Electrochemical oxidation of methanol on Pt3Co bulk alloy

Abstract

The electrochemical oxidation of methanol was investigated on a Pt3Co bulk alloy in acid solutions. Kinetic parameters such as transfer coefficient reaction orders with respect to methanol and H+ ions and energy of activation were determined. It was found that the rate of methanol oxidation is significantly diminished by rotation of the electrode. This effect was attributed to the diffusion of formaldehyde and formic acid from the electrode surface. Stirring of the electrolyte also influenced the kinetic parameters of the reaction. It was speculated that the predominant reaction pathway and rate determining step are different in the quiescent and in the stirred electrolyte. Cobalt did not show a promoting effect on the rate of methanol oxidation on the Pt3Co bulk alloy with respect to a pure Pt surface.

Elektrohemijska oksidacija metanola je ispitivana na leguri Pt3Co u kiselim rastvorima. Određeni su kinetički parametri reakcije: koeficijent prelaza redovi reakcije po metanolu i H+ jonu i energija aktivacije. Utvrđeno je da se brzina reakcije značajno smanjuje kada elektroda rotira. Taj efekat je pripisan difuziji formaldehida i mravlje kiseline sa površine elektrode. Mešanje elektrolita takođe utiče na kinetičke parametre reakcije. Diskutovana je mogućnost da su dominantan reakcioni put i spori stupanj u mehanizmu reakcije različiti u mirnom i mešanom elektrolitu. Prisustvo kobalta u leguri nije uticalo na povećanje brzine oksidacije metanola u poređenju sa čistom platinom.