Synthesis and Characterization of WO₃/CeO₂ Heterostructured Nanoparticles for Photodegradation of Indigo Carmine Dye

Abstract

WO3/CeO2 heterostructured nanocomposites containing different WO3 ratios (0.1, 0.3, 0.5, and 1.0 wt %) were synthesized by a precipitation method. The coupling of CeO2 and WO3 with a high specific surface area noticeably enhanced the photocatalytic activity of indigo carmine (IC) degradation under visible-light irradiation. The degradation rate constants (k) of 0.5 wt % WO3/CeO2 nanocomposites reached 4 and 5 times higher than those of CeO2 and WO3, respectively. Regarding the experimental results, the X-ray diffraction (XRD) patterns of the CeO2 spherical nanoparticles and rod-shaped WO3 were assigned to the cubic fluorite and orthorhombic phase structures, respectively. The increasing photocatalytic activity of nanocomposite samples could be attributed to the heterojunction of the photocatalysts with efficient charge separation and strong oxidative ability, which were confirmed by the photoluminescence spectra and diffuse reflectance spectrometry. The staggered heterojunction of the nanocomposite promoted efficient electron transfer and suppressed the recombination of photogenerated electrons and holes during the process.

Valorization of Waste Tungsten Filament into mpg-C3N4–WO3 Photocatalyst: A Sustainable e-Waste Management and Wastewater Treatment

“…The photocatalytic performance of the mpg-C 3 N 4 –WO 3 composite may be related to the heterojunction formed between the mpg-C 3 N 4 and WO 3 with different energy levels. Based on the UV-vis analysis, their values of E CB and E VB can be calculated by the following relations: E CB = X − E e − 0.5 E normalg E VB = E CB + E normalg Here, X is the electronegativity, and the values of X for mpg-C 3 N 4 and WO 3 are 4.73 and 6.59 eV, respectively; E e is the energy of free electrons (4.5 eV), E CB and E VB are the potentials of the CB and VB, respectively, and E g is the band gap energy. , The calculated band-gap values of mpg-C 3 N 4 and WO 3 are 2.7 and 2.5 eV, respectively. Therefore, the resulting E CB and E VB values are −1.12, + 1.58 eV and +0.84, + 3.34 eV for mpg-C 3 N 4 and WO 3 , respectively.…”

“…Here, X is the electronegativity, and the values of X for mpg-C 3 N 4 and WO 3 are 4.73 and 6.59 eV, respectively; E e is the energy of free electrons (4.5 eV), E CB and E VB are the potentials of the CB and VB, respectively, and E g is the band gap energy. 48,49 The calculated band-gap values of mpg-C 3 N 4 and WO 3 are 2.7 and 2.5 eV, respectively. Therefore, the resulting E CB and E VB values are −1.12, + 1.58 eV and +0.84, + 3.34 eV for mpg-C 3 N 4 and WO 3 , respectively.…”

Efficient Photocatalytic Degradation of Methylene Blue Dye from Aqueous Solution with Cerium Oxide Nanoparticles and Graphene Oxide-Doped Polyacrylamide

“…Since it is difficult to remove metal oxide and graphene oxide from the pollutant medium, the polyacrylamide hydrogel allows to keep them together. Active dye photodegradation of CeO 2 -NPs, WO 3 /CeO 2 , and Fe 3 O 4 –CeO 2 -mixed NPs , has been reported. Lately, a review on the photocatalytic degradation of various pollutants with a CeO 2 semiconductor as a photocatalyst was reported .…”

Enhanced photocatalytic crystal-violet degradation performances of sonochemically-synthesized AC-CeO2 nanocomposites

“…For example, several kinds of hazardous pollutants such as organic/inorganic dyes, pharmaceuticals, heavy metals, herbicides, surfactants, microorganisms, and pesticides were amputated from industrial wastewater via the oxide semiconductor-based photocatalysis [4] , [5] , [6] , [7] , [8] , [9] . Among various OSs, cerium dioxide (CeO 2 ) has attracted significant attention as an efficient photocatalyst because of its high photo-stability, high oxygen storage capacity, non-toxicity, photocorrosion resistance behavior, low cost, high thermal stability, and strong light absorption in the ultra-violet (UV) wavelength region [10] , [11] , [12] . However, the large bandgap energy (3.2 eV) and the high photocarrier recombination rate of the CeO 2 nanostructures have somewhat degraded their photocatalytic activities [13] , [14] .…”