Table 1 Chemical formula and silanol concentration of activated nanosized AP-CHA, K-CHA, and Cs-CHA zeolite samples determined by in situ FTIR and 1H MAS NMR spectroscopy.

From: Interplay between alkali-metal cations and silanol sites in nanosized CHA zeolite and implications for CO2 adsorption

Sample

Chemical formula

FTIR

1H MAS NMR

εOH*

COH/cm−1 g−1

COH/mmol g−1

cm mmol−1

AP-CHA

Na1.8K5.7Cs4.0Al11.1Si24.8O72

644

3.7

348

K-CHA

K10.4Cs1.0Al11.4Si24.9O72

726

5.7

255

Cs-CHA

K1.8Cs10.5Al11.7Si24.2O72

531

3.4

316

  1. *The molar absorption coefficients (εOH) are calculated using εOH = A S / nOH where A is the OH concentration based on FTIR, S is the area of pellets (2.01 cm2), and nOH is the OH concentration based on 1H MAS NMR.
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