Cathodic Corrosion of Cu Substrates as a Route to Nanostructured Cu/M (M = Ag, Au, Pd) Surfaces

Abstract

The electrochemical formation of nanostructured materials is generally achieved by reduction of a metal salt onto a substrate that does not influence the composition of the deposit. In this work, we report that Ag, Au and Pd electrodeposited onto Cu under conditions where galvanic replacement is not viable and hydrogen gas is evolved results in the formation of nanostructured surfaces that unexpectedly incorporate a high concentration of Cu in the final material. Under cathodic polarisation conditions, the electrodissolution/corrosion of Cu occurs, which provides a source of ionic copper that is reduced at the surface-electrolyte interface. The nanostructured Cu/M (M=Ag, Au and Pd) surfaces are investigated for their catalytic activity for the reduction of 4-nitrophenol by NaBH 4, where Cu/Ag was found to be extremely active. This work indicates that a substrate electrode can be utilised in an interesting manner to make bimetallic nanostructures with enhanced catalytic activity. Feeling rusty: Electrodeposition of Ag, Au or Pd onto a Cu electrode under hydrogen evolution conditions results in unexpected deposition of Cu within the nanostructured metal deposit. This occurs through cathodic corrosion of Cu, which provides a source of Cu ions that can be reduced during the deposition process. The morphology of the final porous material and Cu content are highly dependent on the metal salt in solution, which impacts on the catalytic performance of the material where Cu/Ag is found to be highly active. Copyright