CO adsorption on nanometer-thin layer of surface alloys of Pt-Ru and Pt-Pd prepared by electrochemical codeposition has been studied using in situ FTIR spectroscopy. Abnormal infrared effects (AIREs) that consist of the enhancement of IR absorption by adsorbed CO on different surface sites and the inversion of IR band direction have been observed on the thin-layer prepared. The results also demonstrate the considerable significance of Pt-Ru and Pt-Pd surface alloys in electrocatalysis applications. CO adsorption on nanometer-thin layer of surface alloys of Pt-Ru and Pt-Pd prepared by electrochemical codeposition has been studied using in situ FTIR spectroscopy. Abnormal infrared effects (AIREs) that consist of the enhancement of IR absorption by adsorbed CO on different surface sites and the inversion of IR band direction have been observed on the thin-layer prepared. The results also demonstrate the considerable significance of Pt-Ru and Pt-Pd surface alloys in electrocatalysis applications.