In Situ Stress and Nanogravimetric Measurements During Underpotential Deposition of Pd on (111)-Textured Au

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• 作者：G. R. Stafford ; U. Bertocci
• 刊名：Journal of Physical Chemistry C
• 出版年：2009
• 出版时间：January 8, 2009
• 年：2009
• 卷：113
• 期：1
• 页码：261-268
• 全文大小：359K
• 年卷期：v.113,no.1(January 8, 2009)
• ISSN：1932-7455

文摘

The surface stress associated with the electrodeposition of Pd onto (111)-textured Au cantilever electrodes in 0.1 M H₂SO₄ supporting electrolyte has been examined. An electrochemical quartz crystal nanobalance was also used in order to correlate the stress development with the Pd coverage. PdSO₄ and H₂PdCl₄ were separately examined as electroactive species, in order to determine the influence of [PdCl₄]²⁻ adsorption on the stress response. The stress associated with Pd underpotential deposition (upd), as well as with the growth of subsequent adlayers, is tensile, whose primary source is the +4.9% lattice mismatch between Pd and Au. However the expected tensile stress is in part counterbalanced by the formation of Pd−Au bonds as well as anion adsorption onto the Pd surface. Pd upd causes a surface stress change of +0.4 N m⁻¹ whereas a second monolayer produces an additional stress change of +0.6 N m⁻¹. We attribute this larger tensile stress change for the second monolayer to the diminished electronic influence of the Au substrate. A similar stress response is observed for both H₂PdCl₄ and PdSO₄ as sources of Pd²⁺.