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Color Tunable Pigments with high NIR reflectance in Terbium doped Cerate systems for Sustainable Energy Saving Applications
摘要： Color tunable pigments from yellow to red hues were developed in Tb doped A2CeO4 (A = Sr and Ba) system by the conventional ceramic route. The developed pigments were analysed for their phase purity, chemical oxidation state, elemental analysis, morphology and optical properties by various advanced techniques. The Ba substitution in Sr2-xCe0.6Tb0.4O4 gently shifts the absorption edge to higher wavelengths producing bright yellows to reddish orange colors whereas, the Tb substitution in Ba2Ce1-xTbxO4 allows abrupt shift in the absorption edge to longer wavelengths leading to intense red hues. The chemical oxidation state analysis indicates the modifications of Tb3+ concentrations in both the environments due to metal to metal charge transfer transitions induced by lattice expansion. Typically the compositions SrBaCe0.6Tb0.4O4 (yellow; b* = 75.36, R = 91%) and Ba2Ce0.4Tb0.6O4 (red; a* = 30.09, R = 89%) exhibit brilliant coloristic and reflectance properties. The applicability studies revealed good coloring performance in the polymer matrix and on concrete slab with high solar reflectance. Further, the pigments are proven to be weather resistant in acid/alkali/moisture atmospheres with good thermal stability. These color characteristics with high solar reflectance of sustainable and eco-friendly compositions make them promising colorants for exterior coating formulations to mitigate the cooling energy consumption.
关键词： Yellow and Red pigments,Cerium,Terbium,Solar reflectance
更新于2025-11-21 11:18:25
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A Combined Experimental and Theoretical Insights into the Synergistic Effect of Cerium Doping and Oxygen Vacancies into BaZrO <sub/>3-δ</sub> Hollow Nanospheres for Efficient Photocatalytic Hydrogen Production
摘要： The long-standing debate over the influence of oxygen vacancies and various dopants has been the center point in perovskite-based compounds for their photocatalytic applications. Hydrothermally synthesized Cerium doped BaZrO3 (BZO) hollow nanospheres has been systematically studied by experimental and theoretical calculations to understand the effect of Cerium doping and oxygen vacancies on the photocatalytic properties. Compounds synthesized by a template-free route were composed of hollow nanospheres generated by Ostwald ripening of spherical nanospheres, which were formed by agglomeration of nanoparticles. The high alkaline condition and high temperature during the hydrothermal condition may lead to the formation of local disorders and oxygen vacancies in the compounds, confirmed by ultraviolet-visible diffuse reflectance spectroscopy (UV-Vis DRS), X-ray photoelectron spectroscopy (XPS) and electron spin resonance (ESR) analysis and density functional theoretical (DFT) calculations. Combination of oxygen vacancies and progressive doping of Ce onto BZO, BaZr1–xCexO3 (x = 0.00 – 0.04), creates additional energy levels stipulated by vacancy defects and Ce mixed valance states within the band gap of BZO thereby reducing its band gap. The photocatalytic efficacy of the compounds has been examined by photo-driven H2 generation concomitant with oxidation of a sacrificial donor. In this study, BaZr0.97Ce0.03O3 shows the highest efficiency (823 μmol h-1 g-1) with an apparent quantum yield (AQY) of 6% in photocatalytic H2 production among all five synthesized samples. The data obtained from the UV–Vis DRS, XPS, ESR analysis and DFT calculations, the synergistic effect of decreasing the band gap due to Ce doping and the presence of Ce (III)/Ce (IV) pairs along with oxygen vacancies and lattice distortions could be the reasons behind the enhanced photocatalytic efficacy of BaZr1–xCexO3 (x = 0.00 – 0.04) under UV–Visible light.
关键词： Photocatalytic hydrogen production,Cerium doping,Oxygen vacancies,BaZrO3,Hollow nanospheres
更新于2025-11-21 11:01:37
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A hybrid nanomaterial with NIR-induced heat and associated hydroxyl radical generation for synergistic tumor therapy
摘要： Although photothermal therapy (PTT) and photodynamic therapy (PDT) are widely commended for tumor treatment recently, they still suffer severe challenges due to the non-specificity of photothermal agents (PTAs)/photosensitizers (PSs) and hypoxic tumor microenvironment. Here, an oxygen independent biomimetic nanoplatform based on carbon sphere dotted with cerium oxide and coated by cell membrane (MCSCe) was designed and synthesized with good biocompatibility, homologous targeting ability, and improved photophysical activity. Notably, MCSCe could realize accumulation of hydrogen peroxide (H2O2) in tumor cells and hyperthermia under single laser (808 nm) irradiation, which were simultaneously utilized by itself to produce more toxic hydroxyl radical (·OH). Resultantly, the synergistic therapeutic effect against tumor cells was obtained under near infrared (NIR) laser irradiation.
