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

Abstract

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.