الفهرس 
CHAPTER IOnly 14 pages are availabe for public view
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Abstract
More than 20 % of the gross national product of industrial countries rely on catalytic processes; thus catalysts play a major technological role in society covering wide range of processes from biological reactions to large-scale production of chemicals [1]. A catalyst provides an alternative reaction pathway in which the activation energies of a reaction are lowered and the reaction rate is increased. Generally, catalysis is classified into three main categories, namely: heterogeneous, homogeneous, and enzymatic ( biocatalysts). The application of catalysts is found to be widespread in different areas including petrochemical, automotive, electrocatalysis, photocatalysis, fuel cells, sensors, energy, and environmental applications [2, 3]. Traditionally, a significant number of catalytic processes involve the use of transition-metal catalysts, particularly precious noble metals which are not susceptible to oxidation. Some of the most common metals used for catalysis are Pd, Pt, Ru, Rh, Ni, and Cu [4]. Thus, optimizing the usage of active (precious) materials has been a major aspect of catalyst optimization and thus many scientists have studied catalysis by nanoparticles in order to take advantage of the higher surface areas exposed to the reactants [5]. Another important factor is the unique physical and chemical properties associated with the small size of nanoparticles [6]. As the numbers of methods to synthesize and characterize nanoparticles have grown during the nanotechnology revolution, this has spurred a re-growth of the field of ―nanocatalysis.