A simple method was proposed to produce tungsten(W)particles with controllable shape and size by employing the salt-assisted hydrogen reduction.W particles with controlled shape and size were prepared by adjusting the...A simple method was proposed to produce tungsten(W)particles with controllable shape and size by employing the salt-assisted hydrogen reduction.W particles with controlled shape and size were prepared by adjusting the amount of chlorine salts and the temperature.After adding salt additives,the dispersibility of final particles was obviously improved and more adequate growth of particles was obtained.It was found that the effect of NaCl and LiCl is particularly significant.The average sizes of the obtained W particles at 1038 K after adding 0.1 wt.%NaCl and 0.1 wt.%LiCl were 0.924 and 1.128μm,respectively.With the increase of temperature and amount of chlorine salts,the dispersity of the produced W particles became much better,the size of W sub-particles was increased,and the shape of W sub-particles was changed from spherical to polyhedral.At 1349 K,the addition of chlorine salts even multiplied the particle size,and the average sizes of W particles with 1 wt.%NaCl and 1 wt.%LiCl were raised up to 21.367 and 29.665μm,respectively.Based on the conventional pseudomorphic transformation and chemical vapor transport mechanisms,the effects of adding salts on the reaction mechanism were investigated in detail as well.展开更多
A novel salt-assisted combustion process with ethylene glycol as a fuel and nitrate as an oxidant to synthesize high surface area celia nanopowders was reported. The effects of various tunable conditions, such as fuel...A novel salt-assisted combustion process with ethylene glycol as a fuel and nitrate as an oxidant to synthesize high surface area celia nanopowders was reported. The effects of various tunable conditions, such as fuel-to-oxidant ratio, type of salts, and amount of added salts, on the characteristics of the as-prepared powders were investigated by X-ray diffraction, transmission electron microscopy and BET surface area measurement. A mechanism scheme was proposed to illustrate the possible formation processes of well-dispersed ceria nanoparticles in the salt-assisted combustion synthesis. It was verified that the simple introduction of leachable inert inorganic salts as an excellent agglomeration inhibitor into the redox mixture precursor leads to the formation of well-dispersed ceria particles with particle size in the range of 4 ～6 nm and a drastic increase in the surface area. The presence of KCl results in an over ten-fold increment in specific surface area from 14.10 m^2·g^-1 for the produced ceria powders via the conventional combustion synthesis process to 156.74 m^2·g^-1 for the product by the salt-assisted combustion synthesis process at the same molar ratio of ethylene glycol-nitrate.展开更多
A novel salt-assisted low temperature solid state method using CoCl2.6H2O, FeCl3.6H2O and NaOH as precursor and using NaCI as a dispersant to synthesize high surface area CoFe2O4 nanoparticles, has been investigated. ...A novel salt-assisted low temperature solid state method using CoCl2.6H2O, FeCl3.6H2O and NaOH as precursor and using NaCI as a dispersant to synthesize high surface area CoFe2O4 nanoparticles, has been investigated. The effects of the molar ratio of added salt and calcination temperature on the characteristics of the products were investigated by X-ray diffraction （XRD）, transmission electron microscopy （TEM）, vibrating sample magnetometer （VSM） and Brunauer, Emmett and Teller （BET） surface area analysis. Results showed that the introduction of leachable inert inorganic salt as a hard agglomeration inhibitor in the mixture precursor led to the formation of high dispersive CoFe2O4 nanoparticles; and the increase in specific surface area from 28.28 to 73.97 m^2/g, and the saturation magnetization is 84.6 emu/g.展开更多
