Detailed mineralogical and gemological records were conducted on 340 unheated spinels from the Horana, Eheliyagoda, Ratnapura, and Okkampatiya mining areas in Sri Lanka. The color of Sri Lankan spinel varies greatly: ...Detailed mineralogical and gemological records were conducted on 340 unheated spinels from the Horana, Eheliyagoda, Ratnapura, and Okkampatiya mining areas in Sri Lanka. The color of Sri Lankan spinel varies greatly: in addition to the mainstream pink to purple pink, green and blue can also be seen. Compared with spinel from other regions such as Myanmar, Vietnam, and Tanzania, Sri Lanka's spinel has more abundant inclusions: several mining areas generally have inclusions such as dolomite, apatite, zircon, and chondrodite. Minerals such as graphite and forsterite are also found in spinel produced in the Horana region;graphite and rutile have been found in spinel produced in the Okkamptiya region. Partially healed fissures are most common in spinel in the Okkampatiya mining area;Unlike Vietnamese spinel, dislocations and growth structures are almost absent in Sri Lankan spinel. The LA-ICP-MS analysis results showed that there were no significant differences among the mining areas. LA-ICP-MS analysis of 5 Sri Lankan cobalt blue spinels showed a variation of 11 to 120 ppm in this chromogenic element. The UV visible absorption spectrum results show that Sri Lankan spinel has a combination spectra with variable ratios of the spectral components Cr 3+ , V 3+ and Fe 2+ from pink to red, orange, purple to purple, and blue-green. The results of infrared spectroscopy and laser Raman spectroscopy analysis showed that all samples showed no indications for heat treatment.展开更多
Chromium plays a vital role in stainless steel due to its ability to improve the corrosion resistance of the latter.However,the re-lease of chromium from stainless steel slag(SSS)during SSS stockpiling causes detrimen...Chromium plays a vital role in stainless steel due to its ability to improve the corrosion resistance of the latter.However,the re-lease of chromium from stainless steel slag(SSS)during SSS stockpiling causes detrimental environmental issues.To prevent chromium pollution,the effects of iron oxide on crystallization behavior and spatial distribution of spinel were investigated in this work.The results revealed that FeO was more conducive to the growth of spinels compared with Fe2O3 and Fe3O4.Spinels were found to be mainly distrib-uted at the top and bottom of slag.The amount of spinel phase at the bottom decreased with the increasing FeO content,while that at the top increased.The average particle size of spinel in the slag with 18wt%FeO content was 12.8μm.Meanwhile,no notable structural changes were observed with a further increase in FeO content.In other words,the spatial distribution of spinel changed when the content of iron oxide varied in the range of 8wt%to 18wt%.Finally,less spinel was found at the bottom of slag with a FeO content of 23wt%.展开更多
Urea holds promise as an alternative water-oxidation substrate in electrolytic cells.High-valence nickelbased spinel,especially after heteroatom doping,excels in urea oxidation reactions(UOR).However,traditional spine...Urea holds promise as an alternative water-oxidation substrate in electrolytic cells.High-valence nickelbased spinel,especially after heteroatom doping,excels in urea oxidation reactions(UOR).However,traditional spinel synthesis methods with prolonged high-temperature reactions lack kinetic precision,hindering the balance between controlled doping and highly active two-dimensional(2D)porous structures design.This significantly impedes the identification of electron configuration-dependent active sites in doped 2D nickel-based spinels.Herein,we present a microwave shock method for the preparation of 2D porous NiCo_(2)O_(4)spinel.Utilizing the transient on-off property of microwave pulses for precise heteroatom doping and 2D porous structural design,non-metal doping(boron,phosphorus,and sulfur)with distinct extranuclear electron disparities serves as straightforward examples for investigation.Precise tuning of lattice parameter reveals the impact of covalent bond strength on NiCo_(2)O_(4)structural stability.The introduced defect levels induce unpaired d-electrons in transition metals,enhancing the adsorption of electron-donating amino groups in urea molecules.Simultaneously,Bode plots confirm the impact mechanism of rapid electron migration caused by reduced band gaps on UOR activity.The prepared phosphorus-doped 2D porous NiCo_(2)O_(4),with optimal electron configuration control,outperforms most reported spinels.This controlled modification strategy advances understanding theoretical structure-activity mechanisms of high-performance 2D spinels in UOR.展开更多
