Experimental and computational study of Bi2O3/WO3 heterostructures as efficient solar driven photocatalyst

Abstract

Industrial wastewater is always a matter of challenge, polluting the environment and ultimately causing a hazardous effect on human beings and various other species. For the elimination of these pollutants, in this study, we synthesized Bi2O3 nanoparticles and Bi2O3/WO3 heterostructures by chemical co-precipitation method and investigated their photocatalytic activity for the degradation of methylene blue (MB) under solar light irradiation. The synthesized nanoparticles were characterized by various analytical techniques, including X-ray diffraction (XRD), Scanning-electron-microscopy (SEM), Fourier-Transform-Infrared Spectroscopy (FTIR), and UV–Vis. absorption Spectroscopy. Results of this study revealed that the pure Bi2O3 sample has a band gap of 3.5 eV, however, Bi2O3/WO3 heterostructure exhibited a reduction in band gap to 3.1 eV. The decrease in band gap significantly enhanced absorption of solar light, which correlated with an increase in photocatalytic activity as Bi2O3/WO3 nanocomposite degraded 81.5 % of MB in 240 min, while pristine Bi2O3 only degraded 58.7 % of the MB in the same period. The enhanced photocatalytic performance of the nanocomposite can be attributed to the synergistic action between Bi2O3 and WO3, which enhances the production of reactive oxygen species (ROSs) and the efficiency of charge separation, thus promoting the degradation of MB. A type-II heterostructure has been proposed to enhance the separation of charge carriers. Moreover, our computational study supported these findings, indicating a decrease in trends of the band gap of heterostructure as compared to pristine Bi2O3. The results of this study highlight the potential of Bi2O3/WO3 nanocomposites as promising materials for environmental remediation applications, particularly for the efficient removal of organic pollutants from wastewater under solar irradiation.