Undoped and Mn＋Ni doped ZnO nanopowders were synthesized using a simple soft chemical route by varying the Ni doping level （1, 3, 5 and 7 at.%） and keeping the Mn doping level （10 at.%） constant, X-ray diffractio...Undoped and Mn＋Ni doped ZnO nanopowders were synthesized using a simple soft chemical route by varying the Ni doping level （1, 3, 5 and 7 at.%） and keeping the Mn doping level （10 at.%） constant, X-ray diffraction studies reveal that the incorporated Ni^2＋ ions form a secondary phase of cubic NiO beyond the Ni doping level of 3 at.%, which is also confirmed by Fourier transform infrared spectroscopy. The band gap of the nanopowders increases （from 3.32 to 3.44 eV） up to 3 at.% of Ni doping and decreases with further doping. ZnO：Mn：Ni nanopowders with 3 at.% of Ni concentration exhibit good antibacterial efficiency. The variation in the size of the nanoparticles, as observed from the TEM images and hydroxyl radicals as evidenced from the photoluminescence results, clearly substantiate the discussion on the antibacterial efficiency of the synthesized nanopowders. Magnetic properties of the synthesized nanopowders were studied using a vibrating sample magnetometer, and the results showed that the doping of Mn and Ni largely influences the magnetic properties of ZnO nanopowders.展开更多
（Ag ＋ Fe）-doped ZnO nanopowders have been synthesized using combustion method. Ag doping level was kept as 2 at.%, and Fe doping level was varied from 3 to 6 at,%, and the structural, optical, surface morphological...（Ag ＋ Fe）-doped ZnO nanopowders have been synthesized using combustion method. Ag doping level was kept as 2 at.%, and Fe doping level was varied from 3 to 6 at,%, and the structural, optical, surface morphological, and antibacterial properties have been investigated. The structural studies show that ZnO/（Ag 4-Fe） nanopowders have hexagonal wurtzite structure with a preferential orientation along the （101） plane. The FE-SEM images indicate that there is a gradual decrease in the grain size with the increase in the doping level of Fe, and the TEM images are correlated well with FE-SEM images. The XPS profile clearly confirms the presence of expected elemental composition. Photolumi- nescence studies reveal the presence of extrinsic defects in the material. Antibacterial activity of Ag- and Fe-doped ZnO nanopowders against Vibrio parahaemolyticus, Vibrio Cholerae, and Staphylococcus aureus bacteria was also investigated.展开更多
A type of dysprosium-doped ZnO （ZnO：Dy） nanopowder was synthesized by high temperature calcinations. XRD was used to analyze the structure. Photoluminescence spectra were used to study the optical characteristic. P...A type of dysprosium-doped ZnO （ZnO：Dy） nanopowder was synthesized by high temperature calcinations. XRD was used to analyze the structure. Photoluminescence spectra were used to study the optical characteristic. PL of ZnO：Dy shows two different spectra which are broad band resulted from the defect of Dy in ZnO and sharp lines from the 4f→4f transition of isolated Dy^3 ＋ luminescence center. The emission and excitation spectra depend on the excitation wavelength and the concentration of Dy^3＋ . The broad bands with peaks at 600 and 760 nm are attributed to the recombination from an electron of the defect Dy in ZnO to a hole in VB.展开更多
A hydrothermal method was successfully used for synthesis of CuO/ZnO/AI203 （CZA） nanopowder with atomic ratio of 6：3：1. The effect of crystallization time （3, 6, 9, and 12 h） on physicochemical properties of nan...A hydrothermal method was successfully used for synthesis of CuO/ZnO/AI203 （CZA） nanopowder with atomic ratio of 6：3：1. The effect of crystallization time （3, 6, 9, and 12 h） on physicochemical properties of nanopowder was investigated. Nanopowders were characterized using XRD, FESEM, EDX, FTIR, TG, and BET techniques. The XRD patterns confirmed metal oxides formation and their good crystallinity with average crystallite size of 20nm as obtained by the Scherrer equation. Relative crystallinity was shown to increase with increasing crystallization time. In agreement with XRD results, FESEM images also illustrated nanosized particles. EDX mapping indicated homogenous dispersion of elements. BET specific surface area analysis showed acceptable surface area for CZA nanopowder, FTIR spectroscopy confirmed metal oxides formation during hydrothermal and calcination processing. TG results illustrated high thermal stability of the synthesized nanopowders. TG-DTG and FTIR analyses were used to propose a reaction mechanism for nanopowder formation during processing. Physicochemical characterization showed optimal crystallization time to be 6 h.展开更多