Spinel cobalt oxide(Co_(3)O_(4)),consisting of tetrahedral Co^(2+)(CoTd)and octahedral Co^(3+)(CoOh),is considered as promising earth-abundant electrocatalyst for chlorine evolution reaction(CER).Identifying the catal...Spinel cobalt oxide(Co_(3)O_(4)),consisting of tetrahedral Co^(2+)(CoTd)and octahedral Co^(3+)(CoOh),is considered as promising earth-abundant electrocatalyst for chlorine evolution reaction(CER).Identifying the catalytic contribution of geometric Co site in the electrocatalytic CER plays a pivotal role to precisely modulate electronic configuration of active Co sites to boost CER.Herein,combining density functional theory calculations and experiment results assisted with operando analysis,we found that the Co_(Oh) site acts as the main active site for CER in spinel Co_(3)O_(4),which shows better Cl^(-)adsorption and more moderate intermediate adsorption toward CER than CoTd site,and does not undergo redox transition under CER condition at applied potentials.Guided by above findings,the oxygen vacancies were further introduced into the Co_(3)O_(4) to precisely manipulate the electronic configuration of Co_(Oh) to boost Cl^(-)adsorption and optimize the reaction path of CER and thus to enhance the intrinsic CER activity significantly.Our work figures out the importance of geometric configuration dependent CER activity,shedding light on the rational design of advanced electrocatalysts from geometric configuration optimization at the atomic level.展开更多
LiMnOand LiNiAlyMnO(x= 0.50;y = 0.05-0.50) powders have been synthesized via facile solgel method using Behenic acid as active cheiating agent.The synthesized samples are subjected to physical characterizations such...LiMnOand LiNiAlyMnO(x= 0.50;y = 0.05-0.50) powders have been synthesized via facile solgel method using Behenic acid as active cheiating agent.The synthesized samples are subjected to physical characterizations such as thermo gravimetric analysis(TG/DTA),X-ray diffraction(XRD),Fourier transform infrared spectroscopy(FT-IR),field-emission scanning electron microscopy(FESEM),transmission electron microscopy(TEM) and electrochemical studies viz.,galvanostatic cycling properties,electrochemical impedance spectroscopy(EIS) and differential capacity curves(dQ/dE).Finger print XRD patterns of LiMnOand LiNiAlMnOfortify the high degree of crystallinity with better phase purity.FESEM images of the undoped pristine spinel illustrate uniform spherical grains surface morphology with an average particle size of 0.5 μm while Ni doped particles depict the spherical grains growth(50nm) with ice-cube surface morphology.TEM images of the spinel LiMnOshows the uniform spherical morphology with particle size of(100 nm) while low level of Al-doping spinel(LiNio.5Alo.05Mn1.45O4) displaying cloudy particles with agglomerated particles of(50nm).The LiMnOsamples calcined at 850℃ deliver the discharge capacity of 130 mAh/g in the first cycle corresponds to 94%coiumbic efficiency with capacity fade of 1.5 mAh/g/cycle over the investigated 10 cycles.Among all four dopant compositions investigated,LiNiAlMnOdelivers the maximum discharge capacity of 126 mAh/g during the first cycle and shows the stable cycling performance with low capacity fade of 1 mAh/g/cycle(capacity retention of 92%) over the investigated 10 cycles.Electrochemical impedance studies of spinel LiMnOand LiNiAlMnOdepict the high and low real polarization of 1562 and 1100 Ω.展开更多
The magnetic properties of inverse ferrite Fe_(3+) Fe_(3+)Co_(2+) O^(2-)_4, Fe^(3+) Fe^(3+)Cu^(2+) O^2_(-4), Fe^(3+) Fe^(3+)Fe^(2+) O^2_(-4),and Fe^(3+) Fe^(3+)Ni^(2+) O^(2-)_4spinels have been studied using Monte Car...The magnetic properties of inverse ferrite Fe_(3+) Fe_(3+)Co_(2+) O^(2-)_4, Fe^(3+) Fe^(3+)Cu^(2+) O^2_(-4), Fe^(3+) Fe^(3+)Fe^(2+) O^2_(-4),and Fe^(3+) Fe^(3+)Ni^(2+) O^(2-)_4spinels have been studied using Monte Carlo simulation. We have also calculated the critical and Curie Weiss temperatures from the thermal magnetizations and inverse of magnetic susceptibilities for each system.Magnetic hysteresis cycles have been found for the four systems. Finally, we found the critical exponents associated with magnetization, magnetic susceptibility, and external magnetic field. Our results of critical and Curie Weiss temperatures are similar to those obtained by experiment results. The critical exponents are similar to those of known 3 D-Ising model.展开更多
A series of manganese spinels LiMn2-yMeyO4 (Me = Li, A1, Mg) were prepared and examined by XRD and electrochemical methods. The spinels doped with Li or high content of A1 can exhibit discharge capacity in the 5 V r...A series of manganese spinels LiMn2-yMeyO4 (Me = Li, A1, Mg) were prepared and examined by XRD and electrochemical methods. The spinels doped with Li or high content of A1 can exhibit discharge capacity in the 5 V region, but spinels doped with Mg do not exhibit any 5 V discharge capacity. It is also observed that the 5 V discharge capacity of Li/A1 doped spinels will be greatly suppressed once calcinated at temperatures above 900 ℃ in preparation. It is suggested that the 5 V discharge capacity of Li/A1 doped spinels may be originated from the special chemical/structural characteristics of spinel phases containing Li or high content of A1 prepared at temperatures below 900 ℃.展开更多