Highly dispersed perovskite NdCoO3 nanoparticles were prepared by a novel salt-assisted combustion process. The effects of NaCl content and calcination temperature on the characteristics of the products were character...Highly dispersed perovskite NdCoO3 nanoparticles were prepared by a novel salt-assisted combustion process. The effects of NaCl content and calcination temperature on the characteristics of the products were characterized by X-Ray Diffraction (XRD), Transmission Electron Microscopy (TEM) and BET surface area measurement. The facile introduction of NaCl in the conventional combustion synthesis process was found to result in the formation of well-dispersed perovskite nanoparticles and increase specific surface areas of the resultants from 1.7 to 43.2 m2·g-1. The catalytic properties of the typical NdCoO3 samples for thermal decomposition of ammonia perchlorate (AP) and their correlation with the NdCoO3 microstructure were investigated by Differential Scanning Calorimetry (DSC). The DSC results indicate that the addition of the amorphous NdCoO3 nanoparticles to AP incorporates two small exothermic peaks of AP into a strong exothermic peak, decreases the temperature of the AP exothermic peak to 314.0 ℃ by reduction of 138.3 ℃ and increases the apparent decomposition heat from 515 J·g-1 to over 1441 J·g-1, showing the intense catalytic activity for thermal decomposition of AP. It is also clear that the catalytic activity of the resultant NdCoO3 is related to their microstructure. According to Kissinger′s method, the kinetics parameters of the thermal decomposition of AP catalyzed by the as-prepared NdCoO3 samples were calculated to account for the order of their catalytic activity.展开更多
Two-dimensional(2D) materials with atomic thickness are promising candidates for the applications in future semiconductor devices, owing to their fascinating physical properties and superlative optoelectronic performa...Two-dimensional(2D) materials with atomic thickness are promising candidates for the applications in future semiconductor devices, owing to their fascinating physical properties and superlative optoelectronic performance. Chemical vapor deposition(CVD) is considered to be an efficient method for large-scale preparation of 2D materials toward practical applications.However, the high melting points of metal precursors and the thermodynamics instabilities of metastable phases limit the direct CVD synthesis of plenty of 2D materials. The salt has recently been introduced into the CVD process, which proved to be effective to address these issues. In this review, we highlighted the latest progress in the salt-assisted CVD growth of 2D materials, including layered and non-layered crystals. Firstly, strategies of adding salts are summarized. Then, the salt-assisted growth of various layered materials is presented, emphasizing on the transition metal chalcogenides of stable and metastable phases. Furthermore, strategies to grow ultrathin non-layered materials are discussed. We provide viewpoints into the techniques of using salt, the effects of salt, and the growth mechanisms of 2D crystals. Finally, we offer the challenges to be overcome and further research directions of this emerging salt-assisted CVD technique.展开更多
A salt-assistant stearic acid method （SAM） capable of forming ultrafine K4Ce2Nb10O30 products was described. XRD pattern re-vealed that tetragonal K4Ce2Nb10O30 products could be obtained by heat treatment at 900 ℃ ...A salt-assistant stearic acid method （SAM） capable of forming ultrafine K4Ce2Nb10O30 products was described. XRD pattern re-vealed that tetragonal K4Ce2Nb10O30 products could be obtained by heat treatment at 900 ℃ for 2 h. Transmission electron microscopy （TEM） observations indicated the introduction of KCl could lead to the formation of rod-like K4Ce2Nb10O30 products. The species of salts played a crucial role in fine tuning the shapes and sizes of K4Ce2Nb10O30 products. Furthermore, the K4Ce2Nb10O30 prepared by salt-assistant SAM had considerable activity under visible light irradiation.展开更多
Designing synergistic heterogeneous catalytic interfaces is the key to developing highly compatible pH-universal electrocatalysts for complex chemical environments.Our theoretical calculation results demonstrate that ...Designing synergistic heterogeneous catalytic interfaces is the key to developing highly compatible pH-universal electrocatalysts for complex chemical environments.Our theoretical calculation results demonstrate that the Ru-Ru2P heterointerface can not only promote the redistribution of charges,but also reduce the d-band center,and then enhances the adsorption capacity of the key intermediate.However,in situ and facile synthesis of Ru-Ru2P heterostructures is severely limited by thermodynamic obstacles.Herein,we propose a molten salt-assisted catalytic synthesis scheme,and successfully build a series of homologous metallic Ru-Ru2P heterostructure catalysts with different molar ratios of Ru to P under atmospheric pressure and low-temperature(400C).The resultant Ru-Ru2P with rich heterostructures show the Pt-like HER performance in different pH media.Particularly,it is prominent under alkaline conditions(18 mV@10 mA cm^(2)),which outperforms the Pt catalyst(37 mV@10 mA cm^(2)).Furthermore,Ru-Ru2P heterostructures also show certain potential in the electrolysis of seawater to produce hydrogen.This work represents a significant supplement of high-efficiency pH-universal HER catalysts,and provides a new light on interface engineering in energy technology fields and beyond.展开更多
