Preferential oxidation of carbon monoxide on CoOx/ZrO2

✍ Scribed by Matthew M. Yung; Zhongkui Zhao; Matthew P. Woods; Umit S. Ozkan

• Publisher: Elsevier Science
• Year: 2008
• Tongue: English
• Weight: 415 KB
• Volume: 279
• Category: Article
• ISSN: 1381-1169
• DOI: 10.1016/j.molcata.2007.09.026

✦ Synopsis

The preferential oxidation (PROX) of carbon monoxide to carbon dioxide in excess H 2 is one of the strategies for obtaining high purity H 2 streams, especially for PEM fuel cells. A CoO x /ZrO 2 catalyst was synthesized and studied for the PROX reaction under various reaction conditions and indicated that in the temperature window of interest (80-200 • C), this catalyst had potential for obtaining high conversions of CO with high O 2 selectivity to CO 2 . Increases in the GHSV and the CO/O 2 ratio led to lower CO conversion but higher O 2 selectivity to CO 2 . High temperature operation led to a decrease in CO oxidation activity and the formation of methane, which was attributed to partial reduction of CoO x /ZrO 2 . The catalyst performance was examined using steady-state and transient temperature-programmed reaction (TPRxn) experiments. Temperatureprogrammed reduction (TPR) and time-on-stream studies were used to examine the catalyst stability in reducing conditions. DRIFTS studies during CO TPD and in situ PROX were used to examine surface species on ZrO 2 and CoO x /ZrO 2 .