The calcium-doped ZnO nanoparticles,Zn1-xCaxO(x=0,0.025,0.05,0.075)were prepared by the solution combustion method.The synthesized nanoparticles were characterized by various techniques such as XRD,FTIR,Raman,FE...The calcium-doped ZnO nanoparticles,Zn1-xCaxO(x=0,0.025,0.05,0.075)were prepared by the solution combustion method.The synthesized nanoparticles were characterized by various techniques such as XRD,FTIR,Raman,FESEM-EDX,PL,Impedance,and UV-Vis.The Rietveld refinement of the X-ray diffractogram yields the crystalline structure and lattice parameters.Also,the XRD analysis shows that the substitution of Ca into ZnO does not alter the Wurtzite structure of ZnO.The crystallite size of the samples,calculated using the Scherer equation,was found to be between 46 nm and 92 nm.FTIR spectra detect the ZnO-related vibration modes of the samples.The FESEM morphological images suggest the spherical shape of the synthesized nanoparticles.The EDAX spectra identify the presence of Zn,Ca,and O atoms in the samples.The Raman active modes of the ZnO phase were identified by Raman spectral analysis.The analysis of Photoluminescence(PL)spectra gives information about the UV emission and other visible bands corresponding to violet,blue,and green emission representing different intrinsic defects in synthesized nanoparticles.Using UV-vis spectroscopy,the optical transparency and band gap values were examined.The energy band gap obtained by Tauc’s plot was decreased with the increase in Ca doping.Impedance analysis shows that the grain conductivity increased with the increase in dopant concentration.Contrarily,the total conductivity decreased with the increasing doping concentration due to increased grain boundary resistance.The proposed work demonstrates the changes in microstructure,electrical conductivity,and optical bandgap energy with Ca-doping.These synthesized Ca-doped ZnO nanoparticles could be promising materials for photocatalytic applications.展开更多
Cobalt oxide（C0304） with different morphologies was achieved by a simple solution-based method. Various parallel experiments show that several experimental parameters, such as the concentrations of NaOH and ethylene...Cobalt oxide（C0304） with different morphologies was achieved by a simple solution-based method. Various parallel experiments show that several experimental parameters, such as the concentrations of NaOH and ethylene glyeol（EG）, play important roles in the morphological controlling of C0304 nanoparticles. A lower concen- tration of NaOH favors quasi-spherical product with a uniform size of about 15 nm, whereas a higher concentration of NaOH generally leads to the formation of nanoplates with wide size distribution. In addition, C0304 nanorods were also obtained partially by introducing a certain amount of EG. A possible mechanism was proposed for the selective formation of C0304 with various morphologies. X-Ray diffraction（XRD）, infrared（IR） spectrometry, scanning elec- tron microscopy（SEM）, transmission electron microscopy（TEM） and UV-Vis spectrometry were used to characterize the samples.展开更多
以硝酸镉和硫代乙酰胺为原料,以N-乙酰-L-半胱氨酸(NAC)为稳定剂,在水溶液中合成了Cd S量子点(Cd S QDs)。通过考察稳定剂的配比、反应温度、反应时间、p H和搅拌时间对Cd S QDs的影响,研究Cd S QDs的光学性能。结果表明:当n(Cd2+)/n(NA...以硝酸镉和硫代乙酰胺为原料,以N-乙酰-L-半胱氨酸(NAC)为稳定剂,在水溶液中合成了Cd S量子点(Cd S QDs)。通过考察稳定剂的配比、反应温度、反应时间、p H和搅拌时间对Cd S QDs的影响,研究Cd S QDs的光学性能。结果表明:当n(Cd2+)/n(NAC)=2/1,p H=7,搅拌10 min,于80℃反应2 h制得的Cd S QDS荧光性能较好。展开更多
基金supported by the Major State Basic Research Development Program of China(No.2007CB613301)the National Natural Science Foundation of China(Nos.50842028 and 50972012)
文摘The calcium-doped ZnO nanoparticles,Zn1-xCaxO(x=0,0.025,0.05,0.075)were prepared by the solution combustion method.The synthesized nanoparticles were characterized by various techniques such as XRD,FTIR,Raman,FESEM-EDX,PL,Impedance,and UV-Vis.The Rietveld refinement of the X-ray diffractogram yields the crystalline structure and lattice parameters.Also,the XRD analysis shows that the substitution of Ca into ZnO does not alter the Wurtzite structure of ZnO.The crystallite size of the samples,calculated using the Scherer equation,was found to be between 46 nm and 92 nm.FTIR spectra detect the ZnO-related vibration modes of the samples.The FESEM morphological images suggest the spherical shape of the synthesized nanoparticles.The EDAX spectra identify the presence of Zn,Ca,and O atoms in the samples.The Raman active modes of the ZnO phase were identified by Raman spectral analysis.The analysis of Photoluminescence(PL)spectra gives information about the UV emission and other visible bands corresponding to violet,blue,and green emission representing different intrinsic defects in synthesized nanoparticles.Using UV-vis spectroscopy,the optical transparency and band gap values were examined.The energy band gap obtained by Tauc’s plot was decreased with the increase in Ca doping.Impedance analysis shows that the grain conductivity increased with the increase in dopant concentration.Contrarily,the total conductivity decreased with the increasing doping concentration due to increased grain boundary resistance.The proposed work demonstrates the changes in microstructure,electrical conductivity,and optical bandgap energy with Ca-doping.These synthesized Ca-doped ZnO nanoparticles could be promising materials for photocatalytic applications.
基金the National Natural Science Foundation of China，the Science and Technology Project of Changsha City,China，the Scientific Research Foundation of Henan Institute of Science and Technology,China
文摘Cobalt oxide（C0304） with different morphologies was achieved by a simple solution-based method. Various parallel experiments show that several experimental parameters, such as the concentrations of NaOH and ethylene glyeol（EG）, play important roles in the morphological controlling of C0304 nanoparticles. A lower concen- tration of NaOH favors quasi-spherical product with a uniform size of about 15 nm, whereas a higher concentration of NaOH generally leads to the formation of nanoplates with wide size distribution. In addition, C0304 nanorods were also obtained partially by introducing a certain amount of EG. A possible mechanism was proposed for the selective formation of C0304 with various morphologies. X-Ray diffraction（XRD）, infrared（IR） spectrometry, scanning elec- tron microscopy（SEM）, transmission electron microscopy（TEM） and UV-Vis spectrometry were used to characterize the samples.
文摘以硝酸镉和硫代乙酰胺为原料,以N-乙酰-L-半胱氨酸(NAC)为稳定剂,在水溶液中合成了Cd S量子点(Cd S QDs)。通过考察稳定剂的配比、反应温度、反应时间、p H和搅拌时间对Cd S QDs的影响,研究Cd S QDs的光学性能。结果表明:当n(Cd2+)/n(NAC)=2/1,p H=7,搅拌10 min,于80℃反应2 h制得的Cd S QDS荧光性能较好。
