The reactivity of three Cu-, Fe-, and Ni-based oxygen carriers to be used in a chemical-looping combustion (CLC) system using syngas as fuel has been analyzed. The oxygen carriers exhibited high reactivity during reduction with fuel gases present in syngas (H2 and CO), with average values in the range 8-30 % min. No effect of the gas products (H2O, CO2) on the reduction reaction rate was detect...