Spinel LiNi_(0.5)Mn_(1.5)O_(4)(LNMO),a 5 V class high voltage cathode,has been regarded as an attractive candidate to further improve the energy density of lithium-ion battery.The issue simultaneously enabling side st...Spinel LiNi_(0.5)Mn_(1.5)O_(4)(LNMO),a 5 V class high voltage cathode,has been regarded as an attractive candidate to further improve the energy density of lithium-ion battery.The issue simultaneously enabling side stability and maintaining high interfacial kinetics,however,has not yet been resolved.Herein,we design a coherent Li_(1.3)A_(l0.3)Ti_(1.7)(PO)_(4)(LATP)layer that is crystally connected to the spinel LNMO host lattices,which offers fast lithium ions transportation as well as enhances the mechanical stability that prevents the particle fracture.Furthermore,the inactive Li_(3)BO_(3)(LBO)coating layer inhibits the corrosion of transition metals and continuous side reactions.Consequently,the coherent-engineered LNMO-LATPLBO cathode material exhibits superior electrochemical cycling stability in a window of 3.0–5.0 V,for example a high-capacity retention that is 89.7%after 500 cycles at 200 m A g-1obtained and enhanced rate performance(85.1 m A h g^(-1)at 800 m A g^(-1))when tested with a LiPF6-based carbonate electrolyte.Our work presents a new approach of engineering 5 V class spinel oxide cathode that combines interfacial coherent crystal lattice design and surface coating.展开更多
Augite-based glass ceramics were synthesised using ZnO,FeO,and Fe_(2)O_(3)as additives,and the spinel formation,matrix structure,crystallisation thermodynamics,and physicochemical properties were investigated.The resu...Augite-based glass ceramics were synthesised using ZnO,FeO,and Fe_(2)O_(3)as additives,and the spinel formation,matrix structure,crystallisation thermodynamics,and physicochemical properties were investigated.The results showed that oxides resulted in numerous preliminary spinels in the glass matrix.FeO,ZnO,and Fe_(2)O_(3)influenced the formation of spinel,while FeO simplified the glass network.FeO and ZnO promoted bulk crystallisation of the parent glass.After adding oxides,the grains of augite phase were refined,and the relative quantities of augite crystal planes were also influenced.All samples displayed good mechanical properties and chemical stability.The 2wt%ZnO-doping sample displayed the maximum flexural strength(170.3 MPa).Chromium leaching amount values of all the samples were less than the national standard(1.5 mg/L),confirming the safety of the materials.In conclusion,an appropriate amount of zinc-containing raw material is beneficial for the preparation of augite-based glass ceramics.展开更多
The colours and chemical composition variations of 160 spinels in peridotite and pyroxenite xenoliths from Cenozoic basalts in eastern China and their petrogeneses have been studied in detail. The relationships betwee...The colours and chemical composition variations of 160 spinels in peridotite and pyroxenite xenoliths from Cenozoic basalts in eastern China and their petrogeneses have been studied in detail. The relationships between major elements of spinels are discussed. The equilibrium temperatures, pressures and oxygen fugacities of spinels and their coexisting olivines, orthopyroxenes and clinopyroxenes have been determined using the Brey—kohler's T—P calculation methods (1990) and Ballhaus' fo2 calculation method (1991). The relationships between the composition and the equilibrium temperatures, pressures or oxygen fugacities of spinels in peridotite xenoliths from the basalts and the stable field of the spinels in the upper mantle have been shown.展开更多
With satisfactory high temperature properties,thermal shock resistance and mechanical properties,refractories in the MgO-Al_(2)O_(3) system have become promising alternative to MgO-Cr_(2)O_(3) counterpart used as RH s...With satisfactory high temperature properties,thermal shock resistance and mechanical properties,refractories in the MgO-Al_(2)O_(3) system have become promising alternative to MgO-Cr_(2)O_(3) counterpart used as RH snorkel lining.High purity dead burned magnesia,fused magnesia and sintered spinel were used as raw materials and sulfite pulp waste as the binder,specimens of the refractories in the Mg0-Al_(2)O_(3) system were prepared for the purpose of investigating the influences in terms of the addition of three kinds of spinels,with Al_(2)O_(3) 50%,66% and 78%,by mass,respectively,and the size of MA50 spinel on properties of the specimens.Relatively superior comprehensive properties can be achieved when 16%of MA50 spinel with sizes under 1mm is adopted.展开更多
Listwaenite,carbonate-talc schist,and serpentinite of Sartohay ophioliticmélange,Xinjiang,northwestern China,contain variably altered chromian spinels.During the hydrothermal alteration from serpentinite to listw...Listwaenite,carbonate-talc schist,and serpentinite of Sartohay ophioliticmélange,Xinjiang,northwestern China,contain variably altered chromian spinels.During the hydrothermal alteration from serpentinite to listwaenite展开更多
一个僵硬离子的模型被用来计算力量常数和硫醚和硒化物尖晶石的有效动态费用。拉曼和正常立方的硫醚尖晶石宏 <SUB>2</SUB 的红外线的声子模式> S <SUB>4</SUB>( M = Mn ,公司, Fe , Hg , Zn ,和 Cd )和...一个僵硬离子的模型被用来计算力量常数和硫醚和硒化物尖晶石的有效动态费用。拉曼和正常立方的硫醚尖晶石宏 <SUB>2</SUB 的红外线的声子模式> S <SUB>4</SUB>( M = Mn ,公司, Fe , Hg , Zn ,和 Cd )和硒化物尖晶石宏 <SUB>2</SUB > Se <SUB>4</SUB>( M = Hg , Zn ,并且 Cd )用上面在第一 Brillouin 地区中心被计算模型。现在的工作的重要结果是(i)内部在 Cr-S ( Se )之间的原子相互作用在 Cr-S ( Se )和 S-S ( Se-Se )类型上统治内部原子相互作用,( i i )二原子价的金属离子的有效动态费用是将近零,并且( iii )硒化物尖晶石作为 MnCr <SUB>2</SUB 不比硫醚尖晶石和 ionicity 减少离子> S <SUB>4</SUB>】
