Novel Nanostructures of Rutile Fabricated by Templating
against Yarns of Polystyrene Nanofibrils and Their Catalytic Applications
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Abstract
This Article describes a facile approach
to the synthesis of rutile nanostructures in the form of porous fibers
or bundles of nanotubes by maneuvering the surface wettability of
yarns made of polystyrene nanofibrils. Specifically, hierarchically
porous fibers were obtained by hydrolyzing titanium tetraisopropoxide
to form TiO<sub>2</sub> nanoparticles in the void spaces among hydrophobic
nanofibrils in each yarn. After calcination in air at 800 °C,
the resultant fibers were comprised of many interconnected rutile
nanoparticles whose diameters were in the range 20–80 nm. After
converting the nanofibrils and yarns into hydrophilic surfaces through
plasma treatment, however, the TiO<sub>2</sub> formed conformal coatings
on the surfaces of nanofibrils in each yarn during hydrolysis instead
of just filling the void spaces among the nanofibrils. As a result,
bundles of rutile nanotubes were obtained after the sample had been
calcined in air at 800 °C. The thermodynamically stable rutile
nanostructures were then explored as supports for Pt nanoparticles
whose catalytic activity was evaluated using the reduction of <i>p</i>-nitrophenol by NaBH<sub>4</sub>. The Pt supported on porous
rutile fibers exhibited a better performance than the Pt on rutile
nanotubes in terms of both induction time (<i>t</i><sub>ind</sub>) and apparent rate constant (<i>k</i><sub>app</sub>)