Synthesis and Characterization of CaO Nanopods for High Temperature CO2 Capture

A hollow structured CaO sorbent with high CO2 absorption capacity and good cyclic performance at high temperatures was derived from the corresponding CaCO3 precursor, which was prepared by bubbling gaseous CO2 through a Ca(OH)2 slurry in the presence of the triblock copolymer surfactant, P123 (PEO20PPO70PEO20). Field-emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM) images showed the novel sorbent to be comprised of nanosized platelets forming hollow particles resembling a pod of approximately 200 nm in diameter and up to 600 nm in length. Thermogravimetric analysis showed that the tailored sorbent had the highest CO2 absorption capacity when compared with calcines derived from precipitated CaCO3 without P123 and a commercially available CaCO3, retaining >50% CO2 absorption capacity after 50 CO2 capture-and-release cycles for carbonation temperatures from 600 to 700 °C.