The preparation of Zn Se/Cd Se core-shell structure nanocomposites by using the re-prepared Zn Se microspheres as the template under the hydrothermal condition was presented. The influence of different mole ratios of ...The preparation of Zn Se/Cd Se core-shell structure nanocomposites by using the re-prepared Zn Se microspheres as the template under the hydrothermal condition was presented. The influence of different mole ratios of ZnS e to Cd（NO3）2 on the morphology and structure of the final product was investigated. And the performances of ZnS e/Cd Se core-shell structure nanocomposites were characterized by the means of X-ray diffraction（XRD） analyses, scanning electron microscopy（SEM）, transmission electron microscopy（TEM） and photoluminescence（PL） spectroscopy. The results indicate that the core-shell structure product can be prepared, when the mole ratio of Zn Se to Cd（NO3）2 is larger than 1：1; and the product will be ball solid structure, when the mole ratio of Zn Se to Cd（NO3）2 is equal to 1：1. The photo luminescence results show that Zn Se/Cd Se core-shell structures have high photo luminescence emission properties, and the product with mole ratio of Zn Se to Cd（NO3）2 being 1：0.5 has the best luminescence properties.展开更多
Vanadium （III） phosphate monoclinic VPO4·H2O was synthesized hydrothermally. The ε-VOPO4 nanosheets, formed by the oxidative de-intercalation of protons from monoclinic VPO4·H2O, can reversibly react wit...Vanadium （III） phosphate monoclinic VPO4·H2O was synthesized hydrothermally. The ε-VOPO4 nanosheets, formed by the oxidative de-intercalation of protons from monoclinic VPO4·H2O, can reversibly react with more than 1 mol lithium atoms in two steps. Crystal XRD analysis revealed that the structure of the ε-VOPO4 nanosheets is monoclinic with lattice parameters of α=7.2588（4） A, b=6.8633（2） A and c=7.2667（4） A. The results show that the ε-VOPO4 nanosheets have a thickness of 200 nm and uniform crystallinity. Electrochemical characterization of the ε-VOPO4 monoclinic nanosheets reveals that they have good electrochemical properties at high current density, and deliver high initial capacity of 230.3 mA· h/g at a current density of 0.09 mA/cm2. Following the first charge cycle, reversible electrochemical lithium extraction/insertion at current density of 0.6 mA/cm2 affords a capacity retention rate of 73.6% （2.0？4.3 V window） that is stable for at least 1000 cycles.展开更多
Electrochemical water splitting,as a promising method for hydrogen production,has attracted significant attention.However,the lack of an electrocatalyst with a small energy loss and fast reaction kinetics has hindered...Electrochemical water splitting,as a promising method for hydrogen production,has attracted significant attention.However,the lack of an electrocatalyst with a small energy loss and fast reaction kinetics has hindered the development of this technology.Amorphous nanomaterials with short-range order and long-range disorder features have recently shown superior activity compared to their crystalline counterparts in water electrolysis.The enhanced activity arising from their intrinsic disordered structure results in more active sites and a higher intrinsic activity of such sites.In this regard,this review is aimed at summarizing the progress in amorphous electrocatalysts for water splitting.First,the synthesis strategies for amorphous electrocatalysts are discussed.Characterization tools for amorphous nanomaterials are then summarized.Moreover,the origin of the enhanced activity and stability of amorphous nanomaterials is analyzed.Finally,the current challenges and promising opportunities in this research area are discussed.This review aims to provide a guide for designing and developing amorphous nanomaterials with a fascinating electrocatalytic water splitting performance.展开更多
Highly pure active γ-Al2O3 nanoparticles were synthesized from aluminum nitrate and ammonium carbonate with a little surfactant by chemical precipitation method. The factors affecting the synthesis process were studi...Highly pure active γ-Al2O3 nanoparticles were synthesized from aluminum nitrate and ammonium carbonate with a little surfactant by chemical precipitation method. The factors affecting the synthesis process were studied. The properties of γ-Al2O3 nanoparticles were characterized by DTA, XRD, BET, TEM, laser granularity analysis and impurity content analysis. The results show that the amorphous precursor AI（OH）3 sols are produced by using 0.1 mol/L Al（NO3）3·9H2O and 0.16 mol/L （NH4）2CO3·H2O reaction solutions, according to the volume ratio 1.33, adding 0.024%（volume fraction） surfactant PEG600, and reacting at 40℃, 1000 r/min stirring rate for 15min. Then, after stabilizing for 24 h, the precursors were extracted and filtrated by vacuum, washed thoroughly with deionized water and dehydrated ethanol, dried in vacuum at 80℃ for 8h, final calcined at 800℃ for 1h in the air, and high purity active γ-Al2O3 nanoparticles can be prepared with cubic in crystal system, OH^7-FD3M in space group, about 9 nm in crystal grain size, about 20 nm in particle size and uniform size distribution, 131.35 m^2/g in BET specific surface area, 7 - 11 nm in pore diameter, and not lower than 99.93% in purity.展开更多
