Tuned hydrothermal synthesis of vanadium dioxide nanotubes

Tuned synthesis of vanadium dioxide (VO2) nanotubes has been realized during a hydrothermal process with octadecylamine (ODA) as the reducing agent and structure directing template. Vanadium was reduced from V(V) to V(IV) by ODA after the formation of nanotubular morphology. Importantly, it is found that the morphology of products can be tuned by the reaction pH due to its influence on the form of vanadium precursor, and by the ODA concentration due to the rolling force resulting from hydrophobic clustering of ODA molecules. The dimension of VO2 nanotubes can be tuned by the volume fraction of ethanol solvent via adjusting the rolling force for vanadium oxide lamellae. This work could provide insights for tuned synthesis of various nanotubes that have resulted from lamella rolling.