Selective low-temperature removal of carbon monoxide from hydrogen-rich fuels over Cu-Ce-Al catalysts

摘要

The selective oxidation of CO in the presence of excess H_2 was investigated over a ceria-promoted Cu-alumina catalyst. This catalyst shows nearly exclusive oxidation of CO versus H_2 with an O_2 concentration in stoichiometric proportion to CO, making it possible to purify a fuel cell feed stream with a minimum loss of energy content associated with H_2. The effect of the presence of CO_2 and H_2O in the feed on the activity and selectivity of the catalyst, and the long-term stability were also investigated. The catalysts were characterized by X-ray diffraction (XRD), CO chemisorption and temperature-programmed reduction (TPR). Copper is better dispersed on the ceria-promoted alumina support in comparison to alumina alone. CuO is the active phase for selective CO oxidation. Oxygen vacancies supplied and enhanced by ceria are responsible for improved activity.