Banana peel extract for CeO2 nanoflower synthesis: Enhancing photocatalytic activity for methyl orange dye removal and bactericidal effects

The cube architecture associated with the CeO2 nanoflowers (NFs) that generated, which had an average crystallization width of 7 nm, has been confirmed by X-ray crystallographic investigations. The method used is environmentally acceptable since it converts wasted banana peel extracts into CeO2 nanoflower. On the basis of artwork obtained from a High-Resolution Transmission Electron Microscope (HR-TEM), CeO2 nanoparticles have been observed to possess a spherical shape and an average particle diameter of 21 nm. To take the purpose of this study, green-fabricated CeO2-NFs were used to investigate the photocatalytic oxidation of methyl orange (MO) dye when exposed to sunshine. CeO2 nanofibers showed a degradation performance of 98% when compared to methyl orange dye. Evidently is a possibility that this may be caused by the presence of CeO2 nanoflowers, whereby enhance the interaction of electrons, which are holes dissolution, and adherence. Upon a single day of being exposed, the biocidal potential was tested against both gram-positive and gram-negative bacteria, including E. coli, B. cereus, and S. aureus, among others. Due to the fact that its 32 mm minimum inhibitory concentration (MIC) for B. cereus was the highest among conventional medicines. As shown by the extraordinary capabilities of WBP@CeO2 tiny particles, manipulating of flexible tiny particles to feed the purpose of achieving effective and customizable infections and dermatologist advancements is really stunning.

Breakthrough in High-Efficiency Photocatalytic Degradation of Acebutolol by Advanced Binary CeO2-MnO2 Oxide System

The sustainable catalytic efficacy of transition metal oxides (TMO) and rare earth element-based oxides positions them as pivotal materials for effectively treating contaminated wastewater. This study successfully synthesized a series of Ce@MnO2 photocatalysts using a straightforward hydrothermal method. These photocatalysts were thoroughly characterized for their optical properties, structural morphology, and phase purity. Among the synthesized materials, the Ce@MnO2 (40:60) exhibited the highest photocatalytic activity for the degradation of Acebutolol (ACB), achieving a remarkable degradation efficiency of 92.71% within 90 min under visible light irradiation. This superior performance is attributed to the increased presence of active species and the efficient separation of photogenerated carriers. Additionally, the photocatalytic reaction mechanism was elucidated, highlighting the catalyst's surface charge properties which significantly enhanced performance in a solution with pH 8. The outstanding photo-response in the visible spectrum renders this method not only cost-effective but also environmentally benign, presenting a promising approach for large-scale water purification.

A neoteric antibacterial ceria-silver nanozyme for abiotic surfaces

Community-associated and hospital-acquired infections caused by bacteria continue to yield major global challenges to human health. Bacterial contamination on abiotic surfaces is largely spread via high-touch surfaces and contemporary standard disinfection practices show limited efficacy, resulting in unsatisfactory therapeutic outcomes. New strategies that offer non-specific and broad protection are urgently needed. Herein, we report our novel ceria-silver nanozyme engineered at a molar ratio of 5:1 and with a higher trivalent (Ce3+) surface fraction. Our results reveal potent levels of surface catalytic activity on both wet and dry surfaces, with rapid, and complete eradication of Pseudomonas aeruginosa, Staphylococcus aureus, and methicillin resistant S. aureus, in both planktonic and biofilm form. Preferential electrostatic adherence of anionic bacteria to the cationic nanozyme surface leads to a catastrophic loss in both aerobic and anaerobic respiration, DNA damage, osmodysregulation, and finally, programmed bacterial lysis. Our data reveal several unique mechanistic avenues of synergistic ceria-Ag efficacy. Ag potentially increases the presence of Ce3+ sites at the ceria-Ag interface, thereby facilitating the formation of harmful H2O2, followed by likely permeation across the cell wall. Further, a weakened Ag-induced Ce-O bond may drive electron transfer from the Ec band to O2, thereby further facilitating the selective reduction of O2 toward H2O2 formation. Ag destabilizes the surface adsorption of molecular H2O2, potentially leading to higher concentrations of free H2O2 adjacent to bacteria. To this end, our results show that H2O2 and/or NO/NO2-/NO3- are the key liberators of antibacterial activity, with a limited immediate role being offered by nanozyme-induced ROS including O2•- and OH•, and likely other light-activated radicals. A mini-pilot proof-of-concept study performed in a pediatric dental clinic setting confirms residual, and continual nanozyme antibacterial efficacy over a 28-day period. These findings open a new approach to alleviate infections caused by bacteria for use on high-touch hard surfaces.

Pioneering superior efficiency in Methylene blue and Rhodamine b dye degradation under solar light irradiation using CeO2/Co3O4/g-C3N4 ternary photocatalysts

In this research work, we have successfully synthesized the CeO2/Co3O4/g-C3N4 ternary nanocomposite for hydrothermal method for photocatalytic applications. The synthesized nanocomposites were characterized using X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, Field emission scanning electron microscopy (FE-SEM), Transmission electron microscopy TEM, Photoluminescent spectra (PL), X-ray photoelectron spectroscopy (XPS), Brunauer- Emmett-Teller (BET) and Ultraviolet diffuse reflectance spectroscopy (UV-DRS) technique. As per the optical spectroscopic investigations CeO2/Co3O4/g-C3N4 ternary nanocomposite exhibited the high optical absorption range and its band gap is reduced from 2.95 eV to1.83 eV. The PL spectra showed the lowered emission peak intensity of ternary nanocomposite which is revealed that the better charge separation and slow recombination of electron hole pairs. The highest photocatalytic degradation efficiency of CeO2/Co3O4/g-C3N4 ternary nanocomposite showed 93 % and 86 % towards the pollutant methylene blue and Rhodamine B. Moreover, photodegradation of the pollutants followed pseudo-first order kinetics with a very high-rate constant of 0.02211 min-1 and 0.017756 min-1. Additionally, the ternary nano catalyst was delivered the remarkable stability performance even after five cycles. This research may provide a low-cost approach for synthesized visible light responsive catalysts for use in environmental remediation applications.

