• • At a Mg/Ba molar ratio of 1:1 and 700 °C, the co-doped La2O3 catalyst achieved a CH4 conversion of 29.5%, a C2+ selectivity of 54.5%, and a C2+ yield of 16.1%, demonstrating a balanced activity-selectivity profile that is industrially relevant for OCM process intensification.
• • In situ DRIFTS confirmed a significantly more intense signal for superoxide (O2−) species on the Mg-Ba co-doped catalyst compared to single-doped counterparts, indicating a synergistic effect that enhances the density of reactive oxygen intermediates critical for C–H bond activation.
• • O2/H2-TPR and CH4/O2 pulse experiments showed that the co-doped catalyst exhibits superior O2 activation and faster establishment of oxygen adsorption equilibrium, which directly correlates with improved CH4 activation and C2 product formation kinetics.
• • The hydrothermal synthesis method yields a catalyst with a stable Mg-Ba co-doped La2O3 structure, offering a scalable route to tune surface oxygen species, a key lever for optimizing OCM performance beyond conventional single-dopant systems.