Metal oxide (Al, Zr and Ce)-modified Fe-CaO dual functional materials for O2-containing simulate flue gas

[Display omitted] •Al, Zr and Ce modified Fe-CaO DFMs with the performance of FCZ > FCCe > FCA.•The CO2 and H2O was competitive adsorption during CO2 capture.•The main activity sites were Ca2Fe2O5 and Fe3+/Fe3+,2+ with O2-containing condition.•Ca12Al14O33 and CaZrO3 exhibits good resistance of O2-containing during CO2 capture. In this study, a bifunctional material was synthesis with Fe-CaO doped by Al, Zr and Ce using a one-pot sol–gel method. The doped materials exhibiting a sustainable CO2 capture performance at 650 °C, with initial CO2 absorption capacities of FCZ > FCCe > FCA (16.46, 15.5 and 15.1 mmol/g, respectively). The respective CO yields were 8.71, 7.68 and 6.78 mmol/g. The incorporation of metal oxides into the CaO matrix serves to enhance the structural framework stability, while the strong basic sites can facilitate improved Fe-CaO for CO2 capture and conversion. The doping of Al, Zr and Ce into Fe-CaO enhances the reduction of Fe3+ to Fe0, which is accompanied by the formation of numerous O2− species that are capable of adsorbing CO2. Additionally, Fe3+/Fe3+,2+ serves as the active species in the high-temperature reverse-water–gas-shift (RWGS) reaction. In the presence of O2-containing, the competitive adsorption of CO2 and H2O on the adsorbent surface was observe during CO2 capture. It is noteworthy that the structure of Ca12Al14O33 and CaZrO3 within the CaO matrix acts as a physical barrier and enhances electron interactions, thereby mitigating the influence of O2-containing species on the material performance after 10 cycles during the CO2 capture stage.