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

Abstract

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.