The Origin of the Selectivity and Activity of Ruthenium‐Cluster Catalysts for Fuel‐Cell Feed‐Gas Purification: A Gas‐Phase Approach |
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| Authors: | Dr. Sandra M. Lang Prof. Dr. Thorsten M. Bernhardt Marjan Krstić Prof. Dr. Vlasta Bonačić‐Koutecký |
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| Affiliation: | 1. Institute of Surface Chemistry and Catalysis, University of Ulm, Albert‐Einstein‐Allee 47, 89069 Ulm (Germany);2. Interdisciplinary Center for Advanced Sciences and Technology (ICAST), University of Split, Me?trovi?evo ?etali?te 45, 21000 Split (Croatia);3. Chemistry Department, Humboldt University of Berlin, Brook‐Taylor‐Strasse 2, 12489 Berlin (Germany) |
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| Abstract: | Gas‐phase ruthenium clusters Run+ (n=2–6) are employed as model systems to discover the origin of the outstanding performance of supported sub‐nanometer ruthenium particles in the catalytic CO methanation reaction with relevance to the hydrogen feed‐gas purification for advanced fuel‐cell applications. Using ion‐trap mass spectrometry in conjunction with first‐principles density functional theory calculations three fundamental properties of these clusters are identified which determine the selectivity and catalytic activity: high reactivity toward CO in contrast to inertness in the reaction with CO2; promotion of cooperatively enhanced H2 coadsorption and dissociation on pre‐formed ruthenium carbonyl clusters, that is, no CO poisoning occurs; and the presence of Ru‐atom sites with a low number of metal–metal bonds, which are particularly active for H2 coadsorption and activation. Furthermore, comprehensive theoretical investigations provide mechanistic insight into the CO methanation reaction and discover a reaction route involving the formation of a formyl‐type intermediate. |
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| Keywords: | ab initio calculations heterogeneous catalysis CO methanation mass spectrometry ruthenium clusters |
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