A series of well-dispersed titania-doped ceria nanoparticles Ce1–xTixO2 were rapidly prepared by a novel salt-assisted solution combustion process using correspondent metal nitrates as oxidizers and ethyl glycol as f...A series of well-dispersed titania-doped ceria nanoparticles Ce1–xTixO2 were rapidly prepared by a novel salt-assisted solution combustion process using correspondent metal nitrates as oxidizers and ethyl glycol as fuel, and then coated with amorphous silica by seeded polymerization using tetraethyl orthoslicate （TEOS）. The as-prepared samples were characterized by transmission electron microscopy （TEM）, X-ray diffraction （XRD）, Fourier-transform infrared spectroscopy （FTIR）, and ultraviolet-visible light （UV-Vis） diffuse reflectance spectroscopy. The results indicated that compared with the as-prepared pure ceria nanoparticles, the red-shift phenomenon occurred for Ti-doped ceria nanoparticles with Ti incorporation. Meanwhile, the absorption intensity in the UV light region slightly decreased and transmission rate in visible light region was somewhat enhanced. In comparison with the silica-coated CeO2 nanopowders, the silica-coated Ce0.95Ti0.05O2 nanopowders displayed the same absorption intensity in the UV light region, broader UV absorption band and higher transmission rate in visible light region.展开更多
基金Project(171111)supported by Fok Ying Tung Education Foundation,ChinaProjects(cx2018055,cx2019041)supported by the Venture&Innovation Support Program for Chongqing Overseas Returnees,China。
文摘A simple method was proposed to produce tungsten(W)particles with controllable shape and size by employing the salt-assisted hydrogen reduction.W particles with controlled shape and size were prepared by adjusting the amount of chlorine salts and the temperature.After adding salt additives,the dispersibility of final particles was obviously improved and more adequate growth of particles was obtained.It was found that the effect of NaCl and LiCl is particularly significant.The average sizes of the obtained W particles at 1038 K after adding 0.1 wt.%NaCl and 0.1 wt.%LiCl were 0.924 and 1.128μm,respectively.With the increase of temperature and amount of chlorine salts,the dispersity of the produced W particles became much better,the size of W sub-particles was increased,and the shape of W sub-particles was changed from spherical to polyhedral.At 1349 K,the addition of chlorine salts even multiplied the particle size,and the average sizes of W particles with 1 wt.%NaCl and 1 wt.%LiCl were raised up to 21.367 and 29.665μm,respectively.Based on the conventional pseudomorphic transformation and chemical vapor transport mechanisms,the effects of adding salts on the reaction mechanism were investigated in detail as well.
基金Project supported bythe National Natural Science Foundation of China (50306008) andthefundfromthe Preli minary ResearchProject of General Equipment Ministry (41328030507)
文摘A novel salt-assisted combustion process with ethylene glycol as a fuel and nitrate as an oxidant to synthesize high surface area celia nanopowders was reported. The effects of various tunable conditions, such as fuel-to-oxidant ratio, type of salts, and amount of added salts, on the characteristics of the as-prepared powders were investigated by X-ray diffraction, transmission electron microscopy and BET surface area measurement. A mechanism scheme was proposed to illustrate the possible formation processes of well-dispersed ceria nanoparticles in the salt-assisted combustion synthesis. It was verified that the simple introduction of leachable inert inorganic salts as an excellent agglomeration inhibitor into the redox mixture precursor leads to the formation of well-dispersed ceria particles with particle size in the range of 4 ～6 nm and a drastic increase in the surface area. The presence of KCl results in an over ten-fold increment in specific surface area from 14.10 m^2·g^-1 for the produced ceria powders via the conventional combustion synthesis process to 156.74 m^2·g^-1 for the product by the salt-assisted combustion synthesis process at the same molar ratio of ethylene glycol-nitrate.
