CdS/NiS nanocomposites were synthesized by electrochemical method. Ni and Cd is one of the important II-VI semiconducting materials with a direct band gap of 3.26 eV which finds applications in electrical conductivity...CdS/NiS nanocomposites were synthesized by electrochemical method. Ni and Cd is one of the important II-VI semiconducting materials with a direct band gap of 3.26 eV which finds applications in electrical conductivity and photo-catalysis. The synthesized nanocomposites were characterized by BET, UV-VIS, XRD, FE-SEM (EDAX) techniques. X-Ray diffraction (XRD) reveals crystallite size to be 23.22 nm which was calculated using Williamson-Hall (W-H) plot method. The energy of the band gap for CdS/NiS could be thus estimated to be 3.26 eV. The photocatalytic activity of the sample was evaluated by the degradation of textile dye methylene Blue (MB) in aqueous solutions under UV radiation. Hydrogen energy is regarded as a promising alternative in terms of energy conversion and storage. Hydrogen Evolution Reaction (HER) was carried out in both visible light and UV light by using Hydrazine (N<sub>2</sub>H<sub>4</sub>H<sub>2</sub>O) in the presence of CdS/NiS nanocomposite. The synthesized photocatalyst shows applicable performance for kinetics of Hydrogen Evolution Reaction (HER) in Visible light and UV light. The decomposition of hydrazine (N<sub>2</sub>H<sub>4</sub>H<sub>2</sub>O) proceeded rapidly to generate free hydrogen rich gas through OH radical contact with CdS/NiS nanocomposite at room temperature. The rate of HER is limited by either proton adsorption onto an active site or evolution of formed hydrogen from the surface. A high Tafel slope is indicative of proton adsorption as the rate limiting step, while a lower Tafel slope (20 - 45 mV) indicates that the evolution of molecules hydrogen from the catalyst is rate limiting. In the present case the Tafel slopes for visible light 23.5 mV and 42.5 mV for UV light. Blank experiments show poor activity for HER <em>i.e.</em> 10.1 - 13.5 mV.展开更多
In the present paper an effort has been made to investigate effect of dispersion of CdS nanoparticles on the thermal and mechanical properties of PS/PMMA blends. Samples have been prepared through dispersion of CdS na...In the present paper an effort has been made to investigate effect of dispersion of CdS nanoparticles on the thermal and mechanical properties of PS/PMMA blends. Samples have been prepared through dispersion of CdS nanoparticles (prepared separately) during solution casting blend fabrication processing. These nanocomposites samples are structurally characterized through Wide angle X-ray Scattering (WAXS) and Small Angle X-ray Scattering (SAXS) techniques. Scanning Electron Microscopy (SEM) analyses of these samples have been carried out in lieu of surface morphological characterization. The measurements of glass transition temperature and stress-strain analyses have been performed through Dynamic Mechanical Analyzer (DMA). The thermal conductivity of nanocomposite samples has been determined using Hot Disk Thermal Constants Analyzer. The study shows that the incorporation of dispersed CdS nanoparticles in PS/PMMA blend matrix significantly alter their glass transition behaviour, thermal conductivity and tensile properties.展开更多
Polymeric nanocomposites of PS/PMMA/CdS and PS/PVC/CdS samples have been synthesized through dispersion solution casting technique. The nanoparrticles of CdS were prepared by simple chemical method using CdCl2 and H2S...Polymeric nanocomposites of PS/PMMA/CdS and PS/PVC/CdS samples have been synthesized through dispersion solution casting technique. The nanoparrticles of CdS were prepared by simple chemical method using CdCl2 and H2S gas produced from thiourea. The nanoscale morphology of the prepared polymeric nanocomposite samples is probed through small angle X-ray scattering (SAXS). The SAXS study reveals that CdS nanoparticles take place at voids position in the respective plymer blend matrix and exhibit their nano nature with very little tendency to agglomerates.展开更多
The CoO/CoVO/Ni nanocomposites were rationally designed and prepared by a two-step hydrothermal synthesis and subsequent annealing treatment. The one-dimensional（1D） CoOnanowire arrays directly grew on Ni foam, wher...The CoO/CoVO/Ni nanocomposites were rationally designed and prepared by a two-step hydrothermal synthesis and subsequent annealing treatment. The one-dimensional（1D） CoOnanowire arrays directly grew on Ni foam, whereas the 1D CoVOnanowires adhered to parts of CoOnanowires.Most of the hybrid nanowires were inlayed with each other, forming a 3D hybrid nanowires network.As a result, the discharge capacity of CoO/CoVO/Ni nanocomposites could reach 1201.8 mAh/g after100 cycles at 100 mA/g. After 600 cycles at 1 A/g, the discharge capacity was maintained at 828.1 mAh/g.Moreover, even though the charge/discharge rates were increased to 10 A/g, it rendered reversible capacity of 491.2 mAh/g. The superior electrochemical properties of nanocomposites were probably ascribed to their unique 3D architecture and the synergistic effects of two active materials. Therefore, such CoO/CoVO/Ni nanocomposites could potentially be used as anode materials for high-performance Li-ion batteries.展开更多
