Elements Of X Ray Diffraction

【臨床医学の展望 2012】 呼吸器病学

Phosphorus compounds, such as metal phosphides and phosphates have shown excellent performances and great potential in electrochemical energy storage, which are demonstrated by research works published in recent years. Some of these metal phosphides and phosphates and their hybrids compare favorably with transition metal oxides/hydroxides, which have been studied extensively as a class of electrode materials for supercapacitor applications, where they have limitations in terms of electrical and ion conductivity and device stability. To be specific, metal phosphides have both metalloid characteristics and good electric conductivity. For metal phosphates, the open-framework structures with large channels and cavities endow them with good ion conductivity and charge storage capacity. In this review, we present the recent progress on metal phosphides and phosphates, by focusing on their advantages/disadvantages and potential applications as a new class of electrode materials in supercapacitors. The synthesis methods to prepare these metal phosphides/phosphates are looked into, together with the scientific insights involved, as they strongly affect the electrochemical energy storage performance. Particular attentions are paid to those hybrid-type materials, where strong synergistic effects exist. In the summary, the future perspectives and challenges for the metal phosphides, phosphates and hybrid-types are proposed and discussed.

Metal Phosphides and Phosphates-based Electrodes for Electrochemical Supercapacitors.

Acinetobacter baumannii is a multi-drug resistant opportunistic pathogen, which causes respiratory and urinary tract infections. Its prevalence increases gradually in the clinical setup. Carbapenems (beta-lactam) are most effective antibiotics till now against A. baumannii, but the development of resistance against it may lead to high mortality. Therefore, it is of utmost importance to develop an alternative drug against A. baumannii. In the present study, we have synthesized ZnO nanoparticle (ZnO-NP) and characterized by X-ray diffraction, Fourier transform infrared (FTIR) spectroscopy and UV-Visible spectroscopy. Prepared ZnO-NPs have the size of 30 nm and have different characteristics of ZnO-NPs. Growth kinetics and disk diffusion assay showed that ZnO-NP demonstrated good antibacterial activity against carbapenem resistant A. baumannii. We have also investigated the mechanism of action of ZnO-NPs on the carbapenem resistant strain of A. baumannii. The proposed mechanism of action of ZnO involves the production of reactive oxygen species, which elevates membrane lipid peroxidation that causes membrane leakage of reducing sugars, DNA, proteins, and reduces cell viability. These results demonstrate that ZnO-NP could be developed as alternative therapeutics against A. baumannii.

Mechanism of Anti-bacterial Activity of Zinc Oxide Nanoparticle Against Carbapenem-Resistant Acinetobacter baumannii.

The effects of pH value on crystal size and optical property of zinc oxide nanoparticles prepared by chemical precipitation method were investigated. Prepared samples have been characterized by means of X-ray diffraction, scanning electron microscopy, ultraviolet–visible spectrometer and photoluminescence spectrometer. From X-ray diffraction profile, it is found that the particle size of sample increases from 13.8 to 33 nm when the pH value of the solution was increased from 6 to 13. Microstructural study also shows that the particle size increases with pH value. Hexagonal shape of the zinc oxide nanoparticle has been confirmed by the scanning electron microscopy image. The recorded ultraviolet–visible spectrum shows excitonic absorption peaks around 381 nm. The energy gap of the prepared samples has been determined from the ultraviolet–visible absorption spectrum, effective mass model equation and Tauc’s relation. It was found that the energy gap of the prepared samples decreases with increase in pH value. The recorded blue shift confirmed the quantum confinement effect in the prepared zinc oxide samples. Photoluminescence spectrum infers that the increase in pH value shifts the ultraviolet–visible emission but not the violet and green emissions.

Effect of pH on Crystal Size and Photoluminescence Property of ZnO Nanoparticles Prepared by Chemical Precipitation Method

Influence of Ce doping on CuO nanoparticles synthesized by microwave irradiation method

In this article, synthesis of undoped and zinc doped cadmium oxide with different zinc concentration (0, 2, and 5 wt%) using simple chemical precipitation method has been discussed. Influence of zinc dopant on crystal structure, microstructure and optical properties of the nanoparticles was investigated by means of X-ray diffractometer, field emission scanning electron microscope, ultraviolet–visible spectrometer, and photoluminescence spectrometer. Crystal structure analysis reveals that zinc doping appreciably increases the crystalline size and also it shows the polycrystalline nature of the samples. Microstructural investigation shows that the samples contain nanoparticles. Optical bandgap of the prepared samples found to vary from 2.67 to 2.61 eV for various dopant concentrations. With these specifications we can fabricate semiconductor nanocrystals and these can be used for some large scale applications of nanotechnology.

Structural and optical properties of Zn doped CdO nanoparticles synthesized by chemical precipitation method

Violet emission from Fe doped ZnO nanoparticles synthesized by precipitation method

This article deals with the synthesis and characterization of cobalt-doped zinc oxide nanopowder prepared by precipitation method. Prepared nanopowders were analyzed for morphological, structural and optical properties. X-ray diffraction study confirmed the substitution of cobalt ion without disturbing the basic wurtzite structure of zinc oxide. The average particle size was found to increase on cobalt doping as compared to undoped zinc oxide. The lattice constants increased with composition. Scanning electron microscope study also confirmed the existence of particles in nanometer size. Furthermore, scanning electron micrograph confirmed the increase of particle size on cobalt doping. Optical transmittance spectrum shows that cobalt dopant decreases the transmittance of zinc oxide less than 60%. Energy gap of the samples determined from the absorption spectrum shows that it decreases with the increase of cobalt content. The blue and green emission lines of photoluminescence spectrum also confirmed the sub...

K. Pushpanathan

Papers

Effect of pH on Crystal Size and Photoluminescence Property of ZnO Nanoparticles Prepared by Chemical Precipitation Method

Influence of Ce doping on CuO nanoparticles synthesized by microwave irradiation method

Structural and optical properties of Zn doped CdO nanoparticles synthesized by chemical precipitation method

Violet emission from Fe doped ZnO nanoparticles synthesized by precipitation method

Structural and Optical Properties of Co-Doped ZnO Nanoparticles Synthesized by Precipitation Method