Chemical looping partial oxidation (CLPO) is a promising strategy of methane conversion to syngas with low cost and minimal environmental impact. A major challenge is the development of oxygen carriers that have high reactivity, high oxygen carrying capacity and recyclability with low cost. Iron-based oxygen carriers are singled out as commercial viable materials for chemical looping technology due to their high oxygen carrying capacity and low cost. However, it remains challenging to improve the moderate reactivity of iron oxide without increasing the cost substantially. Modified Pechini synthesis was used to fabricate phase pure LaFeO3, Fe2O3 and hybrid LaFeO3-Fe2O3 oxygen carriers. The La ion concentration is between 0.5% and 5% in the hybrid oxygen carriers, yet the hybrid oxygen carriers can promote methane conversion rate 300% higher than that of either LaFeO3 or Fe2O3, at 600-800°C operating temperatures. La ions in LaFeO3 clusters provides catalytic sites that lowers methane conversion activation energy, while Fe2O3 acts as an oxygen reservoir for methane partial oxidation. These results are substantiated by ab initio DFT+U and thermochemistry analyses. Thus, our findings provide a pathway to significantly increasing the methane reaction conversion rates in chemical looping systems, which will lead to substantial energy savings.

Reactivity improvement using hybrid LaFeO3-Fe2O3 oxygen carriers for chemical looping methane partial oxidation

256th National Meeting (2018)

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