Servizio Comunitario di Informazione in materia di Ricerca e Sviluppo - CORDIS

Partial oxidation of light hydrocarbons in fuel cell-like electrochemical devices

The project concerns the development of new efficient techniques for the production of oxygenates from light paraffins under mild conditions in fuel cell-like electrochemical devices with gas-diffusion electrodes and solid polymer electrolytes.

Results obtained revealed that ethane can be selectively oxidized at carbon diffusion cathodes in a fuel cell-like electrochemical devices under mild conditions. Improved gas chromatographic and high performance liquid chromatography (HPLC) analysis proved that ethanol and acetaldehyde are the only oxygenated products of the reaction, the selectivity towards such products exceeds 95 %. The reaction rate has been found to be enhanced by transition metal ions. The reaction rate can be controlled by the current applied and the acidity of the reaction medium. Substantial progress has been achieved in clarifying the kinetics and mechanism of the partial oxidation of ethane in electrocatalytic regime. Reaction occurs by a radical chain oxidation mechanism involving hydroxyl radicals. New catalytic active electrode materials, based on copper and silver have been proposed. Their activity in ethane partial oxidation is not less than the activity of the electro-Fenton system. Morphology of the carbon membranes has been studied using physical techniques in the presence and absence of catalytic additives. Experiments carried out under catalytic regime have demonstrated that Nafion based catalytic membranes are much more active than membranes prepared by using different heteropoliacids, notwithstanding Nafion membranes are characterized by a lower number of acidic sites. Probably the higher stability of Nafion in the presence of hydrogen peroxide could justify such a result. Experiments performed on different Nafion loading membranes revealed that a linear relationship between acidic sites and reaction rate exists, confirming that the activation of methane on acidic sites is a fundamental step in the reaction pathway.

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