Hindering nanoparticle growth in reverse microemulsion synthesized CeO₂/γ-Al₂O₃ reverse water gas shift catalyst

Efficient CO₂ conversion to fuels and chemicals is of paramount importance for mitigating greenhouse gas emissions that accelerate climate change. In CO₂ conversion reactions, catalyst nanoparticle growth and sintering under reaction conditions pose significant challenges, limiting the catalytic performance and catalyst stability. In this study, high surface area CeO₂/γ-Al₂O₃ nano-catalysts were synthesized via the reverse microemulsion method and evaluated for reverse water gas shift. The effect of the active phase dispersion on the CeO₂ nanoparticle growth was investigated via X-ray diffraction and gas adsorption. The 47.9 wt% CeO₂/Al₂O₃ catalyst showed complete selectivity to CO generation, while attaining nearly equilibrium values for CO₂ conversion at 600 °C and 8000 mL/(g h). As compared to bulk CeO₂, nanoparticle growth in the CeO₂/Al₂O₃ catalyst was hindered significantly, resulting in a relatively stable catalytic performance, similar to that of the bulk CeO₂. Our findings reveal that the reverse microemulsion synthesized γ-Al₂O₃ support significantly decreases CeO₂ nanoparticle growth and agglomeration. This reduction in nanoparticle sintering contributes to the enhanced catalytic performance and stability, facilitating efficient CO₂ reduction.