Modulating Oxygen Transfer via A‐Site Doping in LaFeO ₃ for Coke‐Resistant Chemical Looping Steam Methane Reforming

Chemical looping steam methane reforming (CL‐SMR) is a promising technology for the simultaneous production of high‐purity hydrogen and syngas without the need for external gas separation units. This study evaluates a series of A‐site doped perovskite‐type oxygen carriers, La 0.8 A 0.2 FeO 3 (A = Ca, Sr, Ba), to investigate the influence of alkaline earth metal doping on redox behavior and catalytic performance in CL‐SMR. Substituting divalent cations at the A‐site effectively promotes oxygen vacancy formation and enhances lattice oxygen transfer. Among the evaluated oxygen carriers, Sr‐doped LaFeO 3 (La 0.8 Sr 0.2 FeO 3 ) exhibits the most favorable performance. This is attributed to the optimal concentration of oxygen vacancies, which improved oxygen transfer, as confirmed by X‐ray photoelectron spectroscopy, cerimetric titration, and O 2 ‐temperature programmed desorption. While undoped LaFeO 3 (LF) exhibits the highest methane activation, its limited oxygen mobility leads to severe coke formation. Enhanced oxygen transfer in La 0.8 Sr 0.2 FeO 3 effectively suppresses carbon deposition, while it shows the highest CO and hydrogen production. It achieves consistently high CO and H 2 yields (6.22–6.51 and 6.48–6.69 mmol/g cat , respectively) and demonstrates excellent stability over 50 redox cycles.