Revealing structural effects, part II: the influence of molecular structure on the adsorption of butanol isomers on platinum.
The nature of the adsorbates formed when butanol isomers interact with platinum electrodes in a perchloric acid medium was investigated by the application of on-line differential electrochemical mass spectrometry (DEMS) and cyclic voltammetry. In this way, the reactivity of the residues remaining on the electrode surface after a flow-cell experiment was established for the different molecules. It was found that the four isomers form strongly adsorbed species on the electrode, which undergo both electro-oxidation and electroreduction, depending on the potential applied at the electrode. Oxidative stripping of the adsorbates produces CO2 as the only oxidation product, whereas propane and the corresponding butane isomer are obtained on platinum in the hydrogen adsorption potential region. The yields of these hydrocarbons were found to depend strongly on the nature of the butanol isomer and on the adsorption potential. According to these results, it can be concluded that fragmentation of the butanol isomers occurs during adsorption and reduction reactions. C4 alkene and acetyl species are proposed as the adsorbed intermediates in all cases.
Souto
Ricardo M
RM
Department of Physical Chemistry, University of La Laguna, 38071 La Laguna (Tenerife), Canary Islands, Spain. rsouto@ull.es
Rodríguez
José L
JL
Pastor
Elena
E