FeCr <SUB>2</SUB > S <SUB>4</SUB>】
CoCr <SUB>2</SUB > S <SUB>4</SUB>】
和 CdCr <SUB>2</SUB > C <SUB>4</SUB>】
ZnCr <SUB>2</SUB > C <SUB>4</SUB>】
HgCr <SUB>2</SUB > C <SUB>4</SUB>( C = S 和 Se )。地区中心声子频率,用这些参数计算,被发现在对观察结果的很好的同意。展开更多
Ammonium dinitramide(ADN)based liquid monopropellants have been identified as environmentally benign substitutes for hydrazine monopropellant.However,new catalysts are to be developed for making ADN monopropellants co...Ammonium dinitramide(ADN)based liquid monopropellants have been identified as environmentally benign substitutes for hydrazine monopropellant.However,new catalysts are to be developed for making ADN monopropellants cold-start capable.In the present study,performance of Co and Ba doped CuCr_2O_4 nanocatalysts prepared by hydrothermal method was evaluated on the decomposition of aqueous ADN solution and ADN liquid monopropellant(LMP103X).The catalysts were characterized by PXRD(Powder X-ray Diffraction),FTIR(Fourier Transform Infrared spectroscopy),SEM(Scanning Electron Microscopy),TEM(Transmission Electron Microscopy),EDS(Energy Dispersive X-ray Spectroscopy),and XPS(X-ray Photoelectron Spectroscopy).The nanosize was confirmed by SEM and TEM,while the nanoflake morphology was confirmed by the SEM analysis.Further,we obtained the elemental composition from the EDS analysis.We investigated the catalytic activity of the catalysts by thermogravimetric(TG)analysis and the developed catalysts lowered the decomposition temperature of ADN monopropellant by about 55℃.The XPS analysis confirmed the presence of metal ions with different chemical states.Apparently,increase in the surface area of the catalysts and the mixed active sites as well as the development of oxygen vacancy on the catalyst surface introduced by metal doping are influencing the decomposition temperature of ADN samples.展开更多
The poor structural stability and capacity retention of the high-voltage spinel-type LiNi_(0.5)Mn_(1.5)O_(4)(LNMO)limits their further application.Herein,Al and Co were doped in LNMO materials for a more stable struct...The poor structural stability and capacity retention of the high-voltage spinel-type LiNi_(0.5)Mn_(1.5)O_(4)(LNMO)limits their further application.Herein,Al and Co were doped in LNMO materials for a more stable structure and capacity.The LNMO,LiNi_(0.45)Al_(0.05)Mn_(1.5)O_(4)(LNAMO)and LiNi_(0.45)Co_(0.05)Mn_(1.5)O_(4)(LNCMO)were synthesized by calcination at 900℃ for 8 h,which was called as solid-phase method and applied universally in industry.XRD,FT-IR and CV test results showed the synthesized samples have cation disordering Fd-3m space group structures.Moreover,the incorporation of Al and Co increased the cation disordering of LNMO,thereby increasing the transfer rate of Li+.The SEM results showed that the doped samples performed more regular and ortho-octahedral.The EDS elemental analysis confirmed the uniform distribution of each metal element in the samples.Moreover,the doped samples showed better electrochemical properties than undoped LNMO.The LNAMO and LNCMO samples were discharged with specific capacities of 116.3 mA·h·g^(-1)and 122.8 mA·h·g^(-1)at 1 C charge/discharge rate with good capacity retention of 95.8% and 94.8% after 200 cycles at room temperature,respectively.The capacity fading phenomenon of the doped samples at 50℃ and 1 C rate was significantly improved.Further,cations doping also enhanced the rate performance,especially for the LNCMO,the discharge specific capacity of 117.9 mA·h·g^(-1)can be obtained at a rate of 5 C.展开更多
Unburned magnesium aluminate spinel refractories were prepared using sintered magnesium aluminate spinel as the main raw material,phenolic resin as the binder,aluminum powder(2%,4%,and 6%by mass)and silicon powder(whe...Unburned magnesium aluminate spinel refractories were prepared using sintered magnesium aluminate spinel as the main raw material,phenolic resin as the binder,aluminum powder(2%,4%,and 6%by mass)and silicon powder(when Al powder addition is 4%,Si powder addition varies:1%and 2%,by mass)as additives.The effects of the Al powder and Si powder additions on the properties and microstructure of the refractories heat treated at different temperatures(1000,1400,and 1600℃for 3 h)were studied.The results show that the Al powder addition can greatly enhance the cold modulus of rupture of the samples fired at 1000 or 1400℃,and meanwhile AlN reinforcement phase forms in the matrix,which greatly improves the hot modulus of rupture of the samples at 1400℃;however,the heat treatment at 1600℃has little influence on the strength;the addition of Al powder and Si powder results in the formation of low melting point phases,greatly reducing the hot modulus of rupture.However,the low melting point phases promote sintering,which enhances the density and the cold modulus of rupture,and decreases the volume change during heating.The samples added with Al and Si all have higher cold modulus of rupture than those added with Al powder only.展开更多
