Ca(NO3)2·4H2O, CaO, Ca(OH)2, CaCO3, and Ca(CH3COO)2·H2O were used as precursors for synthesis of calcium oxide sorbents of CO2. Calcium acetate based sorbents led to the best adsorption performance of CO2. At 600°-800°C, this sorbent exhibited high adsorption of CO2, 90% of which were achieved at the first 15 min of adsorption period. Calcium acetate based sorbents also showed great regenerability in multi adsorption-desorption cycles. After 25 cyclic adsorptions/desorption, the sorbent still had a conversion of 64% during adsorption of CO2. High conversion and good regenerability of calcium acetate based sorbents are due to relatively large volume of mesopores and macropores produced during multi steps decomposition of synthesis. Sorbents from other precursors showed poorer performance since they had smaller pores, less pore volume and lower BET surface area. These high performance calcium oxide sorbents have great potential for numerous high temperature applications such as fuel cells, carbon sequestration, novel reactors, and coal gasification etc. This is an abstract of a paper presented at the AIChE Annual Meeting and Fall Showcase (Cincinnati, OH 10/30/2005-11/4/2005).