Oxidation of (C2H5OH)-C-13 by NO and O-2 on the surface of stepped Pt(332) was studied using Fourier transform infrared reflection-absorption spectroscopy combined with thermal desorption spectroscopy. Upon annealing, adsorbed (C2H5OH)-C-13 molecules undergo stepwise dissociation. Desorption of H-2, released from the scission of O-H, C-13-H (alpha-C-13), and C-13-H (beta-C-13) bonds in sequence, covers a broad temperature range from similar to 260 to similar to 550 K. Desorption of (CO)-C-13 gives rise to a peak at 500-510 K. This surface process does not change greatly in the presence of O-2. Oxidation of (C2H5OH)-C-13 and, consequently, the generation of the products are strongly dependent on the pretreatment of (C2H5OH)-C-13. Thermal desorption spectra of H-2 and (CO2)-C-13 indicate that oxidation of (C2H5OH)-C-13 to H2O and (CO2)-C-13 is a primary process in most cases. However, when (C2H5OH)-C-13 adsorbed at 90 K is preannealed to 250 K before being exposed to O-2, reaction of O with H predominates. Consequently, oxidation of carbon-related species to (CO2)-C-13 is completely suppressed. (C2H5OH)-C-13 dissociation, in particular, the cleavage of the C-13-C-3 bonds, is suppressed in the presence of NO. Desorption of H-2, released from dehydrogenation of (13)CHx (beta-C) at surface temperatures above 400 K, is not detectable from the co-adlayers following the adsorptions of (C2H5OH)-C-13 and NO at 90 K. Oxidation of (C2H5OH)-C-13 related species with NO to (CO)-C-13 and (CO2)-C-13 proceeds to a much smaller extent compared to that with O-2. The presence of (C2H5OH)-C-13, irrespective of whether it is preadsorbed or postadsorbed, results in more NO desorption from terraces (at 350-360 K), due to a site-swapping effect exerted by (C2H5OH)-C-13 derivatives ((CO)-C-13 and (13)CHx). Nonetheless, NO reduction and subsequent N-2 production is promoted in the presence of (C2H5OH)-C-13. This effect, however, does not strongly depend on the exposure of (C2H5OH)-C-13. It is concluded that reduction of NO and subsequent N-2 production proceeds through a mechanism of NO dissociation and subsequent O removal, NO dissociation on the steps of the Pt(332) being a rate-limiting step. The reaction of (C2H5OH)-C-13-related species with O effectively scavenges O atoms arising from NO dissociation, therefore giving rise to vacant sites that accommodate O atoms from further NO dissociation. This accounts for the (C2H5OH)-C-13-induced enhancement in N-2 production.