الفهرس 
Characterization techniquesOnly 14 pages are availabe for public view
 |  | from | 280 |  |  |
| | | from | 280 | | |
Abstract
Nanoparticulated metal oxides play a very important role in many areas of chemistry, physics, and material sciences. In technological applications, oxides are used in the fabrication of microelectronic circuits, sensors, electrochemical devices, fuel cells, coatings for the passivation of surfaces against corrosion, and as catalysts. Metal oxide nanoparticles can exhibit unique physical and chemical properties due to their limited size and a high density of corner/edge surface sites.
Our study is divided into three chapters:
Chapter one: Introduction; This chapter includes a general introduction on nanotechnology and nanomaterials with a focusing on nanoparticulated metal oxides such as nanoceria (CeO2 NPs), nanoruthenia (RuO2 NPs) and their composites. It also includes the different methods of preparation of metal oxides and their several applications. A literature survey on Cerium oxide nanoparticles, ruthenium oxide nanoparticles and their composites is achieved. Up to date references related to our research have been entitled in that chapter.
Chapter two: Materials and Methods; all chemicals and instruments used in this research are reported in this chapter. This chapter deals with the different experimental techniques that have been employed to prepare metal oxides under investigation such as: wet chemical technique, hydrothermal methods, and microwave-mediated technique which are used to prepare CeO2, CeO2/CdSe, CeO2/CdTe, RuO2, RuO2/CeO2 nanoparticles. Studies of some applications of the prepared nanoparticles such as: antimicrobial activity, photocatalytic reactivity and electrochemical capacitance have been mentioned in that chapter.
Chapter three: Results and Discussion; CeO2 NPs have been prepared by both wet chemical and hydrothermal methods in the presence of different concentrations of the non-ionic surfactants Tween 20 and Tween 80 of hydrophilic-lipophilic balance (HLB) values of 16.7 and
15.0, respectively. The role of these surfactants in controlling the size and the synthetic route in controlling the shape of CeO2 NPs have been discussed. The synthesized CeO2 NPs were characterized by Fourier transform infrared (FT-IR), Raman spectroscopy, UV-Visible spectroscopy, X-ray
diffraction (XRD), Transmission Electron Microscopy
(TEM) and Scanning Electron Microscopy (SEM).
Tween 20 with higher HLB value has been found to be more effective in producing smaller sizes of CeO2 NPs. The TEM micrographs confirmed the semi-spherical structure of CeO2 NPs synthesized by wet chemical method with ultrafine particle sizes ranging from 6.0 nm to 12.0 nm whereas the main shape for hydrothermally prepared CeO2
NPs is nanorods with typical diameters ranging from 15-60
nm. FT-IR and Raman spectral analysis confirmed the identities of the oxides.
In vitro antimicrobial studies show significant zone of inhibition against bacterial and fungal strains. The samples with smaller particle sizes show higher antimicrobial activity. The efficiency of CeO2 NPs as a promising candidate in photocatalysis was evaluated using a methylene blue (Mb) and Congo red (CR) as organic contaminant dyes irradiated with UV light from conventional high-efficiency low- pressure and low power (6 watt) mercury lamp is also established using a home-made photoreactor.
The Nanosized CeO2 samples produced in the presence of Tween 20 show higher photocatalytic activity than CeO2
NPs produced in the presence of Tween 80 and this may be attributed to the smaller particle sizes which produced in case of using Tween 20.
To enhance photocatalytic activity of the prepared ceria nanoparticles, CeO2/CdSe and CeO2/CdTe nanocomposites have been prepared using hydrothermal technique. These composites transfer photocatalytic degradation reactions into visible region. It is noted that CeO2/CdSe nanocomposite has high adsorption removal capacitance toward methylene blue dye and relatively high photodegradation efficiency toward Congo red dye.
Moreover, RuO2, CeO2 NPs and their composite material i.e. RuO2/CeO2 nanocomposite have been synthesized by microwave mediated technique, characterized by different characterization techniques and then their antibacterial activities have been studied.