Synthesis of Nano Metal Powder by Electrochemical Reduction of Iron Oxides

Synthesis of iron nanopowder by room-temperature electrochemical reduction process of α-Fe2O3 nanopowder was investigated in terms of phase evolution and microstructure. As process variables, reduction time and applied voltage were changed in the range of 1~20 h and 30~40 V, respectively. From XRD analyses, it was found that volume of Fe phase increased with increasing reduction time and applied voltage, respectively. The crystallite size of Fe phase in all powder samples was less than 30 nm, implying that particle growth was inhibited by the reaction at room temperature. Based on the distinct equilibrium shape of crystalline particle, phase composition of nanoparticles was identified by TEM observation.

Synthesis of Nano Metal Powder by Electrochemical Reduction of Metal Oxides

This work has attempted to find a new low temperature reduction process for fabrication of Cu nanopowder from fine CuO powder. For this purpose, we used electrochemical reduction method which is conducted in an electrolyte of NaCl aqueous solution at room temperature. It was found that ball-milled CuO powder (particle size ~100 nm and grain size ~40 nm) was completely reduced under the conditions of 20 V power, 0.5 mol NaCl solution and 2 h reaction time, producing Cu nanopowder (particle size ~80 nm and crystallite size ~25 nm). Simultaneously, we observed that sintering of nanopowders occurred during the reduction process, leading to agglomeration of nanopowder. Based upon the experimental results, the correlation between electrochemical reduction process and its related powder characteristics was discussed in terms of material transport.