关键词： cerium oxide,H2O2 self-accumulation,cell membrane,tumor therapy,carbon sphere
更新于2025-11-21 11:01:37
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Effect of conduction band potential on cocatalyst-free plasmonic H <sub/>2</sub> evolution over Au loaded on Sr <sup>2+</sup> -doped CeO <sub/>2</sub>
摘要： There is little information on the effect of the conduction band (CB) position on plasmonic hydrogen (H2) formation under visible light irradiation over gold (Au) nanoparticles supported on semiconductors because there were no appropriate materials for which the CB position gradually changes. In this study, we analyzed the flatband potential of strontium ion (Sr2+)-doped cerium(IV) oxide (CeO2:Sr) and found that the CB position gradually shifted negatively from +0.031 V to ?1.49 V vs. NHE with an increase in the Sr2+ mole fraction. Plasmonic photocatalysts consisting of Au nanoparticles, CeO2:Sr and a platinum (Pt) cocatalyst were prepared and characterized by using X-ray diffraction, UV-vis spectroscopy, and transmission electron spectroscopy. Photocatalytic reaction under visible light irradiation revealed that H2 was produced over Au nanoparticles supported on CeO2:Sr having the CB potential of ?0.61 V vs. NHE and that the negative limit of the CB position for electron injection from Au nanoparticles existed between ?0.61 V and ?1.49 V vs. NHE. We found that Au/CeO2:Sr plasmonic photocatalysts also produced H2 without the aid of a Pt cocatalyst due to the sufficiently negative potential of electrons injected into the CB of CeO2:Sr.
关键词： hydrogen evolution,visible light irradiation,gold nanoparticles,plasmonic photocatalysts,strontium-doped cerium oxide
更新于2025-11-19 16:51:07
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Photocatalytic activity of biosynthesized CeO2 nano particles
摘要： This paper focuses on a cost effective and environment friendly technique for green synthesis of cerium oxide (CeO2) nano particles from cerium (III) nitrate hexahydrate solution by co-precipitation method using the leaf extract of different species of Artemisia pallens which acts as reducing and capping agent. The prepared CeO2 nano particles were characterized by XRD, TEM, FTIR, UV–Vis spectroscopy. The Photocatalytic activity of the prepared ceria powders was determined by their ability to degrade Methylene blue solution under UV-light radiation. The photo degradation result observed with 10 mg/L ceria at pH = 11 for 180 min have highest output and pseudo 1st order rate constant was 0.983.
关键词： Nanoparticles,Photocatalysis,Electronic material,Cerium oxide
更新于2025-09-23 15:23:52
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A Mechanical and modelling study of magnetron sputtered Cerium-Titanium Oxide film coatings on Si (100)
摘要： Ce/Ti mixed metal oxide thin films have well known optoelectrical properties amongst several other physio-chemical properties. Changes in the structural and mechanical properties of magnetron sputtered Ce/Ti oxide thin films on Si (100) wafers with different Ce:Ti ratios are investigated experimentally and by modelling. X-ray Photoemission Spectroscopy (XPS) and X-ray diffraction (XRD) confirm the primary phases as trigonal Ce2O3 and rutile form of TiO2 with SiO2 present in all prepared materials. FESEM imaging delivers information based on the variation of grain size, the mixed Ce/Ti oxides providing much smaller grain sizes in the thin film/substrate composite. Nanoindentation analysis concludes that the pure cerium oxide film has the highest hardness value (20.1 GPa), while the addition of excess titanium oxide decreases the hardness of the film coatings. High temperature in-situ XRD (up to 1000 °C) results indicate high thermal phase stability for all materials studied. The film with Ce:Ti = 68%:32% has a new additional minor oxide phase above 800 °C. Contact angle experiments suggest that the chemical composition of the surface is insignificant affecting the water contact angle. Results show a narrow band of 87.7o to 95.7o contact angle. The finite element modelling (FEM) modelling of Ce/Ti thin film coatings based on Si(100); Si(110); silica and steel substrates shows a variation in stress concentration.
关键词： in-situ X-ray diffraction,Finite element modelling,Nanoindentation,Cerium titanium oxides,Mechanical properties
更新于2025-09-23 15:23:52
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CeO2/TiO2 nanostructures enhance adsorption and photocatalytic degradation of organic compounds in aqueous suspension
摘要： Mixed oxide interfaces are critical in the delivery of active components in photocatalytic processes. Cerium doped TiO2 photocatalysts were prepared using a hydrothermal route to manipulate the morphology of the photocatalyst and improve the interaction between CeO2 and TiO2 nanoparticles. These changes were compared with the photocatalytic activity and adsorption capacity of the solids. The photocatalysts were used to degrade polyvinylpyrrolidone (PVP) and methylene blue (MB) as test compounds. A low photodegradation rate of PVP (0.0001 min?1 and 0.0005 min?1 under visible and UV light, respectively) was observed using Ce-doped photocatalysts, with no adsorption. The high adsorption capacity of MB (34.46 mg g?1) proved that the local morphology of the nanostructured CeO2/TiO2 photocatalysts is more important than the amount of CeO2 in the sample, and the main role of the CeO2 on mixed photocatalysts is to improve thermal stability during the synthesis. XRD, XPS, BET surface area, UV–vis and TEM techniques confirmed this conclusion. The rate of degradation of MB by the Ce-doped photocatalyst decreased dramatically when using the singlet oxygen scavenger L-Histidine (0.0214 min?1 to 0.0001 min?1), indicating a photocatalysis sensitized by the dye, under visible and UV light.
