Coprecipitation and hydrolysis of CaO have been employed to produce Ca-based synthetic sorbents suitable for capturing CO2 in a fluidized bed. Their composition, CO2 uptake, volume in small pores (2 - 200 nm) and resistance to attrition were measured and compared to those of limestone and dolomite. Sorbents produced by hydrolysis showed the highest uptake and resistance to attrition. After 20 cycles of carbonation and calcination, two sorbents exceeded the uptake of both limestone and dolomite, when subjected to the same regimes of reaction. A sorbent's uptake of CO2 was shown to be determined by the volume in pores narrower than similar to 200 nm.