Catalysts, bimetallic multiple-site

These results can be easily rationalized if ethane hydrogenolysis requires an ensemble of multiple Ni surface atoms to form an active site. The concentration of active ensembles will decline sharply with composition as the active Ni atoms are diluted with inactive Cu atoms in the surface.. Additional information on how bimetallic catalysts affect chemical reactions can be found in the excellent monograph by Sinfelt (J. H. Sinfelt, Bimetallic Catalysts Discoveries, Concepts, and Applications, Wiley, New York, 9st, . 

Noteworthy, the arene ligands undergo multiple hapticity changes during the course of the proposed catalytic cycle, which regulates the activity and stability of the catalyst by providing the vacant coordination sites required for substrate coordination while, at the same time, maintains the integrity of the bimetallic entity. 

Yue and Cohen prepared (ZnCd)S2 colloids by multiple loading experiments [164]. The carboxylic acid coordination sites are regenerated and can be re-used to make onion-type binary clusters. This technique allows for the possibility of cluster-size control and the synthesis of core-shell clusters through multiple metal-loading and reduction cycles. Recharging leads to ZnCdS colloids. In a similar fashion, bimetallic Au/Pd nanocolloids have been synthesized as catalysts for hydrogenation of dienes [244]. Eisenberg and coworkers used this method to increase the size of CdS colloids [267]. A one step precipitation approach was used to prepare the bicomponent particles Cd and Se in the presence of polyvinyl alcohol (PVA) [268]. 

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