Enhancement of electrocatalytic hydrogen evolution on tantalum by submonolayer electrodeposition of silver

• Published in: International journal of hydrogen energy Vol. 28; no. 3; pp. 285 - 295
• Main Authors: Walters, M.J., Assiongbon, K.A., Marr, D.R., Shepardson, B.T., Roy, D.
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 2003; Elsevier
• Subjects: Alternative fuels. Production and utilization; Applied sciences; Energy; Exact sciences and technology; Fuels; Hydrogen; Hydrogen evolution; Metal electrocatalyst; Tafel reaction; Tantalum; Underpotential deposition; Tantalum; Tafel reaction; Metal electrocatalyst; Hydrogen evolution; Underpotential deposition; Cyclic voltammetry; Silver; Electrocatalysis; Hydrogen; Electrodeposition; Electrode material; Catalyst activity
• ISSN: 0360-3199; 1879-3487
• DOI: 10.1016/S0360-3199(02)00061-7

Often it is possible to enhance the catalytic properties of a metal by electrochemically decorating its surface with submonolayer amounts of a foreign metal. The earlier studies of this phenomenon have focused primarily on substrate metals that exhibit some intrinsic catalytic properties of their own. In the present work, we demonstrate that it is possible to extend this catalytic effect of foreign metal deposition to the case of a chemically inert substrate metal. We study a catalytically inefficient polycrystalline Ta electrode in aqueous solutions of NaNO 3 (pH 3–5) at room temperature, using the hydrogen evolution reaction (HER) as a probe of electrode reactivity. We show that the catalytic efficiency of the Ta electrode (expressed in terms of the charge transfer resistance for HER) is increased by more than an order of magnitude as a result of covering a small fraction of the Ta surface with an electrodeposited foreign metal, Ag.