Thermodynamics Research Today is a free monthly online journal that collates and summarizes the latest research about Thermodynamics, including details on enthalpy, entropy, energy transitions.

FTIR spectroscopy and thermodynamics of hydrogen adsorbed in a cross-linked polymer.

Spoto G, Vitillo JG, Cocina D, Damin A, Bonino F, Zecchina A

Dipartimento di Chimica IFM and NIS Centre of Excellence of the Turin University, Via Giuria 7, I-10125, Torino, Italy. giuseppe.spoto@unito.it

The adsorption of H(2) in a cross-linked poly(styrene-co-divinylbenzene) (St-DVB) microporous polymer (BET surface area 920 m(2) g(-1)) is studied by volumetric and gravimetric methods, FTIR spectroscopy at variable temperature (300-14 K) and ab initio calculations. At 77 K the polymer reversibly stores up to 1.3 mass% H(2) at a pressure of 1 bar and 1.8 mass% at 10 bar. The adsorption process involves the specific interaction of H(2) with the structural phenyl rings through weak dispersive forces. The interacting molecules become IR active and give rise to vibrational and rotational-vibrational manifestations which are affected by the temperature, the contact time and the H(2) equilibrium pressure. The spectra of the H(2)/St-DVB system reported here represent the first IR evidence of the adsorption of hydrogen on unsaturated molecules. The adsorption enthalpy is evaluated by the VTIR (variable temperature IR spectroscopy) method (C. Otero Areán et al., Phys. Chem. Chem. Phys., 2007, DOI: 10.1039/b615535a) and compared with the results of ab initio calculations for the H(2)/benzene interaction and with literature data.

Published 13 September 2007 in Phys Chem Chem Phys, 9(36): 4992-9.
Full-text of this article is available online (may require subscription).

© 2005-2008 Thermodynamics Research Today. All Rights Reserved.