A facile and practical route was introduced to prepare LiFePO4/C cathode material with nano-sized primary particles and excellent electrochemical performance. LiH2PO4 was synthesized by using H3PO4 and LiOH as raw mat...A facile and practical route was introduced to prepare LiFePO4/C cathode material with nano-sized primary particles and excellent electrochemical performance. LiH2PO4 was synthesized by using H3PO4 and LiOH as raw materials. Then, as-prepared LiH2PO4, reduced iron powder andα-D-glucose were ball-milled, dried and sin-tered to prepare LiFePO4/C. X-ray diffractometry was used to characterize LiH2PO4, ball-milled product and LiFePO4/C. Differential scanning calorimeter-thermo gravimetric analysis was applied to investigate possible reac-tions in sintering and find suitable temperature for LiFePO4 formation. Scanning electron microscopy was em-ployed for the morphology of LiFePO4/C. As-prepared LiH2PO4 is characterized to be in P21cn（33） space group, which reacts with reduced iron powder to form Li3PO4, Fe3（PO4）2 and H2 in ball-milling and sintering. The appro-priate temperature for LiFePO4/C synthesis is 541.3-976.7 ℃. LiFePO4/C prepared at 700 ℃ presents nano-sized primary particles forming aggregates. Charge-discharge examination indicates that as-prepared LiFePO4/C displays appreciable discharge capacities of 145 and 131 mA·h·g^-1 at 0.1 and 1 C respectively and excellent discharge ca-pacity retention.展开更多
Carbon capture and storage （CCS） is amongst the possible options to reduce CO2 emission. In the application of CCS, CO2 capture techniques such as adsorption and membrane system have been proposed due to less energy...Carbon capture and storage （CCS） is amongst the possible options to reduce CO2 emission. In the application of CCS, CO2 capture techniques such as adsorption and membrane system have been proposed due to less energy requirement and environmental benign than the absorption process. However, membrane system has drawbacks such as poor membrane reproducibility, scale-up difficulty and high cost of the membrane supports. In this study synthesis and characterization of nanocomposite sodalite （HS）/ceramic membrane via ＂pore-plugging＂ hydrothermal synthesis （PPH） protocol for pre- combustion CO2 capture is reported. The morphology and crystallinity of the as-prepared membranes were checked with scanning electron microscopy and X-ray diffraction. Surface chemistry of the membrane was examined with Fourier Transform Infrared spectroscopy. In nanocomposite architecture membranes, zeolite crystals are embedded within the pores of the supports instead of forming thin-film layers of the zeolite crystals on the surface of the supports. Compared to the conventional in situ direct hydrothermal synthesis, membranes obtained from PPH possess higher mechanical strength and thermal stability. In addition, defect control with nanocomposite architecture membranes is possible because the zeolite crystals are embedded within the pores of the support, thereby limiting the maximum defect size to the pore size of the support. Furthermore, the nanocomposite architecture nature of the membranes safeguards the membrane from shocks or abrasion that could promote formation of defects. The aforementioned advantages of the nanocomposite architecture membranes could be beneficial in developing high performance and cost-effective membrane materials for pre-combustion CO2 capture.展开更多
The hydrogen adsorption （storage） studies upon Ni/A1203 nano-composite prepared by metal organic chemical vapor deposition technique （MOCVD） exploiting single source molec ular precursor （SSP） approach were carr...The hydrogen adsorption （storage） studies upon Ni/A1203 nano-composite prepared by metal organic chemical vapor deposition technique （MOCVD） exploiting single source molec ular precursor （SSP） approach were carried out. The Ni/A1203 nano-composite is prepared in cold walled MOCVD reactor by the decomposition of SSP, [H2AI（OtBu）]2, on a substrate holding Ni（acac）2 powder. The SSP is a reducing agent which reduces Ni＋2 to Ni0 and works as source for Al203 matrix in which the Ni0 is dispersed. The resulting Ni/A1203 nano-composite is characterized by XRD, SEM, TEM, and EDX. The hydrogen adsorption （storage） studies are performed using home-made Sievert＇s type apparatus. The hydrogen storage studies reveal that approximately 2.9% （mass ratio） hydrogen can be stored in the Ni/A1203 nano-composite. The results show that Ni/A1203 nano-composite can be a po- tential candidate for hydrogen storage which can be used for onboard fuel purposes.展开更多
