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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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Enhanced UV and visible light - driven Photocatalytic degradation of Tartrazine by Nickel-doped Cerium oxide Nanoparticles
摘要： Nickel-doped cerium oxide nanoparticles were synthesized via a simple aqueous coprecipitation method. The synthesized nanoparticles were thoroughly characterized by PXRD, TEM, SEM, EDX, Raman, and UV-Vis spectroscopic techniques. XRD study confirmed the doping of nickel in the cerium oxide lattice. The shift in Raman spectra revealed the formation of nanoparticles in their pure phase with fluorite structure. EDX revealed the formation of a solid solution on doping Ni- to CeO2. SEM images revealed considerable agglomeration. TEM analysis asserted the average particle size of 8-10 nm with a well-defined spherical shape. The particle size was found to be sensitive to dopant concentration, i.e., it decreased with increase in the concentration of the dopant. A comparative UV-visible spectroscopic analysis showed the remarkable red shift in the band gap of nickel-doped cerium oxide nanoparticles. Investigation of photocatalytic activity towards degradation of azo dye tartrazine showed that 3 mol% and 5 mol% Ni- CeO2 nanoparticles exhibited 53.4% and 63.7% photodegradation respectively under visible irradiation while 57.4% and 65.4% respectively under UV irradiation. The study suggests that the band gap of cerium oxide nanoparticles can be easily tuned (decreased) by doping of nickel at different concentrations. The observed improved photocatalytic activity upon Nickel doping is attributed to the narrow band gap.
关键词： azo dye,mechanism,tartrazine,photocatalysis,Nickel-doped cerium oxide nanoparticles
更新于2025-09-23 15:21:01
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Effect of oxygen vacancy on structural, optical, and photocatalytic properties of ceria films grown by magnetron sputtering deposition
摘要： Cerium oxide is of crucial importance for intrinsic redox reaction, which is attributed to the active sites neighboring oxygen vacancies. However, the role of oxygen vacancy (Ov) on the various properties of ceria ?lms remains to be elucidated. Herein, ceria ?lms were deposited by magnetron sputtering and the e?ect of electric current intensity on the creation of Ov was systematically investigated. X-ray photoelectron spectroscopy (XPS) results show that the Ce4+ concentration decreases with the increase of current intensity, which demonstrates that Ov can be created and tuned during ?lm deposition by controlling electric current intensity. The ?lm fabricated by 6 A current intensity has 42% Ce4+, approaching that of rhombohedral-Ce7O12, which is a stabilized bulk phase ceria. X-ray di?raction patterns reveal that 6 A ?lm shows mixed crystalline phases with the majority of peaks very close to rhombohedral-Ce7O12, while 1 A, 2 A, and 4 A ceria ?lms show simple crystalline phase. Raman analysis presents that dioxygen species are heavily absorbed on the surface of 6 A ?lm with more active sites on di?erent crystalline surfaces, which is con?rmed by photocatalytic degradation of Methylene Blue. The calculated bandgap by DFT (density functional theory) + U is consistent with that obtained from Tauc plots curves. This work demonstrates that Ov plays an important role on the properties of the ceria ?lm.
关键词： XPS,Raman,Oxygen vacancy,Magnetron sputtering,Cerium oxide
更新于2025-09-23 15:21:01
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Plasmon-induced Ag decorated CeO <sub/>2</sub> nanorod array for photodetector application
摘要： In this work, glancing angle deposition (GLAD) has been used to grow Ag decorated CeO2 nanorod (NR) array on n-type Si substrate. The length of the NRs obtained was ～235 nm and the size of the Ag NPs varied from 13 to 41 nm. The polycrystalline and crystalline nature of CeO2 and Ag respectively was revealed via selected area electron diffraction (SAED) analysis as well as x-ray diffraction (XRD) pattern. Optical absorption measurement depicts a distinct broad peak around 413 nm that is ascribed to the localized surface plasmon resonance (LSPR) effect of Ag NPs. The Ag decorated CeO2 NR device exhibited a turn on voltage at ～3.2 V under dark, which then reduced to ～1.3 V under 35 min illumination along with the increase in device current from 2.8 to 24.5 μA cm?2 (4 V) on continuous exposure to light. Under white light illumination, a responsivity of 4.51 A W?1 was obtained at 370 nm along with the detectivity and noise equivalent power (NEP) values of 4.15×1012 jones and 0.01 pW respectively. Additionally, a fast response characteristic with rise and fall times of 74 ms and 42 ms respectively was demonstrated. Thus, these findings manifest the underlying LSPR mechanism at work in Ag/CeO2 heterojunction and reveal its high potential in UV photodetector application.