文摘Detailed mineralogical and gemological records were conducted on 340 unheated spinels from the Horana, Eheliyagoda, Ratnapura, and Okkampatiya mining areas in Sri Lanka. The color of Sri Lankan spinel varies greatly: in addition to the mainstream pink to purple pink, green and blue can also be seen. Compared with spinel from other regions such as Myanmar, Vietnam, and Tanzania, Sri Lanka's spinel has more abundant inclusions: several mining areas generally have inclusions such as dolomite, apatite, zircon, and chondrodite. Minerals such as graphite and forsterite are also found in spinel produced in the Horana region;graphite and rutile have been found in spinel produced in the Okkamptiya region. Partially healed fissures are most common in spinel in the Okkampatiya mining area;Unlike Vietnamese spinel, dislocations and growth structures are almost absent in Sri Lankan spinel. The LA-ICP-MS analysis results showed that there were no significant differences among the mining areas. LA-ICP-MS analysis of 5 Sri Lankan cobalt blue spinels showed a variation of 11 to 120 ppm in this chromogenic element. The UV visible absorption spectrum results show that Sri Lankan spinel has a combination spectra with variable ratios of the spectral components Cr 3+ , V 3+ and Fe 2+ from pink to red, orange, purple to purple, and blue-green. The results of infrared spectroscopy and laser Raman spectroscopy analysis showed that all samples showed no indications for heat treatment.
基金the National Natural Science Foundation of China(Nos.52074078 and 52374327)the Applied Fundamental Research Program of Liaoning Province(No.2023JH2/101600002)+2 种基金the Shenyang Young Middle-Aged Scientific and Technological Innovation Talent Support Program(No.RC220491)the Liaoning Province Steel Industry-University-Research Innovation Alliance Cooperation Project of Bensteel Group(No.KJBLM202202)the Fundamental Research Funds for the Central Universities(Nos.N2201023 and N2325009).
文摘Chromium plays a vital role in stainless steel due to its ability to improve the corrosion resistance of the latter.However,the re-lease of chromium from stainless steel slag(SSS)during SSS stockpiling causes detrimental environmental issues.To prevent chromium pollution,the effects of iron oxide on crystallization behavior and spatial distribution of spinel were investigated in this work.The results revealed that FeO was more conducive to the growth of spinels compared with Fe2O3 and Fe3O4.Spinels were found to be mainly distrib-uted at the top and bottom of slag.The amount of spinel phase at the bottom decreased with the increasing FeO content,while that at the top increased.The average particle size of spinel in the slag with 18wt%FeO content was 12.8μm.Meanwhile,no notable structural changes were observed with a further increase in FeO content.In other words,the spatial distribution of spinel changed when the content of iron oxide varied in the range of 8wt%to 18wt%.Finally,less spinel was found at the bottom of slag with a FeO content of 23wt%.
基金financial support from the National Natural Science Foundation of China(52203070)the Open Fund of State Key Laboratory of New Textile Materials and Advanced Processing Technologies(FZ2022005)+2 种基金the Open Fund of Hubei Key Laboratory of Biomass Fiber and Ecological Dyeing and Finishing(STRZ202203)the financial support provided by the China Scholarship Council(CSC)Visiting Scholar Programfinancial support from Institute for Sustainability,Energy and Resources,The University of Adelaide,Future Making Fellowship。
文摘Urea holds promise as an alternative water-oxidation substrate in electrolytic cells.High-valence nickelbased spinel,especially after heteroatom doping,excels in urea oxidation reactions(UOR).However,traditional spinel synthesis methods with prolonged high-temperature reactions lack kinetic precision,hindering the balance between controlled doping and highly active two-dimensional(2D)porous structures design.This significantly impedes the identification of electron configuration-dependent active sites in doped 2D nickel-based spinels.Herein,we present a microwave shock method for the preparation of 2D porous NiCo_(2)O_(4)spinel.Utilizing the transient on-off property of microwave pulses for precise heteroatom doping and 2D porous structural design,non-metal doping(boron,phosphorus,and sulfur)with distinct extranuclear electron disparities serves as straightforward examples for investigation.Precise tuning of lattice parameter reveals the impact of covalent bond strength on NiCo_(2)O_(4)structural stability.The introduced defect levels induce unpaired d-electrons in transition metals,enhancing the adsorption of electron-donating amino groups in urea molecules.Simultaneously,Bode plots confirm the impact mechanism of rapid electron migration caused by reduced band gaps on UOR activity.The prepared phosphorus-doped 2D porous NiCo_(2)O_(4),with optimal electron configuration control,outperforms most reported spinels.This controlled modification strategy advances understanding theoretical structure-activity mechanisms of high-performance 2D spinels in UOR.
