Neste trabalho são apresentados os resultados dos estudos do comportamento eletroquímico do eletrodo de níquel em H2SO4 1,0 N, na ausência e na presença de álcool propargílico (Propin-2-ol-1). Observou-se uma forte interação entre o composto orgânico e a superfície do eletrodo. A incidência de um feixe de luz policromática afeta o processo de transferência de carga sobre o mesmo. Os processos anódicos, associados à eletrooxidação da superfície do eletrodo, foram inibidos com a presença de álcool propargílico no meio. Esta interação aumenta quando o sistema está sob iluminação. A ação inibidora do álcool propargílico foi observada mesmo em soluções de ácido sulfúrico aeradas e a 30 °C.

The electrochemical behavior of a nickel electrode in 0.5 M H2SO4 in the absence and presence of propargyl alcohol (2-Propyn-1-ol) was investigated. Three different electrochemical methods were used in this paper: potentiometry, partial polarization curves and cyclic voltammetry. A strong interaction between the organic compound and the electrode surface was observed. The incidence of polychromatic light on the electrode surface affects the charge transfer process on it. The anodic reactions related to the electrooxidation of the electrode surface were inhibited by the presence of propargyl alcohol in the medium. The interaction between the organic compound and the electrode surface increases when the system is under illumination. The inhibitory action of propargyl alcohol on the electrooxidation reactions of nickel was observed even at 30 °C in aerated sulfuric acid.

In this paper is presented electrochemical evidences of the influence of the light on the electrochemical behavior of nickel electrode in diluted sulfuric acid. The current densities related with the electrooxidation of the metal decreases when the electrode is under illumination. The corrosion potential, Ecorr , shift to a more positive value in this condition. This effect was observed with polychromatic light and with different wavelength glass filters such as 700 nm and 520 nm. It was observed that increasing the temperature of the solution, the current densities related with cathodic and anodic processes, increases instead of decreases. The activation energy related with the electrooxidation of the electrode was higher under illumination than in the dark. It is suggested that this behavior may be related or with a photo-inhibition effect either with dessorption of adsorbed water involved in the electrooxidation mechanism.