The Electrochemical Promotion of Ethylene Oxidation at a Pt/YSZ Catalyst

✍ Scribed by Arafat Toghan; Liz M. Rösken; Ronald Imbihl

• Publisher: John Wiley and Sons
• Year: 2010
• Tongue: English
• Weight: 326 KB
• Volume: 11
• Category: Article
• ISSN: 1439-4235
• DOI: 10.1002/cphc.200900936

✦ Synopsis

Abstract

The electrochemical promotion of the C~2~H~4~+O~2~ reaction to form CO~2~ and H~2~O is studied in the 10^−5^ and 10^−4^ mbar range with a Pt catalyst interfaced as working electrode to yttrium‐stabilized zirconia (YSZ). Photoemission electron microscopy (PEEM) was used as spatially resolving method. Under open‐circuit conditions, that is, without an external voltage applied, the CO~2~ production exhibits a pronounced hysteresis upon cyclic variation of p__(C~2~H~4~). The hysteresis is attributed to the build‐up of a carbonaceous CH__~x~ layer inhibiting O~2~ adsorption and hence poisoning the reaction. It is shown that the application of a positive potential of 1 V triggers a transition from the unreactive branch of the reaction to an active branch. The large non‐Faradayicity reported in the literature for this reaction system is explained as an ignition effect caused by the partial removal of the inhibiting carbonaceaous layer.