(673f) Catalytic Effects of CeO2 and/or La2O3 on Fe2O3-Al2O3 Based Chemical-Looping Dry (CO2) Reforming of CH4

Chemical-looping dry (CO₂) reforming (CLDR) technology has been proposed which utilizes CO₂ as oxidant instead of air or steam to replenish reduced oxygen carrier (OC) with oxygen. The challenge of CLDR lies in the low oxidation degree of OC and slow oxidation rate due to the weaker oxidation ability of CO₂ compared to air and steam. Moreover, it is also critical to select appropriate OC materials that favor partial oxidation of CH₄ (POM) for syngas production. In this regard, the aim of this study is to use CeO₂ and/or La₂O₃ for catalyzing Fe₂O₃-Al₂O₃ based CLDR. The OCs were prepared via ultrasonication and freeze-drying assisted co-precipitation (UFDAC) method. The reaction performance of all the composite OCs was carried out in a fixed-bed reactor under atmospheric pressure condition by periodically switching CH₄ and CO₂. The influencing factors, including temperature, time-on-stream (TOS) and number of cycles were investigated. The characteristics of OCs were checked with Brunauer-Emmett-Teller (BET) analysis, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM). The reducibility, basicity and oxidation ability of the composite materials were elucidated with temperature-programmed reduction by H₂ (H₂-TPR) and CH₄ (CH₄-TPR), temperature-programmed desorption of CO₂ (CO₂-TPD) and temperature-programmed oxidation of CO₂ (CO₂-TPO), respectively. Experimental results suggest that the simultaneous presence of CeO₂ and La₂O₃ can not only enhance the selectivity of Fe₂O₃-Al₂O₃ toward POM and its oxygen releasing rate for fast reaction kinetics, but also improve the reactivity of the reduced OC toward CO₂ splitting reaction (CSR).