CeO2 nanopowders as solid sorbents for efficient CO2 capture/release processes

- Solid sorbents based on metal oxides as an alternative to liquid sorbents for CO2 capture.
- Acid-base properties of cerium oxide make it an excellent candidate for CO2 capture at rather low temperature.
- Quantification of CO2 adsorption/desorption capacities at 25 °C and 0.1 MPa by TGA technique.
- CO2 capture capacities as function of the specific surface area of the cerium oxide powders.

Solid sorbents based on metal oxides have been investigated as an alternative to liquid sorbents for CO2 capture. Amongst them, acid-base properties of cerium oxide make it an excellent candidate for such applications at rather low temperature. In order to assess the suitability of this material, we quantified CO2 adsorption/desorption capacities at 25 °C and 0.1 MPa by TGA technique. The adsorption results show the importance of a preliminary thermal treatment of the sorbents under inert gas, in order to maximize the CO2 capture capacities via the thermal cleaning of CeO2 surfaces (atmospheric and synthetic pollutants) liberating the access to CO2 adsorption sites. CO2 capture capacities depend on the specific surface area of the cerium oxide powders, reaching a maximum of 50 mg of CO2 adsorbed per gram of CeO2 displaying a specific surface area of 200 m2 g−1. The study also demonstrates the partial reversibility of this adsorption at 25 °C and its quantification, which can represent an important piece of information depending on the application (e.g., catalysis or CO2 capture). Finally, the CO2 adsorption/desorption cycling of our best material was investigated exhibiting promising results for the use of CeO2 powders as CO2 solid sorbent with moderate temperature-swing conditions (between 25 °C and 150 °C).