Facile synthesis of WO3 fibers via centrifugal spinning as an efficient UV-and VIS-light-driven photocatalyst

This paper demonstrates, for the first time, synthesis of uniform and crystalline WO3 mesopomus fibers with a diameter of approximate to 1 mu m via centrifugal spinning. This was achieved by using a stable aqueous precursor solution based on ammonium metatungstate (AMT, (NH4)6H(2)W(12)O(40)center dot xH(2)O)) and polyvinyl pyrrolidone (PVP, (C6H9NO)(n)). Annealing at 300 degrees C for 1 h followed by an additional annealing at 500 degrees C for 6 h was conducted to obtain crystalline WO3 fibers. The resulting centrifugally spun WO3 fibers possess approx. 1.4-4 times enhancement in photocatalytic activity under UV (k = 0.0205 min(-1)) and VIS (k = 0.0109 min(-1)) light irradiation compared to that of electrospun WO3 fibers and commercially available WO3 nanoparticles. This is due to the increased specific surface area of the centrifugally spun WO3 fibers (S-BET = 22.3 m(2)/g) compared to electrospun WO3 fibers (S-BET = 7.4 m(2)/g) and WO3 nanoparticles (S-BET = 6.4 m(2)/g). On the other hand, optical properties of all tested materials (including optical band gap) were nearly the same.