Palladium Electrodeposition onto Pt(100): Two-Layer Underpotential Deposition

Bruno Previdello (1) , Eric Sibert (1) , Mireille Maret (2) , Yvonne Soldo-Olivier (3)

1 LEPMI - Laboratoire d'Electrochimie et de Physico-chimie des Matériaux et des Interfaces
2 SIMaP - Science et Ingénierie des Matériaux et Procédés
3 NEEL - SIN - Surfaces, Interfaces et Nanostructures

Electrodeposition of the first Pd layers onto Pt(100) was investigated using cyclic voltammetry at a low scan rate (0.1 mV·s–1). Ultrathin films were characterized by cyclic voltammetry in 0.1 M H2SO4 solution and with ex situ AFM (atomic force microscopy). For the first time, we evidenced the underpotential character of the deposition of the first two Pd layers, characterized by a two-step mechanism, each step corresponding to the deposition of a complete Pd atomic layer. For thicker deposits, especially above 10 monolayers as equivalent thickness, the electrochemical characterization displays a strong irreversibility and a broadening of the adsorption/desorption peaks, associated with a reduction of long-range ordered flat areas. Ex situ AFM images are in agreement with this description. They show rough thick deposits and the growth of (100)-oriented rectangular shaped islands with their sides aligned with the two [011] and [0-11] perpendicular directions of the (100) Pt surface.

Domaines: Physique [physics]; Matière Condensée [cond-mat]

Bruno Previdello, Eric Sibert, Mireille Maret, Yvonne Soldo-Olivier. Palladium Electrodeposition onto Pt(100): Two-Layer Underpotential Deposition. Langmuir, 2017, 33 (9), pp.2087-2095. ⟨10.1021/acs.langmuir.6b03968⟩. ⟨hal-01980830⟩