reaction between vanadium and calcium is easier than that between vanadium and manganese.展开更多
Two types of spinel cathode powders, LiMn2O4 and LiAl0.1Mn1.9O3.9F0.1, were synthesized by solid-state reaction, X-ray diffraction （XRD） patterns of the prepared samples were identified as the spinel structure with ...Two types of spinel cathode powders, LiMn2O4 and LiAl0.1Mn1.9O3.9F0.1, were synthesized by solid-state reaction, X-ray diffraction （XRD） patterns of the prepared samples were identified as the spinel structure with a space group of Fd 3^- m. The cubic lattice parameter was determined from least-squares fitting of the XRD data. The LiAl0.1Mn1.9O3.9F0.1 sample showed a little lower initial capacity, but better cycling performance than the LiMn2O4 sample at both room temperature and an elevated temperature. The Vanderbilt method was used to test the electrochemical conductivity of the LiMn2O4 samples. The electrochemical impedance spectroscopy （EIS） method was employed to investigate the electrochemical properties of these spinel LiMn2O4 samples.展开更多
Three individual peaks of thermal solid-state reaction processes of the synthesized Mn0.90Co0.05Mg0.05HPO4?3H2O were observed corresponding to dehydration I,dehydration II and polycondensation processes.An alternative...Three individual peaks of thermal solid-state reaction processes of the synthesized Mn0.90Co0.05Mg0.05HPO4?3H2O were observed corresponding to dehydration I,dehydration II and polycondensation processes.An alternative method for the calculation of the extent of conversion was proposed from the peak area of the individual DTG peak after applying the best fitting deconvolution function(Frazer–Suzuki function).An iterative integral isoconversional equation was used to compute the values of the apparent activation energy Eαand they were found to be 65.87,78.16 and 119.32 kJ/mol for three peaks,respectively.Each individual peak was guaranteed to be a single-step kinetic system with its unique kinetic parameters.The reaction mechanism functions were selected by the comparison between experimental and model plots.The results show that the first,second and final individual peaks were two-dimensional diffusion of spherical symmetry(D2),three-dimensional diffusion of spherical symmetry(D3)and contracting cylinder(cylindrical symmetry,R2)mechanisms.Pre-exponential factor values of 3.91×106,1.35×107 and 2.15×107 s?1 were calculated from the Eαvalues and reaction mechanisms.The corresponded standard thermodynamic functions of the transition-state(activated)complexes were determined and found to agree well with the experimental data.展开更多
LiNi_(0.5)Mn_(1.5)O_(4)was prepared under various conditions by one-step solid-state reaction in air and its properties were investigated by X-ray diffractormetry(XRD),scanning electron microscopy(SEM)and electrochemi...LiNi_(0.5)Mn_(1.5)O_(4)was prepared under various conditions by one-step solid-state reaction in air and its properties were investigated by X-ray diffractormetry(XRD),scanning electron microscopy(SEM)and electrochemical measurement.XRD patterns show that LiNi_(0.5)Mn_(1.5)O_(4)synthesized under various conditions has cubic spinel structure.SEM images exhibit that the particle size increases with increasing calcination temperature and time.Electro chemical test shows that the LiNi_(0.5)Mn_(1.5)O_(4)calcined at 700℃for 24 h delivers up to 143 mA·h/g,and the capacity retains 132 mA·h/g after 30 cycles.展开更多
Nano-sized cerium-titanium pyrophosphates Ce1-xTixP2O7 （with x = 0, 0.2, 0.5, 0.7, 0.9, and 1.0） were obtained by grinding a mixture of Ce（SO4）2·4H2O, Ti（SO4）2, and Na4P2O7·10H2O in the presence of sur...Nano-sized cerium-titanium pyrophosphates Ce1-xTixP2O7 （with x = 0, 0.2, 0.5, 0.7, 0.9, and 1.0） were obtained by grinding a mixture of Ce（SO4）2·4H2O, Ti（SO4）2, and Na4P2O7·10H2O in the presence of surfactant PEG-400 at room temperature, washing the mixture with water to remove soluble inorganic salts, and drying at 100℃. The products and their calcined samples were characterized using ultraviolet-visible spectroscopy （UV-vis）, thermogravimetry and differential thermal analyses （TG/DTA）, X-ray powder diffraction （XRD）, and transmission electron microscopy （TEM）. The results show that nano-sized Ce1-xTixP2O7 behave as an excellent UV-shielding material. Thereinto, the CeP2O7 has the most excellent UV-shielding effect, and the amorphous state of Ce0.8Ti0.2P2O7 can keep at a higher temperature than CeP2O7. Therefore, the stabilization of the amorphous state of the cerium pyrophosphates was carded out by doping titanium. This stabilization is a significant improvement, which enables to apply these amorphous pyrophosphates not only to cosmetics and paints, but also plastics and films.展开更多
