Evidence of the substrate effect in hydrogen electroinsertion into palladium atomic layers by means of in situ surface X-ray diffraction.
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.
Lebouin
Chrystelle
C
Laboratoire d'Electrochimie et de Physicochimie des Matériaux et des Interfaces, CNRS-Grenoble INP-UJF, 1130 rue de la Piscine, 38402 Saint Martin d'Hères, France.
Soldo-Olivier
Yvonne
Y
Sibert
Eric
E
De Santis
Maurizio
M
Maillard
Frédéric
F
Faure
René
R