This paper describes an investigation of the effect of ZrO2 nanoparticles on the abrasive properties,crystalline texture developments,and tribocorrosion behavior of Ni-P nanostructured coatings.In the investigation,Ni...This paper describes an investigation of the effect of ZrO2 nanoparticles on the abrasive properties,crystalline texture developments,and tribocorrosion behavior of Ni-P nanostructured coatings.In the investigation,Ni-P and Ni-P-ZrO2 nanostructured coatings are deposited on St52 steel via the electroless method.Transmission electron microscopy(TEM),field emission scanning electron microscopy(FE-SEM),X-ray diffraction(XRD),energy dispersive spectroscopy(EDS),cyclic-static polarization tests in 3.5wt%NaCl solution,the tribocorrosion test(by back-and-forth wear in electrochemical cell),and the microhardness test using the Vickers method were performed to characterize and analyze the deposited coatings.The results of this study showed that the addition of ZrO2 nanoparticles to the Ni-P electroless bath produced the following:a sharp increase in wear and hardness resistance,the change of the wear mechanism from sheet to adhesive mode,the reduction of pitting corrosion resistance,significant reduction in the tribocorrosion protective properties,change in the preferred orientation of the crystalline texture coating from(111)to(200),increase in the sedimentation rate during the deposit process,and a sharp increase in the thickness of the Ni-P nanostructured coatings.展开更多
The point of zero charge(PZC) of SiC nanoparticles was determined by means of standard potentiometric titration method, while the influences of the main technological parameters on the microstructure of electrodeposit...The point of zero charge(PZC) of SiC nanoparticles was determined by means of standard potentiometric titration method, while the influences of the main technological parameters on the microstructure of electrodeposited Ni-SiC composite film were studied and optimized. The results show that high bath pH value favors SiC nanoparticles negatively charged and high bath temperature promotes them positively charged. Under the experimental conditions, sodium dodecyl-glycol is proven to be an effective surface modification anionic surfactant for SiC nanoparticles. The results also show that the optimized Ni-SiC composite film is composed of the nanoparticles with the average grain size in the nanometer range (100 nm), and SiC nanoparticles disperse into the nickel matrix uniformly.展开更多
Ni-SiC nanocomposites were fabricated by co-electrodeposition of nickel with silicon carbide nanoparticles on the pure nickel substrates from a nickel sulfate bath with and without the addition of Co2+. The presence o...Ni-SiC nanocomposites were fabricated by co-electrodeposition of nickel with silicon carbide nanoparticles on the pure nickel substrates from a nickel sulfate bath with and without the addition of Co2+. The presence of Co2+ in the electrolyte modifies the Ni matrix to Ni-Co solid solution matrix. It helps to refine the grain size of the nanocomposite coating and improves the content of SiC dispersed in the matrix, and consequently results in higher microhardness. The cathodic polarization curves and electrochemical impedance spectroscopy (EIS) at cathodic potential were investigated in the electrolyte with and without Co2+. A modified cathodic polarization curve with a positive shift in reduction potential and a smaller capacitive loop of EIS are observed. These are attributed to the strong adsorption of Co2+ on the SiC nanoparticles. Consequently, it increases the forces of electrostatic attraction between the SiC nanoparticles and the cathode, which promotes the codeposition of SiC nanoparticles in the matrix.展开更多
