Intrazeolite CO Methanation by Small Ruthenium Carbonyl Complexes: Translation from Free Clusters into the Cage. Issue 15 (3rd June 2020)

• Record Type: Journal Article
• Authors: Mravak, Antonija; Krstić, Marjan; Lang, Sandra M.; Bernhardt, Thorsten M.; Bonačić‐Koutecký, Vlasta
• Is Part Of: ChemCatChem. Volume 12:Issue 15(2020)
• Page Start: 3857
• Page End: 3862
• Publication Date: 2020-06-03
• Subjects: CO methanation -- density functional calculations -- fuel cell feed gas purification -- ruthenium carbonyl cluster -- zeolites; Catalysis -- Periodicals; 541.39505
• DOI: 10.1002/cctc.202000716
• Languages: English
• ISSNs: 1867-3880

Abstract

Abstract: Catalytic CO methanation represents an important reaction to improve the feed gas quality for hydrogen fuel cells. Previously, the large potential of small bare and ligated ruthenium clusters as highly selective and active catalysts has been shown by employing gas phase clusters as model systems. Now, density functional theory (DFT) calculations are employed to demonstrate the possibility to translate the gas phase CO methanation reaction mediated by a ligated Ru4 (CO)13 H2 + complex into the framework of a ZSM‐5 zeolite. Such a translation, manifested by a reaction pathway which is mechanistically and energetically similar to the gas phase analogue, is possible since the zeolite framework does not influence the reactive center. Furthermore, we reveal the important role of the CO ligand environment in protecting the Ru4 + metal core from formation of bonds with the zeolite and in the creation of the reactive center by promoting the cooperatively enhanced adsorption and dissociation of H2 . Abstract : Protecting and Assisting Ligands : CO ligands protect the Ru4 + cluster core from chemical bonding when placed into the framework of a ZSM‐5 zeolite pore and at the same time facilitates the creation of a reactive center. Since the reactive center is not influenced by the zeolite framework, subsequent CO methanation inside the zeolite pore is mechanistically and energetically similar to the reaction observed on free clusters.