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Electrochemical quartz-crystal nanobalance (EQCN) analysis of the behavior of Pt in aqueous H(2)SO(4) reveals that the interfacial mass reaches a minimum, the potential of minimum mass (E(pmm)), at 0.045 V. A similar behavior is observed for Pt in aqueous HClO(4) and NaOH. E(pmm) is a new parameter describing the electrochemical interface. The value of E(pmm) coincides with the completion of the saturation layer of electroadsorbed H (H(UPD)) and the commencement of H(2)(g) generation or H(2)(g) electro-oxidation. The value of E(pmm) and the structure of the Pt/electrolyte interface are discussed in terms of the interactions of the anions H(3)O(+), H(UPD), H(OPD), and H(2)O with Pt. The layer of H(UPD) embedded in the Pt surface lattice minimizes the surface dipole-water dipole and surface charge-water dipole interactions, thus reduces the wetting ability of Pt. Consequently, the discharge of H(3)O(+) in the electrolytic formation of H(2)(g) or the dissociative adsorption of H(2)(g) that precedes its electro-oxidation to H(3)O(+) proceed easily on Pt, because the species do not have to displace H(2)O molecules. Effective and inexpensive non-platinum electrocatalysts for the electrolytic H(2)(g) generation in water electrolyzers or H(2)(g) electro-oxidation in polymer electrolyte membrane fuel cells should mimic the interfacial behavior of Pt by minimizing the interaction of H(2)O molecules with the electrode.

Cyclic voltammetry and differential pulse voltammetry were used to investigate the electrochemical behavior of ascorbic acid (AA) on palladium coated nanoporous gold film (PdNPGF) electrode. The deposition of palladium was done through oxidation of copper UPD layer by palladium ions. This low Pd-loading electrode behaved as the nanostructured Pd for electrocatalytic reaction. The PdNPGF electrode exhibits excellent electrocatalytic behavior by enhancing the AA oxidation peak current due to synergistic influence of the Pd film and NPGF. The kinetic parameters such as electron transfer coefficient, a, was 0.47 and the voltammetric responses of the PdNPGF electrode were linear against concentration of AA in the ranges of 2.50-33.75 mM and 0.10-0.50 mM with CV and DPV respectively.