Photocatalytic properties of WO3 nanoparticles obtained by precipitation in presence of urea as complexing agent

WO3 nanoparticles were synthesized by a precipitation method in presence of urea at different calcination temperatures. The characterization of the WO3 samples was carried out by X-ray powder diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), adsorption–desorption N2 isotherms (BET), and diffuse reflectance spectroscopy (DRS). During the precipitation process, the presence of urea led to the formation of WO3 nanoparticles with rectangular and ovoid shapes as a function of calcination temperature. The photocatalytic activity of WO3 samples was evaluated in the degradation of rhodamine B (rhB), indigo carmine (IC) and congo red (CR) molecules in aqueous solution under UV and visible-light radiation. The best results were obtained with the sample synthesized at 500 °C due to a contribution of factors such as morphology, surface area and the degree of aggregation of their particles. The photocatalytic activity for the degradation of organic dyes followed the sequence IC > rhB > CR. When the best photocatalyst was tested, the reached mineralization degrees after 96 h of irradiation were 29% for rhB and 86% for IC.

. The degradation of organic dyes by the action of WO3 can take place by two ways, by (a) true photocatalysis and by (b) photosensitization process.Figure optionsDownload high-quality image (161 K)Download as PowerPoint slideHighlights
► WO3 nanoparticles were able to the partial mineralization of rhB and IC.
► Participation of OH radicals in the degradation of dyes over WO3 was confirmed.
► WO3 can be considered as a photocatalyst active under visible-light irradiation.