Home › Analytical Chem › In situ FTIR Spectroscopy as a Tool for Investigation of Gas/Solid Interaction: Water-Enhanced CO2 Adsorption in UiO-66 Metal-Organic Framework
Analytical Chem JoVE (Open Access) Citable · DOI

In situ FTIR Spectroscopy as a Tool for Investigation of Gas/Solid Interaction: Water-Enhanced CO2 Adsorption in UiO-66 Metal-Organic Framework

DOI: 10.3791/60285-v
What you'll learn
  • ✓ Prepare self-supporting pellets for FTIR spectroscopy analysis
  • ✓ Perform sample activation and pretreatment procedures
  • ✓ Characterize surface properties using probe molecule adsorption
  • ✓ Investigate gas-solid interactions and CO2 adsorption mechanisms
Protocol

The use of FTIR spectroscopy for investigation of the surface properties of polycrystalline solids is described. Preparation of sample pellets, activation procedures, characterization with probe molecules and model studies of CO2 adsorption are discussed.

Difficulty
advanced
Total time
~4–6 hours per sample (including activation, equilibration, and multi-temperature measurements)

Steps

1
Prepare self-supporting pellets for analysis

Create compact polycrystalline solid pellets from powdered sample material suitable for FTIR transmission spectroscopy. Proper pellet preparation ensures optimal optical properties and reproducible spectra.

▶ 00:54
2
Activate sample under vacuum or inert atmosphere

Remove adsorbed water and contaminants from the pellet surface through controlled heating and evacuation. Pretreatment creates clean active sites for subsequent adsorption studies.

▶ 02:05
3
Record baseline spectrum of activated sample

Acquire FTIR spectrum of the clean solid in transmission mode to establish reference peaks and functional group signatures before adsorption experiments.

▶ 03:11
4
Adsorb CD3CN probe at room temperature

Introduce deuterated acetonitrile vapor to characterize Lewis acid and basic sites on the metal-organic framework surface. Monitor spectral changes to identify binding modes.

▶ 04:16
5
Adsorb CO at cryogenic temperature

Cool sample to 100 K and expose to carbon monoxide to probe coordinatively unsaturated metal centers and weak interaction sites via vibrational shifts.

▶ 06:07
6
Analyze CO2 adsorption and water enhancement effects

Measure CO2 adsorption behavior with and without preadsorbed water; interpret spectroscopic data to elucidate surface interactions and mechanisms of gas binding in UiO-66.

▶ 07:47
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