الفهرس 
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Abstract
Synthesis and Some Nanocomposites Based on WO3 and Their Photocatalytic Applications
Nanotechnology is a worldwide science that deals with how we can deal with matter at the molecular and atomic level. A typical atom is about one-tenth of a nanometer in diameter. Properties of nano-materials might not be as those of larger scales where the nano-materials have a significantly differences in the physical, chemical, and biological properties (Theron et al., 2008). In addition, a different shapes and sizes have been observed. Nanotechnology could affect the generation of virtually every human-made- object from automobiles and electronics to advanced diagnostics, tissue and bone replacements, medicines and surgery.
Main other applications of nano-catalysts are fuel cells, energy storage, composite solid rocket propellants, bio diesel production, medicine and applications of carbon nano tubes.
The bimetallic nanoparticles are composed of two metals have which drawn a greater importance than the monometallic counterparts. They offer the ability to optimize the energy of Plasmon absorption band of metallic mixture, which gives us multi-purposed materials for bio-sensing. The used synthetic method is expected to have a critical role in producing nanoparticles with defined properties. Researchers have discovered many biological, chemical and physical methods to synthesize nanoparticles as Ball milling, melt mixing, vapor deposition, microorganisms, plants, sol-gel and laser vaporization. Unfortunately, many of these methods are neither environmentally friendly nor cost effective. In order to yield a large product of nano to micro size particles, hydrothermal deposition synthesis techniques are used. These processes provide a facile, rapid, cheap and superior technique for bimetallic nanoparticles synthesis.
The study presented in this thesis includes development and combination between more than one technique such as analytical chemistry, photochemistry and Nanotechnology for the degradation of Diclofenac (DCF) and the reduction of 4-nitrophrnols which considered, as an important hazardous product in industrial waste, using photo-catalytic approach under visible light illumination. These photo-catalytic processes provide superior technique for wastewater treatment.
The thesis is divided into three chapters:
Chapter One:
Introduction and literature review: this chapter includes a general introduction on nanotechnology, nanoparticles, bimetallic nanoparticles, application of bimetallic complexes and different chemical, physical and biological synthetic methods. An overview on the synthesized bimetallic Ag2O/WO3, Ag2S/WO3, Ag2O/WS2 and Ag2S/WS2 nano-composites were mentioned. Applications of silver-tungstate nano-composites were also mentioned.
Chapter Two:
This chapter includes the different experimental techniques that have been employed to characterize Ag2O/WO3, Ag2S/WO3, Ag2O/WS2 and Ag2S/WS2 nano-composites prepared using a simple hydrothermal deposition method. In this chapter, the preparation of those catalysts methods in addition to techniques used to trace both the photo-degradation of Diclofenac and the reduction of 4-nitrophenols under visible light illumination were discussed.
Chapter Three:
This chapter includes three sections:
i- The first section deals with the synthesis of silver deposited Ag2O/WO3, Ag2S/WO3, Ag2O/WS2 and Ag2S/WS2 using a facile chemical hydrothermal precipitation method with a nominal molar ratio of 0.03 % Ag2O or Ag2S: 0 .97 % WO3 or WS2. the important results obtained can be summarized as follows:
(a) The Ag2O/WO3, Ag2S/WO3, Ag2O/WS2 and Ag2S/WS2 resulted powder had pale blue, blue, black and dark black colors, respectively, which is a physical parameter that characterized for each of them.
(b) The TEM results indicate that the average size of the Ag2O/WO3, Ag2S/WO3, Ag2O/WS2 and Ag2S/WS2 prepared catalysts were 8.4, 6.8, 7.1, 7 nm with a Ag2O spherical shape, Ag2S rod shape, WO3 rectangular shape and WS2 plate shape.
(c) XRD pattern of the prepared catalysts exhibited number of Bragg reflections and indexed on the bases of the face centered cubic (fcc) structure that confirmed their structure. It also confirmed the presence of AgNPs deposited on the surface of the prepared catalysts.
(d) FTIR measurements and X-ray photoelectron spectroscopy confirmed the chemical structure of the prepared catalysts.
(e) Photoluminescence results showed that the Ag2O/WO3, Ag2S/WO3, Ag2O/WS2 and Ag2S/WS2 prepared catalysts have slower e-, h+ pair recombination rates than that of their individual counterparts which were the cause for the high catalytic activities of the prepared catalyst than their individuals.
(f) UV-vis diffuse reflectance spectra determined the band gaps of Ag2O/WO3, Ag2S/WO3, Ag2O/WS2 and Ag2S/WS2 prepared catalysts that showed to be 2.87 and 2.67, 2.3 and 2.5, respectively.
(g) Surface texturing analysis used to determine surface area, pore diameters and pore volumes of the prepared catalysts. The surface area for the Ag2O/WO3, Ag2S/WO3, Ag2O/WS2 and Ag2S/WS2 prepared catalysts showed to be 22.450, 16.554, 15.511 and 26.172 nm, respectively.
ii- The second section deals with the using of the prepared catalysts for the photo-catalytic degradation of potassium diclofenac under visible light illumination (mercury lamp, 160W) with the aid of H2O2 as an oxidizing agent at pH 12. The Ag2O/WO3, Ag2S/WO3, Ag2O/WS2 and Ag2S/WS2 nano-composites showed a high catalytic activities rates, which are 0.03204 min-1, 0.01839 min-1, 0.025min-1 and 0.0436 min-1, respectively, towards DCF degradation. Thus, these catalysts provide an eco-friendly and cost-effective method for water treatment.
iii- The third section deals with the photo-catalytic reduction of 4-NP using the prepared catalysts under visible light illumination (mercury lamp, 160W) with the aid of NaBH4 as a reducing agent. The Ag2O/WO3, Ag2S/WO3, Ag2O/WS2 and Ag2S/ WS2 prepared catalysts showed high catalytic activities which are 8.3 x10-3 sec-1, 1.67 x10-3 sec-1, 1.4 x10-3 sec-1 and 0.66 x10-3 sec-1, respectively, towards 4-NP reduction.