The electrosorption of methane on platinized platinum and the potentiodynamic oxidation of the electrosorbed species in 1N H2SO4 solution is studied at 60°C. Two electrosorbed species are distinguished through the I/E characteristics recorded under different perturbation conditions. These species are assigned to COH‐type and CO‐type adsorbed species. The latter can be transformed into the former by electrochemical reduction in the potential range of the hydrogen adatoms. The number of the electrocatalyst sites per adsorbed species is estimated. The reported results contribute to the understanding of the kinetics of the methane electrooxidation under both stationary and nonstationary electrolysis conditions.

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The adsorption of dopamine (DA) on gold electrodes in aqueous sulfuric solutions of pH = 1 has been analyzed with the aid of in situ voltammetric and ellipsometric techniques. The initial stage of the process is the formation of an approximately 50-nm thick incipient hydrous gold oxide interface on the metal. Dopamine diffused into the incipient-oxide adlayer is weakly adsorbed. Significant variations of the pseudocapacity in the 0.6 < E < 0.9 V potential region were detected as a function of the adsorption time and of the gold surface state that was obtained when cycling the potential in sulfuric or perchloric solutions. The optical index and thickness of the incipient oxide were estimated.

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The growth of polypyrrole (Ppy) layers on gold electrodes in nearly neutral pH solutions is analysed using "in situ" voltametric and ellipsometric techniques. Different film structures are obtained depending on the potentiodynamic programme and the composition of the electrolyte. More compact dodecylsulphate-(DS) doped Ppy layers were grown at 1.2 V versus RHE than those obtained by applying a higher potential. The more compact layers correspond to the growth of an oxidised Ppy/DS layer that shows low pseudo capacity behaviour. After dipping, the doped Ppy/DS film in KCl solution-significant variations in optical indices and thickness are detected as a function of the applied potential. Higher electrochromism as well as decrease in film thickness after cathodisation is achieved. The optical indices and the thickness of the Ppy layer formed under different applied potential/time programmes are estimated.