Figure 3. Time evolution of the vibrational bands ν_as(CO₂) ν_as(SO₂) and δ(CH₂) upon evacuation.

(a) Normalized integrated area of CO₂ asymmetric stretching mode ν_as upon evacuation (<20 mTorr) in pristine (red circles) and EDA post-loaded (black diamonds). The spectral evolution of ν_as(CO₂) bands is shown in Supplementary Fig. 11. The error bar of normalized integrated area does not exceed ∼0.025 for the intensity determination of the ν_as(CO₂) band. The inset of a shows the spectra of ν_as(CO₂) band at t=0 and ∼120 min. (b) Normalized integrated areas of SO₂ asymmetric stretching mode ν_as upon evacuation (<20 mTorr) in pristine (red circles) and EDA post-loaded (black diamonds), The spectral evolution of the ν_as(SO₂) is shown in Supplementary Fig. 12. The larger error bar in b for the ν_as(SO₂) band was due to interferences of the MOF phonon bands, leading to uncertainties in determining the baseline in the difference spectra (Supplementary Fig. 12c). (c) Normalized integrated areas of C₂H₄ wagering mode δ upon evacuation (<20 mTorr) in pristine (red circles) and EDA post-loaded (black diamonds). The spectral evolution of δ(CH₂) bands is shown in Supplementary Fig. 13. The error bar of normalized integrated area does not exceed ∼0.025 for the intensity determination of the δ(CH₂) bands. For the pristine sample, the initial point (that is, t=0) is chosen as the peak intensity after evacuation of gas phase (CO₂, SO₂, C₂H₄) for ∼10 s; for MOFs post-loaded with EDA, the starting point is still after gas removal at the end of EDA exposure (that is, t=0); the integrated areas are normalized to the maximum value obtained at t=0.