Impact of Co-Doping on the Visible Light-Driven Photocatalytic and Photoelectrochemical Activities of Eu(OH)3

The microwave-assisted synthesis approach was used to synthesize Eu(OH)3 and Co-Eu(OH)3 nanorods. Various techniques were used to investigate the structural, optical, and morphological features of the Eu(OH)3 and Co-Eu(OH)3 NRs. Both Eu(OH)3 and Co-Eu(OH)3 NRs were found to be hexagonal with crystallite sizes ranging from 21 to 35 nm. FT-IR and Raman spectra confirmed the formation of Eu(OH)3 and Co-Eu(OH)3. Rod-shaped Eu(OH)3 and Co-Eu(OH)3 with average lengths and diameters ranging from 27 to 50 nm and 8 to 12 nm, respectively, were confirmed by TEM. The addition of Co was found to increase the particle size. Furthermore, with increased Co doping, the band gap energies of Co-Eu(OH)3 NRs were lowered (3.80-2.49 eV) in comparison to Eu(OH)3, and the PL intensities with Co doping were quenched, suggesting the lessening of electron/hole recombination. The effect of these altered properties of Eu(OH)3 and Co-Eu(OH)3 was observed through the photocatalytic degradation of brilliant green dye (BG) and photoelectrochemical activity. In the photocatalytic degradation of BG, 5% Co-Eu(OH)3 had the highest response. However, photoelectrochemical experiments suggested that 10% Co-Eu(OH)3 NRs showed improved activity when exposed to visible light. As a result, Co-Eu(OH)3 NRs have the potential to be a promising visible-light active material for photocatalysis.

Sn-doped BiOCl for photoelectrochemical activities and photocatalytic dye degradation under visible light

In this work, bismuth oxychloride (BiOCl) and Sn-doped BiOCl (SBCl) with improved visible light photocatalytic activity were synthesized via the co-precipitation method. The XRD analysis determined the tetragonal phase of BiOCl, 1 %, 5 %, and 10 % SBCl. The crystallite sizes were in the range of 20-34 nm. These results confirmed that the Sn ion was successfully incorporated into the BiOCl lattice. This was further confirmed by FT-IR and Raman analysis. The optical properties, such as the band gap energy, were studied using UV-vis DRS. It was found that doping BiOCl with Sn has a minor effect on the band gap tuning. BET shows that the SBCl samples have acquired a larger specific surface area (14.66-42.20 m2/g) than BiOCl (13.49 m2/g). The photocatalytic performance showed that SBCl samples have higher photocatalytic activity than BiOCl in degrading Rhodamine B (RhB) dye under visible light irradiation. Among the SBCl samples, 5 % SBCl exhibited the highest photocatalytic efficiency which degraded 91.2 % of the RhB dye in 60 min. Moreover, the photoelectrochemical activities of the as-synthesized BiOCl and SBCl were investigated using linear sweep voltammetry (LSV) and electrochemical impedance spectroscopy (EIS) in the dark and under visible light irradiation. Both studies showed that SBCl exhibits enhanced photoelectrochemical activities than BiOCl. Hence, it can be suggested that SBCl possesses visible light active properties and can be potentially used as a photocatalyst and photoelectrode material.

Cellulose acetate/polyurethane blend as support matrix with high optical transparency and improved mechanical properties for photocatalyst CeO2 nanoparticles immobilization

Advanced manufacturing technologies for efficient catalytic materials have triggered the rational design of catalysts as well as extensive investigation into preparative methodologies. Herein, we report the preparation of new versatile cellulose acetate/polyurethane (CA/PU) blends for efficient immobilization of CeO2 nanoparticles, the appropriate composition of polymer mixture being chosen after rigorous analysis (SEM, FTIR, optical, mechanical). The band gap energy for hybrid films ranged between 3.02 eV and 2.05 eV, the lowest value being measured for the film with Co-doped CeO2 NPs (B3 film). The best results in photodegradation of methylene blue under visible-light irradiation was attained after 50 min for B3 film (rate constant k = 45.34× 10-3 min-1), while the total mineralization of MB in the same conditions as evaluated by HPLC-ESI MS and TOC analyses was achieved after 90 min. Effect of co-ions (SO42-, Cl- or NO3-) on photocatalytic performance was studied, and scavenger tests were used to identify the active species involved in the photocatalytic mechanism. Also, the photocatalytic efficiency of B3 sample was tested for rhodamine B, metronidazole and 4-nitrophenol degradation. Evaluation of the stability and integrity of hybrid film after 5 catalysis cycles reveal that the photocatalytic potential is retained with no substantial structural changes.

Photocatalytic Co-Reduction of N2 and CO2 with CeO2 Catalyst for Urea Synthesis

The effective conversion of carbon dioxide (CO2 ) and nitrogen (N2 ) into urea by photocatalytic reaction under mild conditions is considered to be a more environmentally friendly and promising alternative strategies. However, the weak adsorption and activation ability of inert gas on photocatalysts has become the main challenge that hinder the advancement of this technique. Herein, we have successfully established mesoporous CeO2-x nanorods with adjustable oxygen vacancy concentration by heat treatment in Ar/H2 (90 % : 10 %) atmosphere, enhancing the targeted adsorption and activation of N2 and CO2 by introducing oxygen vacancies. Particularly, CeO2 -500 (CeO2 nanorods heated treatment at 500 °C) revealed high photocatalytic activity toward the C-N coupling reaction for urea synthesis with a remarkable urea yield rate of 15.5 μg/h. Besides, both aberration corrected transmission electron microscopy (AC-TEM) and Fourier transform infrared (FT-IR) spectroscopy were used to research the atomic surface structure of CeO2 -500 at high resolution and to monitor the key intermediate precursors generated. The reaction mechanism of photocatalytic C-N coupling was studied in detail by combining Density Functional Theory (DFT) with specific experiments. We hope this work provides important inspiration and guiding significance towards highly efficient photocatalytic synthesis of urea.

Doped Ceria Nanomaterials: Preparation, Properties, and Uses

Doping is a powerful strategy for enhancing the performance of ceria (CeO2) nanomaterials in a range of catalytic, photocatalytic, biomedical, and energy applications. The present review summarizes recent developments in the doping of ceria nanomaterials with metal and non-metal dopants for selected applications. The most important metal dopants are grouped into s, p, d, and f block elements, and the relevant synthetic methods, novel properties, and key applications of metal doped ceria are collated and critically discussed. Non-metal dopants are similarly examined and compared with metal dopants using the same performance criteria. The review reveals that non-metal (N, S, P, F, and Cl) doped ceria has mainly been synthesized by calcination and hydrothermal methods, and it has found applications mostly in photocatalysis or as a cathode material for LiS batteries. In contrast, metal doped ceria nanomaterials have been prepared by a wider range of synthetic routes and evaluated for a larger number of applications, including as catalysts or photocatalysts, as antibacterial agents, and in devices such as fuel cells, gas sensors, and colorimetric detectors. Dual/co-doped ceria containing both metals and non-metals are also reviewed, and it is found that co-doping often leads to improved properties compared with single-element doping. The review concludes with a future outlook that identifies unaddressed issues in the synthesis and applications of doped ceria nanomaterials.

