Remediation of recalcitrant pollutants in water solution using visible light responsive cerium-doped tungsten trioxide nanoparticles

Abstract In order to attain solar energy driven photocatalyst for wastewater remediation, cerium doped WO3 (W1-xCexO3 with x = 0, 0.02, 0.04, 0.06, and 0.08) nanoparticles have been synthesized via a chemical co-precipitation technique. X-ray diffraction (XRD) analysis confirmed that W1-xCexO3 nanoparticles retained its monoclinic structure even after doping. The presence of the vast number of defects produced in the WO3 lattice was corroborated by Raman spectroscopy. Scanning electron microscopy confirmed the spherical shape of the nanoparticles with particles size range 50–76 nm. The optical band gap of W1-xCexO3 nanoparticles decreases from 3.07 eV to 2.36 eV with increase in the x as confirmed by the UV-Vis spectroscopy. Photoluminescence (PL) spectroscopy confirmed that the minimum rate of recombination was observed for W1-xCexO3 with x = 0.04. The maximum photo decolorization towards methyl violet (94%) and Rhodamine-B (79.4%) was observed in x = 0.04 sample in just 90 minutes because of its least recombination rate, highest adsorption capacity and optimum band edge positions. Intriguingly, it has been observed that the modification with cerium in WO3 nanoparticles enhance the photocatalytic activity by narrowing the bandgap and by efficaciously lowering the recombination rate due to electron entrapment by defects produced in the lattice.