Hydrogen desorption kinetics of CeCl3-doped sodium aluminum hydride compacts measured by parallel in situ FTIR-ATR-spectroscopy and gravimetry. (22nd March 2015)

• Record Type: Journal Article
• Authors: Franke, Ingo; Flick, Tobias; Bauer, Hans-Dieter; Scheppat, Birgit
• Is Part Of: International journal of hydrogen energy. Volume 40:Number 11(2015)
• Page Start: 4175
• Page End: 4183
• Publication Date: 2015-03-22
• Subjects: Hydrogen storage -- Hydride -- Alanate -- Spectrometry -- Gravimetry -- Hydrogen desorption kinetics; Hydrogen as fuel -- Periodicals; Hydrogène (Combustible) -- Périodiques; Hydrogen as fuel; Periodicals; 665.81
• DOI: 10.1016/j.ijhydene.2015.01.108
• Languages: English
• ISSNs: 0360-3199

Abstract

Abstract: In this work, in situ FTIR-ATR-spectroscopy and gravimetry were used in parallel to determine the dehydrogenation reaction kinetics of 2 mol% CeCl3 -doped NaAlH4 compacts. Dehydrogenation measurements were performed under isothermal and isobaric conditions at different temperatures. Subsequently spectroscopic and gravimetric data were fitted by Johnson-Mehl-Avrami and Arrhenius equation to obtain the rate constants of the dehydrogenation and activation energy of the NaAlH4 –Na3 AlH6 phase change. On the one hand the measurements showed that cycling of the powder compacts enhances the dehydrogenation reaction kinetics of the NaAlH4 phase, whereby a decrease of the activation energy by 3.4 kJ/mol was measured. On the other hand an influence on the calibration of the spectroscopic signal to the mass of desorbed hydrogen was observed. Highlights: Novel set-up for parallel gravimetrical and IR in-situ measurements on powder. FTIR-ATR measurements made on sodium alanate during desorption of hydrogen. Measurements performed under isothermal and isobaric conditions at different temperatures. Rate constants of the dehydrogenation and activation energy of the NaAlH4 –Na3 AlH6 phase change have been determined. Effects on kinetics observed after cycling are discussed.