基金Project(13JJ1005)supported by the Natural Science Foundation for Distinguished Young Scholars of Hunan Province,China
文摘The preparation of Zn Se/Cd Se core-shell structure nanocomposites by using the re-prepared Zn Se microspheres as the template under the hydrothermal condition was presented. The influence of different mole ratios of ZnS e to Cd（NO3）2 on the morphology and structure of the final product was investigated. And the performances of ZnS e/Cd Se core-shell structure nanocomposites were characterized by the means of X-ray diffraction（XRD） analyses, scanning electron microscopy（SEM）, transmission electron microscopy（TEM） and photoluminescence（PL） spectroscopy. The results indicate that the core-shell structure product can be prepared, when the mole ratio of Zn Se to Cd（NO3）2 is larger than 1：1; and the product will be ball solid structure, when the mole ratio of Zn Se to Cd（NO3）2 is equal to 1：1. The photo luminescence results show that Zn Se/Cd Se core-shell structures have high photo luminescence emission properties, and the product with mole ratio of Zn Se to Cd（NO3）2 being 1：0.5 has the best luminescence properties.
基金Projects(51172065,51404097,51504083,U1404613)supported by the National Natural Science Foundation of ChinaProject(16A150009)supported by the Key Scientific Research Project for Higher Education of Henan Province,China+2 种基金Project(16A150009)supported by the Natural Science Foundation of Henan Province(General Program)ChinaProject(166115)supported by the Postdoctoral Science Foundation of Henan Province,China
文摘Vanadium （III） phosphate monoclinic VPO4·H2O was synthesized hydrothermally. The ε-VOPO4 nanosheets, formed by the oxidative de-intercalation of protons from monoclinic VPO4·H2O, can reversibly react with more than 1 mol lithium atoms in two steps. Crystal XRD analysis revealed that the structure of the ε-VOPO4 nanosheets is monoclinic with lattice parameters of α=7.2588（4） A, b=6.8633（2） A and c=7.2667（4） A. The results show that the ε-VOPO4 nanosheets have a thickness of 200 nm and uniform crystallinity. Electrochemical characterization of the ε-VOPO4 monoclinic nanosheets reveals that they have good electrochemical properties at high current density, and deliver high initial capacity of 230.3 mA· h/g at a current density of 0.09 mA/cm2. Following the first charge cycle, reversible electrochemical lithium extraction/insertion at current density of 0.6 mA/cm2 affords a capacity retention rate of 73.6% （2.0？4.3 V window） that is stable for at least 1000 cycles.
文摘Electrochemical water splitting,as a promising method for hydrogen production,has attracted significant attention.However,the lack of an electrocatalyst with a small energy loss and fast reaction kinetics has hindered the development of this technology.Amorphous nanomaterials with short-range order and long-range disorder features have recently shown superior activity compared to their crystalline counterparts in water electrolysis.The enhanced activity arising from their intrinsic disordered structure results in more active sites and a higher intrinsic activity of such sites.In this regard,this review is aimed at summarizing the progress in amorphous electrocatalysts for water splitting.First,the synthesis strategies for amorphous electrocatalysts are discussed.Characterization tools for amorphous nanomaterials are then summarized.Moreover,the origin of the enhanced activity and stability of amorphous nanomaterials is analyzed.Finally,the current challenges and promising opportunities in this research area are discussed.This review aims to provide a guide for designing and developing amorphous nanomaterials with a fascinating electrocatalytic water splitting performance.
文摘Highly pure active γ-Al2O3 nanoparticles were synthesized from aluminum nitrate and ammonium carbonate with a little surfactant by chemical precipitation method. The factors affecting the synthesis process were studied. The properties of γ-Al2O3 nanoparticles were characterized by DTA, XRD, BET, TEM, laser granularity analysis and impurity content analysis. The results show that the amorphous precursor AI（OH）3 sols are produced by using 0.1 mol/L Al（NO3）3·9H2O and 0.16 mol/L （NH4）2CO3·H2O reaction solutions, according to the volume ratio 1.33, adding 0.024%（volume fraction） surfactant PEG600, and reacting at 40℃, 1000 r/min stirring rate for 15min. Then, after stabilizing for 24 h, the precursors were extracted and filtrated by vacuum, washed thoroughly with deionized water and dehydrated ethanol, dried in vacuum at 80℃ for 8h, final calcined at 800℃ for 1h in the air, and high purity active γ-Al2O3 nanoparticles can be prepared with cubic in crystal system, OH^7-FD3M in space group, about 9 nm in crystal grain size, about 20 nm in particle size and uniform size distribution, 131.35 m^2/g in BET specific surface area, 7 - 11 nm in pore diameter, and not lower than 99.93% in purity.
