Evidence of the Substrate Effect in Hydrogen Electroinsertion into Palladium Atomic Layers by Means of in Situ Surface X-ray Diffraction

Chrystelle Lebouin (1) , Yvonne Soldo-Olivier (1) , Eric Sibert (1) , Maurizio de Santis (2) , Frédéric Maillard (1) , René Faure (1)

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

In this work, we report an in situ surface X-ray diffraction study of the hydrogen electroinsertion in a two-monolayer equivalent palladium electrodeposit on Pt(111). The role of chloride in the deposition solution in favoring layer-by-layer film growth is evidenced. Three Pd layers are necessary to describe the deposit structure correctly, but the third-layer occupancy is quite low, equal to about 0.22. As a major result, resistance to hydriding of the two atomic Pd layers closest to the Pt interface is observed, which is linked to a strong effect of the Pt(111) substrate. As a consequence, we observe the lowering of the total hydride stoichiometry compared to bulk Pd. Our measurements also reveal good reversibility of the deposit structure, at least toward one hydrogen insertion−desorption cycle.

Domaines: Matériaux

Chrystelle Lebouin, Yvonne Soldo-Olivier, Eric Sibert, Maurizio de Santis, Frédéric Maillard, et al.. Evidence of the Substrate Effect in Hydrogen Electroinsertion into Palladium Atomic Layers by Means of in Situ Surface X-ray Diffraction. Langmuir, 2009, 25 (8), pp.4251-4255. ⟨10.1021/la803913e⟩. ⟨hal-00384872⟩