| 저자(한글) |
Bach Delpeuch, A.,Maillard, F.,Chatenet, M.,Soudant, P.,Cremers, C. |
| 초록 |
The ethanol oxidation reaction (EOR) was studied on Pt/C, Rh/C, Pt-Rh/C, Pt-SnO 2 /C and Pt-Rh-SnO 2 /C using on-line differential electrochemical mass spectrometry (DEMS) in a flow-cell system and in situ Fourier transform infrared spectroscopy (in situ FTIR). The electrocatalysts were synthesized by a modified polyol method and physically characterized by inductively-coupled plasma atomic emission spectroscopy (ICP-AES), X-ray diffraction (XRD) and transmission electron microscopy (TEM). The electrocatalytic activity of the materials was tested for the EOR and the electrooxidation of a monolayer of adsorbed CO (CO ad being an intermediate of the EOR). Both in situ FTIR and DEMS investigations revealed that CO ad electrooxidation occurs at lower potentials on Pt-SnO 2 /C and Pt-Rh-SnO 2 /C than on Pt/C, Rh/C and Pt-Rh/C. A good correspondence was found between the (intensity vs. potential) variations of the m/z=22 mass-to-charge signal and of the IR band at 2343cm -1 , both strictly assigned to CO 2 . The addition of Rh to Pt enhances the tolerance to adsorbed CO molecules during the EOR (CO 2 molecules were detected at more negative potentials in FTIR on Rh-containing electrocatalysts), and the simultaneous presence of Pt, Rh and SnO 2 in the catalysts resulted in enhanced EOR selectivity towards CO 2 . The CO 2 current efficiency (CCE) calculations indicate quantitatively that the tri-metallic Pt-Rh-SnO 2 /C electrocatalyst yields more complete ethanol electrooxidation into CO 2 . Finally, FTIR experiments enabled to detect high-potential (E gt;0.95V vs. RHE) CO 2 formation, which likely originates from the oxidation of either CH x - or ethoxy-adsorbates that only oxidize at high potential. |