基金Supported partially by the Natural Science Foundation of Yunnan Province(2010ZC051)Analysis and Testing Foundation(2009-041)Starting Research Fund(14118245) from Kunming University of Science and Technology
文摘A facile and practical route was introduced to prepare LiFePO4/C cathode material with nano-sized primary particles and excellent electrochemical performance. LiH2PO4 was synthesized by using H3PO4 and LiOH as raw materials. Then, as-prepared LiH2PO4, reduced iron powder andα-D-glucose were ball-milled, dried and sin-tered to prepare LiFePO4/C. X-ray diffractometry was used to characterize LiH2PO4, ball-milled product and LiFePO4/C. Differential scanning calorimeter-thermo gravimetric analysis was applied to investigate possible reac-tions in sintering and find suitable temperature for LiFePO4 formation. Scanning electron microscopy was em-ployed for the morphology of LiFePO4/C. As-prepared LiH2PO4 is characterized to be in P21cn（33） space group, which reacts with reduced iron powder to form Li3PO4, Fe3（PO4）2 and H2 in ball-milling and sintering. The appro-priate temperature for LiFePO4/C synthesis is 541.3-976.7 ℃. LiFePO4/C prepared at 700 ℃ presents nano-sized primary particles forming aggregates. Charge-discharge examination indicates that as-prepared LiFePO4/C displays appreciable discharge capacities of 145 and 131 mA·h·g^-1 at 0.1 and 1 C respectively and excellent discharge ca-pacity retention.
文摘Carbon capture and storage （CCS） is amongst the possible options to reduce CO2 emission. In the application of CCS, CO2 capture techniques such as adsorption and membrane system have been proposed due to less energy requirement and environmental benign than the absorption process. However, membrane system has drawbacks such as poor membrane reproducibility, scale-up difficulty and high cost of the membrane supports. In this study synthesis and characterization of nanocomposite sodalite （HS）/ceramic membrane via ＂pore-plugging＂ hydrothermal synthesis （PPH） protocol for pre- combustion CO2 capture is reported. The morphology and crystallinity of the as-prepared membranes were checked with scanning electron microscopy and X-ray diffraction. Surface chemistry of the membrane was examined with Fourier Transform Infrared spectroscopy. In nanocomposite architecture membranes, zeolite crystals are embedded within the pores of the supports instead of forming thin-film layers of the zeolite crystals on the surface of the supports. Compared to the conventional in situ direct hydrothermal synthesis, membranes obtained from PPH possess higher mechanical strength and thermal stability. In addition, defect control with nanocomposite architecture membranes is possible because the zeolite crystals are embedded within the pores of the support, thereby limiting the maximum defect size to the pore size of the support. Furthermore, the nanocomposite architecture nature of the membranes safeguards the membrane from shocks or abrasion that could promote formation of defects. The aforementioned advantages of the nanocomposite architecture membranes could be beneficial in developing high performance and cost-effective membrane materials for pre-combustion CO2 capture.
文摘The hydrogen adsorption （storage） studies upon Ni/A1203 nano-composite prepared by metal organic chemical vapor deposition technique （MOCVD） exploiting single source molec ular precursor （SSP） approach were carried out. The Ni/A1203 nano-composite is prepared in cold walled MOCVD reactor by the decomposition of SSP, [H2AI（OtBu）]2, on a substrate holding Ni（acac）2 powder. The SSP is a reducing agent which reduces Ni＋2 to Ni0 and works as source for Al203 matrix in which the Ni0 is dispersed. The resulting Ni/A1203 nano-composite is characterized by XRD, SEM, TEM, and EDX. The hydrogen adsorption （storage） studies are performed using home-made Sievert＇s type apparatus. The hydrogen storage studies reveal that approximately 2.9% （mass ratio） hydrogen can be stored in the Ni/A1203 nano-composite. The results show that Ni/A1203 nano-composite can be a po- tential candidate for hydrogen storage which can be used for onboard fuel purposes.
