Influence of hydrogen reduction on growth of tungsten oxide nanowires

A simple method for synthesising W17O47 nanowires on tungsten oxide thin films deposited by sol-gel method on mica substrate has been reported. After thermally annealing thin films at 700 degrees C in H-2 ambient for different durations and subsequently in N-2 ambient for 60 min, single-crystalline W17O47 nanowires along < 0 0 1 > direction were formed on the surface. Experimental results revealed that annealing under H-2 ambient has an important effect on the growth of W17O47 nanowires. According to scanning electron microscopic observations, the synthesised nanowires have similar to 70nm in width and a few microns in length after annealing under H-2 ambient for 30 min and subsequently under N-2 ambient for 60 min. A vapour-solid mechanism was proposed for describing the growth process of the nanowires.