Synthesis of cupric oxide using different methods

Full text: Cupric oxide (CuO) is a semiconductor with an energy band gap of 1.21–1.5 eV. It has been extensively studied for various applications such as in gas sensors, catalysis, batteries, high temperature superconductors, solar energy conversion and field emission devices [1]. There is much research about this oxide with different morphologies and sizes. In this study, the CuO particles were obtained by different methods. The methods used were hydrothermal, solvothermal and quick coprecipitation. In the hydrothermal method copper nitrate (Cu(NO₃)₂ ) was employed as precursor and for solvothermal process an alcoholic medium and copper acetate (Cu(CH₃COO)₂ ) was used during the synthesis. By quick coprecipitation rout, copper acetate and sodium hydroxide (NaOH) were used as precursor and mineralizing reactants, respectively. CuO particles were successfully obtained with high degree of crystallinity for all the methods, according to X-ray diffraction results. The forms, size and distribution of the particles varied according to the synthesis method, as observed by the scanning electron microscopy (FEG). In addition, studies by infrared spectroscopy (FTIR) confirmed the presence of the Cu-O bonds. To the hydrothermal and solvothermal synthesis, the products presented micrometer size typical hierarchical structure, where aggregate nanostructures produce microstructures, while in the coprecipitation synthesis were obtained nanoparticles. The hydrothermal method produces nanoflowers, and in the solvothermal method were obtained nanourchins. Finally the chemical coprecipitation resulted in nanospheres with diameters around 20 nm. (author)