الفهرس 
CHAPTER (1) INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
The objective of this thesis was to produce novel materials
possessing promising characteristics suitable for applications in
photocatalysis and optoelectronics. The study employed three distinct
synthesis techniques, namely co-precipitation, sol-gel, and auto-
combustion, to produce pure and mono-doped bismuth oxide (Bi2O3) and
bismuth ferrite (BiFeO3). The investigation encompassed an analysis of
the influence of synthesis methods, the choice of precipitation agents, and
the effect of doping with various metals. The resulting oxides were
subjected to a comprehensive examination utilizing techniques such as X-
ray diffraction, scanning electron microscopy with energy-dispersive X-
ray analysis (SEM-EDX), transmission electron microscopy, Fourier-
transform infrared spectroscopy, diffuse reflectance (DR), and UV-Vis
spectroscopy. The photocatalytic performance of the synthesized oxides
was assessed through the degradation of dyes (Congo red and Methylene
Blue) under visible light. The thesis is structured into three main chapters,
which are summarized as follows:
The first chapter (Introduction): This chapter composed of two
sections:
The first section presented a general overview on metal oxide
semiconductors MOS, their properties, and their potential applications. It
emphasizes solar light photocatalysis and photocatalytic applications of
metal oxides semiconductors. It provides insights on routes followed to
enhance their efficiency. It throws light also on the dielectric
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characteristics of MOS and investigates the effect of doping on their
properties.
The second section provided a literature review of recent studies
on metal oxides under study; bismuth oxide (Bi2O3) and bismuth ferrites
(BiFeO3). It also investigated the effect of doping specific metal ions on
the properties of these metal oxides and these modifications were
explored in terms of their impact on their structural, electrical, optical,
and photocatalytic properties.
The second chapter (Experimental): This chapter provided a
comprehensive description of the chemicals and the synthetic procedures
employed to create the nanostructured metal oxides under study. Firstly,
the co-precipitation method was utilized for the synthesis of undoped
Bi2O3 materials using different precipitating agents: NaOH, KOH and
NH4OH. The precipitation process was followed by a calcination step at
500 °C. Secondly, the sol-gel technique was employed to fabricate pure
Bi2O3, as well as In, Cu, and Li-doped Bi2O3 photocatalysts optimized for
visible-light-driven applications. The third class of materials under
investigation included pure and doped bismuth ferrite compositions,
namely pure BiFeO3 and Ce-doped-BiFeO3/Bi25FeO40 were prepared
successfully through the auto-combustion method. The chapter further
outlines the procedures employed to assess the photocatalytic activity of
these oxides by degrading organic dyes.