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

Abstract

Sodium cobaltate works as a bifunctional material, in the catalysis of CO oxidation and subsequent CO2 chemisorption.

CO2—H2O Capture and Cyclability on Sodium Cobaltate at Low Temperatures (30–80 °C): Experimental and Theoretical Analysis

“…Previous works have shown that sodium cobaltate has different physicochemical CO 2 capture properties and other catalytic processes involving carbon oxides, such as carbon monoxide oxidation, water gas shift, and reforming reactions, although this ceramic does not have a Na/Co molar ratio as high as other alkaline ceramics . Therefore, it is important to understand the CO 2 capture properties of this ceramic at low temperatures, induced by the presence of water vapor, as under dry conditions NaCoO 2 is not able to trap CO 2 chemically at temperatures lower than 200 °C.…”

“…Therefore, in reactions (3) and (4), the formation of a cobalt oxide is proposed, as for this type of alkaline ceramics, CO 2 capture always leads to the formation of carbonates and the corresponding metal oxide. [3,[54][55][56] As stated in the literature, [64,65] NaCoO 2 does not chemisorb CO 2 at temperatures lower than 200 C, on dry conditions. Thus, water vapor highly activates CO 2 chemisorption at lower temperatures, forming two different carbonate phases, Na 2 CO 3 (as in dry conditions) and NaHCO 3 .…”

“…In addition, thermodynamic properties of NaCoO 2 and NaOH capturing CO 2 under vapor condition were calculated, where calculation details are given in our previous studies . Ab initio thermodynamic calculations were performed by combining density functional theory (DFT) with lattice phonon dynamics .…”

“…Recently, this material has been probed as a possible CO 2 captor, showing that it is able to chemisorb up to , between 150 and 740 °C, producing Na 2 CO 3 and different cobalt oxides. In addition, its bifunctionality, as a catalyst in the CO oxidation reaction and subsequent CO 2 capture, has been reported . Furthermore, it was recently reported that Fe, Ni, or Cu addition into NaCoO 2 modifies its CO 2 chemisorption, where Fe presents higher CO 2 capture capacities, in comparison with pristine NaCoO 2 .…”

“…In addition, its bifunctionality, as a catalyst in the CO oxidation reaction and subsequent CO 2 capture, has been reported. [63,64] Furthermore, it was recently reported that Fe, Ni, or Cu addition into NaCoO 2 modifies its CO 2 chemisorption, where Fe presents higher CO 2 capture capacities, in comparison with pristine NaCoO 2 . [65] According to those studies, sodium cobaltate and metal-containing phases are not able to chemisorb CO 2 at low temperatures (T < 150 C) in dry conditions.…”