Synthesis of some nanocomposites based on WO3 and their photocatalytic applications

Abstract

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.