(509b) Conversion of CO2 to CO over a Cu-Fe Based Catalyst Via the Reverse Water-Gas Shift Reaction (RWGS)

The RWGS reaction offers a viable route to convert CO₂ into CO, an essential building block for producing C/H-containing products. Despite the progress in developing RWGS catalysts, several challenges still exist, including very high reactivity of emerging metals (e.g., Noble metals) leading to production of CH₄ , high manufacturing cost (e.g., precious metals), poor thermal stability of cost-effective metals with proper CO selectivity (e.g., Cu), and low RWGS activity of the other catalysts used for CO₂ hydrogenations (e.g., Fe-based to produce C₂₊). The addition of promoters, bimetallic synergetic effect, metal-support interaction, and support intrinsic activity can improve the catalyst performance. Reducible supports (e.g., Ceria (CeO₂)) contribute to the reaction as the oxygen can be exchanged between the reactants (e.g., CO₂) and support. There are not many studies exploring the behaviour of CeO₂-supported bimetallic Cu-Fe for the RWGS reaction. The presence of Cu-Fe sites combined with the Ce redox properties, can improve the CO₂ conversion at moderate temperatures. Moreover, the addition of lanthanides, e.g., samarium (Sm), to CeO₂ improves the oxygen mobility. In this work, Sm-doped CeO₂ catalysts with Cu/Fe loadings of 2.6/1.8 and 5/5 (wt/wt%) were synthesized using ultrasound-assisted, co-precipitation and impregnation techniques. The ultrasound method is an effective means to synthesize the catalysts with smaller particle sizes and better crystallinity. The catalyst from the incipient wetness impregnation (IWI) was used as the reference material. The materials were characterized by XRD/BET/SEM/TPR. The material performances were additionally evaluated at temperatures 300 to 780 °C (H₂:CO₂ 1:1 & 2:1). The catalyst cyclic behavior and prolonged stability were also investigated. Overall, the material activity study revealed that the catalyst from the ultrasound-assisted co-precipitation demonstrated superior reactivity (see Fig 1). The smaller bimetal crystals exhibited stronger interaction with the support and resulted in enhanced metal dispersion, thus leading to better performance and improved properties.