Enhancement of photocatalytic and electrochemical properties of hydrothermally synthesized WO3 nanoparticles via Ag loading

In this article, pure and silver (Ag) loaded tungsten oxide (WO3) nanoparticles have been produced by a simple and cost effective hydrothermal method. The crystal morphology and structure properties of the fabricated pure WO3 and Ag (4 and 8 wt%) loaded WO3 nanoparticles have been determined by X-ray diffraction, transmission electron microscopy, micro-Raman spectroscopy and Fourier transform infrared spectroscopy. Both crystallographic (X-ray diffraction and Raman spectra) data indicated the monoclinic structure of prepared samples. Transmission electron microscopic analysis showed that pure and silver loaded tungsten oxide nanoparticles have spherically shaped morphology with average size 25-35 nm which found to be in fair agreement with the average crystallite sizes 28-34 nm as estimated from Scherrer's equation. UV-visible absorption spectra revealed that the optical energy band gap of Ag loaded WO3 nanoparticles decreased with increasing the Ag content. The photocatalytic activity of WO3 with different Ag concentration was evaluated by the photocatalytic degradation of methylene blue under irradiation with visible light; and it exhibited significant enhancement in photocatalytic activity of Ag loaded WO3 as compared to pure WO3. In this way, it acts as a very efficient photocatalyst employable for degradation of toxic dyes and chemicals usually present in textile effluents. In addition, the diffusion coefficient of WO3 increases considerably with Ag loading, which is favourable for its application in energy storage devices.