Polishing and cold welding of gold nanoparticles under the action of Fenton’s reagent

The possibility of chemical polishing of gold nanoparticles and composite FeOOH core/Au shell nanoparticles in their colloidal solutions with the use of Fenton’s reagent has been studied. The addition of Fenton’s reagent to a citrate gold sol causes oxidation of citrate ions, which stabilize the system, down to their almost complete elimination from the nanoparticle surface. This leads to the formation of crystallization contacts between the nanoparticles (i.e., to their “cold welding”) even at a rather low temperature (70°C). At the same time, the action of Fenton’s reagent on FeOOH/Au composite particles results in the polishing of the gold shells, i.e., a reduction in the degree of their roughness.