The behavior of ethanol oxidation reaction on composite electrodes prepared by deposition platinum on a gold surface (Pt/Au) were studied by cyclic voltammetry and surface enhanced infrared absorption spectroscopy (SEIRAS) analysis. The results show that the Pt electrode has high oxidation activity and significant poison behavior; on the contrary, the Au electrode demonstrates low activity without a poison peak. The SEIRAS analyses reveal that both carbon monoxide (CO) and carbon dioxide (CO2) appear during anode sweeping, and the CO peak density decreases with increasing potential and finally is eliminated. During the cathodic scanning, the CO peak reappears, and the peak intensity increases with scanning cycles, demonstrating a high poison behavior and the C1 reaction route on Pt. On the Au electrode, CO2 and CO peaks were not observed; instead, an acetic acid peak appeared, indicating a C2 reaction path. For the Pt/Au composited electrodes, the electrochemical activities of the electrodes, as well as their poison behavior, increased with the deposition amount of Pt. However, the intensities of the poison peaks are smaller than those of oxidation ones; therefore, a higher tolerance to the CO poison can be achieved. For the 2 m-Pt/Au composite electrode, the activity is close to that of pure Pt, but the poison tolerance is 3 times the value of Pt.
Keywords: Carbon monoxide poison; Composite electrodes; Cyclic voltammetry; Ethanol oxidation; Gold/platinum; In-situ SEIRAS analysis.
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