WO3 Nanorods Supported on Mesoporous TiO2 Nanotubes as One-Dimensional Nanocomposites for Rapid Degradation of Methylene Blue under Visible Light Irradiation

One dimensional (1D) WO3 nanorod (WR)/TiO2 nanotube (TN) composites were fabricated by employing a simple impregnation method for the photodegradation of methylene blue (MB), where WRs and TNs were synthesized by the hydrothermal method and rapid breakdown anodization, respectively. As a comparative study for the photodegradation process, nanocomposites of WRs/TiO2 Degussa P-25 nano-particles (TPs) were prepared utilizing the same impregnation approach. X-ray diffraction studies confirm the structure of WO3 and TiO2 to be monoclinic and anatase, respectively. Morphological studies revealed the formation of 1D nanocomposite with a mesoporous surface having an increased presence of hydroxyl groups, as indicated by Brunauer- Emmett-Teller and electron paramagnetic resonance analyses. Ultraviolet-diffuse reflectance spectroscopy and photo luminescence profiles displayed a bathochromic shift in wavelength along with a reduction in the electron hole pair recombination rate, signifying the activation of the nanocomposite in the visible region. The ability to remove organic pollutants through adsorptive photodegradation is determined by employing Fourier transform-infrared, temperature-programmed ammonia desorption, and thermogravimetric analyses. Kinetic studies revealed the degradation pathway to be of second-order kinetics adhering to the Freundlich adsorption isotherm. The 4% WO3 -loaded TNs exhibited excellent photocatalytic activity providing a maximum adsorption capacity of 107 mg g(-1) in neutral MB solution, indicating the diminished loading requirement for WR/TN compared to WR/TP nanocomposites.