Adsorption and oxidation processes of cyanate (OCN-) were studied on polycrystalline platinum and Pt(1 0 0), Pt(1 1 0) and Pt(1 1 1) surfaces in alkaline solution (pH 9). On Pt(poly), Pt(1 0 0) and Pt(1 1 0), it has been found that cyanate chemisorbs dissociatively, with production of adsorbed CO. Oxidation of cyanate thus follows a pathway involving COad on polycrystalline Pt and these single crystal faces. COad has not been observed during oxidation of cyanate on Pt(1 1 1); thus another pathway, involving direct oxidation of OCN-, has been identified for cyanate oxidation on platinum surfaces. (C) 2004 Elsevier Ltd. All rights reserved.