Amine-modified graphene oxide: Reaction mechanism with functional groups and enhanced CO2 adsorption-separation performance

Amine-modified adsorbents exhibit remarkable potential for efficient CO₂ capture. Nevertheless, the understanding of the reaction mechanism between amines and adsorbents, as well as the influence of polar groups on CO₂ adsorption, remains rather limited. In this study, a series of amine-containing chemicals were used to modify graphene oxide (GO). This exploration revealed the reaction mechanism between amine groups and GO's oxygen functional groups and emphasized that GO with a higher amine density and stronger polar groups demonstrates enhanced CO₂ adsorption and separation capabilities. Compared with pristine GO, urea-modified GO shows a significantly increased CO₂ adsorption capacity (from 0.42 to 1.70 mmol/g) and CO₂/N₂ selectivity (from 3.0 to 28.0). After 10 adsorption-desorption cycles, its adsorption capacity decreased by only 7.56 %, confirming its good regenerative stability. Overall, the modified GO co-regulated by amine groups and polar groups prepared in this study is considered an effective CO₂ adsorption/separation material, showing great potential for green and sustainable applications.