FeO controls the sintering of iron-based oxygen carriers in chemical looping CO2 conversion

• Published in: Journal of CO2 utilization 2020-09, Vol.40, p.101216, Article 101216
• Main Authors: Hu, Jiawei, Poelman, Hilde, Marin, Guy B., Detavernier, Christophe, Kawi, Sibudjing, Galvita, Vladimir V.
• Format: Article
• Language: English
• Subjects: CO2 utilization; FeO intermediate; Iron oxide; Redox cycling; Sintering resistance
• ISSN: 2212-9820; 2212-9839
• DOI: 10.1016/j.jcou.2020.101216

[Display omitted] •The origin of sintering of iron-based oxygen carriers was explored using Fe2O3/ZrO2 as representative.•Sintering originates from the formation of FeO as intermediate during redox cycling.•A prolonged FeO presence leads to more severe sintering.•Sintering can be mitigated by shortening the FeO lifespan. Enhancement of sintering resistance is key to the application of iron-based oxygen carriers in chemical looping CO2 conversion processes. This drives research to seek the origin of iron oxide sintering during redox cycling. Herein, we explored it by using a Fe2O3 material on a stable ZrO2 support, based on a thermodynamic analysis and time-resolved in-situ X-ray diffraction characterization. Sintering of iron oxide particles originates from the formation of FeO as intermediate during reduction. A prolonged FeO presence leads to more severe sintering. Although quite counter-intuitive, increasing the reaction temperature can mitigate sintering as it shortens the transition time between FeO and Fe phases. These findings provide important insight for the rational design of iron-based oxygen carriers, as well as for the optimization of operating conditions to resist sintering in chemical looping processes.