Synthesis of Thermally Spherical CuO Nanoparticles

Copper oxide (CuO) nanoparticles were successfully synthesized by a thermal method. The CuO nanoparticles were further characterized by thermogravimetric analysis (TGA), differential thermal analysis (DTA), X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectrometry (EDS), and high resolution transmission electron microscopy (HRTEM), respectively. The specific surface area ( ) of CuO nanoparticles was determined by nitrogen adsorption. The was found to be 99.67？m2/g ( of 9.5？nm). The average diameter of the spherical CuO nanoparticles was approximately 6–9？nm. 1. Introduction Metal oxides play a very important role in many areas of chemistry, physics, and materials science [1–6]. The metal elements can form a large diversity of oxide compounds [7]. These elements can adopt much structural geometry with an electronic structure that can exhibit metallic, semiconductor, or insulator character. In technological applications, oxides are used in the fabrication of microelectronic circuits, sensors, piezoelectric devices, fuel cells, and coatings for the passivation of surfaces against corrosion and as catalysts. For example, almost all catalysts used in industrial applications involve an oxide as active phase, promoter, or “support.” In the chemical and petrochemical industries, products worth billions of dollars are generated every year through processes that use oxide and metal/oxide catalysts [8]. For the control of environmental pollution, catalysts or sorbents that contain oxides are employed to remove the CO, NOx, and SOx species formed during the combustion of fossil-derived fuels [9, 10]. Furthermore, the most active areas of the semiconductor industry involve the use of oxides [11]. Thus, most of the chips used in computers contain an oxide component. Oxide nanoparticles can exhibit unique physical and chemical properties due to their limited size and high density of corner or edge surface sites. Particle size is expected to influence three important groups of basic properties in any material. The first one comprises the structural characteristics, namely, the lattice symmetry and cell parameters [12]. Bulk oxides are usually robust and stable systems with well-defined crystallographic structures. However, the growing importance of surface-free energy and stress with decreasing particle size must be considered: changes in thermodynamic stability associated with size can induce modification of cell parameters and/or structural transformations [13], and in extreme cases the nanoparticle can disappear due to