Formation process of metallic copper fine particles from cupric oxide microparticles at room temperature

Copper (Cu) fine particles were prepared by room-temperature hydrazine reduction of Cu oxide microparticles. In this study, to reveal the formation process of metallic Cu homogeneous fine particles from cupric oxide (CuO) microparticles, hydrazine was added to a CuO slurry at room temperature. The morphological changes in the product during the reduction with and without ammonia were observed by using scanning electron microscopy (SEM). The SEM images indicated that not only did the Cu2+ dissolve in water by complex formation with ammonia or hydrazine, but also that Cu2+ ions on the surface of CuO microparticles were reduced by hydrazine to form metallic Cu fine particles. Tuning the sizes of Cu particles by the stabilizing reagent is also discussed.