Preparation of copper nanoparticles in a water/oleic acid mixed solvent via two-step reduction method

Copper nanoparticles are synthesized from copper sulfate pentahydrate using a novel method. To control the nuclei process, a two-step reduction process is applied. To prevent nanoparticles from oxidization and agglomeration, oleic acid is employed as an extractant and a surfactant. The influence of process parameters (ratio of Cu2+ to NaH2PO2, pH values, and temperature) on the morphology and dispersion is investigated. All products are cubic phase copper, as determined from X-ray diffraction measurements. Scanning electron microscopy and transmission electron microscopy reveal that the copper nanoparticles are spherical and have sizes of approximately 30 nm. The FT-IR spectrum shows that the copper nanoparticles were coated with oleic acid.