الفهرس 
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Abstract
Metal nanoparticles (NPs) have attracted a great attention because of their unique catalytic, optical, magnetic, and electrical properties, most of which mainly depend on the size, morphology, and surface oxidation state. Copper nanoparticles (Cu NPs) have been expected to be one of the future materials because of its high conductivity and low cost. There have been many known synthesis methods such as microemulsion, thermal reduction, laser ablation, metal vapor synthesis and chemical reduction. Among these methods, the chemical reduction is widely used because the size and morphology of Cu NPs are easily controlled by varying metal salts type, solvents, reduction temperature, reducing agents and concentrations.
Since copper nanoparticles are easily agglomerate, coalesce and oxidize due to its high surface energy in aqueous solutions, in most cases, surfactants and polymer have been employed in an organic solution to avoid the agglomeration, and to overcome the surface oxidation of Cu. It is important today to develop a synthesis method in an aqueous solution to synthesize Cu NPs for a green synthesis method. In this work, Cu nanoparticles in the aqueous solution under atmospheric condition at room temperature employing plant extract.
Copper oxide (CuO) as a p-type functional oxide semi conductor material exhibits superior properties like direct band gap 1.2 eV, non-toxicity and excellent chemical stability. Abundant availability of copper and low production cost makes CuO a promising candidate for diverse applications like gas sensors, solar cells, catalysts and magnetic storage material. Most of the properties of CuO strongly depend on its structures, including the morphology, size and aspect ratio. CuO nanostructures with structures such as wires, tubes, seeds, belts, sheets rods, leaves, needles and platelets, are previously, synthesized via different paths. Among different methods, wet chemical route has drawn more attention due to its simplicity and easy chemical reactions.
In this study synthesis of CuNps using plant extracts as stabilizing agent were investigated. Also CuO nanocrystals were synthesized using different copper salts and two precipitation agents (NaOH and NH4OH) at different temperature of addition and sequence of addition of copper salt and NaOH.
The present study is divided into four chapter as the following:
Chapter 1: Introduction and literature review:
This chapter includes a general introduction on nanoparticles and nanotechnology. The chemical and biological methods especially the methods using plant extract for synthesis of copper and copper oxides and their importance are reviewed.
Chapter 2: Materials and Methods
This chapter includes detailed preparation of the reagents used in the study and the different experimental techniques that have been employed to synthesize copper and copper oxide. Further more, description of the instruments used for characterizations of CuNps and CuO nanocrystals are given.
Results and Discussion (Chapters 3 and 4)
Chapter 3:
This chapter deals with green synthesis of copper nanoparticles using the aqueous extract of Rhuscoriaria L. (Sumaq) and Portulacaoleracea L. seeds (Regla seeds) as stabilizing agent, hydrazine hydrate as reducing agent and NaOH as a catalyst and also to adjust the pH was described. The results revealed that the two extracts were not able to reduce Cu2+ to Cu0 without addition of external reducing agent but excellent in stabilization of the copper nanoparticles. The as-prepared Cu nanoparticles were characterized using Uv-Vis spectroscopy where a band at 568 nm (using sumaq extract) and at 584 nm (Portulaca oleracea L. seeds) due to surface plasmon resonance of Cu nanoparticles. The size of the nanoparticles depends on the extract concentrations. FTIR spectra of the CuNps suggested that the surface of the CuNps is covered with the extract molecules. The synthesized CuNps exhibited antimicrobial activity toward some bacterial strains.
Chapter 4:
This chapter deals with the study of different reaction parameters on the size and morphology of CuO nanocrystals. CuO synthesis using simple precipitation method in aqueous solution without addition of other chemicals. The copper sources used are CuSO4 and CuCl2 and the precipitating agents as NaOH and NH4OH. The reaction carried out under different reaction conditions such as salt type, sequence of addition of copper salts and precipitation agent, mixing temperature and precipitation agent. Eighteen samples were prepared (8 using CuSO4 and 8 using CuCl2 as coper source). The results revealed that using CuSO4, addition of NaOH in the ratio 1:2 (Cu2+:NaOH) for samples S1-S6 leads to the formation of CuO nanocrystals accompanied with Cu4(SO4)(OH)6 at different ratio depending on the reaction parameter. Increasing NaOH to the ratio (1:3, Cu:NaOH) leads to the formation of pure CuO without the complex suggesting that the optimum ratio to obtain pure CuO is 1:3 and the concentration of NaOH is the most important parameter. The same was found when CuCl2 was used as copper source where only pure CuO was obtained when NH4OH was added in the ratio (1:3, Cu: NH4OH) and this support the idea that the concentration of OH- is important not the its source. The addition temperature or the sequence was less important parameter. The XRD of all samples are discussed from which the quantity of the CuO and complexes are calculated and also the size of the crystals formed. The absorption spectra of the samples are used to study the optical properties of the samples and calculation of their band gap. The band gap of the samples were between 1.05-2.5 eV make it possible for application in solar cells. The antimicrobial activity of the samples prepared using CuSO4 was investigated and found that the CuO nanocrystals have better antimicrobial activity than Cu nanoparticles.