Related Experiment Video
Updated: Jul 13, 2026

In situ FTIR Spectroscopy as a Tool for Investigation of Gas/Solid Interaction: Water-Enhanced CO2 Adsorption in UiO-66 Metal-Organic Framework
Published on: February 1, 2020
Adsorption properties of HKUST-1 toward hydrogen and other small molecules monitored by IR
1Dipartimento di Chimica IFM and NIS Centre of Excellence, Università di Torino, INSTM UdR Torino, Via Pietro Giuria 7, 10125, Torino, Italy. silvia.bordiga@unito.it
Abstract:
Among microporous systems metal organic frameworks are considered promising materials for molecular adsorption. In this contribution infrared spectroscopy is successfully applied to highlight the positive role played by coordinatively unsaturated Cu2+ ions in HKUST-1, acting as specific interaction sites. A properly activated material, obtained after solvent removal, is characterized by a high fraction of coordinatively unsaturated Cu2+ ions acting as preferential adsorption sites that show specific activities towards some of the most common gaseous species (NO, CO2, CO, N2 and H2). From a temperature dependent IR study, it has been estimated that the H2 adsorption energy is as high as 10 kJ mol(-1). A very complex spectral evolution has been observed upon lowering the temperature. A further peculiarity of this material is the fact that it promotes ortho-para conversion of the adsorbed H2 species.
Related Concept Videos
Adsorption Isotherms I
Adsorption Isotherms II
Adsorption of Gases on Solids
IR Spectrum Peak Broadening: Hydrogen Bonding
However, the extent of hydrogen bonding influences the observed stretching frequency and band broadening. Intermolecular or intramolecular hydrogen bonding...
IR Spectroscopy: Hooke's Law Approximation of Molecular Vibration
According to Hooke's law, the vibrational frequency is directly proportional to the...
IR Absorption Frequency: Hybridization
Among the sp, sp2, and sp3 hybridized orbitals, sp orbitals have the maximum s character (50%). Consequently, the electrons are held more closely to the nucleus, resulting in stronger and shorter C–H bonds that stretch at a...

