Ce0.8Sm0.15Sr0.05O2 as Possible Oxidation Catalyst and Assessment of the CaO Addition in the Coupled CO Oxidation-CO2 Capture Process

A synergetic system for the coupled CO oxidation [GRAPHIC] and CO, trapping was proposed and studied in the present work by using a ceria-based material and CaO as catalyst and absorbent, respectively. Specifically, Ce0.8Sm0.15Sr0.05O2 (CSSO) was synthesized by the EDTA-citrate complexing method and the resultant powders were characterized by XRD, SEM, and N-2 adsorption desorption measurements. The structure was identified as a fluorite phase, and the BET analysis showed specific areas of 25.6 and 2.6 m(2)/g for the samples heat-treated at 650 and 1000 degrees C, respectively. Dynamic thermogravimetric analyses performed under CO2, CO, CO-O-2, and O-2 containing atmospheres showed the thermal stability and reactivity of the ceria-based catalyst. Then, the CO oxidation tests were evaluated in two stages: first, the dynamic and isothermal analyses for the CO oxidation by the CSSO treated at 650 and 1000 degrees C; then, the evaluation of the CO oxidation properties of the proposed catalyst with in situ CO, capture by adding CaO to the system. The results for the CSSO1000-CaO system evidenced simultaneous double process produced by the synergetic CO oxidation at temperatures between 350 and 650 degrees C and the CO, chemisorption on the CaO. Furthermore, the combined materials reduce the different temperature processes probably due to the CaO partial catalytic activity.