High-pressure solid-state metathesis(HPSSM)reaction is an effective route to novel metal nitrides.A recent advance in HPSSM reactions is presented for a number of examples,including 3d transition metal nitrides(ε-Fe_...High-pressure solid-state metathesis(HPSSM)reaction is an effective route to novel metal nitrides.A recent advance in HPSSM reactions is presented for a number of examples,including 3d transition metal nitrides(ε-Fe_(3)N,ε-Fe_(3-x)Co_(x)N,CrN,and Co_(4)N_(x)),4d transition metal nitrides(MoNx),and 5d transition metal nitrides(Re_(3)N,WN_(x)).Thermodynamic investigations based on density functional theory(DFT)calculations on several typical HPSSM reactions between metal oxides and boron nitride indicate that the pressure could reduce the reaction enthalpy △H.High-pressure confining environment thermodynamically favors an ion-exchange process between metal atom and boron atom,and successfully results in the formation of well-crystalized metal nitrides with potential applications.展开更多
Hydrogen storage and delivery technology is still a bottleneck in the hydrogen industry chain.Among all kinds of hydrogen storage methods,light-weight solid-state hydrogen storage(LSHS)materials could become promising...Hydrogen storage and delivery technology is still a bottleneck in the hydrogen industry chain.Among all kinds of hydrogen storage methods,light-weight solid-state hydrogen storage(LSHS)materials could become promising due to its intrinsic high hydrogen capacity.Hydrolysis reaction of LSHS materials occurs at moderate conditions,indicating the potential for portable applications.At present,most of review work focuses on the improvement of material performance,especially the catalysts design.This part is important,but the others,such as operation modes,are also vital to to make full use of material potential in the practical applications.Different operation modes of hydrolysis reaction have an impact on hydrogen capacity to various degrees.For example,hydrolysis in solution would decrease the hydrogen capacity of hydrogen generator to a low value due to the excessive water participating in the reaction.Therefore,application-oriented operation modes could become a key problem for hydrolysis reaction of LSHS materials.In this paper,the operation modes of hydrolysis reaction and their practical applications are mainly reviewed.The implements of each operation mode are discussed and compared in detail to determine the suitable one for practical applications with the requirement of high energy density.The current challenges and future directions are also discussed.展开更多
Oily cold rolling mill （CRM） sludge is one of the pollutants emitted by iron and steel plants. Recycling oily CRM sludge can not only reduce pollution but also bring social and environmental benefits. In this study,...Oily cold rolling mill （CRM） sludge is one of the pollutants emitted by iron and steel plants. Recycling oily CRM sludge can not only reduce pollution but also bring social and environmental benefits. In this study, using oily CRM sludge as sources of iron oxide, the strontium ferrite powders were synthesized in multiple steps including vacuum distillation, magnetic separation, oxidizing roasting, and solidstate reaction. The optimal technological conditions of vacuum distillation and oxidizing roasting were studied carefully. To consider the effects of Fe203/ SrCO3 tool ratio, calcination temperature, milling time and calcination time on magnetic properties of prepared strontium ferrite powders, the orthogonal experimental method was adopted. The maximum saturation magneti- zation （62.6 mA-m2.g-1） of the synthesized strontium ferrite powders was achieved at the Fe203/SrCO3 mol ratio of 6, 5 h milling time, 1250 ~C calcination temperature, and 1 h calcination time. Strontium ferrite powders syn- thesis method not only provides a cheap, high quality raw material for the production of strontium ferrite powders, but also effectively prevents the environmental pollution.展开更多
Size control of BaTiO3 in solid-state reaction between BaCO3 and TiO2 was demonstrated by varying the size of TiO2 and milling conditions of BaCO3. The smaller TiO2 particles had higher surface area, resulting in fast...Size control of BaTiO3 in solid-state reaction between BaCO3 and TiO2 was demonstrated by varying the size of TiO2 and milling conditions of BaCO3. The smaller TiO2 particles had higher surface area, resulting in faster initial reaction. The mechanically milled BaCO3 particles accelerated the diffusion process and decreased the calcinations temperature. It can be deduced from the results that the size control is possible and nano-sized BaTiO3 particles with about 60 nm can be synthesized by using the conventional solid-state reaction between BaCO3 and TiO2.展开更多
Designing a durable lithium metal anode for solid state batteries requires a controllable and uniform deposition of lithium, and the metal lithium layer should maintain a good interface contact with solid state electr...Designing a durable lithium metal anode for solid state batteries requires a controllable and uniform deposition of lithium, and the metal lithium layer should maintain a good interface contact with solid state electrolyte during cycles. In this work, we construct a robust functional interface layer on the modified LiB electrode which considerably improves the electrochemical stability of lithium metal electrode in solid state batteries. It is found that the functional interface layer consisting of polydioxolane, polyiodide ion and Li TFSI effectively restrains the growth of lithium dendrites through the redox shuttle reaction of I-/I3-and maintains a good contact between lithium anode and solid electrolyte during cycles. Benefit from these two advantages, the modified Li-B anode exhibits a remarkable cyclic performance in comparison with those of the bare Li-B anode.展开更多
The Mg_(2)Si-matrix thermoelectric material was synthesized by low temperature solid-state reaction.This paper studies the effects of holding time and reaction temperature on the particle size and the properties of th...The Mg_(2)Si-matrix thermoelectric material was synthesized by low temperature solid-state reaction.This paper studies the effects of holding time and reaction temperature on the particle size and the properties of the material,and also studies effects of doping elemental Sb,Te and their doping seqence on the properties of the material.The result shows that excessively high temperature and elongated holding time of solid-state reaction are harmful,there is a range of particle size to ensure optimum properties and the doping sequence of Sb or Te without influencing the properties.展开更多
The aim of this study was to investigate the phase transformation and kinetics of the solid-state reaction of CaO−V_(2)O_(5),which is the predominant binary mixture involved in the vanadium recovery process.Thermal an...The aim of this study was to investigate the phase transformation and kinetics of the solid-state reaction of CaO−V_(2)O_(5),which is the predominant binary mixture involved in the vanadium recovery process.Thermal analysis,X-ray diffraction spectroscopy,scanning electron microscopy,and energy dispersive spectrometry were used to characterize the solid-state reaction of the samples.The extent of the solid reac-tion was derived using the preliminary quantitative phase analysis of the X-ray patterns.The results indicate that the solid reaction of the CaO−V_(2)O_(5)mixture is strongly influenced by the reaction temperature and CaO/V_(2)O_(5)mole ratio.The transformation of calcium vanadate in-volves a step-by-step reaction of CaO−V_(2)O_(5),CaO−CaV_(2)O_(6),and CaO−Ca_(2)V_(2)O7 depending on the CaO/V_(2)O_(5)mole ratio.The kinetic data of the solid reaction of the CaO−V_(2)O_(5)(1:1)mixture followed a second-order reaction model.The activation energy(Ea)and preexponential factor(A)were determined to be 145.38 kJ/mol,and 3.67×10^(8)min^(−1),respectively.展开更多
Nanocrystalline NH4ZrH（PO4）2·H2O was obtained by grinding ZrOC12·8H2O and （NH4）2HPO4 in the presence of surfactant PEG-400 via solid-state reaction at room temperature. The product NH4ZrH（PO4）2·H2...Nanocrystalline NH4ZrH（PO4）2·H2O was obtained by grinding ZrOC12·8H2O and （NH4）2HPO4 in the presence of surfactant PEG-400 via solid-state reaction at room temperature. The product NH4ZrH（PO4）2·H2O and its product of thermal decomposition were characterized using thermogravimetry and differential thermal analyses （TG/DTA）, Fourier transform infrared spectroscopy （FT-IR）, X-ray powder diffraction （XRD）, and transmission electron microscopy （TEM）. Nanocrystalline NHaZrH（PO4）2·H2O with an average particle size of 17 nm was obtained when the product was kept at80℃ for 3 h. Its crystalline framework was stable at temperatures below 250℃. In addition, the catalytic performance of NH4ZrH（PO4）2·H2O in the synthesis of butyl acetate was investigated. The results show that NH4ZrH（PO4）2·H2O behaved as an excellent heterogeneous catalyst in the synthesis of butyl acetate.展开更多
