According to an article I've read, reaction path for the formation of Cu from CuO can come from the direct reduction of CuO to Cu or from the dissolution of CuO to Cu2+ ions leading to Cu.
In the paper, it was concluded that Cu nanoparticles were produced from the reduction of Cu2+ ions from the dissolution of CuO because direct reduction of CuO to Cu would have yielded Cu particles with roughly the same diameter as CuO particles, 3 um.
Is particle size enough evidence to believe that dissolution was the reaction path mechanism?
I'm having doubts because presence of Cu2+ should show a blue tinge in the solution which never happened. Also, CuO is barely soluble in water so it would not have been possible for CuO to be completely dissociated to Cu2+ and OH-. I'm angling for the direct reduction mechanism.
What are your thoughts on this? Is it possible that direct mechanism occurred? What are some evidences of direct reduction from CuO to Cu in aqueous solution?
Thank you very much!
Water-insoluble compounds with small size of molecules, atoms are not present. Hydrocarbons dissolved in the water. Metals (copper) is dissolved in water. On Cu surface there are oxides. On the copper produced double layer electrode. Therefore CuO reduction occurs through the formation of copper ions.
Best regards.
Hi,
How did you arrive with the explanation that CuO reduction is due to the formation of Cu ions and not through direct reduction?
is copper oxide soluble in water.if it is not soluble in water than reduction must proceed through meatal ions
Imagine that in a closed reactor you heat copper hydroxide. You get your copper oxide and water.
Cu(OH)2 = CuO + H2O
This reaction is reversible. The reactor is water, copper oxide and copper hydroxide or Cu2+ + OH-.. To increase the content of hydroxide you need to lower the temperature.This reaction has your system (СuO +H2O).
Reduction
Cu2+ + 2e = Cu.
Regards.
In the preparation of Ag NPs in alkaline solution we first get Ag2O and then this oxide is reduced to Ag metal. So CuO can also be reduced to Cu(0). Whatever the mechanism is, the insoluble species such as Cu(OH)2 or CuO can dissociate to Cu(II) cations and hydrodie ions and then the copper cations will be reduced to Cu(0).
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