Combining a robust catalytically active oxygen transport membrane and ceria-based oxides with high oxygen storage capacity has been used in solid oxide fuel cells and three-way catalysts to improve the catalytic process, such as the partial oxidation of methane. This improvement would result in a longer catalytic lifetime and produce hydrogen (H2) and carbon monoxide (CO) gas at a 2:1 molar ratio. This work focuses on how the structural changes of the combined composites, La0.9Sr0.1CoO3 (LSCO) and Ce0.8La0.2O2 (CLO), correlate with the combined composite's catalytic properties during the partial oxidation of methane. The perovskite oxygen transport membrane, La0.9Sr0.1CoO3, and the ceria-based oxide, Ce0.8La0.2O2, have been industrially used and extensively studied. In situ neutron diffraction data and the partial oxidation of methane showcase the correlation between structural changes and catalytic behaviors. This work examines how adding Ce0.8La0.2O2 to La0.9Sr0.1CoO3 affects structural changes and catalytic behaviors relative to La0.9Sr0.1CoO3 alone. The in-situ neutron diffraction data showcased that Ce0.8La0.2O2 neither significantly changes the overall phase transitions La0.9Sr0.1CoO3 undergoes during the partial oxidation of methane nor poisons La0.9Sr0.1CoO3across multiple cycles. However, CLO affected the catalytic properties of LSCO by increasing the selectivity to produce H2 during syngas production, changing the syngas ratio from 2:1 to 2:0.7.