Impact of A‐Site Sr Substitution in LaFeO 3 on Syngas Selectivity During Chemical Looping Dry Reforming of Methane (CL‐DRM)

ABSTRACT La 1‐x Sr x FeO 3 (0 ≤ x ≤ 1) perovskite oxygen carriers (OCs) were evaluated for dry reforming of methane (DRM) at 900°C under co‐feed and chemical‐looping (CL‐DRM) configurations. Sr substitution decreased CH 4 /CO 2 conversions in co‐feed DRM, indicating suppressed intrinsic catalytic activity. In contrast, CL‐DRM enhanced CH 4 conversion by LaFeO 3 to ∼75%–79% but promoted carbon deposition and a deviation of the H 2 /CO ratio from 2 (2.6). Sr‐containing compositions exhibited lower CH 4 conversion but improved carbon balance and syngas selectivity. La 0.7 Sr 0.3 FeO 3 provided the best compromise, achieving ∼40% CH 4 conversion, an ideal H 2 /CO ratio of 2, and a carbon balance above 95%. Sr 2+ substitution induces Fe 4+ /Fe 3+ charge compensation and modifies the oxygen‐defect environment. The improved coke resistance is primarily associated with the suppression of nonselective CH 4 cracking rather than with enhanced oxygen mobility. These findings establish that selective and stable syngas production in CL‐DRM is governed not by maximizing oxygen reactivity, but by precisely balancing oxygen exchange kinetics with methane activation.