Highly efficient capture of CO₂ through the synergy of intramolecular amines within piperazine-derived alcoholamines

Amine-scrubbing-based chemical absorption remains a prominent CO₂ capture process. However, the overall efficiency of conventional amine absorbents is hard to meet the ever-increasing demands for CO₂ capture. Consequently, developing powerful absorbents for efficient and cost-effective CO₂ capture is greatly important but challenging. Here, a new type of amine absorbent with improved solubility and stability was achieved by substituting the secondary amino groups in piperazine (PZ) with aminoethyl and hydroxyalkyl moieties. The developed amine absorbent presents superior CO₂ absorption/desorption abilities through the synergy of their intramolecular amines, leading to a low regeneration energy consumption of 2.56 GJ·t⁻¹ CO₂. Moreover, the enhancement of CO₂ capture and the corresponding mechanism were elucidated using density functional theory calculations and nuclear magnetic resonance analysis. Such newly developed amine absorbent with excellent CO₂ capture performance are expected to greatly contribute to ongoing efforts toward carbon neutrality.