The hydrogen storage properties of the nanocomposite Mg 95 Ni 3(MnO 2) 2 (mass fraction, %) were studied. The temperature changes in hydriding/dehydriding process were investigated. The nanocomposite was fabricated by...The hydrogen storage properties of the nanocomposite Mg 95 Ni 3(MnO 2) 2 (mass fraction, %) were studied. The temperature changes in hydriding/dehydriding process were investigated. The nanocomposite was fabricated by ball milling process of mixed elemental Mg, Ni and oxide maganese MnO 2 under hydrogen pressure (approximately 0.6?MPa). The hydrogen absorption and desorption properties of the samples milled for various times were investigated. A remarkable enhancement of hydrogen absorption kinetics and low operational desorption temperature have been found after the sample milled for over 57?h. For example, this nanocomposite can absorb hydrogen more than 6.0% (mass fraction) in 60?s at 200?℃ under 2.0?MPa, and desorption capacity also exceeds 6.0% (mass fraction) in 400?s at 310?℃ under 0.1?MPa. The storage properties of samples milled for various times were studied and the kinetics of the samples were analyzed.展开更多
Ni-TiN nanocomposite coatings were prepared by ultrasonic electrodeposition, and the effects of the surfactants on the coatings were investigated and the microstructure and micro rigidity of the coatings were characte...Ni-TiN nanocomposite coatings were prepared by ultrasonic electrodeposition, and the effects of the surfactants on the coatings were investigated and the microstructure and micro rigidity of the coatings were characterized. Samples were also submitted to corrosion tests in 3% NaCl solution. The results showed that the surfactants had great effects on Ni-TiN nanocomposite coatings. The composite coatings prepared by ultrasonic electrodeposition with the surfactants were better than that of the coatings prepared without surfactants. The favorable properties of Ni-TiN nanocomposite coatings were prepared with the mixing of the non-ion and positive ion surfactants. The concentration of the mixing was 80 mg/L, and the ratio of the non-ion and positive ion surfactants was 1： 2.展开更多
ZrO2/Ni nanocomposite was produced by pulse electrodeposition and its superplastic properties were investigated by the tensile and bulging tests. The as-deposited nickel matrix has a narrow grain size distribution wit...ZrO2/Ni nanocomposite was produced by pulse electrodeposition and its superplastic properties were investigated by the tensile and bulging tests. The as-deposited nickel matrix has a narrow grain size distribution with a mean grain size of 45 nm. A maximum elongation of 605% was observed at 723 K and a strain rate of 1.67×10-3s-1 by tensile test. Superplastic bulging tests were subsequently performed using dies with diameters of 1 mm and 5 mm respectively based on the optimal superplastic forming temperature. The effects of forming temperature and gas pressure on bulging process were experimentally investigated. The results indicated that ZrO2/Ni nanocomposite samples can be readily bulged at 723 K with H/d value （defined as dome apex height over the die diameter） larger than 0.5, indicating that the nanocomposite has good bulging ability. SEM and TEM were used to examine the microstructure of the as-deposited and bulged samples. The observations showed that significant grain coarsening occurs during superplastic bulging, and the microstructure is found to depend on the forming temperature.展开更多
文摘CdS/NiS nanocomposites were synthesized by electrochemical method. Ni and Cd is one of the important II-VI semiconducting materials with a direct band gap of 3.26 eV which finds applications in electrical conductivity and photo-catalysis. The synthesized nanocomposites were characterized by BET, UV-VIS, XRD, FE-SEM (EDAX) techniques. X-Ray diffraction (XRD) reveals crystallite size to be 23.22 nm which was calculated using Williamson-Hall (W-H) plot method. The energy of the band gap for CdS/NiS could be thus estimated to be 3.26 eV. The photocatalytic activity of the sample was evaluated by the degradation of textile dye methylene Blue (MB) in aqueous solutions under UV radiation. Hydrogen energy is regarded as a promising alternative in terms of energy conversion and storage. Hydrogen Evolution Reaction (HER) was carried out in both visible light and UV light by using Hydrazine (N<sub>2</sub>H<sub>4</sub>H<sub>2</sub>O) in the presence of CdS/NiS nanocomposite. The synthesized photocatalyst shows applicable performance for kinetics of Hydrogen Evolution Reaction (HER) in Visible light and UV light. The decomposition of hydrazine (N<sub>2</sub>H<sub>4</sub>H<sub>2</sub>O) proceeded rapidly to generate free hydrogen rich gas through OH radical contact with CdS/NiS nanocomposite at room temperature. The rate of HER is limited by either proton adsorption onto an active site or evolution of formed hydrogen from the surface. A high Tafel slope is indicative of proton adsorption as the rate limiting step, while a lower Tafel slope (20 - 45 mV) indicates that the evolution of molecules hydrogen from the catalyst is rate limiting. In the present case the Tafel slopes for visible light 23.5 mV and 42.5 mV for UV light. Blank experiments show poor activity for HER <em>i.e.</em> 10.1 - 13.5 mV.
