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.