Ultrasmall nitrogen-doped Cu0·92Co2·08O4 nanocrystal-decorated cerium dioxide nanoparticles for fast and complete degradation of ranitidine via permonosulfate activation

A simple and efficient coagulation method was used for the rapid preparation of nitrogen-doped copper-cobalt oxide (N-Cu_0.92Co_2·08O₄) supported on cerium dioxide (CeO₂), that is, N-Cu_0.92Co_2·08O₄@CeO₂. A low concentration of N-Cu_0.92Co_2·08O₄@CeO₂ (0.15 g L^-1) was shown to rapidly activate permonosulfate (PMS) (0.15 g L^-1) to achieve 100% degradation of ranitidine within 10 min. A 100% degradation of ranitidine enabled by the catalyst was achieved over a wide range of pH (5.5-9.0), which could be completed within 8 min in the presence of anionic H₂PO₄^-. Moreover, the N-Cu_0.92Co_2·08O₄@CeO₂ catalyst enabled more than 90% degradation of various typical antibiotics within 30 min, including tetracycline, sulfaixoxazole, and chloramphenicol, with degradation rates of 100%, 93.51%, and 90.01%, respectively. Even after four catalytic cycles, N-Cu_0.92Co_2·08O₄@CeO₂ could be regenerated to achieve 100% degradation of ranitidine. Electrochemical analysis demonstrated that the combination of N-Cu_0.92Co_2·08O₄@CeO₂ and PMS immediately produced a strong current density, thereby rapidly producing reactive oxygen species (ROS) with high performance for the degradation of the target pollutant. Combined ion quenching and electron paramagnetic resonance analyses indicated that the main ROS was the non-free radical ¹O₂. Finally, a plausible ranitidine degradation pathway was deduced based on liquid chromatography-mass spectrometry (LC-MS) analysis, wherein the toxic substance N-nitrosodimethylamine was not produced during the degradation process. In short, this study provides a new perspective for preparing ternary metal catalysts for advanced oxidation processes with practical application significance.

Self-Powered Bipolar Photodetector Based on a Ce-BaTiO3 PTCR Semiconductor for Logic Gates

Ferroelectric materials bring new opportunities for self-powdered photodetectors, taking advantage of their anomalous bulk photovoltaic effect. However, ferroelectric-based photodetectors suffer from relatively poor responsivity and detectivity due to obstacles of low electrical conductivity and low photoelectric conversion ability. The present work proposes a strategy based on heterovalent ion Ce-doping into BaTiO₃ (Ce-BTO) that gives rise to a good room temperature conductivity combined with a significant PTCR (positive temperature coefficient of resistivity) effect. By utilizing a Ce-BTO PTCR semiconductor, a high-performance self-powered photodetector ITO/Ce-BTO/Ag is fabricated, demonstrating a polarity-switchable photoresponse with the change of wavelength due to the competition between hot electrons induced by the Ag plasmonic effect and electron-hole pairs separated by a Schottky barrier. Moreover, benefiting from the reduced bandgap and the introduced impurity states, good responsivity (9.85 × 10^-5 A/W) and detectivity (1.25 × 10¹⁰ Jones) as well as fast response/recovery time (83/47 ms) is achieved under 450 nm illumination. Finally, four representative logic gates ("OR", "AND", "NOR", and "NAND") are demonstrated with one photodetector via the bipolar photoresponse. This work opens an avenue to promote the application of PTCR semiconductors in optoelectronics, offering a conceivable means toward high-performance self-powered photodetectors.

Solar light-based advanced oxidation processes for degradation of methylene blue dye using novel Zn-modified CeO2@biochar

Herein, a novel nanocomposite, namely, Zn-modified CeO₂@biochar (Zn/CeO₂@BC), is synthesized via facile one-step sol-precipitation to study its photocatalytic activity towards the removal of methylene blue dye. Firstly, Zn/Ce(OH)₄@biochar was precipitated by adding sodium hydroxide to cerium salt precursor; then, the composite was calcined in a muffle furnace to convert Ce(OH)₄ into CeO₂. The crystallite structure, topographical and morphological properties, chemical compositions, and specific surface area of the synthesized nanocomposite are characterized by XRD, SEM, TEM, XPS, EDS, and BET analysis. The nearly spherical Zn/CeO₂@BC nanocomposite has an average particle size of 27.05 nm and a specific surface area of 141.59 m²/g. All the tests showed the agglomeration of Zn nanoparticles over the CeO₂@biochar matrix. The synthesized nanocomposite showed remarkable photocatalytic activity towards removing methylene blue, an organic dye commonly found in industrial effluents. The kinetics and mechanism of Fenton-activated dye degradation were studied. The nanocomposite exhibited the highest degradation efficiency of 98.24% under direct solar irradiation of 90 min, at an optimum dosage of 0.2 g l^-1 catalyst and 10 ppm dye concentration, in the presence of 25% (V/V) 0.2 ml (4 µl/ml) hydrogen peroxide. The hydroxyl radical generated from H₂O₂ during the photo-Fenton reaction process was attributed to the nanocomposite's improved photodegradation performance. The degradation process followed pseudo-first-order kinetics having a rate constant (k) value of 0.0274 min^-1.

Assembling CeO2 nanoparticles on ZIF-8 via the hydrothermal method to promote the CO2 photoreduction performance

Photocatalytic reduction of CO₂ to valuable carbon fuel is a prospective technique to decrease CO₂ emissions and simultaneously generate efficient chemical energy. In this paper, a novel high-efficiency photocatalyst ZIF-8@CeO₂ heterogeneous composite (ZIF = zeolitic imidazolate framework) was prepared by the hydrothermal method, where CeO₂ nanospheres were uniformly grown on the surface of ZIF-8. Compared to pristine ZIF-8 or CeO₂ nanoparticles (NPs), the ZIF-8@CeO₂ composite shows significantly better efficiency in the reduction of CO₂ into CO and CH₄ under light irradiation, that is the CO evolution rate can reach 465.01 μmol g^-1 h^-1 and the CH₄ evolution rate can reach 181.27 μmol g^-1 h^-1. Analyses indicated that the addition of CeO₂ in the composites will expand the photoresponse region; the formation of the ZIF-8/CeO₂ heterojunction significantly promoted the separation of photogenerated electron-hole pairs within the composite. This work provided an effective method to further improve the catalytic activity of ZIF-based materials, which paved a new way for eco-friendly conversion of carbon dioxide into clean fuels and they could also have huge potential for application in energy and environmental science.

