High-efficiency synthesis of Cu superfine particles via reducing cuprous and cupric oxides with monoethanolamine and their antimicrobial potentials

Cuprous oxide (Cu₂O) and cupric oxide (CuO) are widely available and low cost raw materials. Their applications as precursors for wet chemical synthesis of metallic Cu materials are greatly limited due to their insoluble in water and most organic solvents. In this work, copper superfine particles (Cu SPs) are synthesized using Cu₂O and CuO as precursors via a heating process in monoethanoamine (MEA). Due to the strong coordinating character, Cu₂O and CuO can be partially dissolved in MEA. The dissolved copper source is reduced by MEA at elevated temperature with the drastically releasing of NH₃. As the dissolved copper source is reduced, more oxide will be dissolved and finally leads to the full reduction of Cu₂O and CuO to produce the Cu SPs. The advantage of this synthesis method is that MEA acts as both the solvent and the reducing agent. The antimicrobial properties are investigated to find that the obtained Cu SPs depress the growth of Escherichia coli (E. coli) and Staphylococcus aureus (St. aureus) efficiently. More interesting, the composites produced via curing Cu₂O and CuO with a small amount of MEA also exhibit excellent antimicrobial activity, indicating the MEA curing method is high-efficiency. The synthesis is low cost, high-efficiency, high atom-economy and up-scale synthesizing easily, which will benefit the wide applications of Cu SPs.