Scrolled Sheet Precursor Route to Niobium and Tantalum Oxide Nanotubes

The nanoscroll-to-nanotube thermal transformation was studied for H4Nb6O17 center dot 4.4H(2)O scrolls, prepared by exfoliation of K4Nb6O17. Thermal dehydration of the scrolls produces Nb2O5 nanotubes at 400-450 degrees C. The nontopochemical transformation results in polycrystalline nanotubes; however, significant texturing with respect to the tube axis is observed. Substituting Ta for Nb in the precursor compound led to a lower yield of scrolls, most likely because there is less built-in lattice strain to drive scrolling of the unilamellar colloidal sheets.