Effect of Pd-Doping Concentrations on the Photocatalytic, Photoelectrochemical, and Photoantibacterial Properties of CeO2

Cerium oxide (CeO2) can exhibit good photocatalytic and photoantibacterial activities. However, its light-harvesting property is rather limited due to its large band gap. In order to boost these properties, doping with metal ions can improve light absorption and charge mobility. In this report, CeO2 and palladium−doped CeO2 (Pd−CeO2) NPs were synthesized via the microwave-assisted synthesis method. The structural, optical, and morphological studies of CeO2 and Pd−CeO2 NPs were carried out using various techniques. Mixed phases of CeO2/Ce2O3 were observed in pure CeO2 (S−CeO2) and Pd−CeO2. However, the Ce2O3 phase gradually disappeared upon doping with a higher percentage of Pd. Almost spherical particles were observed with average sizes between 6 and 13 nm. It was found that the incorporation of Pd reduced the particle size. Moreover, band gap energies of S−CeO2 and Pd−CeO2 NPs were reduced from 2.56 to 2.27 eV, and the PL intensities were also quenched with more Pd doping. The shifts in the conduction band and valence band were found to cause the reduction in the band gap energies of S−CeO2 and Pd−CeO2 NPs. In the case of photocatalytic degradation of methylene blue, photoelectrochemical, and photoantibacterial activities, Pd−CeO2 NPs showed enhanced activities under visible light irradiation. Therefore, Pd−CeO2 NPs have been shown to be a visible-light active material.

Band Gap Tuning in Transition Metal and Rare-Earth-Ion-Doped TiO2, CeO2, and SnO2 Nanoparticles

The energy gap Eg between the valence and conduction bands is a key characteristic of semiconductors. Semiconductors, such as TiO2, SnO2, and CeO2 have a relatively wide band gap Eg that only allows the material to absorb UV light. Using the s-d microscopic model and the Green's function method, we have shown two possibilities to reduce the band-gap energy Eg-reducing the NP size and/or ion doping with transition metals (Co, Fe, Mn, and Cu) or rare earth (Sm, Tb, and Er) ions. Different strains appear that lead to changes in the exchange-interaction constants, and thus to a decrease in Eg. Moreover, the importance of the s-d interaction, which causes room-temperature ferromagnetism and band-gap energy tuning in dilute magnetic semiconductors, is shown. We tried to clarify some discrepancies in the experimental data.

Antibacterial Z-scheme ZnIn2S4/Ag2MoO4 composite photocatalytic nanofibers with enhanced photocatalytic performance under visible light

Considering the biocompatibility of natural proteins and the strong photo-redox capability of Z-scheme heterojunctions, we fabricated Z-scheme ZnIn₂S₄/Ag₂MoO₄@Zein (Z ZA) photocatalytic membranes via electrospinning and in-situ precipitation for enrofloxacin (ENR) degradation. Z ZA exhibit a fiber structure wrapped with ZnIn₂S₄/Ag₂MoO₄ heterojunctions. Photocatalytic studies and various characterization results certified that the Z-scheme structure between ZnIn₂S₄ and Ag₂MoO₄ significantly increases the lifetime and separation efficiency of photogenerated carriers, which in turn enhances the photodegradation of ENR. The degradation rate of Z ZA-10 (ZnIn₂S₄/10 wt% Ag₂MoO₄@Zein) with the highest catalytic activity could reach 100% within 120 min compared with other samples. For ENR degradation, •O₂^- radicals were certified to be the primary active species by trapping experiments, and several possible conversion pathways of ENR in photocatalytic reactions were proposed. Furthermore, the antibacterial rates of Z ZA-20 (ZnIn₂S₄/20 wt% Ag₂MoO₄@Zein) against B. subtilis, P. aeruginosa, S. aureus, and E. coli could reach 90.09%, 89.78%, 84.34%, and 95.31%, respectively. Antibacterial evaluations and cytotoxicity assays demonstrated that Z ZA photocatalytic films had desirable antibacterial properties and low cytotoxicity, rendering them safe and effective for use in the treatment of antibiotic wastewater.

ZnO/CeO2 Nanocomposites: Metal-Organic Framework-Mediated Synthesis, Characterization, and Estimation of Cellular Toxicity toward Liver Cancer Cells

The Zinc-doped cerium oxide nanocomposite (ZnO/CeO₂ NC) was synthesized using a metal-organic framework as a precursor through the combustion method. It was characterized by powder X-ray diffraction (PXRD), Fourier transform infrared spectroscopy (FTIR), field emission electron microscopy (FESEM), energy dispersive analysis (EDX), transmission electron microscopy (TEM), dynamic light scattering (DLS), and ξ-potential. The PXRD demonstrated the successful synthesis of ZnO/CeO₂ NC with a crystallite size of 31.9 nm. FESEM and TEM images displayed hexagonal and spherical morphologies, and the solid-phase size was 65.03 ± 30.86 nm for ZnO/CeO₂ NCs. DLS, TEM, and FESEM showed that the NCs have a high tendency for agglomeration/aggregation in both aqueous media and solid phase. The anticancer attributes of ZnO/CeO₂ NC were investigated against Liver cancer cells (HepG2), which showed inhibition of cancer cell growth on a concentration-dependent gradient. The cell toxicity effects of ZnO/CeO₂ nanocomposites were also studied toward NIH-3T3, in which the data displayed the lower toxicity of NC compared to the HepG2 cell line.

Ce3+/Ce4+-Doped ZrO2/CuO Nanocomposite for Enhanced Photocatalytic Degradation of Methylene Blue under Visible Light

In recent years, photocatalysis has been used as an environmentally friendly method for the degradation of organic pigments in water. In this study, Ce³⁺/Ce⁴⁺-doped ZrO₂/CuO as a mixed semiconductor oxide was successfully prepared by a one-step hydrothermal method. The Ce³⁺/Ce⁴⁺-doped ZrO₂/CuO has shown high degradation efficiency of methylene blue (MB), and the maximum degradation percentage was observed to be 94.5% at 180 min under irradiation visible light. The photocatalytic activity increases significantly by doping Ce³⁺/Ce⁴⁺ in ZrO₂/CuO for MB degradation. Ce³⁺/Ce⁴⁺ doping is shown to reduce the (e^-/h⁺) recombination rate and improve the charge transfer, leading to enhanced photocatalytic activity of materials. The materials were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), FTIR, EDS, BET and diffuse reflectance spectroscopy (DRS).