文摘Undoped and Mn＋Ni doped ZnO nanopowders were synthesized using a simple soft chemical route by varying the Ni doping level （1, 3, 5 and 7 at.%） and keeping the Mn doping level （10 at.%） constant, X-ray diffraction studies reveal that the incorporated Ni^2＋ ions form a secondary phase of cubic NiO beyond the Ni doping level of 3 at.%, which is also confirmed by Fourier transform infrared spectroscopy. The band gap of the nanopowders increases （from 3.32 to 3.44 eV） up to 3 at.% of Ni doping and decreases with further doping. ZnO：Mn：Ni nanopowders with 3 at.% of Ni concentration exhibit good antibacterial efficiency. The variation in the size of the nanoparticles, as observed from the TEM images and hydroxyl radicals as evidenced from the photoluminescence results, clearly substantiate the discussion on the antibacterial efficiency of the synthesized nanopowders. Magnetic properties of the synthesized nanopowders were studied using a vibrating sample magnetometer, and the results showed that the doping of Mn and Ni largely influences the magnetic properties of ZnO nanopowders.
基金the financial assistance from the director of collegiate education,Govt.of Tamil Nadu,Chennai
文摘（Ag ＋ Fe）-doped ZnO nanopowders have been synthesized using combustion method. Ag doping level was kept as 2 at.%, and Fe doping level was varied from 3 to 6 at,%, and the structural, optical, surface morphological, and antibacterial properties have been investigated. The structural studies show that ZnO/（Ag 4-Fe） nanopowders have hexagonal wurtzite structure with a preferential orientation along the （101） plane. The FE-SEM images indicate that there is a gradual decrease in the grain size with the increase in the doping level of Fe, and the TEM images are correlated well with FE-SEM images. The XPS profile clearly confirms the presence of expected elemental composition. Photolumi- nescence studies reveal the presence of extrinsic defects in the material. Antibacterial activity of Ag- and Fe-doped ZnO nanopowders against Vibrio parahaemolyticus, Vibrio Cholerae, and Staphylococcus aureus bacteria was also investigated.
文摘A type of dysprosium-doped ZnO （ZnO：Dy） nanopowder was synthesized by high temperature calcinations. XRD was used to analyze the structure. Photoluminescence spectra were used to study the optical characteristic. PL of ZnO：Dy shows two different spectra which are broad band resulted from the defect of Dy in ZnO and sharp lines from the 4f→4f transition of isolated Dy^3 ＋ luminescence center. The emission and excitation spectra depend on the excitation wavelength and the concentration of Dy^3＋ . The broad bands with peaks at 600 and 760 nm are attributed to the recombination from an electron of the defect Dy in ZnO to a hole in VB.
基金Sahand University of Technology for the financial support of the project and Iran Nano-technology Initiative Council for supplementary financial supports
文摘A hydrothermal method was successfully used for synthesis of CuO/ZnO/AI203 （CZA） nanopowder with atomic ratio of 6：3：1. The effect of crystallization time （3, 6, 9, and 12 h） on physicochemical properties of nanopowder was investigated. Nanopowders were characterized using XRD, FESEM, EDX, FTIR, TG, and BET techniques. The XRD patterns confirmed metal oxides formation and their good crystallinity with average crystallite size of 20nm as obtained by the Scherrer equation. Relative crystallinity was shown to increase with increasing crystallization time. In agreement with XRD results, FESEM images also illustrated nanosized particles. EDX mapping indicated homogenous dispersion of elements. BET specific surface area analysis showed acceptable surface area for CZA nanopowder, FTIR spectroscopy confirmed metal oxides formation during hydrothermal and calcination processing. TG results illustrated high thermal stability of the synthesized nanopowders. TG-DTG and FTIR analyses were used to propose a reaction mechanism for nanopowder formation during processing. Physicochemical characterization showed optimal crystallization time to be 6 h.
