Alkali metal-promoted graphene oxide-doped stearate-intercalated layered double oxide composites with high performance of CO2 capture

Abstract

The alkali metal (M)-promoted graphene oxide (GO)-doped stearate-intercalated layered double oxide (M/GO−LDO-SA; M = Li, Na, K, and Cs) samples were prepared via an in-situ impregnation approach, representing the first reported instance of medium-temperature (200–300 °C) CO₂ adsorbents employing this novel composite architecture. The loading of alkali metals could improve adsorption capacity of these composites. The alkalinity of the M/GO−LDO-SA adsorbents enhanced with the increase in alkali metal ion radium, whose trend was the same as that of the alkali metal oxides. Among the synthesized materials, the 11K/GO−LDO-SA composite demonstrated superior CO₂ adsorption capacity (1.14 mmol/g), outperforming other alkali metal-promoted counterparts. This enhanced capture performance was correlated with its alkaline site amount. The CO₂ adsorption mechanism on the nanocomposite was primarily governed by chemisorption, with the adsorbed CO₂ molecules being primarily stabilized as carbonate species through chemical interactions. Notably, the 11K/GO−LDO-SA composite demonstrated exceptional regeneration efficiency, maintaining over 87 % of its initial adsorption capacity after 10 consecutive adsorption-desorption cycles, highlighting its remarkable regeneration efficiency. The synergistic combination of enhanced basicity, optimized textural properties, and improved thermal stability positions these new nanocomposites as promising candidates for post-combustion carbon capture applications.