Initial stages of Pt deposition on Au(111) and Au(100)

• Published in: Electrochimica acta Vol. 47; no. 9; pp. 1461 - 1467
• Main Authors: Waibel, H.-F, Kleinert, M, Kibler, L.A, Kolb, D.M
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 15.02.2002; Elsevier
• Subjects: Adsorption of [PtCl 4] 2; Chemistry; Cyclic voltammetry; Electrochemistry; Electrodeposition; Exact sciences and technology; General and physical chemistry; Gold single crystals; In-situ STM; Platinum deposition; Study of interfaces; Cyclic voltammetry; Gold single crystals; In-situ STM; Platinum deposition; Adsorption of [PtCl 4] 2; Electrode adsorption; Gold; Platinum Complexes; Electrode electrolyte interface; Anionic complex; Crystal face; Transition metal Complexes; Experimental study; Scanning tunneling microscopy; Crystal electrode; Adsorption structure; Electrodeposition; Chloro complex; Electrodissolution
• ISSN: 0013-4686; 1873-3859
• DOI: 10.1016/S0013-4686(01)00861-1

The deposition of Pt onto unreconstructed Au(111) and Au(100) was studied with cyclic voltammetry and in-situ STM. The latter revealed that in [PtCl 4] 2− containing electrolytes, both surfaces are covered by an ordered adlayer of the complex. For the adsorbed [PtCl 4] 2− a slightly compressed (√7×√7) R19.1°-structure was assumed for Au(111) and a (3×√10) for Au(100). In both cases, a rather high overpotential for Pt deposition was observed, most probably due to the high stability of the [PtCl 4] 2− complex. Nucleation of Pt starts mainly at defects like step edges for low deposition rates and three-dimensional clusters are formed. Due to the high overpotential, some nuclei appear also on terraces at random sites. Higher coverages of Pt lead to a cauliflower like appearance. It is not possible to dissolve the platinum clusters at positive potentials without severely roughening the gold surface. The [PtCl 4] 2− complex is oxidized to the [PtCl 6] 2− complex at about 0.7 V, when metallic Pt is on the surface.