In Situ Stress and Nanogravimetric Measurements During Hydrogen Adsorption/Absorption on Pd Overlayers Deposited onto (111)-Textured Au

• Published in: Journal of physical chemistry. C Vol. 113; no. 30; pp. 13249 - 13256
• Main Authors: Stafford, G. R, Bertocci, U
• Format: Journal Article
• Language: English
• Published: American Chemical Society 30.07.2009
• Subjects: C: Surfaces, Interfaces, Catalysis
• ISSN: 1932-7447; 1932-7455
• DOI: 10.1021/jp902382q

The stress induced by electrochemical hydrogen adsorption and absorption in very thin palladium layers electrodeposited onto (111)-textured gold has been examined in 0.1 M H2SO4 by the cantilever curvature method and by comparing resonant frequency changes on AT- and BT-cut quartz crystals. A compressive surface stress change of about −0.25 N m−1 is measured in the hydrogen adsorption region. Compressive stress for hydrogen adsorption is not expected from charge distribution models for adsorbate-induced surface stress but is consistent with first-principles calculations in the literature as well as experimental data for H adsorbed on Pt(111). Cantilever measurements in the hydrogen absorption region are consistent with a maximum atomic H/Pd loading of 0.63 and give a compressive stress-thickness change of −0.45 N m−1 per monolayer of Pd, corresponding to a biaxial stress change of −2.0 GPa. A somewhat lower value of −0.80 GPa for a H/Pd loading of 0.68 was obtained from EQNB data using the double crystal technique. These stress values fall well within the range of experimental values reported in the literature for β-hydride generated both electrochemically and from the gas phase.