Programmed Fabrication of Metal Oxides Nanostructures Using Dual Templates to Spatially Disperse Metal Oxide Nanocrystals

Multiwalled carbon nanotubes (MWCNTs) and metal oxide composites, including MWCNTs@SnO2, MWCNTs@ZrO2, MWCNTs@Fe2O3, as well as corresponding metal oxides (MO) hollow structure consisted of SnO2, ZrO2, or CeO2 metal oxide single crystals, respectively, are produced using porous carbonaceous coating and multiwalled carbon nanotube core as dual templates. The synthesis procedure involves programmed steps in which the templates are removed in a controlled sequence. The carbonaceous layer coated on MWCNTs provides porous surface for the adsorption of metal oxide precursors and a buffer zone to help the dispersion of metal oxide nanocrystals. The MWCNTs provide mechanical supports during the whole process before they are removed. MWCNTs@MO nanocomposite are obtained by the removal of the porous carbonaceous layer, and metal oxides hollow structure is produced after the removal of the MWCNTs. MWCNTs@SnO2 nanocomposite shows excellent lithium storage property as anode material for lithium-ion batteries, and SnO2 hollow structure shows high sensitivity and response rate as gas sensor material.