Our focus has been on understanding how the metal/oxide interface can 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 (lattice parameter, acidity, etc.) 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. The support synthesis paves the way for different surface structures or morphologies to be obtained, which further influence the metal/support interface. Hydrothermal synthesis of SrTiO3, for example, may produce materials that are controllably terminated with either 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, and exploiting the Strong Metal-Support Interaction further improves the selectivity.2

Faceted rare earth and alkaline earth oxide perovskite nanoparticles as catalyst supports

2019 Spring National Meeting

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