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

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. CO<sub>2</sub>, CO and traces of SO<sub>2&...

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Bibliographic Details
Authors: Arvia, Alejandro Jorge, Triaca, Walter Enrique, Videla, Héctor A.
Format: article
Status:Published version
Publication Date:1970
Country:Argentina
Institution:Universidad Nacional de La Plata
Repository:SEDICI (UNLP)
Language:English
OAI Identifier:oai:sedici.unlp.edu.ar:10915/121692
Online Access:http://sedici.unlp.edu.ar/handle/10915/121692
Access Level:Open access
Keyword:Ciencias Exactas
Química
Electrochemical oxidation
Kinetics
Graphite
Description
Summary: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. CO<sub>2</sub>, CO and traces of SO<sub>2</sub> are formed during the electrochemical reaction. Assuming 4 Faraday/mol of CO<sub>2</sub>, the anodic efficiency is about 90%. The CO<sub>2</sub>/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.