Lithium-substituted LixMn2O4 （x = 0.98, 1.03, 1.08） spinel samples were synthesized by solid-state reaction. X-ray diffraction （XRD） patterns show that the prepared samples have a spinel structure with a space gro...Lithium-substituted LixMn2O4 （x = 0.98, 1.03, 1.08） spinel samples were synthesized by solid-state reaction. X-ray diffraction （XRD） patterns show that the prepared samples have a spinel structure with a space group of Fd 3 m. The cubic lattice parameter was determined from least-squares fitting of the XRD data. Li1.03Mn2O4 shows high capacity at both low and high current densities, while Lil.08Mn2O4shows good cycling performance but relatively low capacity when cycled at both room and elevated temperatures. A variety of electrochemical methods were employed to investigate the electrochemical properties of these series of spinel LixMn2O4.展开更多
Superfine cerium-zinc oxides Ce1-xZnxO2-x with x = 0, 0.1, 0.3, 0.5, and 1.0 were obtained by grinding Ce（SO4）2·4H2O, ZnSO4·7H2O and NH4HCO3 under the condition of surfactant PEG-400 being present at room ...Superfine cerium-zinc oxides Ce1-xZnxO2-x with x = 0, 0.1, 0.3, 0.5, and 1.0 were obtained by grinding Ce（SO4）2·4H2O, ZnSO4·7H2O and NH4HCO3 under the condition of surfactant PEG-400 being present at room temperature, washing the mixture with water to remove soluble inorganic salts, drying at 80°C, and calcining.The precursor and its calcined samples were characterized using thermogravimetry and differential thermal analyses（TG/DTA）, UV-vis absorption spectroscopy, X-ray powder diffraction（XRD）, and scanning electron microscopy（SEM）.The results showed that superfine Ce1-xZnxO2-x behaved as an excellent UV-shielding material.The ZnO-doped CeO2 can facilitate the formation of crystalline state CeO2.The catalytic ability of products used in air oxidation of castor oil was investigated.The results showed that the catalytic abilities of products decreased with increasing zinc amount.展开更多
Dielectric polarization performance induced by defect engineering approach has been proved to be an effective way for improving the microwave absorption property of carbon-based materials.Assisting by the solid-state ...Dielectric polarization performance induced by defect engineering approach has been proved to be an effective way for improving the microwave absorption property of carbon-based materials.Assisting by the solid-state reaction,the structural integrity of multi-walled carbon nanotubes(MWCNTs)would be broken along with the volume expansion and etching process of cobalt oxides.Therefore,the defects could be obtained and result in the enhancement of microwave absorption property.Ascribing to the broken wall structures,the defect-distances(L_(D))and concentrations(n_(D))have been optimized to be 9.80 nm and3.37×10^(11) cm^(-2).The minimum reflection loss(RL)had reached-54.6 dB at 4.5 GHz with a thickness of4.13 mm and the corresponding effective absorption bandwidth(EAB_(<-10 dB))was analyzed to be 14.6 GHz.Such enhancement is correlated to the dielectric polarization and the permeability-to-permittivity transformation raised from the defect structures and concentrations.The present work demonstrates an effective strategy for tailoring the microwave absorption property of MWCNTs by engineering defect concentrations,and could be further extended to other carbon-based absorbents.展开更多
基金Funded by the National Key Research and Development Program of China(2021YFB3802002)the National Natural Science Foundation of China(Nos.52172021 and U22A20126)+4 种基金the Science Foundation for Excellent Young Scholars of Shandong Province(No.ZR2023YQ041)the Natural Science Foundation of Shandong Province(ZR2021ME123)the Taishan Scholars Program(No.tsqn202306224)the Science and Technology Innovation Support Plan for Young Researchers in Institutes of Higher Education in Shandong(No.2019KJA017)the'111 Center'。
文摘Calcium-barium sulfo-ferritealuminate(C_3BA_(3-y)F_(y)$)was synthesized by doping Ba-bearing calcium sulphoaluminate(C_3BA_3$)with Fe^(3+).The effects of calcination temperature,holding time and Fe-doping concentration on the solid-state reaction process of the C_(3)BA_(3-y)F_(y)$(y=0,0.2,0.25,0.4,and 0.6)were investigated by the Rietveld/XRD quantitative phase analysis.The experimental results show that Fe-doping not only significantly improvs the synthesis of C_(3)BA_(3-y)F_(y)$,but also reduces the solid-state reaction potential energy barrier and then promots mineral formation.Nevertheless,the mineral begins to decompose when the Fe/Al ratio exceeds 2/13 and the calcination temperature exceeds 1300℃.The Ginstling equation is found to be the most appropriate kinetic model for the statistical fitting of C_(3)BA_(3-y)F_(y)$formation process,based on the mathematical model.It is observed that the apparent activation energy of C_(3)BA_(3-y)F_(y)$decreases and then increases with increasing Fe-doping concentration.
基金supported by the National Natural Science Foundation of China(52072410 and 51602349).
