Pr^（3＋）-activated barium tungsto-molybdate solid solution phosphor Ba（Mo_（1-z）W_z）O_4：Pr^（3＋）is successfully fabricated via a facile molten-salt approach. The as-synthesized microcrystal is of truncated oct...Pr^（3＋）-activated barium tungsto-molybdate solid solution phosphor Ba（Mo_（1-z）W_z）O_4：Pr^（3＋）is successfully fabricated via a facile molten-salt approach. The as-synthesized microcrystal is of truncated octahedron and exhibits deep-red-emitting upon blue light excitation. Powder x-ray diffraction and Raman spectroscopy techniques are utilized to investigate the formation of solid solution phosphor. The luminescence behaviors depend on the resulting composition of the microcrystals with fixed Pr^（3＋）-doping concentration, while the host lattices remain in a scheelite structure. The forming solid solution via the substitution of [WO_4] for [MoO_4] can significantly enhance its luminescence, which may be due to the fact that Ba（Mo_（1-z）W_z）O_4：Pr^（3＋）owns well-defined facets and uniform morphologies. Owing to its properties of high phase purity,well-defined facets, highly uniform morphologies, exceptional chemical and thermal stabilities, and stronger emission intensity, the resulting solid solution phosphor is expected to find potential applications in phosphor-converted white lightemitting diodes（LEDs）.展开更多
In order to provide data on diffusion coefficients and solubility constants of tritium in molten salts for the critical issue of tritium control in the Thorium Molten Salt Reactor(TMSR)program,a two-chamber permeabili...In order to provide data on diffusion coefficients and solubility constants of tritium in molten salts for the critical issue of tritium control in the Thorium Molten Salt Reactor(TMSR)program,a two-chamber permeability apparatus separated by a nickel plate had been developed for determining the permeability of hydrogen isotope in molten salts.Descriptions on the permeability apparatus,experimental procedure and the analytical method for determining the diffusivity and solubility of hydrogen isotope in molten salts were presented in this paper.To assess the performance of the apparatus,the blank tests without molten salt were conducted at300-700℃.The results showed that the nickel plate acting as the window for hydrogen isotope permeation in the apparatus seemed to have less effect on experiments of determining the permeability of hydrogen isotope in molten slat at 500-700℃.Furthermore,the applicability of the apparatus with molten salt was also evaluated experimentally,with test experiments of molten Flinak(LiF-NaF-KF)at 500℃,600℃and 700℃.Diffusion coefficients and solubility constants of hydrogen in molten Flinak can be derived from those test experiments,which were correlated to D_(Flinak-H)=7.06×10^(-5)e^(-54.9/(R_gT))m^2/s and s_(Flinak-H)=1.67×10^(-7)e^(27.0/(r_gt))mol-H_2/(m^3 Pa).展开更多
Sr0.6 Ba0.4 Nb2 O6 micro-rods are prepared by the molten-salt method with K2 SO4,KCl-K2 SO4,and KCl as fluxes.It reveals that the Sr0.6 Ba0.4 Nb2 O6 synthesized with KCl as a flux exhibits a single phase with tetragon...Sr0.6 Ba0.4 Nb2 O6 micro-rods are prepared by the molten-salt method with K2 SO4,KCl-K2 SO4,and KCl as fluxes.It reveals that the Sr0.6 Ba0.4 Nb2 O6 synthesized with KCl as a flux exhibits a single phase with tetragonal tungsten bronze structure.The measurement of X-ray diffraction indicates that the Sr0.6 Ba0.4 Nb2 O6 micro-rods synthesized at 1 300℃are anisotropic.The morphology of the powers is examined by transmission electron microscope.It reveals that the length-diameter ratio of Sr0.6 Ba0.4 Nb2 O6 micro-rods increases with increasing annealing temperature from 900℃to 1 300℃.At 1 300℃,the rod possesses a large length-diameter ratio of 8∶1.Moreover,the analysis of the piezoelectric properties of single micro-rods using apiezo-response force microscope indicates that the domains of the material are arranged along its radial direction.展开更多
Fluorinated rare earth molten-salt electrolytic slag contains a considerable amount of rare earth elements,as well as a variety of heavy metals and fluorides that cause environmental pollution.Therefore,it is of great...Fluorinated rare earth molten-salt electrolytic slag contains a considerable amount of rare earth elements,as well as a variety of heavy metals and fluorides that cause environmental pollution.Therefore,it is of great importance to fully utilise this resource.In this study,the transformation mechanism of fluorinated rare earth molten-salt electrolytic slag roasted with sodium carbonate,and the regulation mechanism of rare earth leaching under different roasting conditions were investigated with the help of thermodynamic calculation of the reactions and kinetic analysis.The thermodynamic and differential thermal thermogravimetric(DTA-TG)analysis shows that the transformation of rare earth fluoride to rare earth oxide is promoted at elevated temperature.Furthermore,the leaching experimental results show that increasing the temperature,time,hydrochloric acid concentration,and liquid-solid ratio can effectively promote the recovery of rare earths.The optimum experimental conditions are a roasting temperature of 700℃,roasting time of 2 h,and sodium carbonate to molten salt electrolytic slag mass ratio of 0.6,followed by leaching at 80℃with a liquid-solid ratio of 10:1 by adding 3 moI/L hydrochlo ric acid with stirring for 2 h.Under these conditions,the rare earths in the molten salt electrolytic slag are biologically transformed at a lower temperature and the leaching efficiency of rare earths exceeds 98%.展开更多