关键词： Cerium,Photosensitization,Reactive oxygen species,Adsorption,Morphology
更新于2025-09-23 15:23:52
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Tailoring lattices of Bi2WO6 crystals via Ce doping to improve the shielding properties against low-energy gamma rays
摘要： In this study, lattices of Bi2WO6 crystals were tuned by cerium doping in a hydrothermal process in order to enhance the shielding properties against low-energy gamma rays. The products obtained were characterized by Raman, X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy, and transmission electron microscopy techniques. The results demonstrated that cerium ions were successfully introduced into the lattices of the Bi2WO6 crystals and they partially replaced the bismuth ion sites. The shielding results showed that 10 mol% cerium doping allowed the Ce-doped Bi2WO6 crystals to shield against 59.5 keV gamma rays at a 49.41% better level compared with the original crystals. The enhanced shielding against low-energy gamma rays was ascribed to the expanded K-edge absorbing area of bismuth after cerium doping. In this study, we developed a facile synthetic method for obtaining Ce-doped Bi2WO6 materials. Importantly, these crystals could be used as functional fillers in rubber composites to prepare wearable products (such as clothing) with desirable shielding properties and no requirement for lead.
关键词： Bismuth tungstate,Gamma ray shielding,Cerium doping
更新于2025-09-23 15:23:52
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Radiation induced luminescence properties of Ce-doped Y2O3-Al2O3-SiO2 glass prepared using floating zone furnace
摘要： We synthesized Y2O3-Al2O3-SiO2 glasses doped with various concentrations of Ce (0, 0.03%, 0.10%, 0.30%, and 1.00%). The glasses were obtained by melt-quenching using an IR mirror furnace, and then they were studied in terms of their optical, dosimetric and scintillation properties. The obtained samples indicated photoluminescence (PL) and scintillation due to the 5d-4f transitions of Ce3+ characterized as a broad emission peaking around 350 nm. The PL and scintillation decay times were 35.4-38.1 ns and 47-109 ns, respectively. The 0.10% Ce-doped sample showed the highest PL quantum yield (20%) among the synthesized samples. The quantum yield was well-correlated with the decay time of PL and scintillation. Thermally- and optically-stimulated luminescence were observed after the irradiation of X-rays (10 Gy). The thermally- and optically-stimulated luminescence spectra were confirmed that the luminescence was due to the 5d-4f transitions of Ce3+ in the 0.03% and 0.10% Ce-doped samples. Overall, the samples showed sensitive response of thermally-stimulated luminescence, and it was the highest for the 0.10% and 0.30% Ce-doped samples, having the dynamic range from 0.01 mGy to 1 Gy.
关键词： Cerium,Scintillator,Dosimeter,Glass
更新于2025-09-23 15:23:52
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Photocatalytic oxidation of thiophene over cerium doped TiO2 thin film
摘要： Samples of TiO2 and TiO2 doped with 2% and 8% cerium ions were prepared by a sol-gel method and used as photocatalysts for the oxidation of vaporized thiophene. X-ray diffraction patterns showed a mixed phase of anatase and rutile for TiO2, while 2%Ce/TiO2 and 8%Ce/TiO2 were dominated by the anatase phase. As seen in the transmission electron microscopy image, the particle size of Ce/TiO2 was about 10 nm which was smaller than the undoped TiO2. The extended x-rays absorption fine structures revealed the substitutional effect of cerium in the TiO2 structure. Cerium-doped TiO2 exhibited a smaller photocurrent compared to that of TiO2, which suggested the electrons were trapped by cerium ions. In situ diffuse reflectance infrared spectroscopy under UV irradiation and x-ray photoemission spectroscopy were used to investigate the photocatalytic oxidation of thiophene on the prepared catalysts. Doping of cerium ions in TiO2 resulted in an enhanced adsorption of thiophene on the catalyst surface. The oxidation products of carboxylic acid with small amounts of sulfate ions were observed. As seen from the infrared absorption spectrum, 2%Ce/TiO2 and 8%Ce/TiO2 exhibited higher photocatalytic activity than those of the undoped TiO2.
关键词： Thiophene oxidation,Thin film,Cerium,Photocatalysis,Titanium dioxide
更新于2025-09-23 15:23:52