文摘Multiphase design is a promising approach to achieve superior ablation resistance of multicomponent ultra-high temperature ceramic,while understanding the ablation mechanism is the foundation.Here,through investigating a three-phase multicomponent ceramic consisting of Hf-rich carbide,Nb-rich carbide,and Zr-rich silicide phases,we report a newly discovered solid-state reaction process among multiphase multicomponent ceramic during ablation.It was found that this solid-state reaction occurred in the matrix/oxide scale interface region.In this process,metal cations are counter-diffused between the multicomponent phases,thereby resulting in their composition evolution,which allows the multicomponent phases to exist stably under a higher oxygen partial pressure,leading to the improvement of thermodynamic stability of three-phase multicomponent ceramic.Additionally,this solid-state reaction process appears synergistic with the preferential oxidation behavior among the oxide scale in enhancing the ablation performance.
基金supported by the National Natural Science Foundation of China(Nos.52174277 and 51874077)the Fundamental Funds for the Central Universities,China(No.N2225032)+1 种基金the China Postdoctoral Science Foundation(No.2022M720683)the Postdoctoral Fund of Northeastern University,China。
文摘The formation mechanism of calcium vanadate and manganese vanadate and the difference between calcium and manganese in the reaction with vanadium are basic issues in the calcification roasting and manganese roasting process with vanadium slag.In this work,CaO–V_(2)O_(5) and MnO_(2)–V_(2)O_(5) diffusion couples were prepared and roasted for different time periods to illustrate and compare the diffusion reaction mechanisms.Then,the changes in the diffusion product and diffusion coefficient were investigated and calculated based on scanning electron microscopy (SEM) with energy dispersive X-ray spectroscopy (EDS) analysis.Results show that with the extension of the roasting time,the diffusion reaction gradually proceeds among the CaO–V_(2)O_(5) and MnO_(2)–V_(2)O_(5) diffusion couples.The regional boundaries of calcium and vanadium are easily identifiable for the CaO–V_(2)O_(5) diffusion couple.Meanwhile,for the MnO_(2)–V_(2)O_(5) diffusion couple,MnO_(2) gradually decomposes to form Mn_(2)O_(3),and vanadium diffuses into the interior of Mn_(2)O_(3).Only a part of vanadium combines with manganese to form the diffusion production layer.CaV_(2)O_(6) and MnV_(2)O_(6) are the interfacial reaction products of the CaO–V_(2)O_(5) and MnO_(2)–V_(2)O_(5) diffusion couples,respectively,whose thicknesses are 39.85 and 32.13μm when roasted for 16 h.After 16 h,both diffusion couples reach the reaction equilibrium due to the limitation of diffusion.The diffusion coefficient of the CaO–V_(2)O_(5) diffusion couple is higher than that of the MnO_(2)–V_(2)O_(5) diffusion couple for the same roasting time,and the diffusion reaction between vanadium and calcium is easier than that between vanadium and manganese.
基金This work was financially supported by the National Natural Science Foundation of China (No.50272012).
文摘Two types of spinel cathode powders, LiMn2O4 and LiAl0.1Mn1.9O3.9F0.1, were synthesized by solid-state reaction, X-ray diffraction （XRD） patterns of the prepared samples were identified as the spinel structure with a space group of Fd 3^- m. The cubic lattice parameter was determined from least-squares fitting of the XRD data. The LiAl0.1Mn1.9O3.9F0.1 sample showed a little lower initial capacity, but better cycling performance than the LiMn2O4 sample at both room temperature and an elevated temperature. The Vanderbilt method was used to test the electrochemical conductivity of the LiMn2O4 samples. The electrochemical impedance spectroscopy （EIS） method was employed to investigate the electrochemical properties of these spinel LiMn2O4 samples.
基金supported by King Mongkut’s Institute of Technology Ladkrabang [KREF146001]
文摘Three individual peaks of thermal solid-state reaction processes of the synthesized Mn0.90Co0.05Mg0.05HPO4?3H2O were observed corresponding to dehydration I,dehydration II and polycondensation processes.An alternative method for the calculation of the extent of conversion was proposed from the peak area of the individual DTG peak after applying the best fitting deconvolution function(Frazer–Suzuki function).An iterative integral isoconversional equation was used to compute the values of the apparent activation energy Eαand they were found to be 65.87,78.16 and 119.32 kJ/mol for three peaks,respectively.Each individual peak was guaranteed to be a single-step kinetic system with its unique kinetic parameters.The reaction mechanism functions were selected by the comparison between experimental and model plots.The results show that the first,second and final individual peaks were two-dimensional diffusion of spherical symmetry(D2),three-dimensional diffusion of spherical symmetry(D3)and contracting cylinder(cylindrical symmetry,R2)mechanisms.Pre-exponential factor values of 3.91×106,1.35×107 and 2.15×107 s?1 were calculated from the Eαvalues and reaction mechanisms.The corresponded standard thermodynamic functions of the transition-state(activated)complexes were determined and found to agree well with the experimental data.
