Dehydrogenation mechanism of liquid organic hydrogen carriers: Dodecahydro-N-ethylcarbazole on Pd(111)

Journal article
(Original article)


Publication Details

Author(s): Amende M, Schernich S, Sobota M, Nikiforidis I, Hieringer W, Assenbaum D, Gleichweit C, Drescher HJ, Papp C, Steinrück HP, Görling A, Wasserscheid P, Laurin M, Libuda J
Journal: Chemistry - A European Journal
Publisher: Wiley-VCH Verlag
Publication year: 2013
Volume: 19
Journal issue: 33
Pages range: 10854-10865
ISSN: 0947-6539


Abstract


Dodecahydro-N-ethylcarbazole (H-NEC) has been proposed as a potential liquid organic hydrogen carrier (LOHC) for chemical energy storage, as it combines both favourable physicochemical and thermodynamic properties. The design of optimised dehydrogenation catalysts for LOHC technology requires a detailed understanding of the reaction pathways and the microkinetics. Here, we investigate the dehydrogenation mechanism of H-NEC on Pd(111) by using a surface-science approach under ultrahigh vacuum conditions. By combining infrared reflection-absorption spectroscopy, density functional theory calculations and X-ray photoelectron spectroscopy, surface intermediates and their stability are identified. We show that H-NEC adsorbs molecularly up to 173 K. Above this temperature (223 K), activation of C-H bonds is observed within the five-membered ring. Rapid dehydrogenation occurs to octahydro-N-ethylcarbazole (H-NEC), which is identified as a stable surface intermediate at 223 K. Above 273 K, further dehydrogenation of H -NEC proceeds within the six-membered rings. Starting from clean Pd(111), C-N bond scission, an undesired side reaction, is observed above 350 K. By complementing surface spectroscopy, we present a temperature-programmed molecular beam experiment, which permits direct observation of dehydrogenation products in the gas phase during continuous dosing of the LOHC. We identify H-NEC as the main product desorbing from Pd(111). The onset temperature for H-NEC desorption is 330 K, the maximum reaction rate is reached around 550 K. The fact that preferential desorption of H -NEC is observed even above the temperature threshold for H -NEC dehydrogenation on the clean surface is attributed to the presence of surface dehydrogenation and decomposition products during continuous reactant exposure. © 2013 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.



FAU Authors / FAU Editors

Amende, Maximilian
Lehrstuhl für Physikalische Chemie II
Drescher, Hans-Jörg
Naturwissenschaftliche Fakultät
Gleichweit, Christoph
Sonderforschungsbereich 953/2 Synthetische Kohlenstoffallotrope
Görling, Andreas Prof. Dr.
Lehrstuhl für Theoretische Chemie
Hieringer, Wolfgang PD Dr.
Lehrstuhl für Theoretische Chemie
Laurin, Mathias Dr.
Lehrstuhl für Physikalische Chemie II
Libuda, Jörg Prof. Dr.
Professur für Physikalische Chemie
Nikiforidis, Ioannis
Sonderforschungsbereich 953/2 Synthetische Kohlenstoffallotrope
Papp, Christian PD Dr.
Lehrstuhl für Physikalische Chemie II
Schernich, Stefan
Lehrstuhl für Physikalische Chemie II
Sobota, Marek
Graduiertenzentrum der FAU
Steinrück, Hans-Peter Prof. Dr.
Lehrstuhl für Physikalische Chemie II
Wasserscheid, Peter Prof. Dr.
Lehrstuhl für Chemische Reaktionstechnik


Additional Organisation
Exzellenz-Cluster Engineering of Advanced Materials


How to cite

APA:
Amende, M., Schernich, S., Sobota, M., Nikiforidis, I., Hieringer, W., Assenbaum, D.,... Libuda, J. (2013). Dehydrogenation mechanism of liquid organic hydrogen carriers: Dodecahydro-N-ethylcarbazole on Pd(111). Chemistry - A European Journal, 19(33), 10854-10865. https://dx.doi.org/10.1002/chem.201301323

MLA:
Amende, Maximilian, et al. "Dehydrogenation mechanism of liquid organic hydrogen carriers: Dodecahydro-N-ethylcarbazole on Pd(111)." Chemistry - A European Journal 19.33 (2013): 10854-10865.

BibTeX: 

Last updated on 2019-08-04 at 21:50