Reduction of Ag+ irreversibly adsorbed on cyanide-modified Pt(111)

We report a study of the electrochemical reduction of Ag+ immobilised on a cyanide modified Pt(111) electrode in a Ag+-free solution using cyclic voltammetry and in-situ STM. We show that, upon reduction at 0.29 V, Ag deposits directly on the platinum substrate, resulting in the formation of an AgPt surface alloy without loss of the cyanide adlayer The large affinity of Ag+ for CNad is responsible for this large negative shift of the Ag+/Ag redox couple.. A fraction of the electrodeposited Ag is reoxidised at 0.34 V to yield again Ag+ coordinated to the CN adlayer. Therefore, successive cycling with a positive limit below 0.90 V results in a roughening of the surface and in the gradual transformation of cyanide-modified Pt(111) to a cyanide-modified AgPt surface alloy on Pt(111).