Bifunctional application of sodium cobaltate as a catalyst and captor through CO oxidation and subsequent CO2 chemisorption processes

Abstract

The potential bifunctional mechanism of sodium cobaltate (NaCoO₂) in the catalysis of CO oxidation and subsequent CO₂ chemisorption was systematically analysed. Different catalytic and gravimetric experiments were performed dynamically and isothermally at multiple temperatures. Initially, the CO oxidation process was evaluated using a catalytic reactor connected to a gas chromatograph. Once the production of CO₂ was confirmed, its chemisorption capacity with NaCoO₂ was studied gravimetrically. Catalytic and gravimetric analysis products were studied by XRD, FTIR and SEM to elucidate the double reaction mechanism. Sodium cobaltate exhibited interesting catalytic properties over a wide temperature range, although the NaCoO₂ crystalline structure and chemical composition changed during the CO₂ capture process. Furthermore, all the experiments were theoretically supported by first-principles density functional theory thermodynamic calculations. The calculated thermodynamic properties of the CO oxidation and CO₂ capture reactions with NaCoO₂ under different oxidation conditions were in good agreement with the experimental measurements.