• • Fe58Cu2Al achieved an oxygen storage capacity of 6.5 mmol/g and the highest oxygen loss of 12.1 g/100 g oxygen carrier during CH4 reduction, indicating superior lattice oxygen availability for syngas production.
• • The 2% Cu-modified carrier produced 5.13 mmol/g H2 in the first cycle, 1.51 times that of pristine Fe60Al, with purity exceeding 98%, demonstrating enhanced hydrogen yield and quality.
• • After ten redox cycles, Fe58Cu2Al maintained H2 yield of 3.61 mmol/g, surpassing the single-cycle yield of Fe60Al (3.39 mmol/g), confirming excellent cyclic stability and resistance to deactivation.
• • Cu addition promoted formation of spinel CuFe2O4, which facilitated deeper reduction of Fe2O3, whereas La and Ce formed less reactive phases (LaFeO3, CeO2), ranking reactivity as Fe58Cu2Al > Fe60Al > Fe58La2Al > Fe58Ce2Al.