Europium-doped cerium oxide nanoparticles: investigating oxygen vacancies and their role in enhanced photocatalytic and magnetic properties.

In this study, pure and europium-doped (2%, 4%, 6%, and 8%) cerium oxide (CeO2) nanoparticles (NPs) were employed for efficient dye removal through photocatalytic approach. XRD and TEM confirmed the formation of pure CeO2 nanoparticles, while XPS and Raman spectroscopy were used to analyze the electronic properties and lattice defects, such as oxygen vacancies. The presence of lattice defects, which increased with the concentration of Eu, was found to be responsible for the enhanced degradation of Rose Bengal dye (82.4% for 8% Eu-doped sample) in 75 min. FTIR confirmed the chemical composition of the synthesized sample. The band at 617 cm-1, corresponding to the symmetrical stretching vibration mode of (Ce-O-Ce) or (Ce-O-Eu). The magnetic properties of synthesized samples were examined using VSM, revealing an increase from 4.48 to 11.0 emu/g in magnetization. This enhancement was attributed to F-center exchange mechanism (FCE), resulting from the presence of oxygen vacancies. These findings contribute to the development of advanced materials for sustainable wastewater treatment and spintronics.

A Review on Photocatalysis Used For Wastewater Treatment: Dye Degradation.

Water pollution is a global issue as a consequence of rapid industrialization and urbanization. Organic compounds which are generated from various industries produce problematic pollutants in water. Recently, metal oxide (TiO2, SnO2, CeO2, ZrO2, WO3, and ZnO)-based semiconductors have been explored as excellent photocatalysts in order to degrade organic pollutants in wastewater. However, their photocatalytic performance is limited due to their high band gap (UV range) and recombination time of photogenerated electron-hole pairs. Strategies for improving the performance of these metal oxides in the fields of photocatalysis are discussed. To improve their photocatalytic activity, researchers have investigated the concept of doping, formation of nanocomposites and core-shell nanostructures of metal oxides. Rare-earth doped metal oxides have the advantage of interacting with functional groups quickly because of the 4f empty orbitals. More precisely, in this review, in-depth procedures for synthesizing rare earth doped metal oxides and nonocomposites, their efficiency towards organic pollutants degradation and sources have been discussed. The major goal of this review article is to propose high-performing, cost-effective combined tactics with prospective benefits for future industrial applications solutions.

Enhanced photocatalytic degradation of organic dye by CeO2/CNT/GO hybrid nanocomposites under UV light for wastewater treatment.

Development of nanocomposites as efficient photocatalysts for the removal of hazardous organic pollutants is always in dire demand due to increase in water pollution. In this article, a facile sol-gel method has been used to synthesize cerium oxide (CeO2) nanoparticles followed by their decoration over multi-walled carbon nanotubes (CNTs) and graphene oxide (GO) to construct binary as well ternary hybrid nanocomposites using ultrasonic treatment. The oxygen vacancy defects have been depicted using X-ray photoelectron spectroscopy (XPS) that may result into improved photocatalytic efficiency. The ternary hybrid nanocomposites (CeO2/CNT/GO) showed excellent photocatalytic efficiency towards degradation of rose bengal (RB) dye up to 96.9% in 50 min. CNTs and GO provide the interfacial charge transfer which inhibits the electron-hole pair recombination. The results obtained here indicate that these composites can be effectively utilized as promising materials for the degradation of harmful organic pollutants for wastewater treatment.

Development of hierarchical magnesium oxide anchored cerium oxide nanocomposites with improved magnetic properties and photocatalytic performance.

A facile strategy was introduced for the development of pure MgO and its nanocomposites using different CeO2 contents (3%-7%) to enhance their magnetic properties and photocatalytic performance. Different morphologies (namely nanoflowers and rhombohedral type nanostructures) were obtained using an in situ hydrothermal method at different concentrations of CeO2. X-ray diffraction results revealed that peaks of CeO2 were observed along with peaks of MgO, which confirms the presence of both phases. The crystallite size and particle size were found to increase with changing CeO2 content in the host matrix of MgO. Moreover, the band gap reduces while the magnetic character increases with CeO2 content. The magnetic behaviour of the nanocomposites was elucidated on the basis of oxygen intrinsic defects, which are shown through XPS. EPR measurements were carried out to understand the valence electrons and establish the defects present in the material, which are related to the size of the nanostructures. The degradation of Rose Bengal dye was performed to probe the photocatalytic activity of the MgO@CeO2 nanocomposites. Hence the facile synthesis of these nanostructures conveyed good magnetic properties along with its application towards dye degradation.