基金Project(76600)supported by Postdoctoral Science Foundation of Central South University
文摘LiNi_(0.5)Mn_(1.5)O_(4)was prepared under various conditions by one-step solid-state reaction in air and its properties were investigated by X-ray diffractormetry(XRD),scanning electron microscopy(SEM)and electrochemical measurement.XRD patterns show that LiNi_(0.5)Mn_(1.5)O_(4)synthesized under various conditions has cubic spinel structure.SEM images exhibit that the particle size increases with increasing calcination temperature and time.Electro chemical test shows that the LiNi_(0.5)Mn_(1.5)O_(4)calcined at 700℃for 24 h delivers up to 143 mA·h/g,and the capacity retains 132 mA·h/g after 30 cycles.
基金supported by the Natural Sci-ence Foundation of Guangxi Province, China (No. 0640009)
文摘Nano-sized cerium-titanium pyrophosphates Ce1-xTixP2O7 （with x = 0, 0.2, 0.5, 0.7, 0.9, and 1.0） were obtained by grinding a mixture of Ce（SO4）2·4H2O, Ti（SO4）2, and Na4P2O7·10H2O in the presence of surfactant PEG-400 at room temperature, washing the mixture with water to remove soluble inorganic salts, and drying at 100℃. The products and their calcined samples were characterized using ultraviolet-visible spectroscopy （UV-vis）, thermogravimetry and differential thermal analyses （TG/DTA）, X-ray powder diffraction （XRD）, and transmission electron microscopy （TEM）. The results show that nano-sized Ce1-xTixP2O7 behave as an excellent UV-shielding material. Thereinto, the CeP2O7 has the most excellent UV-shielding effect, and the amorphous state of Ce0.8Ti0.2P2O7 can keep at a higher temperature than CeP2O7. Therefore, the stabilization of the amorphous state of the cerium pyrophosphates was carded out by doping titanium. This stabilization is a significant improvement, which enables to apply these amorphous pyrophosphates not only to cosmetics and paints, but also plastics and films.
基金This work was supported by Research Foundation of Key Laboratory of Neutron Physics(Grant No.2015BB03)National Natural Science Foundation of China(Grant Nos.11774247 and 21301122)+2 种基金Science Foundation for Excellent Youth Scholars of Sichuan University(Grant No.2015SCU04A04)Specialized Research Fund for the Doctoral Program of Higher Education(Grant No.20130181120116)Premier Research Institution for Ultrahigh-pressure Sciences(PRIUS).
文摘High-pressure solid-state metathesis(HPSSM)reaction is an effective route to novel metal nitrides.A recent advance in HPSSM reactions is presented for a number of examples,including 3d transition metal nitrides(ε-Fe_(3)N,ε-Fe_(3-x)Co_(x)N,CrN,and Co_(4)N_(x)),4d transition metal nitrides(MoNx),and 5d transition metal nitrides(Re_(3)N,WN_(x)).Thermodynamic investigations based on density functional theory(DFT)calculations on several typical HPSSM reactions between metal oxides and boron nitride indicate that the pressure could reduce the reaction enthalpy △H.High-pressure confining environment thermodynamically favors an ion-exchange process between metal atom and boron atom,and successfully results in the formation of well-crystalized metal nitrides with potential applications.
基金financially supported by the National Key R&D Program of China(2022YFE0101300)the National Natural Science Foundation of China(52176203 and 52050027)the China Education Association for International Exchange(202006)。
文摘Hydrogen storage and delivery technology is still a bottleneck in the hydrogen industry chain.Among all kinds of hydrogen storage methods,light-weight solid-state hydrogen storage(LSHS)materials could become promising due to its intrinsic high hydrogen capacity.Hydrolysis reaction of LSHS materials occurs at moderate conditions,indicating the potential for portable applications.At present,most of review work focuses on the improvement of material performance,especially the catalysts design.This part is important,but the others,such as operation modes,are also vital to to make full use of material potential in the practical applications.Different operation modes of hydrolysis reaction have an impact on hydrogen capacity to various degrees.For example,hydrolysis in solution would decrease the hydrogen capacity of hydrogen generator to a low value due to the excessive water participating in the reaction.Therefore,application-oriented operation modes could become a key problem for hydrolysis reaction of LSHS materials.In this paper,the operation modes of hydrolysis reaction and their practical applications are mainly reviewed.The implements of each operation mode are discussed and compared in detail to determine the suitable one for practical applications with the requirement of high energy density.The current challenges and future directions are also discussed.