ZnS with hexagonal prism morphology has been synthesized successfully by molten-salt method with ZnS nanoparticles as precursors, and the ZnS nanoparticles were prepared by one-step solid-state reaction of Zn（CH3COO...ZnS with hexagonal prism morphology has been synthesized successfully by molten-salt method with ZnS nanoparticles as precursors, and the ZnS nanoparticles were prepared by one-step solid-state reaction of Zn（CH3COO）2·2H2O with Na2S·9H2O at ambient temperature. Crystal structure and morphology of the product were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy and HRTEM. Ultraviolet-visible optical absorption spectrum of the ZnS hexagonal prism shows a distinct red shift from that of bulk ZnS crystals and photoluminescence spectrum exhibits strong emissions at 380 and 500 nm, respectively. Further experiments were designed and the formation mechanism of the ZnS hexagonal prism has been also discussed in brief.展开更多
The development of an efficient and low-cost electrocatalyst for the oxygen evolution reaction （OER） via an eco-efficient route is a desirable, although challenging, outcome for overall water splitting. Herein, an i...The development of an efficient and low-cost electrocatalyst for the oxygen evolution reaction （OER） via an eco-efficient route is a desirable, although challenging, outcome for overall water splitting. Herein, an iron-rich La0.6Sr0.4Co0.2Fe0.8O2.9 （LSCF28） perovskite with an open porous topographic structure was developed as an electrocatalyst by a straightforward molten-salt synthesis approach. It was found that porosity correlates with both the iron content and the molten-salt approach. Benefiting from the large surface area, high activity of the porous internal surface, and the optimal electronic configuration of redox sites, this inexpensive material exhibits high performance with a large mass activity of 40.8A·g^-1 at a low overpotential of 0.345 V in 0.1 M KOH, surpassing the state-of-the-art precious metal IrO2 catalyst and other well-known perovskites, such as Ba0.5Sr0.5Co0.8Fe0.2O3 and SRCoO2.7. Our work illustrates that the molten- salt method is an effective route to generate porous structures in perovskite oxides, which is important for energy conversion and storage devices.展开更多
基金Project supported by the Construction Fund for Science and Technology Innovation Group from Jiangsu University of Technology,Chinathe Key Laboratory of Atmospheric Environment Monitoring and Pollution Control,China(Grant No.KHK1409)+1 种基金the Priority Academic Program Development of Jiangsu Higher Education Institutions,Chinathe National Natural Science Foundation of China(Grant No.21373103)
文摘Pr^（3＋）-activated barium tungsto-molybdate solid solution phosphor Ba（Mo_（1-z）W_z）O_4：Pr^（3＋）is successfully fabricated via a facile molten-salt approach. The as-synthesized microcrystal is of truncated octahedron and exhibits deep-red-emitting upon blue light excitation. Powder x-ray diffraction and Raman spectroscopy techniques are utilized to investigate the formation of solid solution phosphor. The luminescence behaviors depend on the resulting composition of the microcrystals with fixed Pr^（3＋）-doping concentration, while the host lattices remain in a scheelite structure. The forming solid solution via the substitution of [WO_4] for [MoO_4] can significantly enhance its luminescence, which may be due to the fact that Ba（Mo_（1-z）W_z）O_4：Pr^（3＋）owns well-defined facets and uniform morphologies. Owing to its properties of high phase purity,well-defined facets, highly uniform morphologies, exceptional chemical and thermal stabilities, and stronger emission intensity, the resulting solid solution phosphor is expected to find potential applications in phosphor-converted white lightemitting diodes（LEDs）.
文摘In order to provide data on diffusion coefficients and solubility constants of tritium in molten salts for the critical issue of tritium control in the Thorium Molten Salt Reactor(TMSR)program,a two-chamber permeability apparatus separated by a nickel plate had been developed for determining the permeability of hydrogen isotope in molten salts.Descriptions on the permeability apparatus,experimental procedure and the analytical method for determining the diffusivity and solubility of hydrogen isotope in molten salts were presented in this paper.To assess the performance of the apparatus,the blank tests without molten salt were conducted at300-700℃.The results showed that the nickel plate acting as the window for hydrogen isotope permeation in the apparatus seemed to have less effect on experiments of determining the permeability of hydrogen isotope in molten slat at 500-700℃.Furthermore,the applicability of the apparatus with molten salt was also evaluated experimentally,with test experiments of molten Flinak(LiF-NaF-KF)at 500℃,600℃and 700℃.Diffusion coefficients and solubility constants of hydrogen in molten Flinak can be derived from those test experiments,which were correlated to D_(Flinak-H)=7.06×10^(-5)e^(-54.9/(R_gT))m^2/s and s_(Flinak-H)=1.67×10^(-7)e^(27.0/(r_gt))mol-H_2/(m^3 Pa).
