Controlling Ethylene Hydrogenation Reactivity on Pt13 Clusters by Varying the Stoichiometry of the Amorphous Silica Support. Issue 31 (29th June 2016)

• Record Type: Journal Article
• Authors: Crampton, Andrew S.; Rötzer, Marian D.; Schweinberger, Florian F.; Yoon, Bokwon; Landman, Uzi; Heiz, Ueli
• Is Part Of: Angewandte Chemie international edition. Volume 55:Issue 31(2016)
• Page Start: 8953
• Page End: 8957
• Publication Date: 2016-06-29
• Subjects: clusters -- density functional calculations -- ethylene hydrogenation -- platinum -- silica support stoichiometry; Chemistry -- Periodicals; 540
• DOI: 10.1002/anie.201603332
• Languages: English
• ISSNs: 1433-7851

Abstract

Abstract: Ethylene hydrogenation was investigated on size‐selected Pt13 clusters supported on three amorphous silica (a‐SiO2 ) thin films with different stoichiometries. Activity measurements of the reaction at 300 K revealed that on a silicon‐rich and a stoichiometric film, Pt13 exhibits a similar activity to that of Pt(111), in line with the known structure insensitivity of the reaction. On an oxygen‐rich film, a threefold increased rate was measured. Pulsing ethylene at 400 K, then measuring the activity at 300 K, resulted in complete loss of activity on the silicon‐rich surface compared to only marginal losses on the other surfaces. The measured reactivity trends correlate with charging characteristics of a Pt13 cluster on the SiO2 films, predicted through first‐principle calculations. The results reveal that the stoichiometry‐dependent charging by the support can be used to tune the selectivity of reaction pathways during a catalytic hydrogenation reaction. Abstract : Precise control of thin‐film stoichiometry, and application of such films as heterogeneous catalyst supports, enables the investigation of their effect on catalytic reactivity. With the application of a single cluster size as catalyst (Pt13 ), the deconvolution of individual characteristics imparted by each stoichiometrically unique film is attainable through calculations, and the subsequent influence on a model hydrocarbon reaction is elucidated.