基金the National Natural Science Foundation of China(U21A20286,22206054 and 21805069)Natural Science Foundation of Hubei(2021CFB094)the Fundamental Research Funds for the Central China Normal University(CCNU)for financial support。
文摘Spinel cobalt oxide(Co_(3)O_(4)),consisting of tetrahedral Co^(2+)(CoTd)and octahedral Co^(3+)(CoOh),is considered as promising earth-abundant electrocatalyst for chlorine evolution reaction(CER).Identifying the catalytic contribution of geometric Co site in the electrocatalytic CER plays a pivotal role to precisely modulate electronic configuration of active Co sites to boost CER.Herein,combining density functional theory calculations and experiment results assisted with operando analysis,we found that the Co_(Oh) site acts as the main active site for CER in spinel Co_(3)O_(4),which shows better Cl^(-)adsorption and more moderate intermediate adsorption toward CER than CoTd site,and does not undergo redox transition under CER condition at applied potentials.Guided by above findings,the oxygen vacancies were further introduced into the Co_(3)O_(4) to precisely manipulate the electronic configuration of Co_(Oh) to boost Cl^(-)adsorption and optimize the reaction path of CER and thus to enhance the intrinsic CER activity significantly.Our work figures out the importance of geometric configuration dependent CER activity,shedding light on the rational design of advanced electrocatalysts from geometric configuration optimization at the atomic level.
基金support given under the "Brain Pool Program of the Korean Federation of Science and Technology Societies" (KOFST), Republic of South Koreasupported by the Human Resources Development Program (No. 20124010203270) of the Korea Institute of Energy Technology EvaluationPlanning (KETEP) grant funded by the Korea Government Ministry of Trade, Industry and Energy
文摘LiMnOand LiNiAlyMnO(x= 0.50;y = 0.05-0.50) powders have been synthesized via facile solgel method using Behenic acid as active cheiating agent.The synthesized samples are subjected to physical characterizations such as thermo gravimetric analysis(TG/DTA),X-ray diffraction(XRD),Fourier transform infrared spectroscopy(FT-IR),field-emission scanning electron microscopy(FESEM),transmission electron microscopy(TEM) and electrochemical studies viz.,galvanostatic cycling properties,electrochemical impedance spectroscopy(EIS) and differential capacity curves(dQ/dE).Finger print XRD patterns of LiMnOand LiNiAlMnOfortify the high degree of crystallinity with better phase purity.FESEM images of the undoped pristine spinel illustrate uniform spherical grains surface morphology with an average particle size of 0.5 μm while Ni doped particles depict the spherical grains growth(50nm) with ice-cube surface morphology.TEM images of the spinel LiMnOshows the uniform spherical morphology with particle size of(100 nm) while low level of Al-doping spinel(LiNio.5Alo.05Mn1.45O4) displaying cloudy particles with agglomerated particles of(50nm).The LiMnOsamples calcined at 850℃ deliver the discharge capacity of 130 mAh/g in the first cycle corresponds to 94%coiumbic efficiency with capacity fade of 1.5 mAh/g/cycle over the investigated 10 cycles.Among all four dopant compositions investigated,LiNiAlMnOdelivers the maximum discharge capacity of 126 mAh/g during the first cycle and shows the stable cycling performance with low capacity fade of 1 mAh/g/cycle(capacity retention of 92%) over the investigated 10 cycles.Electrochemical impedance studies of spinel LiMnOand LiNiAlMnOdepict the high and low real polarization of 1562 and 1100 Ω.
文摘The magnetic properties of inverse ferrite Fe_(3+) Fe_(3+)Co_(2+) O^(2-)_4, Fe^(3+) Fe^(3+)Cu^(2+) O^2_(-4), Fe^(3+) Fe^(3+)Fe^(2+) O^2_(-4),and Fe^(3+) Fe^(3+)Ni^(2+) O^(2-)_4spinels have been studied using Monte Carlo simulation. We have also calculated the critical and Curie Weiss temperatures from the thermal magnetizations and inverse of magnetic susceptibilities for each system.Magnetic hysteresis cycles have been found for the four systems. Finally, we found the critical exponents associated with magnetization, magnetic susceptibility, and external magnetic field. Our results of critical and Curie Weiss temperatures are similar to those obtained by experiment results. The critical exponents are similar to those of known 3 D-Ising model.
基金Funded partly by the Fundamental Research Funds for the Central Universities (No.WHUT-2012-Ia-029)the Foundation of the Ministry of Education of China for Returned Scholars (No.2007-24)
文摘A series of manganese spinels LiMn2-yMeyO4 (Me = Li, A1, Mg) were prepared and examined by XRD and electrochemical methods. The spinels doped with Li or high content of A1 can exhibit discharge capacity in the 5 V region, but spinels doped with Mg do not exhibit any 5 V discharge capacity. It is also observed that the 5 V discharge capacity of Li/A1 doped spinels will be greatly suppressed once calcinated at temperatures above 900 ℃ in preparation. It is suggested that the 5 V discharge capacity of Li/A1 doped spinels may be originated from the special chemical/structural characteristics of spinel phases containing Li or high content of A1 prepared at temperatures below 900 ℃.
