CaO-based sorbents for CO₂ capture prepared by ultrasonic spray pyrolysis

We report the ultrasonic spray pyrolysis (USP) synthesis and characterization of composite calcium oxide-based sorbents for carbon dioxide capture. Inclusion of a small amount of Al₂O₃ into the CaO matrix (as low as Al/Ca: 0.03) yielded significant enhancement of resistance to recycling degradation. The effective homogenous dispersion of additives in the CaO matrix and the relatively high surface area materials obtained via USP explain the sorbent's high performance. All materials were characterized by XRD, STEM, TEM, SEM, and TGA (for CO₂ uptake measurements). Two common phases of CaAl_xO_y, Ca₁₂Al₁₄O ₃₃ and Ca₃Al₂O₆, were formed during multiple cycles of calcination and CO₂ uptake.