The chemical looping strategy offers a potentially viable option for efficient carbonaceous fuel conversion with a reduced carbon footprint. In the chemical looping process, an oxygen carrier is reduced and oxidized in a cyclic manner to convert a carbonaceous fuel into separate streams of concentrated carbon dioxide and carbon-free products such as electricity and/or hydrogen. The chemical looping process relies on a robust, active, and stable oxygen carrier over the redox cycling process. Therefore, oxygen carrier development is a key area for improving chemical looping schemes.The oxygen carrier is typically composed of an active material, a.k.a. primary oxide, which directly participates in the abovementioned cyclic redox operations. Resulting from their suitable thermodynamic properties, first row transition metal oxides such as iron, nickel, copper, manganese, and/or cobalt are among the most frequently used primary oxides for chemical looping applications. Since chemical looping uses redox cycling of an oxygen carrier to convert carbonaceous fuels, it is of upmost importance that these oxygen carriers have stable activity over many redox cycles. With most pure transition metal oxides showing diminishing redox activities over multiple redox cycles, a support material, which is typically selected from ceramic materials with relatively stable structures, is usually added to primary oxide to achieve improved redox performance. Among the various primary oxide options, iron oxide(s) is particularly attractive due to its low cost. In addition, reduced iron and wustite can be effective for hydrogen production through water-splitting. A key challenge for iron oxide based oxygen carrier development is to obtain oxygen carriers with improved reactivity and recyclability.This study attempts to rationalize the activation and deactivation mechanisms of CeO2, MgAl2O4, and perovskite supported iron oxide oxygen carriers. All three oxygen carriers show good activity with CH4. Interestingly, CeO2 supported oxygen carrier tends to deactivate whereas MgAl2O4 supported iron oxide gains activity over time. A number of studies are carried out to elucidate the underlying mechanisms for activation and deactivation.

Supported oxides for methane conversion with integrated CO<sub>2</sub> capture: Activation and deactivation studies

247th National Meeting (2014)

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Supported oxides for methane conversion with integrated CO2 capture: Activation and deactivation studies

Supported oxides for methane conversion with integrated CO₂ capture: Activation and deactivation studies