Atomic Oxygen Activation Alcohol Electro-Oxidation

Atomic Oxygen Activation Alcohol Electro-Oxidation 

The electro-oxidation in a fuel cell of low molecular mass alcohols, such as methanol and ethanol, appears particularly convenient for two main reasons they are liquids 

On a pure Pf/C catalyst, Rousseau et showed that the electro-oxidation of ethanol at the anode of a DEFC working at 80°C mainly led to the formation of acetaldehyde, acetic acid and carbon dioxide, with chemical yields of 47.5%, 32.5% and 20.0%, respectively. By comparing the mass yield and the faradic yields, they concluded that no other products were formed in a significant amount. This result confirms that Pt is able to break the C-C bond to some extent In situ infrared measurements on ethanol adsorption and electro-oxidation at platinum electrodes have clearly shown that the adsorbed CO species are formed from 0.3 V vs RHE at the platinum surface moreover Iwasita and Pastor found some traces of CH4 at potentials lower than 0.4 V vs RHE. Previous studies showed that the initial steps of ethanol adsorption and oxidation on Pt can follow two different modes  

It was shown by Hitmi et al. that acetaldehyde was formed at potentials lower than 0.6 V vs RHE. From long-term electrolysis experiments on a Pt catalyst coupled with high performance liquid chromatography (HPLC) analyses, Vigier et al. detected acetaldehyde at potentials as low as 0.35 V vs RHE whereas no acetic acid was detected in this potential range. It could then be proposed that at E 0.6 V vs RHE the ethanol electro-oxidation occurs following the mechanism  

At E 0.4 V vs RHE, where acetaldehyde is formed, it can adsorb on platinum and form a Pt-CH3-CO species according to  

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Atomic Oxygen Activation Alcohol Electro-Oxidation... 

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