基金supported by the National Key Technology R&D Program (Nos. 2012BAC02B01, 2012BAC12B05, 2011BAE13B07, and 2011BAC10B02)the National High Technology Research and Development Program of China (No. 2012AA063202)+2 种基金the National Natural Science Foundation of China (Nos. 51174247 and 51004011)the Science and Technology Program of Guangdong Province, China (No. 2010A030200003)the Ph.D. Programs Foundation of the Ministry of Education of China (No. 2010000612003)
文摘Oily cold rolling mill （CRM） sludge is one of the pollutants emitted by iron and steel plants. Recycling oily CRM sludge can not only reduce pollution but also bring social and environmental benefits. In this study, using oily CRM sludge as sources of iron oxide, the strontium ferrite powders were synthesized in multiple steps including vacuum distillation, magnetic separation, oxidizing roasting, and solidstate reaction. The optimal technological conditions of vacuum distillation and oxidizing roasting were studied carefully. To consider the effects of Fe203/ SrCO3 tool ratio, calcination temperature, milling time and calcination time on magnetic properties of prepared strontium ferrite powders, the orthogonal experimental method was adopted. The maximum saturation magneti- zation （62.6 mA-m2.g-1） of the synthesized strontium ferrite powders was achieved at the Fe203/SrCO3 mol ratio of 6, 5 h milling time, 1250 ~C calcination temperature, and 1 h calcination time. Strontium ferrite powders syn- thesis method not only provides a cheap, high quality raw material for the production of strontium ferrite powders, but also effectively prevents the environmental pollution.
文摘Size control of BaTiO3 in solid-state reaction between BaCO3 and TiO2 was demonstrated by varying the size of TiO2 and milling conditions of BaCO3. The smaller TiO2 particles had higher surface area, resulting in faster initial reaction. The mechanically milled BaCO3 particles accelerated the diffusion process and decreased the calcinations temperature. It can be deduced from the results that the size control is possible and nano-sized BaTiO3 particles with about 60 nm can be synthesized by using the conventional solid-state reaction between BaCO3 and TiO2.
基金supported by the National Natural Science Foundation of China (NO. 21805113)the Fundamental Research Funds for the Central Universities (NO. 11618410 and NO. 11619103)the China Postdoctoral Science Foundation (NO. 2019M653271)。
文摘Designing a durable lithium metal anode for solid state batteries requires a controllable and uniform deposition of lithium, and the metal lithium layer should maintain a good interface contact with solid state electrolyte during cycles. In this work, we construct a robust functional interface layer on the modified LiB electrode which considerably improves the electrochemical stability of lithium metal electrode in solid state batteries. It is found that the functional interface layer consisting of polydioxolane, polyiodide ion and Li TFSI effectively restrains the growth of lithium dendrites through the redox shuttle reaction of I-/I3-and maintains a good contact between lithium anode and solid electrolyte during cycles. Benefit from these two advantages, the modified Li-B anode exhibits a remarkable cyclic performance in comparison with those of the bare Li-B anode.
文摘The Mg_(2)Si-matrix thermoelectric material was synthesized by low temperature solid-state reaction.This paper studies the effects of holding time and reaction temperature on the particle size and the properties of the material,and also studies effects of doping elemental Sb,Te and their doping seqence on the properties of the material.The result shows that excessively high temperature and elongated holding time of solid-state reaction are harmful,there is a range of particle size to ensure optimum properties and the doping sequence of Sb or Te without influencing the properties.
基金This work was financially supported by the National Natural Science Foundation of China(No.52004044)the Natural Science Foundation of Chongqing,China(No.cstc2019jcyj-bshX0068)Chongqing Postdoctoral Innovation Program(No.CQBX201904),and the Open Project Founded by the State Key Laboratory of Vanadium and Titanium Resources Comprehensive Utilization.
文摘The aim of this study was to investigate the phase transformation and kinetics of the solid-state reaction of CaO−V_(2)O_(5),which is the predominant binary mixture involved in the vanadium recovery process.Thermal analysis,X-ray diffraction spectroscopy,scanning electron microscopy,and energy dispersive spectrometry were used to characterize the solid-state reaction of the samples.The extent of the solid reac-tion was derived using the preliminary quantitative phase analysis of the X-ray patterns.The results indicate that the solid reaction of the CaO−V_(2)O_(5)mixture is strongly influenced by the reaction temperature and CaO/V_(2)O_(5)mole ratio.The transformation of calcium vanadate in-volves a step-by-step reaction of CaO−V_(2)O_(5),CaO−CaV_(2)O_(6),and CaO−Ca_(2)V_(2)O7 depending on the CaO/V_(2)O_(5)mole ratio.The kinetic data of the solid reaction of the CaO−V_(2)O_(5)(1:1)mixture followed a second-order reaction model.The activation energy(Ea)and preexponential factor(A)were determined to be 145.38 kJ/mol,and 3.67×10^(8)min^(−1),respectively.