Exploring the Influence of Synthesis Parameters on the Optical Properties for Various CeO2 NPs

Cerium oxide (CeO₂) nanoparticles were synthesized with a chemical precipitation method in different experimental conditions using cerium nitrate hexahydrate (Ce(NO₃)₃·6H₂O) as a precursor, modifying the solution pH, the reaction time, and Co atoms as dopants, in order to tune the band gap energy values of the prepared samples. The physical characteristics of the synthesized ceria nanoparticles were evaluated by Fourier transform infrared (FT-IR) spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), UV–Vis analyses and photoluminescence measurements. XRD data revealed a pure cubic fluorite structure of CeO₂ NPs, the estimation of crystallite sizes by Scherrer’s formula indicates the formation of crystals with dimensions between 11.24 and 21.65 nm. All samples contain nearly spherical CeO₂ nanoparticles, as well as cubic, rhomboidal, triangular, or polyhedral nanoparticles that can be identified by TEM images. The optical investigation of CeO₂ samples revealed that the band gap energy values are between 3.18 eV and 2.85 eV, and, after doping with Co atoms, the E_g of samples decreased to about 2.0 eV. In this study, we managed to obtain CeO₂ NPs with E_g under 3.0 eV by only modifying the synthesis parameters. In addition, by doping with Co ions, the band gap energy value was lowered to 2.0 eV. This aspect leads to promising results that provide an encouraging approach for future photocatalytic investigations.

Graphene nanoplatelets/CeO2 nanotiles nanocomposites as effective antibacterial material for multiple drug-resistant bacteria

Antibacterial agents with low toxicity to normal cells, redox activity and free radical scavenging property are urgently needed to address the global health crisis. The phenomenal conducting nature of graphene is a best fit to enhance the antibacterial properties of metal oxides. In this work, CeO₂ nanotiles and graphene nanoplatelets/CeO₂ nanotiles nanocomposites (G/CeO₂) have been synthesized by a solvothermal method. The prepared materials have been characterized using XRD, FE-SEM, EDX, and UV–visible spectroscopy techniques to investigate their crystallinity, morphology, composition, and optical bandgap energies. The CeO₂ and G/CeO₂ nanocomposites have also been tested for antibacterial applications. The neat CeO₂ nanotiles sample inhibits the bacterial growth of Pseudomonas aeruginosa and Staphylococcus aureus up to 14.21% and 39.53% respectively. The antibacterial activity was tremendously enhanced using 25% graphene-loaded sample (G/CeO₂-II) i.e., approximately 83% loss of P. aeruginosa and 89% in case of S. aureus has been observed. This can be attributed to the unique nano-architecture, oxidative stress due to the excellent ability of reversible conversion between the two electronic states of CeO₂ and the stress exerted by the planar graphene and CeO₂ nanotiles. Therefore, the G/CeO₂ nanocomposites can find potential application as nano-antibiotics for controlling pathogens.

Determination of Band Structure of Naturally Occurring Goethite with Al Substitution: A Case Study of Zhushan Iron Zone

The photocatalytic property of Fe oxide minerals has long been considered to play an important role in shaping modern terrestrial environments. However, due to the complexity of natural settings, a precise determination of the band structure of natural goethite has not been achieved. In this work, the mineralogical characteristics of natural goethite samples obtained from Zhushan, China, were systematically studied through X-ray diffraction, transmission electron microscopy, X-ray energy dispersive spectroscopy, and X-ray fluorescence spectroscopy. Afterward, the band structure for both natural and synthetic goethite samples was determined by synchrotron-based X-ray absorption and emission spectra and photoelectron spectroscopy. The band gap of natural goethite (2.25 eV) was narrower than that of its synthetic counterpart (2.55 eV), and the valence band position of natural goethite was slightly lifted (−5.06 eV) compared to that of synthetic goethite (−5.38 eV). Al doping in natural goethite crystal, as revealed by the mineralogical tests, was the main reason that contributed to this difference. The theoretical calculation showed the narrowed band gap was caused by the contribution of Al-2p orbits at the top of the valence band. Therefore, free electrons can be created under light irradiation with a shorter wavelength. The experiments showed that natural goethite can photo-catalytically degrade methyl orange, and the degradation efficiency was better (47.5%) than that of the synthetic goethite group (31.5%). This study, for the first time, revealed the band structure and confirmed the photocatalytic properties of natural goethite, which should play an important role in surface substance evolution and elemental cycling.

Passive Film Properties of Martensitic Steels in Alkaline Environment: Influence of the Prior Austenite Grain Size

The role of prior austenite grain size (PAGS) on the passive layer properties of martensitic steels is studied. Electron backscatter diffraction analysis shows that PAGS between 5 and 66 µm were obtained after applying different heat treatments. The barrier properties of passive film deteriorate with grain refinement up to 28 µm, attributed to increased donor density and a decrease in the fraction of γ-Fe2O3 in passive films. However, the further refinement of PAGS to 5 µm leads to improvement in the barrier properties due to the changes within the martensite structure. This improvement stems from the increase in γ-Fe2O3 fraction.

Recent advances, influencing factors, and future research prospects using photocatalytic process for produced water treatment

Oilfield-produced water is the primary by-product generated during oil and gas extraction operations. Oilfield-produced water is often severely toxic and poses substantial health, safety, and environmental issues; adequate treatment technologies can bring these streams to a quality level. Photocatalysis is a photochemical catalytic reaction that is a highly promising tool for environmental remediation due to its efficiency in mineralizing persistent and potentially toxic contaminants. However, there is limited understanding of its application to treat oilfield-produced water with a complex and highly variable water composition. This review article discusses the mechanisms and current state of heterogeneous photocatalytic systems for oilfield-produced water treatment, highlighting impediments to knowledge transfer, including the feasibility of practical applications and the identification of essential research requirements. Additionally, the effects of significant variables such as catalyst quantity, pH, organic compound concentration, light intensity, and wavelength are discussed in detail. Some solutions are proposed for scientists and engineers interested in advancing the development of industrial-scale photocatalytic water treatment technologies.

T, Dhileepan MD, Neppolian B, K. LN. Surface defect-engineered CeO2−x by ultrasound treatment for superior photocatalytic H2 production and water treatment

We designed a CeO2−x photocatalyst under the influence of low-frequency ultrasonic waves to generate surface oxygen vacancies for efficient photocatalytic performance.

