Surfactant-Free Synthesis of Three-Dimensional Perovskite Titania-Based Micron-Scale Motifs Used as Catalytic Supports for the Methanol Oxidation Reaction

We synthesized and subsequently rationalized the formation of a series of 3D hierarchical metal oxide spherical motifs. Specifically, we varied the chemical composition within a family of ATiO₃ (wherein “A” = Ca, Sr, and Ba) perovskites, using a two-step, surfactant-free synthesis procedure to generate structures with average diameters of ~3 microns. In terms of demonstrating the practicality of these perovskite materials, we have explored their use as supports for the methanol oxidation reaction (MOR) as a function of their size, morphology, and chemical composition. The MOR activity of our target systems was found to increase with decreasing ionic radius of the “A” site cation, in order of Pt/CaTiO₃ (CTO) > Pt/SrTiO₃ (STO) > Pt/BaTiO₃ (BTO). With respect to morphology, we observed an MOR enhancement of our 3D spherical motifs, as compared with either ultra-small or cubic control samples. Moreover, the Pt/CTO sample yielded not only improved mass and specific activity values but also a greater stability and durability, as compared with both commercial TiO₂ nanoparticle standards and precursor TiO₂ templates.     

Einfache Kennzeichen polarer Korrelationen

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Die für die Korrelation eines polaren Raumes invarianten linearen Komplexe und die aus ihnen gebildeten zweiΓ-Bündel

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Über das Verhalten des Stärkekorns beim Erhitzen

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Allgemeine Kollineationen und ihre Umkehrungen

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Eine besondere metrische Konstruktion des linearen Strahlenkomplexes

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Formation of CdSe nanocrystals onto oxidized, ozonized single-walled carbon nanotube surfaces

We present the in situ formation of crystalline CdSe quantum dots on the surfaces of oxidized, ozonized single-walled carbon nanotubes, which is a rational synthetic route to the synthesis of complex hierarchical assemblies.     

Ozonized single-walled carbon nanotubes investigated using NEXAFS spectroscopy

The use of NEXAFS spectroscopy in studying the electronic structure and chemical composition of pristine, wet-air oxidized, and sidewall-ozonized nanotubes is illustrated.