TiO2-WO3-Eu2(WO4)3 film heterostructures: Synthesis, luminescent, optoelectronic and photocatalytic properties

Titanium-supported TiO2-WO3-Eu2(WO4)3 film heterostructures have been formed by combining two methods -plasma electrolytic oxidation (PEO) of titanium in acidic tungstate solution and extraction pyrolytic (EP) deposition of europium organic extract paste. As a result of annealing of the composites at 700 and 800 degrees C for 2 h, Eu2(WO4)3 and WO3 crystallize in their composition, while anatase from PEO coating transforms into rutile. WO3 microcrystals and elongated chains of molten formations attributed to Eu2(WO4)3 are visible on SEM images of the composite surfaces. XPS confirms the presence of Eu3+, W6+, W5+, and W4+in the subsurface layers of the composites. The luminescence properties of the resulting composites were evaluated from the luminescence excitation spectra and luminescence spectra at 300 K. All composites exhibit luminescence in the red region with a maximum at lambda max approximate to 620 nm (lambda ex= 250 nm). All formed coatings exhibited photocatalytic activity in the reaction of degradation of indigo carmine (IC, 10 mg/L, pH 4.6) under UV irradiation.(c) 2023 Elsevier B.V. All rights reserved.

Automated summary

Titanium-supported TiO2-WO3-Eu2(WO4)3 film heterostructures were prepared by combining plasma electrolytic oxidation (PEO) and extraction pyrolytic (EP) deposition methods. Annealing at 700 and 800 degrees C transformed the composition into crystallized Eu2(WO4)3 and WO3, while PEO coating changed from anatase to rutile. SEM images revealed the presence of WO3 microcrystals and elongated chains of molten formations attributed to Eu2(WO4)3. XPS analysis confirmed the presence of Eu3+, W6+, W5+, and W4+ in the subsurface layers of the composites. The resulting composites exhibited luminescence in the red region with a maximum wavelength of approximately 620 nm, as evaluated from the luminescence excitation spectra and luminescence spectra at 300 K. Additionally, all coatings showed photocatalytic activity in the degradation of indigo carmine under UV irradiation.