基金supported by the National Natural Sci-ence Foundation of China under grant No. 50602024the Youth Foundation of North University of China
文摘A novel salt-assisted low temperature solid state method using CoCl2.6H2O, FeCl3.6H2O and NaOH as precursor and using NaCI as a dispersant to synthesize high surface area CoFe2O4 nanoparticles, has been investigated. The effects of the molar ratio of added salt and calcination temperature on the characteristics of the products were investigated by X-ray diffraction （XRD）, transmission electron microscopy （TEM）, vibrating sample magnetometer （VSM） and Brunauer, Emmett and Teller （BET） surface area analysis. Results showed that the introduction of leachable inert inorganic salt as a hard agglomeration inhibitor in the mixture precursor led to the formation of high dispersive CoFe2O4 nanoparticles; and the increase in specific surface area from 28.28 to 73.97 m^2/g, and the saturation magnetization is 84.6 emu/g.
基金the National Natural Science Foundation of China (50306008)Start up Research Fund of Nanchang University and the Natural Science Foundation of Higher Education Institutions in Anhui Province (KJ2007B231)
文摘Highly dispersed perovskite NdCoO3 nanoparticles were prepared by a novel salt-assisted combustion process. The effects of NaCl content and calcination temperature on the characteristics of the products were characterized by X-Ray Diffraction (XRD), Transmission Electron Microscopy (TEM) and BET surface area measurement. The facile introduction of NaCl in the conventional combustion synthesis process was found to result in the formation of well-dispersed perovskite nanoparticles and increase specific surface areas of the resultants from 1.7 to 43.2 m2·g-1. The catalytic properties of the typical NdCoO3 samples for thermal decomposition of ammonia perchlorate (AP) and their correlation with the NdCoO3 microstructure were investigated by Differential Scanning Calorimetry (DSC). The DSC results indicate that the addition of the amorphous NdCoO3 nanoparticles to AP incorporates two small exothermic peaks of AP into a strong exothermic peak, decreases the temperature of the AP exothermic peak to 314.0 ℃ by reduction of 138.3 ℃ and increases the apparent decomposition heat from 515 J·g-1 to over 1441 J·g-1, showing the intense catalytic activity for thermal decomposition of AP. It is also clear that the catalytic activity of the resultant NdCoO3 is related to their microstructure. According to Kissinger′s method, the kinetics parameters of the thermal decomposition of AP catalyzed by the as-prepared NdCoO3 samples were calculated to account for the order of their catalytic activity.
基金supported by the National Natural Science Foundation of China (21825103, 51727809)the Fundamental Research Funds for the Central University (2019kfy XMBZ018)the project funded by China Postdoctoral Science Foundation (2018M642832)
文摘Two-dimensional(2D) materials with atomic thickness are promising candidates for the applications in future semiconductor devices, owing to their fascinating physical properties and superlative optoelectronic performance. Chemical vapor deposition(CVD) is considered to be an efficient method for large-scale preparation of 2D materials toward practical applications.However, the high melting points of metal precursors and the thermodynamics instabilities of metastable phases limit the direct CVD synthesis of plenty of 2D materials. The salt has recently been introduced into the CVD process, which proved to be effective to address these issues. In this review, we highlighted the latest progress in the salt-assisted CVD growth of 2D materials, including layered and non-layered crystals. Firstly, strategies of adding salts are summarized. Then, the salt-assisted growth of various layered materials is presented, emphasizing on the transition metal chalcogenides of stable and metastable phases. Furthermore, strategies to grow ultrathin non-layered materials are discussed. We provide viewpoints into the techniques of using salt, the effects of salt, and the growth mechanisms of 2D crystals. Finally, we offer the challenges to be overcome and further research directions of this emerging salt-assisted CVD technique.
