Effect of Transition Element Ions on the Catalytic Activity of Titanium Dioxide during Chemical Deposition of Metallic Copper

We have established the high catalytic activity of TiO₂, modified by Pd²⁺, Cu²⁺, Fe³⁺, and Co²⁺ ions, in reduction of Cu²⁺ ions by formaldehyde in solution. We propose a likely scheme for the electronic processes that occur, including injection of electrons from the reducing agent into the conduction band and formation of metallic nanoparticles on the surface that effectively catalyze deposition of metallic copper.