Oxygen-Promoted Dehydrogenation on Size-Selected Cu–Pd Pentamer Clusters for Low-Temperature Hydrogen Release from Cyclic Hydrocarbons

Abstract Despite extensive studies on cycloalkane and cycloalkene dehydrogenation for liquid organic hydrogen carrier applications, the mechanisms governing selective H2 release under mild conditions remain poorly understood. Here, subnanometer CuxPdy pentamer clusters supported on ZrO2 represent a highly active and selective class of low-temperature dehydrogenation catalysts. Pd5 exhibits the highest benzene and molecular H2 formation rates from dehydrogenation of cyclohexene, followed by Cu2Pd3 and Cu3Pd2, whereas Cu5 is inactive. All active catalysts favored H2 over H2O as the hydrogen-containing product and completely suppressed combustion pathways, with no detectable CO2 formation. Oxygen-lean conditions further favored H2 formation across all active catalysts, with H2 selectivity exceeding 99% for Pd5. Kinetic analysis of Cu3Pd2 reveals positive fractional apparent orders in both C6H10 and O2 and an effective apparent activation energy of approximately 66 kJ·mol–1, while reactant composition and temperature systematically control H2/H2O branching. In situ XPS and in situ GIWAXS reveal that catalytic activity and cluster stability arise from the interplay of atomic composition, electronic structure, metal–oxygen interactions, and the chemical environment, with Cu exhibiting a composition-sensitive redox response and Pd-containing clusters accommodating oxygen while retaining electronically active Pd-derived states near the Fermi level. DFT/MLIP free-energy calculations identify kinetically accessible O-assisted first C–H activation pathways involving H transfer to cluster-bound O, with barriers strongly dependent on cluster composition and O configuration. These findings establish an ensemble-based structure–activity framework for controlling dehydrogenation pathways and provide design principles for catalysts that efficiently promote selective hydrogen release suitable for hydrogen carrier applications.

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Publication Details

Journal
ACS Nano
Published
2026-10-27
DOI
https://doi.org/10.1021/acsnano.6c12121
Primary Topic
Hydrogen Storage and Materials
Type
article
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0.00

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article

Oxygen-Promoted Dehydrogenation on Size-Selected Cu–Pd Pentamer Clusters for Low-Temperature Hydrogen Release from Cyclic Hydrocarbons

Anastassia N. Alexandrova, Pascal Andreazza, Karolína Simkovičová, Claudia de Melo et al.
1 links
ACS Nano
Hydrogen Storage and Materials
article

Oxygen-Promoted Dehydrogenation on Size-Selected Cu–Pd Pentamer Clusters for Low-Temperature Hydrogen Release from Cyclic Hydrocarbons

Anastassia N. Alexandrova, Pascal Andreazza, Karolína Simkovičová, Claudia de Melo, Y. Garreau, Philippe Sautet, Jan M. Macák, Ivan Khalakhan, Michael Vorochta, Mykhailo Vaidulych, Alessandro Coati, Muntaseer Bunian, Stanislav Valtera, Federico Loi, Štefan Vajda, Moon Hyung Jang, Bilal Bawab, Iva Matolı́nová, Samiran Chakraborty, Petr Vítek, Benjamin Voisin, Lei Yu, Yonghyuk Lee
article en

Abstract

Abstract Despite extensive studies on cycloalkane and cycloalkene dehydrogenation for liquid organic hydrogen carrier applications, the mechanisms governing selective H2 release under mild conditions remain poorly understood. Here, subnanometer CuxPdy pentamer clusters supported on ZrO2 represent a highly active and selective class of low-temperature dehydrogenation catalysts. Pd5 exhibits the highest benzene and molecular H2 formation rates from dehydrogenation of cyclohexene, followed by Cu2Pd3 and Cu3Pd2, whereas Cu5 is inactive. All active catalysts favored H2 over H2O as the hydrogen-containing product and completely suppressed combustion pathways, with no detectable CO2 formation. Oxygen-lean conditions further favored H2 formation across all active catalysts, with H2 selectivity exceeding 99% for Pd5. Kinetic analysis of Cu3Pd2 reveals positive fractional apparent orders in both C6H10 and O2 and an effective apparent activation energy of approximately 66 kJ·mol–1, while reactant composition and temperature systematically control H2/H2O branching. In situ XPS and in situ GIWAXS reveal that catalytic activity and cluster stability arise from the interplay of atomic composition, electronic structure, metal–oxygen interactions, and the chemical environment, with Cu exhibiting a composition-sensitive redox response and Pd-containing clusters accommodating oxygen while retaining electronically active Pd-derived states near the Fermi level. DFT/MLIP free-energy calculations identify kinetically accessible O-assisted first C–H activation pathways involving H transfer to cluster-bound O, with barriers strongly dependent on cluster composition and O configuration. These findings establish an ensemble-based structure–activity framework for controlling dehydrogenation pathways and provide design principles for catalysts that efficiently promote selective hydrogen release suitable for hydrogen carrier applications.

ACS Nano
Université d'Orléans (FR), Centre National de la Recherche Scientifique (FR), University of Pardubice (CZ), Czech Academy of Sciences (CZ), Dongguk University (KR), Charles University (CZ), Synchrotron soleil (FR), University of California System (US), Interfaces, Confinement, Matériaux et Nanostructures (FR), Czech Academy of Sciences, J. Heyrovský Institute of Physical Chemistry (CZ), Brno University of Technology (CZ), University of Alabama in Huntsville (US)
Central European Research Infrastructure Consortium, U.S. Department of Energy, Ministerstvo Školství, Mládeže a Tělovýchovy, Grantová Agentura České Republiky, National Research Foundation of Korea
Openalex Percentile: Top 29%
Hydrogen Storage and Materials
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