Tunicate-Inspired Photoactivatable Proteinic Nanobombs for Tumor-Adhesive Multimodal Therapy

Near-IR (NIR) light-responsive multimodal nanotherapeutics have been proposed to achieve improved therapeutic efficacy and high specificity in cancer therapy. However, their clinical application is still elusive due to poor biometabolization and short retention at the target site. Here, innovative photoactivatable vanadium-doped adhesive proteinic nanoparticles (NPs) capable of allowing biological photoabsorption and NIR-responsive anticancer therapeutic effects to realize trimodal photothermal-gas-chemo-therapy treatments in a highly biocompatible, site-specific manner are proposed. The photoactivatable tumor-adhesive proteinic NPs can enable efficient photothermal conversion via tunicate-inspired catechol-vanadium complexes as well as prolonged tumor retention by virtue of mussel protein-driven distinctive adhesiveness. The incorporation of a thermo-sensitive nitric oxide donor and doxorubicin into the photoactivatable adhesive proteinic NPs leads to synergistic anticancer therapeutic effects as a result of photothermal-triggered "bomb-like" multimodal actions. Thus, this protein-based phototherapeutic tumor-adhesive NPs have great potential as a spatiotemporally controllable therapeutic system to accomplish effective therapeutic implications for the complete ablation of cancer.

Defect engineering in trivalent ion doped ceria through vanadium assisted charge compensation: insight using photoluminescence, positron annihilation and electron spin resonance spectroscopy

Pair matching charge compensation with trivalent and pentavalent dopants in ceria was found to be an attractive strategy in engineering defects with minimal distortions in the lattice and obtaining enhanced catalytic properties. In the present study, charge compensation with a vanadium codopant in trivalent ion doped ceria is studied. Defect evolution in the trivalent ion doped ceria with vanadium codoping has been studied in CeO₂:Eu³⁺, CeO₂:La³⁺,Eu³⁺ and CeO₂:Y³⁺,Eu³⁺ systems and the choices of the dopant and co-dopant are triggered by their ionic radius. Eu³⁺ photoluminescence (PL) is used as a spectroscopic probe to monitor local structural changes around the dopants. Positron lifetime studies showed that oxygen vacancies formed due to trivalent ion doping are weakly associated when larger ions are doped and result in the formation of vacancy aggregates. Positron lifetime studies along with XRD studies show that vanadium codoping effectively removes the vacancies but the distortions are significant when the size mismatch between the pair match used for charge compensation is higher. Photoluminescence demonstrated that the oxygen vacancies associated with Eu are more effectively removed in the case of Y codoped samples. Electron Spin Resonance (ESR) studies suggested that vanadium in excess over the stoichiometric concentration of the trivalent ion can lead to additional defects. These studies are expected to help in tuning the vacancy concentrations as well as controlling the lattice distortions for technological applications such as catalysis, ionic conductivity, etc.

Facile and Green Synthesis of Silver Quantum Dots Immobilized onto a Polymeric CTS-PEO Blend for the Photocatalytic Degradation of p-Nitrophenol

Immobilization of inorganic metal quantum dots (especially, noble transition metals) onto organic polymers to synthesize nanometal-polymer composites (NMPCs) has attracted considerable attention because of their advanced optical, electrical, catalytic/photocatalytic, and biological properties. Herein, novel, highly efficient, stable, and visible light-active NMPC photocatalysts consisting of silver quantum dots (Ag QDs) immobilized onto polymeric chitosan-polyethylene oxide (CTS-PEO) blend sheets have been successfully prepared by an in situ self-assembly facile casting method as a facile and green approach. The CTS-PEO blend polymer acts as a reducing and a stabilizing agent for Ag QDs which does not generate any environmental chemical pollutant. The prepared x wt % Ag QDs/CTS-PEO composites were fully characterized through X-ray diffraction, Fourier transform infrared spectroscopy, transmission electron microscopy (TEM), thermogravimetric analysis, and UV/visible spectroscopy. The characterization results indicated the successful synthesis of the Ag QDs/CTS-PEO composites by the interactions and complexation between x wt % Ag QDs and CTS-PEO blend sheets. TEM images revealed small granules randomly distributed onto the CTS-PEO blend sheets, indicating the immobilization of Ag QDs onto CTS-PEO composites. The presence of a surface plasmon resonance (SPR) band and the shifting of the absorption edge toward higher wavelengths in the UV/vis spectra indicated the formation of x wt % Ag QDs/CTS-PEO composites. The Ag QDs in the polymeric blend matrix led to remarkable enhancement in the optical, thermal, electrical, and photocatalytic properties of x wt % Ag QDs/CTS-PEO composites. The photocatalytic efficiency of the prepared composites was evaluated by the photodegradation of p-nitrophenol (PNP) under simulated sunlight. The maximum photocatalytic degradation reached 91.1% efficiency within 3 h for the 12.0 wt % Ag QDs/CTS-PEO photocatalyst. Generally, the Ag QDs immobilized onto CTS-PEO blend composites significantly enhance the SPR effect and the synergistic effect and reduce the band gap, leading to a high photocatalytic activity.

Effect of Zr doping on photoantioxidant and antibiofilm properties of CeO2 NPs fabricated using aqueous leaf extract of Pometia pinnata

Synthesized cerium oxide nanoparticles (S-CeO₂ NPs) and 1%, 5% and 10% zirconium doped CeO₂ (Zr-doped CeO₂) NPs were fabricated using aqueous leaf extract of Pometia pinnata. The synthesized NPs were characterized using standard techniques which confirmed successful synthesis of NPs with particle size ranging from 12 to 23 nm and band gap energy of 2.54-2.66 eV. Photoantioxidant activities showed enhanced activities under visible light irradiation in comparison to the dark condition in the dose-dependent study. Biofilm inhibition studies showed ~ 73% biofilm inhibition of Staphylococcus aureus at 512 µg/mL for S-CeO₂, whereas 10% Zr-doped CeO₂ NPs showed biofilm inhibition of 52.7%. The bactericidal tests showed killing properties at 1024 µg/mL of S-CeO₂ NPs and at 512 µg/mL of 1% Zr-doped CeO₂. Reduced bactericidal activities were observed for 5% and 10% Zr-doped CeO₂. These studies showed that the fabricated NPs have both good photoantioxidant and antibacterial properties.

