title: Thermochemical Energy Storage through De/Hydrogenation of Organic Liquids: Reactions of Organic Liquids on Metal Hydrides.
abstract: A study of the reactions of liquid acetone and toluene on transition metal hydrides, which can be used in thermal energy or hydrogen storage applications, is presented. Hydrogen is confined in TiFe, Ti0.95Zr0.05Mn1.49V0.45Fe0.06 ("Hydralloy C5"), and V40Fe8Ti26Cr26 after contact with acetone. Toluene passivates V40Fe8Ti26Cr26 completely for hydrogen desorption while TiFe is only mildly deactivated and desorption is not blocked at all in the case of Hydralloy C5. LaNi5 is inert toward both organic liquids. Gas chromatography (GC) investigations reveal that CO, propane, and propene are formed during hydrogen desorption from V40Fe8Ti26Cr26 in liquid acetone, and methylcyclohexane is formed in the case of liquid toluene. These reactions do not occur if dehydrogenated samples are used, which indicates an enhanced surface reactivity during hydrogen desorption. Significant amounts of carbon-containing species are detected at the surface and subsurface of acetone- and toluene-treated V40Fe8Ti26Cr26 by X-ray photoelectron spectroscopy (XPS). The modification of the surface and subsurface chemistry and the resulting blocking of catalytic sites is believed to be responsible for the containment of hydrogen in the bulk. The surface passivation reactions occur only during hydrogen desorption of the samples.
authors.affiliation: Karlsruhe Institute of Technology (KIT), Institute of Nanotechnology , P.O. Box 3640, D-76021 Karlsruhe, Germany.
authors.forename: Ulrich
authors.initials: U
authors.lastname: Ulmer
authors.affiliation: Karlsruhe Institute of Technology (KIT), Institute of Micro Process Engineering , P.O. Box 3640, D-76021 Karlsruhe, Germany.
authors.forename: Martin
authors.initials: M
authors.lastname: Cholewa
authors.affiliation: Ulm University , Institute of Surface Chemistry and Catalysis, D-89069 Ulm, Germany.
authors.forename: Thomas
authors.initials: T
authors.lastname: Diemant
authors.affiliation: Karlsruhe Institute of Technology (KIT), Institute of Nanotechnology , P.O. Box 3640, D-76021 Karlsruhe, Germany.
authors.forename: Christian
authors.initials: C
authors.lastname: Bonatto Minella
authors.affiliation: Karlsruhe Institute of Technology (KIT), Institute of Micro Process Engineering , P.O. Box 3640, D-76021 Karlsruhe, Germany.
authors.forename: Roland
authors.initials: R
authors.lastname: Dittmeyer
authors.affiliation: Ulm University , Institute of Surface Chemistry and Catalysis, D-89069 Ulm, Germany.
authors.forename: R Jürgen
authors.initials: RJ
authors.lastname: Behm
authors.affiliation: Karlsruhe Institute of Technology (KIT), Institute of Nanotechnology , P.O. Box 3640, D-76021 Karlsruhe, Germany.
authors.forename: Maximilian
authors.initials: M
authors.lastname: Fichtner
keywords: hydrogen storage; metal hydrides; organic liquids; surface reactions; thermal energy storage