Modification of nickel wire electrodes with platinum in the presence of copper ions via galvanic replacement reactions

Abstract

In the galvanic replacement reaction between Ni wire and PtCl42- in an aqueous solution, the deposition of Pt nanoparticles (PtNPs) on Ni wire is generally unfavorable. However, the addition of Cu2+ into an aqueous solution of PtCl42- was found to promote the deposition of PtNPs effectively for the immersion of Ni wire. This promoted deposition of PtNPs on Ni wire could be confirmed by observing the electrocatalytic responses for ethanol oxidation, electrochemical impedance and the surface images. In addition, the EDS analysis showed that the deposited PtNPs did not contain Cu. The formation of PtNPs without containing Cu was also verified by observing the electrocatalytic properties of other alcohols. Although we had previously reported the stepwise modification of Pt on Ag-deposited Ni wire, the Cu2O-modified Ni wire was useless to allow the deposition of PtNPs in a similar stepwise treatment. Hence, the simple preparation using aqueous solutions containing both PtCl42- and Cu2+ can be proposed as a useful approach to modify PtNPs on Ni materials via galvanic replacement reactions.