Synthesis of Bi2WO6 nanoparticles for antifouling applications

Marine biofouling that caused by marine plant, algae, and colonization of marine organisms, leading to various economical safety problems all over the world. Therefore, efforts to reduce the harm of biofouling have always been considered. Applying antifouling coatings on the surface of marine installations is one the traditional method that shows good results. However, this technique has serious marine ecological hazards. Recent studies show that photoactive materials due to their low-cost and environmentally friendly properties can be used in important applications such as the oxidation and degradation of pollutants, splitting of water and sterilization. Among various photocatalysts, Bi2WO6 is known as an efficient type due to its suitable bandgap, high chemical stability and nontoxic behavior. In this study, Bi2WO6 was fabricated via two facile methods, hydrothermal and co-precipitation. Moreover, the structural, morphological and optical properties were explored using comprehensive analytical techniques.The phase structure of Bi2WO6 nanocrystals prepared via hydrothermal and co-precipitation methods were examined by X-ray diffraction (XRD) measurement (Fig. 1). For both methods, all the peaks were indexed to the orthorhombic phase of Bi2WO6 according to the JCPDS data card No. 00-039-0256. The Scherrer equation was utilized to estimate crystallite size. The calculations for hydrothermal and co-precipitation methods resulted in about 34 and 27.6 nm, respectively. The scanning electron microscopy (SEM) investigations of morphology and microstructure for both Bi2WO6 samples have been illustrated in Fig. 2. It seems that the obtained products through co-precipitation method demonstrate spherical morphology with an approximated diameter of 0.4 μm, while the products obtained via hydrothermal method indicate flower-like morphology with a diameter of 3.9 μm. In additions, it is clear that the surface of Bi2WO6 synthesized by the hydrothermal method is more porous. Specific surface area of Bi2WO6 nanocrystals determined by Brunauer-Emmett-Teller (BET) analysis were 55.06 and 7.07 m2/gr for hydrothermal and co-precipitation methods, respectively. These values are consistent with the SEM observations which confirm the porous structure of nanocrystals obtained by the hydrothermal route.