CO Oxidation and Subsequent CO2 Chemisorption on Alkaline Zirconates: Li2ZrO3 and Na2ZrO3

Two different alkaline zirconates (Li 2 ZrO 3 and Na 2 ZrO 3 ) were studied as possible bifunctional catalytic-captor materials for CO oxidation and the subsequent CO 2 chemisorption process. Initially, CO oxidation reactions were analyzed in a catalytic reactor coupled to a gas chromatograph, using Li 2 ZrO 3 and Na 2 ZrO 3, under different O 2 partial flows. Results clearly showed that Na 2 ZrO 3 possesses much better catalytic properties than Li 2 ZrO 3 . After the CO-O 2 oxidation catalytic analysis, CO 2 chemisorption process was analyzed by thermogravimetric analysis, only for the Na 2 ZrO 3 ceramic. The results confirmed that Na 2 ZrO 3 is able to work as a bifunctional material (CO oxidation and subsequent CO 2 chemisorption), although the kinetic CO 2 capture process was not the best one under the physicochemical condition used in this case. For Na 2 ZrO 3, the best CO conversions were found between 445 and 580 °C (100%), while Li 2 ZrO 3 only showed a 35% of efficiency between 460 and 503 °C. However, in the Na 2 ZrO 3 case, at temperatures higher than 580 °C its catalytic activity gradually decreases as a result of CO 2 capture process. Finally, all these experiments were compared and supported with theoretical thermodynamic data.