Efficient CO₂ capture from ambient air with amine-functionalized Mg–Al mixed metal oxides

Journal article

The search for efficient amine-functionalized materials for direct air capture (DAC) of CO2 is highly important to achieve negative emissions. Here we report a new family of class 1 adsorbents for DAC by loading 67 wt% branched poly(ethylenimine) (PEI) onto Mg–Al–CO3 layered double hydroxide-derived mixed metal oxides (MMOs), which exhibit unexpectedly large CO2 uptakes (2.27 mmol g−1), fast kinetics (1.1 mmol g−1 h−1), and high stability over 20 cycles at 25 °C under 0.4 mbar CO2. The prepared MMO nanosheets are self-assembled into spherical shaped particles with abundant slit-like mesopores and broad pore size distribution. This ideal nanostructure leads to the uniform distribution of the impregnated PEIs and optimal accessibility for CO2 molecules. The defect-abundant MMO layers provide strong electrostatic attraction to the attached polyamines, making the hybrid adsorbents thermally robust up to 300 °C. Enhanced capacity and stability are observed in the presence of moisture, thus facilitating the use of steam stripping to concentrate the desorbed CO2.

Authors: Zhu, X; Ge, T; Yang, F; Lyu, M; Chen, C

• Publication status: Published
• Peer review status: Peer reviewed
• Publisher: Royal Society of Chemistry
• Journal: Journal of Materials Chemistry A
• Volume: 8
• Issue: 32
• Pages: 16421-16428
• Publication date: 2020-07-15
• Acceptance date: 2020-07-15
• DOI: 10.1039/d0ta05079b
• EISSN: 2050-7496
• ISSN: 2050-7488
• Language: English