文摘In the present paper an effort has been made to investigate effect of dispersion of CdS nanoparticles on the thermal and mechanical properties of PS/PMMA blends. Samples have been prepared through dispersion of CdS nanoparticles (prepared separately) during solution casting blend fabrication processing. These nanocomposites samples are structurally characterized through Wide angle X-ray Scattering (WAXS) and Small Angle X-ray Scattering (SAXS) techniques. Scanning Electron Microscopy (SEM) analyses of these samples have been carried out in lieu of surface morphological characterization. The measurements of glass transition temperature and stress-strain analyses have been performed through Dynamic Mechanical Analyzer (DMA). The thermal conductivity of nanocomposite samples has been determined using Hot Disk Thermal Constants Analyzer. The study shows that the incorporation of dispersed CdS nanoparticles in PS/PMMA blend matrix significantly alter their glass transition behaviour, thermal conductivity and tensile properties.
基金supported by the National Natural Science Foundation of China(51672089)the Science and Technology Planning Project of Guangdong Province(2015B020215011)the State Key Laboratory of Advanced Technology for Material Synthesis and Processing(Wuhan University of Technology)(2015-KF-7)~~
文摘Polymeric nanocomposites of PS/PMMA/CdS and PS/PVC/CdS samples have been synthesized through dispersion solution casting technique. The nanoparrticles of CdS were prepared by simple chemical method using CdCl2 and H2S gas produced from thiourea. The nanoscale morphology of the prepared polymeric nanocomposite samples is probed through small angle X-ray scattering (SAXS). The SAXS study reveals that CdS nanoparticles take place at voids position in the respective plymer blend matrix and exhibit their nano nature with very little tendency to agglomerates.
基金supported by the National Natural Science Foundation of China(no.51362018)the Foundation for Innovation Groups of Basic Research in Gansu Province(no.1606RJIA322)
文摘The CoO/CoVO/Ni nanocomposites were rationally designed and prepared by a two-step hydrothermal synthesis and subsequent annealing treatment. The one-dimensional（1D） CoOnanowire arrays directly grew on Ni foam, whereas the 1D CoVOnanowires adhered to parts of CoOnanowires.Most of the hybrid nanowires were inlayed with each other, forming a 3D hybrid nanowires network.As a result, the discharge capacity of CoO/CoVO/Ni nanocomposites could reach 1201.8 mAh/g after100 cycles at 100 mA/g. After 600 cycles at 1 A/g, the discharge capacity was maintained at 828.1 mAh/g.Moreover, even though the charge/discharge rates were increased to 10 A/g, it rendered reversible capacity of 491.2 mAh/g. The superior electrochemical properties of nanocomposites were probably ascribed to their unique 3D architecture and the synergistic effects of two active materials. Therefore, such CoO/CoVO/Ni nanocomposites could potentially be used as anode materials for high-performance Li-ion batteries.
文摘This paper describes an investigation of the effect of ZrO2 nanoparticles on the abrasive properties,crystalline texture developments,and tribocorrosion behavior of Ni-P nanostructured coatings.In the investigation,Ni-P and Ni-P-ZrO2 nanostructured coatings are deposited on St52 steel via the electroless method.Transmission electron microscopy(TEM),field emission scanning electron microscopy(FE-SEM),X-ray diffraction(XRD),energy dispersive spectroscopy(EDS),cyclic-static polarization tests in 3.5wt%NaCl solution,the tribocorrosion test(by back-and-forth wear in electrochemical cell),and the microhardness test using the Vickers method were performed to characterize and analyze the deposited coatings.The results of this study showed that the addition of ZrO2 nanoparticles to the Ni-P electroless bath produced the following:a sharp increase in wear and hardness resistance,the change of the wear mechanism from sheet to adhesive mode,the reduction of pitting corrosion resistance,significant reduction in the tribocorrosion protective properties,change in the preferred orientation of the crystalline texture coating from(111)to(200),increase in the sedimentation rate during the deposit process,and a sharp increase in the thickness of the Ni-P nanostructured coatings.
