The catalytic oxidation of benzyl alcohol is studied by means of on-line differential electrochemical mass spectrometry (DEMS) on both palladium and platinum electrodes. The objective of this work is to investigate the reactivity of the adsorbed species remaining on the electrode surface after a Bow-cell experiment and the influence of electrode composition. It is found that the adsorbates formed during the oxidative adsorption of benzyl alcohol are desorbed in the positive-going potential scan as CO2 for platinum and palladium, although benzene is also detected on the latter. Adsorbate yields depend on both potential and electrode composition.