Effect of Cation Intercalation on the Growth of Hexagonal WO3 Nanorods

The growth mechanism of hexagonal tungsten oxide (h-WO3) nanorods is investigated using molecular dynamics simulation. The results show that cation intercalation has a great impact on the formation of h-WO3 nanorods, reflected from the attractive interaction between the growth species (polytungstate anion, W10O324-) and crystal faces of (001) and (100). In particular, an appropriate amount of intercalated cations not only accelerate the crystal growth but also induce the formation of one-dimensional nanostructure of h-WO3 nanorods along the direction of [001]. An excess of intercalated cations would be unfavorable to the evolution of rod shape. Ammonium ion (NH4+) is found to be the most stable in a hexagonal tunnel, hence being effective in inducing the 1D morphology of h-WO3. The main findings from the simulations are also verified by experiments.