Enhanced adsorption and degradation of methylene blue over mixed niobium-cerium oxide - Unraveling the synergy between Nb and Ce in advanced oxidation processes

Formation of reactive oxygen species (ROS) via H₂O₂ activation is of vital importance in catalytic environmental chemistry, especially in degradation of organic pollutants. A new mixed niobium-cerium oxide (NbCeO_x) was tailored for this purpose. A thorough structural and chemical characterization of NbCeO_x along with CeO₂ and Nb₂O₅ reference materials was carried out using TEM/STEM/EDS, SEM, XRD, XPS, EPR, UV-vis and N₂ physisorption. The ability of the catalysts to activate H₂O₂ towards ROS formation was assessed on the basis of EPR and Raman measurements. Catalytic activity of the oxides was evaluated in degradation of methylene blue (MB) as a model pollutant. Very high activity of NbCeO_x was attributed to the mixed redox-acidic nature of its surface, which originated from the synergy between Nb and Ce species. These two properties (redox activity and acidity) ensured convenient conditions for efficient activation of H₂O₂ and degradation of MB. The activity of NbCeO_x in MB degradation was found 3 times higher than that of the commercial Nb₂O₅ CBMM catalyst and 240 times higher than that of CeO₂. The mechanism of the degradation reaction was found to be an adsorption-triggered process initiated by hydroxyl radicals, generated on the surface via the transformation of O₂^-•/O₂^2-.

Green-synthesized CeO2 nanoparticles for photocatalytic, antimicrobial, antioxidant and cytotoxicity activities

Cerium oxide nanoparticles (CeO2 NPs) are a sought-after material in numerous fields due to their potential applications such as in catalysis, cancer therapy, photocatalytic degradation of pollutants, sensors, polishing agents. Green synthesis usually involves the production of CeO2 assisted by organic extracts obtained from plants, leaves, flowers, bacteria, algae, food, fruits, etc. The phytochemicals present in the organic extracts adhere to the NPs and act as reducing and/or oxidizing agents and capping agents to stabilize the NPs, modify the particle size, morphology and band gap energy of the as-synthesized materials, which would be advantageous for numerous applications. This review focuses on the green extract-mediated synthesis of CeO2 NPs and discusses the effects on CeO2 NPs of various synthesis methods that have been reported. Several photocatalytic, antimicrobial, antioxidant and cytotoxicity applications have been evaluated, compared and discussed. Future prospects are also suggested.

Green synthesis of CeO2 and Zr/Sn-dual doped CeO2 nanoparticles with photoantioxidant and antibiofilm activities

Cerium oxide (CeO2) and 1%, 5% and 10% zirconium/tin-dual doped CeO2 nanoparticles (Zr/Sn-dual doped CeO2 NPs) were synthesized using an aqueous leaf extract of Pometia pinnata. By using UV-visible diffuse reflectance spectroscopy, the band gap energies of these materials were found to be in the range of ∼2.49 to 2.66 eV. The average crystallite sizes of the fluorite phase obtained from X-ray diffraction were between 7 and 16 nm. X-ray photoelectron spectroscopy (XPS) analysis further confirmed the synthesis of CeO2 and Sn-doped CeO2 NPs. Almost spherical shapes of the nanomaterials with an average particle size of 12-17 nm were determined using scanning electron microscopy and transmission electron microscopy studies. Photoantioxidant activities of the synthesized materials showed enhanced photoantioxidant response under visible light irradiation in comparison with those under dark conditions in both dose- and time-dependent manner. The CeO2 NPs exhibited a significant concentration-dependent antibiofilm activity against the Gram-positive bacteria Staphylococcus aureus (S. aureus) and Listeria monocytogenes (L. monocytogenes). Only the 10% Zr/Sn-dual doped-CeO2 NPs were found to inhibit S. aureus biofilm formation at higher concentrations. All Zr/Sn-dual doped CeO2 NPs exhibited a concentration-dependent biofilm inhibition of L. monocytogenes and also bactericidal activity towards S. aureus. These nanomaterials exhibited enhanced photoantioxidant activities and antibacterial properties, which make them suitable for various biological applications.

Unraveling the Origin of Photocatalytic Deactivation in CeO2/Nb2O5 Heterostructure Systems during Methanol Oxidation: Insight into the Role of Cerium Species

The study provides deep insight into the origin of photocatalytic deactivation of Nb₂O₅ after modification with ceria. Of particular interest was to fully understand the role of ceria species in diminishing the photocatalytic performance of CeO₂/Nb₂O₅ heterostructures. For this purpose, ceria was loaded on niobia surfaces by wet impregnation. The as-prepared materials were characterized by powder X-ray diffraction, nitrogen physisorption, UV-visible spectroscopy, X-ray photoelectron spectroscopy, high-resolution transmission electron microscopy, and photoluminescence measurements. Photocatalytic activity of parent metal oxides (i.e., Nb₂O₅ and CeO₂) and as-prepared CeO₂/Nb₂O₅ heterostructures with different ceria loadings were tested in methanol photooxidation, a model gas-phase reaction. Deep insight into the photocatalytic process provided by operando-IR techniques combined with results of photoluminescence studies revealed that deactivation of CeO₂/Nb₂O₅ heterostructures resulted from increased recombination of photo-excited electrons and holes. The main factor contributing to more efficient recombination of the charge carriers in the heterostructures was the ultrafine size of the ceria species. The presence of such highly dispersed ceria species on the niobia surface provided a strong interface between these two semiconductors, enabling efficient charge transfer from Nb₂O₅ to CeO₂. However, the ceria species supported on niobia exhibited a high defect site concentration, which acted as highly active recombination centers for the photo-induced charge carriers.

Novel Ag/cellulose-doped CeO2 quantum dots for efficient dye degradation and bactericidal activity with molecular docking study

In the present study, the novel Ag/cellulose nanocrystal (CNC)-doped CeO₂ quantum dots (QDs) with highly efficient catalytic performance were synthesized using one pot co-precipitation technique, which were then applied in the degradation of methylene blue and ciprofloxacin (MBCF) in wastewater. Catalytic activity against MBCF dye was significantly reduced (99.3%) for (4%) Ag dopant concentration in acidic medium. For Ag/CNC-doped CeO₂ vast inhibition domain of G-ve was significantly confirmed as (5.25-11.70 mm) and (7.15-13.60 mm), while medium- to high-concentration of CNC levels were calculated for G + ve (0.95 nm, 1.65 mm), respectively. Overall, (4%) Ag/CNC-doped CeO₂ revealed significant antimicrobial activity against G-ve relative to G + ve at both concentrations, respectively. Furthermore, in silico molecular docking studies were performed against selected enzyme targets dihydrofolate reductase (DHFR), dihydropteroate synthase (DHPS), and DNA gyrase belonging to folate and nucleic acid biosynthetic pathway, respectively to rationalize possible mechanism behind bactericidal potential of CNC-CeO₂ and Ag/CNC-CeO₂.