基金supported by the Natural Science Foundation of Jiangsu Province(BK20200800)the National Natural Science Foundation of China(22209075,51902165,12004145)+1 种基金the Natural Science Foundation of Jiangxi Province(20212BAB214032,20192ACBL20048)the Key Science and Technology Plan Project of Ji’an City(20211-015311)。
文摘Spinel LiNi_(0.5)Mn_(1.5)O_(4)(LNMO),a 5 V class high voltage cathode,has been regarded as an attractive candidate to further improve the energy density of lithium-ion battery.The issue simultaneously enabling side stability and maintaining high interfacial kinetics,however,has not yet been resolved.Herein,we design a coherent Li_(1.3)A_(l0.3)Ti_(1.7)(PO)_(4)(LATP)layer that is crystally connected to the spinel LNMO host lattices,which offers fast lithium ions transportation as well as enhances the mechanical stability that prevents the particle fracture.Furthermore,the inactive Li_(3)BO_(3)(LBO)coating layer inhibits the corrosion of transition metals and continuous side reactions.Consequently,the coherent-engineered LNMO-LATPLBO cathode material exhibits superior electrochemical cycling stability in a window of 3.0–5.0 V,for example a high-capacity retention that is 89.7%after 500 cycles at 200 m A g-1obtained and enhanced rate performance(85.1 m A h g^(-1)at 800 m A g^(-1))when tested with a LiPF6-based carbonate electrolyte.Our work presents a new approach of engineering 5 V class spinel oxide cathode that combines interfacial coherent crystal lattice design and surface coating.
基金supported by the National Key R&D Program of China(No.2019YFC1905701)the National Natural Science Foundation of China(Nos.U1960201 and 52204336)the China Postdoctoral Science Foundation(No.2022M710359).
文摘Augite-based glass ceramics were synthesised using ZnO,FeO,and Fe_(2)O_(3)as additives,and the spinel formation,matrix structure,crystallisation thermodynamics,and physicochemical properties were investigated.The results showed that oxides resulted in numerous preliminary spinels in the glass matrix.FeO,ZnO,and Fe_(2)O_(3)influenced the formation of spinel,while FeO simplified the glass network.FeO and ZnO promoted bulk crystallisation of the parent glass.After adding oxides,the grains of augite phase were refined,and the relative quantities of augite crystal planes were also influenced.All samples displayed good mechanical properties and chemical stability.The 2wt%ZnO-doping sample displayed the maximum flexural strength(170.3 MPa).Chromium leaching amount values of all the samples were less than the national standard(1.5 mg/L),confirming the safety of the materials.In conclusion,an appropriate amount of zinc-containing raw material is beneficial for the preparation of augite-based glass ceramics.
文摘The colours and chemical composition variations of 160 spinels in peridotite and pyroxenite xenoliths from Cenozoic basalts in eastern China and their petrogeneses have been studied in detail. The relationships between major elements of spinels are discussed. The equilibrium temperatures, pressures and oxygen fugacities of spinels and their coexisting olivines, orthopyroxenes and clinopyroxenes have been determined using the Brey—kohler's T—P calculation methods (1990) and Ballhaus' fo2 calculation method (1991). The relationships between the composition and the equilibrium temperatures, pressures or oxygen fugacities of spinels in peridotite xenoliths from the basalts and the stable field of the spinels in the upper mantle have been shown.
文摘With satisfactory high temperature properties,thermal shock resistance and mechanical properties,refractories in the MgO-Al_(2)O_(3) system have become promising alternative to MgO-Cr_(2)O_(3) counterpart used as RH snorkel lining.High purity dead burned magnesia,fused magnesia and sintered spinel were used as raw materials and sulfite pulp waste as the binder,specimens of the refractories in the Mg0-Al_(2)O_(3) system were prepared for the purpose of investigating the influences in terms of the addition of three kinds of spinels,with Al_(2)O_(3) 50%,66% and 78%,by mass,respectively,and the size of MA50 spinel on properties of the specimens.Relatively superior comprehensive properties can be achieved when 16%of MA50 spinel with sizes under 1mm is adopted.
