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The Origin of the Selectivity and Activity of Ruthenium‐Cluster Catalysts for Fuel‐Cell Feed‐Gas Purification: A Gas‐Phase Approach
Author(s) -
Lang Sandra M.,
Bernhardt Thorsten M.,
Krstić Marjan,
BonačićKoutecký Vlasta
Publication year - 2014
Publication title -
angewandte chemie international edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 1433-7851
DOI - 10.1002/anie.201310134
Subject(s) - ruthenium , methanation , catalysis , dissociation (chemistry) , chemistry , water gas shift reaction , selectivity , syngas , carbon monoxide , hydrogen , reactivity (psychology) , cluster (spacecraft) , inorganic chemistry , chemical engineering , organic chemistry , medicine , alternative medicine , pathology , computer science , engineering , programming language
Gas‐phase ruthenium clusters Ru n + ( 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 CO 2 ; promotion of cooperatively enhanced H 2 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 H 2 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.