基金supported by the National Natural Science Foundation of China(No.11475086)
文摘Sr0.6 Ba0.4 Nb2 O6 micro-rods are prepared by the molten-salt method with K2 SO4,KCl-K2 SO4,and KCl as fluxes.It reveals that the Sr0.6 Ba0.4 Nb2 O6 synthesized with KCl as a flux exhibits a single phase with tetragonal tungsten bronze structure.The measurement of X-ray diffraction indicates that the Sr0.6 Ba0.4 Nb2 O6 micro-rods synthesized at 1 300℃are anisotropic.The morphology of the powers is examined by transmission electron microscope.It reveals that the length-diameter ratio of Sr0.6 Ba0.4 Nb2 O6 micro-rods increases with increasing annealing temperature from 900℃to 1 300℃.At 1 300℃,the rod possesses a large length-diameter ratio of 8∶1.Moreover,the analysis of the piezoelectric properties of single micro-rods using apiezo-response force microscope indicates that the domains of the material are arranged along its radial direction.
基金supported by the National Key Research and Development Project of China(2018YFC1903400)Key Research and Development Program of Jiangxi Province(20212BBG73049)+1 种基金Jiangxi Provincial Department of Education Science and Technology Research Project(GJJ190486)Excellent Doctoral Dissertation Cultivating Project of Jiangxi University of Science and Technology(202202400013)。
文摘Fluorinated rare earth molten-salt electrolytic slag contains a considerable amount of rare earth elements,as well as a variety of heavy metals and fluorides that cause environmental pollution.Therefore,it is of great importance to fully utilise this resource.In this study,the transformation mechanism of fluorinated rare earth molten-salt electrolytic slag roasted with sodium carbonate,and the regulation mechanism of rare earth leaching under different roasting conditions were investigated with the help of thermodynamic calculation of the reactions and kinetic analysis.The thermodynamic and differential thermal thermogravimetric(DTA-TG)analysis shows that the transformation of rare earth fluoride to rare earth oxide is promoted at elevated temperature.Furthermore,the leaching experimental results show that increasing the temperature,time,hydrochloric acid concentration,and liquid-solid ratio can effectively promote the recovery of rare earths.The optimum experimental conditions are a roasting temperature of 700℃,roasting time of 2 h,and sodium carbonate to molten salt electrolytic slag mass ratio of 0.6,followed by leaching at 80℃with a liquid-solid ratio of 10:1 by adding 3 moI/L hydrochlo ric acid with stirring for 2 h.Under these conditions,the rare earths in the molten salt electrolytic slag are biologically transformed at a lower temperature and the leaching efficiency of rare earths exceeds 98%.
基金Project supported by the Doctor Innovation Funds of Nanjing University of Aeronautics and Astronautics （No. BCXJ05-07） and the National Natural Science Foundation of China （No. 50502020）.
文摘ZnS with hexagonal prism morphology has been synthesized successfully by molten-salt method with ZnS nanoparticles as precursors, and the ZnS nanoparticles were prepared by one-step solid-state reaction of Zn（CH3COO）2·2H2O with Na2S·9H2O at ambient temperature. Crystal structure and morphology of the product were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy and HRTEM. Ultraviolet-visible optical absorption spectrum of the ZnS hexagonal prism shows a distinct red shift from that of bulk ZnS crystals and photoluminescence spectrum exhibits strong emissions at 380 and 500 nm, respectively. Further experiments were designed and the formation mechanism of the ZnS hexagonal prism has been also discussed in brief.
文摘The development of an efficient and low-cost electrocatalyst for the oxygen evolution reaction （OER） via an eco-efficient route is a desirable, although challenging, outcome for overall water splitting. Herein, an iron-rich La0.6Sr0.4Co0.2Fe0.8O2.9 （LSCF28） perovskite with an open porous topographic structure was developed as an electrocatalyst by a straightforward molten-salt synthesis approach. It was found that porosity correlates with both the iron content and the molten-salt approach. Benefiting from the large surface area, high activity of the porous internal surface, and the optimal electronic configuration of redox sites, this inexpensive material exhibits high performance with a large mass activity of 40.8A·g^-1 at a low overpotential of 0.345 V in 0.1 M KOH, surpassing the state-of-the-art precious metal IrO2 catalyst and other well-known perovskites, such as Ba0.5Sr0.5Co0.8Fe0.2O3 and SRCoO2.7. Our work illustrates that the molten- salt method is an effective route to generate porous structures in perovskite oxides, which is important for energy conversion and storage devices.