基金supported by the National Natural Science Foundation of China (50902070)the Natural Science Foundation of Jiangsu province (BK2009391)+1 种基金the Research Fund for the Doctoral Program of Higher Education of China (20093219120011)NUST Research Funding (ZDJH07)
文摘A salt-assistant stearic acid method （SAM） capable of forming ultrafine K4Ce2Nb10O30 products was described. XRD pattern re-vealed that tetragonal K4Ce2Nb10O30 products could be obtained by heat treatment at 900 ℃ for 2 h. Transmission electron microscopy （TEM） observations indicated the introduction of KCl could lead to the formation of rod-like K4Ce2Nb10O30 products. The species of salts played a crucial role in fine tuning the shapes and sizes of K4Ce2Nb10O30 products. Furthermore, the K4Ce2Nb10O30 prepared by salt-assistant SAM had considerable activity under visible light irradiation.
基金National Natural Science Foundation of China,Grant/Award Numbers:22075223,22179104State Key Laboratory of Advanced Technology for Materials Synthesis and Processing(Wuhan University of Technology),Grant/Award Number:2021-ZD-4。
文摘Designing synergistic heterogeneous catalytic interfaces is the key to developing highly compatible pH-universal electrocatalysts for complex chemical environments.Our theoretical calculation results demonstrate that the Ru-Ru2P heterointerface can not only promote the redistribution of charges,but also reduce the d-band center,and then enhances the adsorption capacity of the key intermediate.However,in situ and facile synthesis of Ru-Ru2P heterostructures is severely limited by thermodynamic obstacles.Herein,we propose a molten salt-assisted catalytic synthesis scheme,and successfully build a series of homologous metallic Ru-Ru2P heterostructure catalysts with different molar ratios of Ru to P under atmospheric pressure and low-temperature(400C).The resultant Ru-Ru2P with rich heterostructures show the Pt-like HER performance in different pH media.Particularly,it is prominent under alkaline conditions(18 mV@10 mA cm^(2)),which outperforms the Pt catalyst(37 mV@10 mA cm^(2)).Furthermore,Ru-Ru2P heterostructures also show certain potential in the electrolysis of seawater to produce hydrogen.This work represents a significant supplement of high-efficiency pH-universal HER catalysts,and provides a new light on interface engineering in energy technology fields and beyond.
基金Project supported by the National Natural Science Foundation of China (21061011)the Jiangxi Provincial Natural Science Foundation (2008GZC0021)+2 种基金the Scientific & Technological Research Project of Jiangxi Educational Department (GJJ08008)the Jiangxi Provincial Foundation of Training Academic and Technical Leaders for Main Majors (2007DD00800)the Natural Science Foundation of Higher Education Institutions in Anhui Province (KJ 2007B231)
文摘A series of well-dispersed titania-doped ceria nanoparticles Ce1–xTixO2 were rapidly prepared by a novel salt-assisted solution combustion process using correspondent metal nitrates as oxidizers and ethyl glycol as fuel, and then coated with amorphous silica by seeded polymerization using tetraethyl orthoslicate （TEOS）. The as-prepared samples were characterized by transmission electron microscopy （TEM）, X-ray diffraction （XRD）, Fourier-transform infrared spectroscopy （FTIR）, and ultraviolet-visible light （UV-Vis） diffuse reflectance spectroscopy. The results indicated that compared with the as-prepared pure ceria nanoparticles, the red-shift phenomenon occurred for Ti-doped ceria nanoparticles with Ti incorporation. Meanwhile, the absorption intensity in the UV light region slightly decreased and transmission rate in visible light region was somewhat enhanced. In comparison with the silica-coated CeO2 nanopowders, the silica-coated Ce0.95Ti0.05O2 nanopowders displayed the same absorption intensity in the UV light region, broader UV absorption band and higher transmission rate in visible light region.
