Variations of the well known Pt/Sn bimetallic nanoparticle theme are analyzed by the application of density functional theory to a series of tetrahedral Pt3X clusters, with element X taken from the P-block, preferably group 14, or from the D-block near group 10. Almost identical cluster geometries allow a systematic investigation of purely electronic effects induced by the replacement of a single Pt atom by element X. Focusing on the propane-to-propene conversion as the desired dehydrogenation reaction we analyze changes in barrier heights for the rate-determining first C-H cleavage step and estimate the product selectivity towards propene by comparing the propene desorption energy to barriers for alternative reaction pathways. We show that two key steps of the reaction mechanism, namely the first C-H cleavage and the propene desorption, vary significantly between different alloys. Promising candidates beside Pt3Sn are Pt3Ir, Pt3Si and Pt3Ge, for which we find higher activity compared to Pt4. Pt3Ir is particularly interesting due to a much weaker adsorption of the product alkene.

Novel materials for alkane dehydrogenation: A systematic study on Pt based, subnanometer-sized alloy cluster catalysts

248th National Meeting (2014)

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