基金the Natural Science Foundation of Guangxi Province, China (No. 0640009)
文摘Nanocrystalline NH4ZrH（PO4）2·H2O was obtained by grinding ZrOC12·8H2O and （NH4）2HPO4 in the presence of surfactant PEG-400 via solid-state reaction at room temperature. The product NH4ZrH（PO4）2·H2O and its product of thermal decomposition were characterized using thermogravimetry and differential thermal analyses （TG/DTA）, Fourier transform infrared spectroscopy （FT-IR）, X-ray powder diffraction （XRD）, and transmission electron microscopy （TEM）. Nanocrystalline NHaZrH（PO4）2·H2O with an average particle size of 17 nm was obtained when the product was kept at80℃ for 3 h. Its crystalline framework was stable at temperatures below 250℃. In addition, the catalytic performance of NH4ZrH（PO4）2·H2O in the synthesis of butyl acetate was investigated. The results show that NH4ZrH（PO4）2·H2O behaved as an excellent heterogeneous catalyst in the synthesis of butyl acetate.
基金the National Natural Science Foundation of China (No. 50272012).
文摘Lithium-substituted LixMn2O4 （x = 0.98, 1.03, 1.08） spinel samples were synthesized by solid-state reaction. X-ray diffraction （XRD） patterns show that the prepared samples have a spinel structure with a space group of Fd 3 m. The cubic lattice parameter was determined from least-squares fitting of the XRD data. Li1.03Mn2O4 shows high capacity at both low and high current densities, while Lil.08Mn2O4shows good cycling performance but relatively low capacity when cycled at both room and elevated temperatures. A variety of electrochemical methods were employed to investigate the electrochemical properties of these series of spinel LixMn2O4.
基金supported by the Natural Scientific Foundation of Guangxi Province (No. 0832111)the Large Apparatus Cooperation Community Net Foundation of Guangxi Province, China (No. 695-2008-108)the Undergraduate Innovation Foundation of School of Chemistry and Chemical Engineering of Guangxi University
文摘Superfine cerium-zinc oxides Ce1-xZnxO2-x with x = 0, 0.1, 0.3, 0.5, and 1.0 were obtained by grinding Ce（SO4）2·4H2O, ZnSO4·7H2O and NH4HCO3 under the condition of surfactant PEG-400 being present at room temperature, washing the mixture with water to remove soluble inorganic salts, drying at 80°C, and calcining.The precursor and its calcined samples were characterized using thermogravimetry and differential thermal analyses（TG/DTA）, UV-vis absorption spectroscopy, X-ray powder diffraction（XRD）, and scanning electron microscopy（SEM）.The results showed that superfine Ce1-xZnxO2-x behaved as an excellent UV-shielding material.The ZnO-doped CeO2 can facilitate the formation of crystalline state CeO2.The catalytic ability of products used in air oxidation of castor oil was investigated.The results showed that the catalytic abilities of products decreased with increasing zinc amount.
基金the National Natural Science Foundation of China(U1704253 and U1908220)the Zhejiang Provincial Natural Science Foundation of China(LR18E010001)+2 种基金the National Key Research and Development Program of China(2019YFE0121700)the LiaoNing Revitalization Talents Program(XLYC1807177)the Fundamental Research Funds for the Central Universities(N2102010)。
文摘Dielectric polarization performance induced by defect engineering approach has been proved to be an effective way for improving the microwave absorption property of carbon-based materials.Assisting by the solid-state reaction,the structural integrity of multi-walled carbon nanotubes(MWCNTs)would be broken along with the volume expansion and etching process of cobalt oxides.Therefore,the defects could be obtained and result in the enhancement of microwave absorption property.Ascribing to the broken wall structures,the defect-distances(L_(D))and concentrations(n_(D))have been optimized to be 9.80 nm and3.37×10^(11) cm^(-2).The minimum reflection loss(RL)had reached-54.6 dB at 4.5 GHz with a thickness of4.13 mm and the corresponding effective absorption bandwidth(EAB_(<-10 dB))was analyzed to be 14.6 GHz.Such enhancement is correlated to the dielectric polarization and the permeability-to-permittivity transformation raised from the defect structures and concentrations.The present work demonstrates an effective strategy for tailoring the microwave absorption property of MWCNTs by engineering defect concentrations,and could be further extended to other carbon-based absorbents.
