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Kenneth PoeppelmeierNorthwestern UniversityFaceted Rare Earth And Alkaline Earth Oxide Perovskite Nanoparticles As Catalyst Supports Tressaud International Symposium on Solid State Chemistry for Applications and Sustainable Development Back to Plenary Lectures » |
Abstract:The focus of this talk will be on the question: how does the metal/oxide interface modify the activity and selectivity of supported noble metal catalysts? Specifically, we utilize the variable strength of interaction between different perovskite oxide supports and noble metal catalysts. The lattice parameters of LnScO3 match well with several noble metals, which allows for a systematic study of how certain support properties can affect the catalytic performance of these metals. Lanthanide scandates were produced through a low-temperature heat treatment of a stoichiometric hydroxide gel (sol-gel) in a humid environment. (1) Water vapor was necessary to preserve the higher diffusivity of the gel, but an excess of water vapor led to the formation of secondary phases. The temperature of the reaction was used to tune the Gibbs free energy of reaction and kinetics of particle growth to produce faceted nanoparticles. Hydrothermal synthesis of SrTiO3, for example, may produce materials that are controllably terminated with SrO-rich {100}, TiO2-rich {100}, or TiO2-rich {110} surfaces. Supported Pt nanoparticles, which have a close lattice match to SrTiO3, showed a higher selectivity in acrolein hydrogenation towards allyl alcohol on SrTiO3 than BaTiO3 when the Winterbottom shape on SrTiO3 had a higher ratio of facets to edges or corners. Exploiting the Strong Metal-Support Interaction further improves the selectivity. (2,3) References:1) "Synthesis of Gadolinium Scandate from a Hydroxide Hydrogel", R. J. Paull, Z. R. Mansley, T. Ly, L. D. Marks, and K. R. Poeppelmeier, Inorg. Chem., 57(7), 4104-4108 (2018). |
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