Behavior of oxidized platinum nanoparticles on an aligned carbon nanotube forest.

We observed and analyzed the behavior of platinum nanoparticles (PtNPs) supported on alignedcarbon nanotubes (CNTs) at high temperatures by X-ray photoelectron spectroscopy and highresolution transmission electron microscope observations. We found that the PtNPs moved toward the inner-side along each CNT on which they were deposited. The mechanism of this behavior is related to the redox reaction of Pt with the carbon atoms in the CNT. We also performed in-situ observation of this process at a high temperature using an environmental transmission electron microscope under an oxygen atmosphere. We found that the PtNPs penetrated down into a highdensity aligned CNT forest along the tube axis and that the PtNPs changed their shape to fit the structure of the CNTs during their movement. [ABSTRACT FROM AUTHOR]