Fast faradaic processes observed during the potentiodynamic polarization of polycrystalline palladium in acid electrolyte

• Autores: Bolzán, Agustín E.; Chialvo, Abel Cesar; Arvia, Alejandro Jorge
• Año de publicación: 1984
• Idioma: inglés
• Tipo de recurso: artículo
• Materia: Ciencias Exactas; Química; potentiodynamic; polycrystalline; Electroquímica; Electrólitos; Oxígeno; Electrodos
• Institución: Universidad Nacional de La Plata

Two almost reversible electrochemical systems are detected during the potentiodynamic anodization of polycrystalline palladium in 1 M H2SO4 and 1 M HClO₄ by applying the triangular modulated triangular potential sweep technique. The first electrochemical system which appears in the 0.7–0.9 V range (vs. RHE) corresponds to the reaction Pd+H₂O=PdOH+H⁺+e⁻ whose reversible potential is estimated as 0.80±0.02 V and the average half-life time of PdOH species is estimated as 6×10⁻³ s. The second electrochemical system appears when the anodizing potential sweep extends to the oxygen evolution potential region. The appearance of the second electrochemical system is accompanied by a change in colour of the electrode surface, a shift of the current-potential curve of the oxygen evolution reaction and an increase in thickness of the oxide anodic layer. The reversible response is tentatively assigned to the PdO₂/PdO₃ redox couple.
Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas
Facultad de Ciencias Exactas