In Situ Structural Variations of Individual Particles of an Al₂O₃-Supported Cu/Fe Spinel Oxygen Carrier During High-Temperature Oxidation and Reduction

Physical and chemical degradation of the oxygen-carrier materials during high-temperature redox exposures may affect the overall efficiency of the chemical looping process. Therefore, studying real-time physical and chemical changes in these materials when exposed to repeated redox cycles is essential for further development of chemical looping technology. In this work, the National Energy Technology Laboratory’s Al₂O₃-supported Cu/Fe spinel oxygen carrier, in the form of a CuO · Fe₂O₃ solid solution, was examined in situ during 3-h exposures to either oxidizing or reducing environments at 800 °C using a controlled atmosphere heating chamber in conjunction with a confocal scanning laser microscope. A compilation of the physical changes of individual particles using a controlled atmosphere confocal microscope and the microstructural/chemical changes documented using a scanning electron microscope will be discussed.