Simultaneous carbon and nitrogen monoxide oxidations were studied on different platinum surfaces to envisage the kinetics and mechanism of oxidations in acid media. Nanosized platinum specimens were prepared by an electrochemical method without chemical capping agents and platinum ion precursors. Crystalline oriented particles were obtained from a platinum surface by applying symmetric or asymmetric potential programs in concentrated sulfuric acid followed by cathodizations at very large negative potentials. Nitrogen monoxide arising from nitrite solutions showed synergetic oxidation profiles when first scanning the potential towards cathodic values in solutions containing carbon monoxide. Nitrite oxidative desorption to nitrate arose as a mass controlled process, whereas carbon monoxide oxidation to carbon dioxide occurred firstly from its adsorbate and then associated with carbon monoxide bulk solution. Tafel lines were derived including the potential dependence of surface coverages by oxygen containing adsorbates together with those by carbon and nitrogen monoxides. No changes for nitrogen oxide oxidation Tafel slopes were detected either in the presence or the absence of carbon monoxide (ca. 0.120 Vdec(-1)) above 1 V, whereas carbon monoxide oxidation varies the slope from 0.040 to ca. 0.060 Vdec(-1) when nitrogen monoxide adsorbates were formed. (C) 2019 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.