Unusual adsorption state of carbon monoxide on single-crystalline gold electrodes in alkaline media

We report an unusual and not previously reported adsorption state of CO on a Au(1 1 1) electrode and a hexagonally reconstructed Au(1 0 0) surface. Chemisorbed CO exhibits a reversible adsorption feature close to the onset of the oxidation of CO in solution. We suggest that the voltammetric feature is associated with the co-adsorption (and desorption) of OH- from the alkaline solution at low potential.