Properties of Cu-Ni Ferrite Nanopowders Prepared by Coprecipitation Method with Ultrasound Irradiation

초록

Carbon dioxide is one of the greenhouse gases and has been a current subject in the field of environ-mental science. Recently, it has been found that oxygen-deficient ferrite is a good material to convert carbon dioxide into carbon.[1,2] The oxygen-deficient ferrite can be formed by hydrogen reduction of ferrites at a temperature near 300℃ and is represented by a general formula MxFe3-xO4-δ where M is a bivalent metal ion such as Mn, Fe, Co, Ni and Cu ; the oxygen deficiency δ expresses the degree of reduction. In this study, Cu1-xNixFe2O4 nanopowders using coprecipitation method with ultrasound irradiation were synthesized and their CO2 decomposition properties were investigated. Ultrasonic irradiation in liquid can induce a cavitation process. The cavitation leads to hot-spot and microjet impacts on materials, which can result in activating physical and chemical reaction.[3] Cu-Ni ferrite nanopowders synthesized by coprecipitation method with ultrasound irradiation were in a spherical shape of the single phase. The magnetic properties of the powders were determined with vibrat-ing sample magnetometry (VSM) and the maximum value of saturation magnetization was 73.5 emu/g at x=0.5. Thermogravimetric analysis (TGA) of the Cu1-xNixFe2O4 nanopowders during H2 reduction and CO2 decomposition reaction were carried out with Cahn vacuum electrobalance system (D-200). The maximum CO2 decomposition occurred from the Cu0.5Ni0.5Fe2O4 nanopowder. This work was supported by grant No. R01-1999-000-00192-0 from the Basic Research Program of the Korea Science & Engineering Foundation. References [1] Y. Tamaura, M. Tabata, Nature 346, 255 (1990). [2] C. Zhang, S. Li, L. Wang, T. Wu, S. Peng, Mat. Chem. Phys. 62, 52 (2000). [3] D. Peters, J. Mater, Chem. 6, 1605 (1996).