Adsorption, oxidation and reduction of crotyl alcohol on platinum: A DEMS and in situ FTIRS study

The electrochemical reactivity of crotyl alcohol (CA) on Pt in acid media has been studied applying electrochemical methods combined with in situ Fourier transform IR spectroscopy (FTIRS) and on-line mass spectrometry (DEMS). Mass spectrometric cyclic voltammograms (MSCVs) and IR spectra, acquired with the alcohol in the solution, point out the formation of CO2 and crotonaldehyde as oxidation products.On the other hand, spectra recorded during the electroreduction display negative features at 2964, 2934 and 2875 cm−1, which are assigned to the CH3 and CH2 asymmetric stretchings and the CH2 symmetric stretching, respectively. The intensity of these signals confirms that a massive hydrogenation process occurs at E < 0.05 VRHE with a strong production of hydrocarbons. Accordingly, several reduction compounds (2-butene, butane, propane, propene, ethane and methane) were detected by DEMS.The same products, with the exception of the aldehyde, were established from CA adsorbed species, isolated applying an electrolyte exchange procedure. A feature at 2020 cm−1 due to lineal adsorbed CO develops in the IR spectra. These results allow us to propose a general overview of the electrochemical reactions of CA at Pt.