The influence of OH- chemisorption on the catalytic properties of gold single crystal surfaces for oxygen reduction in alkaline solutions

Oxygen reduction on gold single crystal electrodes of various orientations, Au(hkl), in 0.1 M NaOH was studied by rotating disk electrode and rotating disk ring electrode techniques, with a goal to correlate the physical and chemical properties of the electrode surface with its catalytic activity. The characterization of the state of the electrode surface and the interface was carried out by cyclic voltammetry and differential capacity measurements. The geometrical arrangement and symmetry of surface atoms, and the presence of chemisorbed OH- anions, were found to play a key role in determining the catalytic properties of Au(hkl) surfaces for O-2 reduction. It was proposed that chemisorbed anions act as a precursor for the dissociative adsorption of molecular oxygen or for chemisorption of reaction intermediate, catalyzing the 4e(-)-reduction of O-2.