Visible light-driven photo remediation of hazardous cationic dye via Ce-doped WO3 nanostructures

Abstract

Ce-doped WO3 nanoparticles were successfully synthesized by the sol–gel method and characterized through advanced characterization techniques. The high resolution transmission electron microscopy (HRTEM) and scanning electron microscopy (SEM) results show a reduction in the agglomeration of nanoparticles upon doping. The energy dispersive X-ray (EDX) analysis validates the existence of the Ce element in all the doped samples. X-ray photoelectron spectroscopy (XPS) and Raman spectra justify the presence of structural defects (oxygen vacancies) and successful formation of the monoclinic WO3 phase, respectively. The Kubelka–Munk function indicates a decrease in band gap with doping, while photoluminescence (PL) spectra show intense visible and UV emissions. Significantly, all doped samples exhibit higher photocatalytic performance than pure WO3 nanoparticles, with the 6 wt% Ce-doped sample displaying the highest degradation rate. Doping with Ce can help to increase the surface area of WO3, thereby improving its photoactivity. Moreover, a correlation between PL and photocatalysis is established in the light of oxygen vacancies suggesting a direct dependence of high photocatalytic activity on strong PL signals of WO3 nanostructures. Trapping experiments further reveal that the degradation process is primarily driven by active species, providing insight into a plausible photocatalytic mechanism.