Dual Alkaline Active Centers Derived from LaAlO ₃ Perovskite for Enhanced Oxidative Coupling of Methane

Abstract An in‐situ synthesis method is proposed to incorporate alkaline earth metals, such as Ca, Sr, and Ba, into the A‐site of the perovskite material LaAlO 3 , enabling precise regulation of their proportions in this research. Alkali metals such as Li, Na, and K were then introduced via an impregnation method to enhance the catalyst's basicity and improve its OCM performance. Among the catalysts studied, the composition with a La to Sr ratio of 7:3, significantly increased oxygen vacancies and enhanced the O 2− conduction, thereby boosting catalytic activity. Moreover, the emergence of a new SrO crystal phase within the original catalyst improved selectivity for C 2+ hydrocarbon products. At 850 °C, the OCM reaction catalyzed by this material increased the yield of C 2+ hydrocarbons from 9.3% to 13.8%. Further modification through immersion in 0.6 mol of Li enhanced the catalyst's electrophilicity, effectively suppressing excessive oxidation of CH 4 and its products. This process also introduced new basic active centers in the form of Li 2 O 2 , further enhancing OCM performance. As a result, the maximum C 2+ hydrocarbon yield at 850 °C was elevated to 16.7%. This study provides a modification strategy to effectively enhance the reactive performance of perovskite OCM catalysts.