OICC Press Iranian Journal of Catalysis 2345-4865 13 3 2023 09 23 Preparation and Characterization of WO3 Nanosheets and Au/WO3 Nanocomposite for Rabid Photocatalytic degradation of methylene blue dye 10.30495/ijc.2023.1987426.2010 EN Fatima Allawi Abdul Sajad Department of Chemistry, College of Science, University of Kufa, Najaf, Iraq Hanaa Kadtem Egzar Department of Chemistry, College of Science, University of Kufa, Najaf, Iraq 0000-0002-8609-812X Mazin Auny Mahdi Department of Physics, College of Science, University of Basrah, Basra, Iraq 0000-0002-9377-144x- Journal Article 2023 09 23 The sol-gel technique is employed for the synthesis of tungsten trioxide (WO3) nanosheets. The Au/WO3 nanocomposite is prepared using laser ablation employing an Nd-YAG laser operating at a wavelength of 1064 nm and utilizing gold metal. The SEM images demonstrate that WO3 was formed as nanosheets with a thickness between 36nm and 80nm.  X-ray diffraction (XRD) patterns confirmed the monoclinic crystal structure and high crystallinity of the WO3 structure. The optical absorption of both WO3 nanosheets and Au/WO3 nanocomposite exhibited a pronounced absorption edge, with an energy gap of 2.52 eV and 2.41 eV, respectively. The photocatalytic activity of WO3 nanosheets and Au/WO3 nanocomposite was determined by degrading Methylene blue (MB) dye under visible light irradiation using different catalyst doses and pH values. The WO3 nanosheets and Au/WO3 nanocomposites that were prepared demonstrate a fast degradation of MB dye. The highest photodegradation efficiency (PDE) of MB dye was 75.9% when 0.05 g of Au/WO3 nanocomposite was exposed to 7 pH for 6 min of irradiation. Nevertheless, an increase of pH led to a corresponding rise in PDE. Particularly, the PDE values reached 85.5% and 95.7% when using 0.1 g of WO3 nanosheets and Au/WO3 nanocomposite, respectively, under the conditions in a pH level of 12 and an irradiation duration of 6 minutes.