In the combined calcium and copper chemical looping process, the chemical looping combustion of fuel by CuO is utilized to supply the energy required for the regeneration of calcium oxide for CO2 capture in the next cycle. However, the problem of loss-in-capacity of CaO observed in calcium looping still exists and becomes even severer in the new process. The present work synthesized a number of CaO/CuO based sorbents for the new process using selected precursors and examined the effect of thermal pre-treatment of CuO and steam addition on the cyclic reactivity of the composite sorbents. It was found that both thermal pre-treatment of CuO and steam addition were very effective in enhancing the cyclic reactivity of the composite sorbents, therefore can be potentially used to solve the problem of loss-in-capacity in the new process. (C) 2013 Elsevier B.V. All rights reserved.