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

Abstract This paper demonstrates, for the first time, synthesis of uniform and crystalline WO3 mesoporous fibers with a diameter of ≈1 μm via centrifugal spinning. This was achieved by using a stable aqueous precursor solution based on ammonium metatungstate (AMT, (NH4)6H2W12O40·xH2O)) and polyvinyl pyrrolidone (PVP, (C6H9NO)n). Annealing at 300 °C for 1 h followed by an additional annealing at 500 °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 (SBET = 22.3 m2/g) compared to electrospun WO3 fibers (SBET = 7.4 m2/g) and WO3 nanoparticles (SBET = 6.4 m2/g). On the other hand, optical properties of all tested materials (including optical band gap) were nearly the same.