Deposition of platinum nanoparticles on nickel wire electrodes via galvanic replacement reactions enabled by the presence of silver chloride

Suspended solids of AgCl are formed in aqueous solutions containing both K₂PtCl₄ and AgNO₃. When Ni wire is immersed in an aqueous solution containing 1.0 mM K₂PtCl₄ and 1.0 mM AgNO₃, it was found that platinum nanoparticles (PtNPs) were deposited on Ni wire after the immersion of 10 min. This was confirmed by observing the electrocatalytic responses for ethanol oxidation as well as the FE-SEM images with EDS analysis. While the deposition of PtNPs is generally unfavorable on the surface of Ni wire by immersing it in an aqueous solution containing only K₂PtCl₄, it was clarified that the coexistence of PtCl₄²⁻ (or other chemical species that contain Pt²⁺) with AgCl (and Ag⁺) promoted the galvanic replacement reactions with Ni to deposit PtNPs. The electrocatalytic responses for ethanol oxidation significantly changed depending on [K₂PtCl₄] and [AgNO₃] in aqueous solutions for the preparation; AgNPs were dominantly deposited in some conditions. Compared with PtNPs modified Ni (PtNPs/Ni) wire electrodes prepared using other methods, the electrocatalytic current recorded with the present PtNPs/Ni wire electrodes were increased over 50 mAcm⁻².

Graphical abstract