This project studied the properties of nano CaO/Al2O3 as a high-temperature CO2 sorbent for its use in an adsorption enhanced reforming reaction. The sorbent containing nano CaCO3 precursors and aluminum oxide was prepared, and evaluation of the CO2 adsorption properties by a thermogravimetric analyzer, the results show that nano CaO/Al2O3 has a faster decomposition rate and has a higher CO2 adsorption ratio than micro CaO/Al2O3. The maximum adsorption ratio occurs at temperatures of 650 °C under a CO2 partial pressure of 0.33 atm. Durability studies show that the CO2 adsorption ratio remains at 68.3% after 50 cyclic runs under a carbonation temperature of 650 °C and calcination temperature of 800 °C, respectively. XRD, SEM, and BET were used for studying the change of micro characteristics of the CO2 sorbents before and after multiple carbonation−calcination runs. The results showed that the pore size of CaO/Al2O3 sorbents was enlarged and that a new substance (Ca12Al14O33) was formed even under a temper...