Fabrication of mesoporous CeO2–MgO adsorbent with diverse active sites via eggshell membrane-templating for CO2 capture.

There is an increasing demand for the development of highly efficient CO₂ capture techniques to address global warming and climate change. Although adsorption is an effective approach towards capturing CO₂, conventional adsorbents possess limited adsorption capacities and exhibit low adsorption rates. In this study, we successfully fabricated mesoporous composite CeO₂–MgO adsorbents (CM-BT) with diverse active sites via the eggshell membrane (ESM)-templating method, for CO₂ capture applications. The utilisation of ESM-templating produced a CM-BT with better structural and textural properties. The CM-BT possessed a higher surface area (42 m²/g) and pore volume (0.185 cm³/g) than those of the composite prepared using a thermal decomposition method (CM-TD). In addition, the CM-BT possessed more diverse base sites of various strong base site strengths (O²⁻) and abundant hydroxyl groups, and metal–oxygen pair base sites than CM-TD. The diverse strengths of the strong base sites were correlated with the coordination of O²⁻ and the electronegativity of metal ions. With these excellent physicochemical properties, the CM-BT composite exhibited a high CO₂ uptake capacity of 5.7 mmol/g under CO₂ flow and ambient conditions, which is 2.5 times higher than that of CM-TD. [ABSTRACT FROM AUTHOR]