Molecular Layer Deposition-Modified 5A Zeolite for Highly Efficient CO₂ Capture

Effective pore mouth size of 5A zeolite was engineered by depositing an ultrathin layer of microporous TiO₂ on its external surface and appropriate pore misalignment at the interface. As a result, a slightly bigger N₂ molecule (kinetic diameter: 0.364 nm) was effectively excluded, whereas CO₂ (kinetic diameter: 0.33 nm) adsorption was only influenced slightly. The prepared composite zeolite sorbents showed an ideal CO₂/N₂ adsorption selectivity as high as ∼70, a 4-fold increase over uncoated zeolite sorbents, while maintaining a high CO₂ adsorption capacity (1.62 mmol/g at 0.5 bar and 25 °C) and a fast CO₂ adsorption rate.