Preparation And Characterization Of Micro/Nano Cu And Cu₂O By Liquid Reduction Method

Due to the strong correlation between the shape and size of nanomaterials and the physieal and chemical properties of nanomaterials, controlled synthesis of nanomaterials has been received considerable attention in recent years. In this paper try to prepare micro/nano Cu and Cu2O by liquid reduction method that respective utilize ascorbic acid and gallic acid as environmentally friendly reductant. The effects of mixing mode of reagents, pH values and reaction reagents concentration on the phase and morphology of micro/nano Cu and Gu2O were investigated. The evolution process of crystal growth and mechanism effecting the morphology were simply discussed.The detail conclusions are as follows:1. With ascorbic acid as reductant, the transition of phase and morphology of the reaction system pH value between 8 and 13 was researched. With pH value from low to high, the reaction product will change from pure Cu phase into pure Cu2O phase.In the process,Cu2O content increases with the rise of pH value. While the change of morpholopy along with transition of phase at the same time. the morphology changes in this order that micro irregular polyhedron of smooth surface,micro irregular polyhedron that surface geerates a large number of nanoparticles,spherical particles of "burr" type,500nm spherical particles, mixture of spherical and fibrous product,200nm spherical particles of smooth surface.2. With ascorbic acid as reductant, the mixing mode of reagents has a great influence in the copper powder morphology. Copper powder that was prepared by dump way directly has uniform size and inerratic particle morphology, particles was around 1μm and has good dispersion. But copper powder that was prepared by drip way directly has an great difference. The copper powder that was prepared from Cu2+ drip to reductant solution was irregular polyhedron with smaller size.and copper powder that was prepared from reductant solution drip to Cu2+ solution was inerratic polyhedron with greater size.3.With gallic acid as reductant, the reaction product phase that was prepared under differnet pH value has great difference.When pH value is 5, the reaction product was sheet Cu-gallate complexes; pH value rise to 7,the reaction phase appear Cu2O phase.and G12O content and crystallinity is getting better and better with rise of pH value, when the pH value rise to 11,reaction product transforms to pure Cu2O phase of good crystallinity.4.1n alkaline conditions, Cu2O powder of different morphology can be prepared with gallic acid of different concentration, nanorods that length to diameter ratio was 1:50, nanorods that length to diameter ratio was 1:100,500nm 26-facet Cu2O particles,cube Cu2O particles can be prepared respectively under different concentration, gallic acid in reaction system not only has the effect of reductant also can be used as organic additives.