Kinetics and mechanism of the electrochemical oxidation of graphite in bisulphate melts

• Autores: Arvia, Alejandro Jorge; Triaca, Walter Enrique; Videla, Héctor A.
• Año de publicación: 1970
• Idioma: inglés
• Tipo de recurso: artículo
• Materia: Ciencias Exactas; Química; Electrochemical oxidation; Kinetics; Graphite
• Institución: Universidad Nacional de La Plata

The kinetics of the electrochemical oxidation of graphite to volatile compounds by electrolysing molten bisulphates in the temperature range from 180 to 320°C has been studied by conventional steady-state and non-steady-state measurements. CO₂, CO and traces of SO₂ are formed during the electrochemical reaction. Assuming 4 Faraday/mol of CO₂, the anodic efficiency is about 90%. The CO₂/CO ratio is about 2 and is independent of the cd in the range considered. The electrochemical reaction is compared to the thermal oxidation of graphite. The reaction is interpreted through a scheme involving consecutive reactions, where the rate-determining step, under Temkin conditions, is a thermal process involving a desorption of intermediates following either a first-order or second-order process depending on the type of adsorption obeyed. The activation energy derived from the rate constant at the rest potential is about 42·5 Kcal/mol.
Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas