# Can ZnO act as a reducing agent for noble metals like Pd?

Palladium ions (e.g., $$\ce{Pd^2+}$$) can be reduced to $$\ce{Pd}$$ by more reactive metals such as zinc. Metal oxides such as $$\ce{ZnO}$$ are very stable but can its atoms in the oxide structure still be displaced by Pd? I know the answer is probably "No" but in one of my samples $$\ce{ZnO}$$ nanoparticles were removed from the solution after I added $$\ce{Pd^2+}$$ solution to the system and $$\ce{Pd}$$ nanoparticles were formed. The solvent was methanol. After washing the solution and drying I did XPS and no trace of zinc was observed but saw $$\ce{Pd}$$ peaks.

• The metals aren’t connected to the Swedish entrepreneur Alfred Nobel but to the English adjective to nobility: noble. As for the actual question, I sadly cannot give you an answer. – Jan Dec 16 '18 at 17:02
• Did you measure the size of the nano-particles? According to Wikipedia, at most, the XPS instrument will only probe $\pu{20 nm}$ into a sample. Thus, I wonder, $\ce{Pd}$ has been deposited on $\ce{ZnO}$ surface. "Palladium Deposition on $\ce{Pt}$ Surface by Reduction of $\ce{Pd^2+}$ Ions with Organic Substances" has been studied before (link.springer.com/article/10.1023/A:1010314807520). – Mathew Mahindaratne Dec 16 '18 at 22:44