Low Temperature Route to Nanocrystalline CuO Powder

Nanocrystalline CuO with particle size of about 24 nm was directly synthesized by sol-gel auto combustion method using citric acid as a reducing agent/fuel and nitrate as oxidizing agent at low temperature of 200°C. Thermal decomposition of the nitrate-citrate xerogel was investigated by thermogravimetric/differential thermal analysis (TG/DTA) technique in the temperature range 30-500°C. The yielding product calcined at 400°C was characterized for CuO by X-ray diffraction, Field enhanced scanning electron microscope (FESEM) and UV-vis absorption spectroscopy. The morphological properties of the prepared oxide after the combustion synthesis reveal that the particles are bound together into agglomerates of different shapes and sizes. The band gap is estimated to be 2.05 eV according to the results of the optical measurements. A possible mechanism for the formation of CuO has also been discussed.