Facile Synthesis and Photocatalytic Performance of W<sub>18</sub>O<sub>49</sub> Nanorods

W 18 O 49 nanorods photocatalyst was successfully synthesized by a facile pyrolyzing ammonium metatungstate in a reductive atmosphere of H 2 (5 vol %)/Ar. The synthesized W 18 O 49 nanorods were characterized by X-ray diffraction (XRD), Raman spectrum, scanning electron microscopy (SEM), transmission electron microscopy (TEM) and ultraviolet-visible (UV-Vis) absorption spectroscopy. The results show that W 18 O 49 nanorods are about 190 nm in diameter and around 4.8 μm in length, and they possess the band-gap energy of 2.32 eV. Moreover the photocatalytic activity of W 18 O 49 nanorods was evaluated by degrading methylene blue (MB) under visible light irradiation. The result illustrates that the W 18 O 49 nanorods have a photodegradation efficiency of 60% for MB under the irradiation of xenon lamp (250 W, λ > 420 nm) for 2 h.