Electrochemical Ce(III)/Ce(IV) Redox Behavior and Ce Oxide Nanostructure Recovery over Thio-Terpyridine-Functionalized Au/Carbon Paper Electrodes

Understanding the electrochemical behaviors of Ce(III)/Ce(IV) ions is essential for better treatment, separation, and recycling of lanthanide (Ln) and actinide (An) elements. Herein, electrochemical redox behavior and interconversion of Ce(III)/Ce(IV) ions and their recoveries were demonstrated over newly developed thio-terpyridine-functionalized Au-modified carbon paper electrodes in acidic and neutral electrolytes. Cyclic voltammetry and amperometry were performed for the electrodes with and without thio-terpyridine functionalization. Ce oxide nanostructure recovery was successfully conducted by amperometry, and the electrodeposited nanostructured Ce materials were fully characterized by scanning electron microscopy, high-resolution transmission electron microscopy, X-ray diffraction crystallography, and X-ray photoelectron spectroscopy. Geometry optimization and the electronic energy state calculations were conducted by density functional theory at the B3LYP/GENECP level for the complexes of Ce(III) and Ce(IV) ions with the thio-terpyridine in an aqueous state. The present unique results provide valuable information on understanding redox behaviors of Ln and An ions for their recycling and treatment processes.

Enhanced Photocatalytic Degradation of Antibiotic and Hydrogen Production by Iron Doped Cerium(IV) Oxide

Norfloxacin (NF) is an emerging antibiotic contaminant due to its significant accumulation in the environment. Photocatalytic degradation is an effective method for removing emerging contaminant compounds in aqueous solution; however, it is not commonly applied because of the poor solubility of contaminant compounds in water. In this study, a photocatalytic degradation experiment was carried out on NF using a self-made ceria catalyst. At an initial concentration of NF of 2.5 mg L^-1, the dosage of CeO₂ was 0.1 g L^-1 photocatalyst in water, and the initial pH of the NF solution was 8.0. With a reaction time of 180 min, the total removal rate of NF could reach 95%. Additionally, the studies on hydrogen production show that the maximum hydrogen production with 2% Fe-CeO₂ can reach 25,670 μmol h^-1 g^-1 under close to 8 W of 365 nm, a methanol concentration of 20%, and a catalyst dose of 0.1 g L^-1 photocatalyst in water. Furthermore, the intensities of photoluminescence (PL) emission peaks decreased with increased Fe-doped amounts on CeO₂, suggesting that the irradiative recombination seemed to be weakened.

Insight into the Contributions of Surface Oxygen Vacancies on the Promoted Photocatalytic Property of Nanoceria

Oxygen vacancies (OVs) have critical effects on the photoelectric characterizations and photocatalytic activity of nanoceria, but the contributions of surface OVs on the promoted photocatalytic properties are not clear yet. In this work, we synthesized ceria nanopolyhedron (P-CeO₂), ceria nanocube (C-CeO₂) and ceria nanorod (R-CeO₂), respectively, and annealed them at 600 °C in air, 30%, 60% or pure H₂. After annealing, the surface OVs concentration of ceria elevates with the rising of H₂ concentration. Photocatalytic activity of annealed ceria is promoted with the increasing of surface OVs, the methylene blue photodegradation ratio with pure hydrogen annealed of P-CeO₂, C-CeO₂ or R-CeO₂ is 93.82%, 85.15% and 90.09%, respectively. Band gap of annealed ceria expands first and then tends to narrow slightly with the rising of surface OVs, while the valence band (VB) and conductive band (CB) of annealed ceria changed slightly. Both of photoluminescence spectra and photocurrent results indicate that the separation efficiency of photoinduced electron-hole pairs is significantly enhanced with the increasing of the surface OVs concentration. The notable weakened recombination of photogenerated carrier is suggested to attribute a momentous contribution on the enhanced photocatalytic activity of ceria which contains surface OVs.

Photocatalytic Activity of Cellulose Acetate Nanoceria/Pt Hybrid Mats Driven by Visible Light Irradiation

A photocatalytic system for the degradation of aqueous organic pollutants under visible light irradiation is obtained by an innovative approach based on ceria/platinum (Pt) hybrid nanoclusters on cellulose acetate fibrous membranes. The catalytic materials are fabricated by supersonic beam deposition of Pt nanoclusters directly on the surface of electrospun cellulose acetate fibrous mats, pre-loaded with a cerium salt precursor that is transformed into ceria nanoparticles directly in the solid mats by a simple thermal treatment. The presence of Pt enhances the oxygen vacancies on the surface of the formed ceria nanoparticles and reduces their band gap, resulting in a significant improvement of the photocatalytic performance of the composite mats under visible light irradiation. Upon the appropriate pretreatment and visible light irradiation, we prove that the most efficient mats, with both ceria nanoparticles and Pt nanoclusters, present a degradation efficiency of methylene blue of 70% and a photodegradation rate improved by about five times compared to the ceria loaded samples, without Pt. The present results bring a significant improvement of the photocatalytic performance of polymeric nanocomposite fibrous systems under visible light irradiation, for efficient wastewater treatment applications.

Synthesis and Characterization of CeO2/CuO Nanocomposites for Photocatalytic Degradation of Methylene Blue in Visible Light

Removal of hazardous organic dyes from polluted water bodies requires the introduction of strong adsorbents and photocatalysts to industrial wastewaters. Herein, photocatalytic CeO2 nanoparticles and CeO2/CuO nanocomposite were synthesized following a co-precipitation method for low cost elution of methylene blue (MB) from water. The crystallinity and surface structure of the as-prepared materials have been analyzed using characterization techniques including X-ray powder diffraction (XRPD), field emission scanning electron microscopy (FE-SEM), energy-dispersive spectroscopy (EDS), ultra-violet visible spectroscopy (UV–Vis), and Fourier-transform infrared spectroscopy (FTIR). The average particle size of both the nano scaled samples were approximately 20–30 nm. The photocatalytic properties of CeO2/CuO were investigated under visible light against methylene blue (MB). The results showed 91% photodegradation of MB organic pollutant in 3 h as monitored by UV–Vis spectroscopy. Absorbance peaks appeared at around 670 nm corresponding to degradation of MB. Such output displayed the effectiveness of Ce nanocomposites for environmental benefits. Hence, CeO2/CuO nanocomposite could be useful for treatment of industrial wastewaters by removing hazardous MB dye.