Hydrothermal preparation of WO₃ nanorod array and ZnO nanosheet array composite structures on FTO substrates with enhanced photocatalytic properties

Abstract

We reported a simple and effective hydrothermal route for fabricating WO 3 nanorod arrays (WNRs) and ZnO nanosheet arrays (ZNSs) composite structures on FTO substrate. The morphology evolution of the WNRs grown on FTO substrate and the ZNSs deposited on the WNRs were investigated by scanning electron microscopy (SEM), high resolution transmission electron microscopy (HRTEM) and X-ray diffraction (XRD). The growth mechanisms of well aligned WNRs and ZNSs were intensively studied. Moreover, the optical and photocatalytic properties of the WNRs-ZNSs composite structures were also examined.

Vapor Phase Fabrication of Nanoheterostructures Based on ZnO for Photoelectrochemical Water Splitting

“…In this regard, ZnO, a transparent semiconducting oxide with a large exciton binding energy (60 meV) and high carrier mobility, has attracted an extensive interest . Nevertheless, its performances are detrimentally affected by its wide band gap ( E G = 3.3 eV), limiting radiation absorption to the UV interval (≈5% of the overall solar spectrum), and by the rapid charge carriers recombination . To tackle these obstacles and extend the system photoresponse into the vis range, various investigators have focused on doping with substitutional elements to the Zn and O sites .…”

Facile synthesis of iron oxide coupled and doped titania nanocomposites: tuning of physicochemical and photocatalytic properties

“…40 However, the strong absorption of iron oxides causes signicant changes in the absorbance spectrum of composite samples. The band range from 410 to 420 nm is probably due to excitation of 3d electrons from Fe 3+ levels to the TiO 2 CB (a charge transfer transition), whereas the broad band at $500 nm likely originates from 2 42 Absorption edge of S1-S5 samples illustrates a red shi with signicantly a strong absorption in comparison with that of pure TiO 2 in the visible region. As the iron content increases in titania composite system, the absorption edge shis towards longer wavelength side with simultaneous reduction in band gap energy from 3.04 to 1.95 eV.…”

“…9. Ultimately, it indicates that the major process could be the formation, separation, and transfer of electron from trapped Fe doped TiO 2 53 In this system, the real photocatalytic mechanism of the magnetic catalyst is still not clear and further work need to be carried out.…”

“…Moreover, the efficiencies of these photocatalysts are still far from satisfactory due to a high recombination rate of the photogenerated electronhole pair. In our previous studies, ferromagnetic photocatalysts such as Sn-doped TiO 2 , 22 Fe codoped Sn-TiO 2 and CuO coupled Sn-TiO 2 (ref. 23) were successfully developed and used in the photocatalytic degradation of methyl orange and phenol derivatives.…”

“…In fact, Fe x Ti 1Àx O 2 has been proved as a highly efficient visible light tunable photocatalyst and the catalyst illustrated more stability during the decomposition of dyes or other water pollutants. 11 At the same time, numerous efforts have also been carried out on the development of new materials with intrinsic photocatalytic activity under visible light response such as nitrogen codoped FeTiO 2 absorption ne structure (XAFS) techniques. These techniques are precious for identication of chemical states of surface and bulk doped iron with TiO 2 .…”