基金Project(20203015) supported by the National Natural Science Foundation of ChinaProject supported by the State Key Laboratory for Corrosion and Protection of China
文摘The point of zero charge(PZC) of SiC nanoparticles was determined by means of standard potentiometric titration method, while the influences of the main technological parameters on the microstructure of electrodeposited Ni-SiC composite film were studied and optimized. The results show that high bath pH value favors SiC nanoparticles negatively charged and high bath temperature promotes them positively charged. Under the experimental conditions, sodium dodecyl-glycol is proven to be an effective surface modification anionic surfactant for SiC nanoparticles. The results also show that the optimized Ni-SiC composite film is composed of the nanoparticles with the average grain size in the nanometer range (100 nm), and SiC nanoparticles disperse into the nickel matrix uniformly.
基金Project supported by "One Hundred Talents Plan" sponsored by the Chinese Academy of Sciences(CAS)
文摘Ni-SiC nanocomposites were fabricated by co-electrodeposition of nickel with silicon carbide nanoparticles on the pure nickel substrates from a nickel sulfate bath with and without the addition of Co2+. The presence of Co2+ in the electrolyte modifies the Ni matrix to Ni-Co solid solution matrix. It helps to refine the grain size of the nanocomposite coating and improves the content of SiC dispersed in the matrix, and consequently results in higher microhardness. The cathodic polarization curves and electrochemical impedance spectroscopy (EIS) at cathodic potential were investigated in the electrolyte with and without Co2+. A modified cathodic polarization curve with a positive shift in reduction potential and a smaller capacitive loop of EIS are observed. These are attributed to the strong adsorption of Co2+ on the SiC nanoparticles. Consequently, it increases the forces of electrostatic attraction between the SiC nanoparticles and the cathode, which promotes the codeposition of SiC nanoparticles in the matrix.
文摘The hydrogen storage properties of the nanocomposite Mg 95 Ni 3(MnO 2) 2 (mass fraction, %) were studied. The temperature changes in hydriding/dehydriding process were investigated. The nanocomposite was fabricated by ball milling process of mixed elemental Mg, Ni and oxide maganese MnO 2 under hydrogen pressure (approximately 0.6?MPa). The hydrogen absorption and desorption properties of the samples milled for various times were investigated. A remarkable enhancement of hydrogen absorption kinetics and low operational desorption temperature have been found after the sample milled for over 57?h. For example, this nanocomposite can absorb hydrogen more than 6.0% (mass fraction) in 60?s at 200?℃ under 2.0?MPa, and desorption capacity also exceeds 6.0% (mass fraction) in 400?s at 310?℃ under 0.1?MPa. The storage properties of samples milled for various times were studied and the kinetics of the samples were analyzed.
基金National Natural Science Foundation of China(No.50475108)Natural Science Foundation of Liaoning Province,China(No.20042123)
文摘Ni-TiN nanocomposite coatings were prepared by ultrasonic electrodeposition, and the effects of the surfactants on the coatings were investigated and the microstructure and micro rigidity of the coatings were characterized. Samples were also submitted to corrosion tests in 3% NaCl solution. The results showed that the surfactants had great effects on Ni-TiN nanocomposite coatings. The composite coatings prepared by ultrasonic electrodeposition with the surfactants were better than that of the coatings prepared without surfactants. The favorable properties of Ni-TiN nanocomposite coatings were prepared with the mixing of the non-ion and positive ion surfactants. The concentration of the mixing was 80 mg/L, and the ratio of the non-ion and positive ion surfactants was 1： 2.
基金Funded by the National Natural Science Foundation of China(No.50575049)
文摘ZrO2/Ni nanocomposite was produced by pulse electrodeposition and its superplastic properties were investigated by the tensile and bulging tests. The as-deposited nickel matrix has a narrow grain size distribution with a mean grain size of 45 nm. A maximum elongation of 605% was observed at 723 K and a strain rate of 1.67×10-3s-1 by tensile test. Superplastic bulging tests were subsequently performed using dies with diameters of 1 mm and 5 mm respectively based on the optimal superplastic forming temperature. The effects of forming temperature and gas pressure on bulging process were experimentally investigated. The results indicated that ZrO2/Ni nanocomposite samples can be readily bulged at 723 K with H/d value （defined as dome apex height over the die diameter） larger than 0.5, indicating that the nanocomposite has good bulging ability. SEM and TEM were used to examine the microstructure of the as-deposited and bulged samples. The observations showed that significant grain coarsening occurs during superplastic bulging, and the microstructure is found to depend on the forming temperature.
