A simple method for growing high quantity tungsten-oxide nanoribbons under moist conditions

Tungsten oxide is one of the most important transition metal oxide materials, which possesses some unique properties such as electrochromic, optochromic, and gaschromic properties. In this paper, we report a simple method for synthesizing high quantity tungsten oxide nanoribbons by oxidizing a tungsten plate under moist conditions. Using potassium iodide as the catalyst, tungsten oxide nanoribbons with a thickness of 40–100 nm, width up to 1 µm and length up to hundreds of micrometres are obtained on a large scale. The morphology, composition and crystal structure of the nanoribbons are characterized by various methods, such as scanning electron microscopy, transmission electron microscopy and x-ray diffraction. The nanoribbons comprise mainly monoclinic tungsten trioxide (WO 3 ) growing along the [001] direction and the orthorhombic WO 3 (H 2 O) 0.33 . The measured lattice parameters are β = 89.93°, a = 0.7274 nm, b = 0.7501 nm, c = 0.3824 nm for WO 3 and a = 0.7359 nm, b = 1.251 nm, c = 0.7704 nm for WO 3 (H 2 O) 0.33 , respectively.