文摘Listwaenite,carbonate-talc schist,and serpentinite of Sartohay ophioliticmélange,Xinjiang,northwestern China,contain variably altered chromian spinels.During the hydrothermal alteration from serpentinite to listwaenite
文摘一个僵硬离子的模型被用来计算力量常数和硫醚和硒化物尖晶石的有效动态费用。拉曼和正常立方的硫醚尖晶石宏 <SUB>2</SUB 的红外线的声子模式> S <SUB>4</SUB>( M = Mn ,公司, Fe , Hg , Zn ,和 Cd )和硒化物尖晶石宏 <SUB>2</SUB > Se <SUB>4</SUB>( M = Hg , Zn ,并且 Cd )用上面在第一 Brillouin 地区中心被计算模型。现在的工作的重要结果是(i)内部在 Cr-S ( Se )之间的原子相互作用在 Cr-S ( Se )和 S-S ( Se-Se )类型上统治内部原子相互作用,( i i )二原子价的金属离子的有效动态费用是将近零,并且( iii )硒化物尖晶石作为 MnCr <SUB>2</SUB 不比硫醚尖晶石和 ionicity 减少离子> S <SUB>4</SUB>】
FeCr <SUB>2</SUB > S <SUB>4</SUB>】
CoCr <SUB>2</SUB > S <SUB>4</SUB>】
和 CdCr <SUB>2</SUB > C <SUB>4</SUB>】
ZnCr <SUB>2</SUB > C <SUB>4</SUB>】
HgCr <SUB>2</SUB > C <SUB>4</SUB>( C = S 和 Se )。地区中心声子频率,用这些参数计算,被发现在对观察结果的很好的同意。
基金financial support by DST-SERB (Grant No.SRG/2021/001182)DRDO (Grant No.ARMREB/HEM/2021/241)is gratefully acknowledged。
文摘Ammonium dinitramide(ADN)based liquid monopropellants have been identified as environmentally benign substitutes for hydrazine monopropellant.However,new catalysts are to be developed for making ADN monopropellants cold-start capable.In the present study,performance of Co and Ba doped CuCr_2O_4 nanocatalysts prepared by hydrothermal method was evaluated on the decomposition of aqueous ADN solution and ADN liquid monopropellant(LMP103X).The catalysts were characterized by PXRD(Powder X-ray Diffraction),FTIR(Fourier Transform Infrared spectroscopy),SEM(Scanning Electron Microscopy),TEM(Transmission Electron Microscopy),EDS(Energy Dispersive X-ray Spectroscopy),and XPS(X-ray Photoelectron Spectroscopy).The nanosize was confirmed by SEM and TEM,while the nanoflake morphology was confirmed by the SEM analysis.Further,we obtained the elemental composition from the EDS analysis.We investigated the catalytic activity of the catalysts by thermogravimetric(TG)analysis and the developed catalysts lowered the decomposition temperature of ADN monopropellant by about 55℃.The XPS analysis confirmed the presence of metal ions with different chemical states.Apparently,increase in the surface area of the catalysts and the mixed active sites as well as the development of oxygen vacancy on the catalyst surface introduced by metal doping are influencing the decomposition temperature of ADN samples.
基金supported by the National Natural Science Foundation of China(52022109 and 51834008)Beijing Municipal Natural Science Foundation(2202047)+1 种基金National Key Research and Development Program of China(2021YFC2901100)Science Foundation of China University of Petroleum,Beijing(2462021QNX2010,2462020YXZZ019,2462020YXZZ016,and 2462022QZDX008)。
文摘The poor structural stability and capacity retention of the high-voltage spinel-type LiNi_(0.5)Mn_(1.5)O_(4)(LNMO)limits their further application.Herein,Al and Co were doped in LNMO materials for a more stable structure and capacity.The LNMO,LiNi_(0.45)Al_(0.05)Mn_(1.5)O_(4)(LNAMO)and LiNi_(0.45)Co_(0.05)Mn_(1.5)O_(4)(LNCMO)were synthesized by calcination at 900℃ for 8 h,which was called as solid-phase method and applied universally in industry.XRD,FT-IR and CV test results showed the synthesized samples have cation disordering Fd-3m space group structures.Moreover,the incorporation of Al and Co increased the cation disordering of LNMO,thereby increasing the transfer rate of Li+.The SEM results showed that the doped samples performed more regular and ortho-octahedral.The EDS elemental analysis confirmed the uniform distribution of each metal element in the samples.Moreover,the doped samples showed better electrochemical properties than undoped LNMO.The LNAMO and LNCMO samples were discharged with specific capacities of 116.3 mA·h·g^(-1)and 122.8 mA·h·g^(-1)at 1 C charge/discharge rate with good capacity retention of 95.8% and 94.8% after 200 cycles at room temperature,respectively.The capacity fading phenomenon of the doped samples at 50℃ and 1 C rate was significantly improved.Further,cations doping also enhanced the rate performance,especially for the LNCMO,the discharge specific capacity of 117.9 mA·h·g^(-1)can be obtained at a rate of 5 C.
文摘Unburned magnesium aluminate spinel refractories were prepared using sintered magnesium aluminate spinel as the main raw material,phenolic resin as the binder,aluminum powder(2%,4%,and 6%by mass)and silicon powder(when Al powder addition is 4%,Si powder addition varies:1%and 2%,by mass)as additives.The effects of the Al powder and Si powder additions on the properties and microstructure of the refractories heat treated at different temperatures(1000,1400,and 1600℃for 3 h)were studied.The results show that the Al powder addition can greatly enhance the cold modulus of rupture of the samples fired at 1000 or 1400℃,and meanwhile AlN reinforcement phase forms in the matrix,which greatly improves the hot modulus of rupture of the samples at 1400℃;however,the heat treatment at 1600℃has little influence on the strength;the addition of Al powder and Si powder results in the formation of low melting point phases,greatly reducing the hot modulus of rupture.However,the low melting point phases promote sintering,which enhances the density and the cold modulus of rupture,and decreases the volume change during heating.The samples added with Al and Si all have higher cold modulus of rupture than those added with Al powder only.