关键词： GLAD,surface plasmon,nanorod,silver,nanoparticle,cerium oxide
更新于2025-09-23 15:19:57
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Effect of Strontium Doping on the Band Gap of $$\hbox {CeO}_{2}$$ CeO 2 Nanoparticles Synthesized Using Facile Co-precipitation
摘要： Pure, 3 mol% and 5 mol% Sr-doped cerium oxide nanoparticles were synthesized by facile aqueous co-precipitation method using cerium nitrate hexahydrate and strontium chloride hexahydrate as the precursors without using any capping agent. The synthesized material was characterized by XRD, SEM, EDX, TEM, Raman spectroscopy and UV–Vis spectroscopic techniques. SEM analysis showed agglomeration of the particles. The Debye–Scherrer analysis revealed ?uorite structure of the synthesized material with crystallite size in 6–10 nm range. TEM con?rmed the spherical morphology of the particles and particle size distribution in the range of 5–8 nm. UV–Vis spectroscopic study revealed that Sr-doping led to increase in the band gap from 3.2 to 3.7 eV and shifting of absorption edge to the lower wavelength. The blue shift in the band gap with the dopant concentration shows that the band gap of doped cerium oxide nanoparticles can be tuned with variation in the dopant concentration.
关键词： Sr-doped cerium oxide,Blue shift,Band gap
更新于2025-09-19 17:15:36
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Highly efficient photocatalytic degradation of rhodamine B by conical graphene quantum dots/cerium oxide composite
摘要： Graphene Quantum Dots (GQDs) are graphene nanoparticles with a particle size of less than 100 nm. GQDs are used as sensitizers for semiconductor catalytic materials and have a significant enhancement effect on the catalytic performance of the catalyst. We have prepared GQDs/CeO2 composites to improve the catalytic performance of CeO2. GQDs in the GQDs/CeO2 composites were uniformly coated around each CeO2 crystal, which effectively increased the reactive sites and effective contact interfaces. The composite GQDs-4.5/CeO2 absorption edge was broadened to 475 nm, with extremely low electron-hole recombination rate and optimal photoelectric performance. The composite material formed a heterogeneous structure with staggered energy levels. The photogenerated electrons were transferred from the GQDs conduction band to the CeO2 conduction band, which effectively prolonged the carrier lifetime, showed enhanced photocatalytic activity, and decomposed Rhodamine B (RhB) photocatalytic reaction under visible light. The reaction rate constant was up to 13.8 times that of pure CeO2.
关键词： Composite,Photocatalytic,Cerium oxide,Graphene quantum dots
更新于2025-09-19 17:13:59
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Systematic enumeration and proficient chemical sensing applications of Eu3+@CeO2 nanocrystals
摘要： Current study displayed the application of hydrothermal method for the preparation of highly crystalline nanocrystals of Eu3+ doped cerium oxide (Eu@CeO2) particles. The influence of doping percentage and annealing effects were studied on the crystalline nature and morphology of particles. The size, optical properties and lattice parameters were calculated as a function of dopant concentrations and their discrepancies were explained in detail. Integration of Eu3+ ions on CeO2 could unlock a new trail to optimize the photoluminescence properties of formed nanocrystals. The generated oxygen vacancies (Vo··) have the ability to affect the characteristic features of cerium oxide in solid state. The variations in the nature of surface defect in presence of Eu3+ ions with CeO2 nanoparticles were explained with the results of XPS studies. The obtained results validated that defect-induced band gap modification by Eu3+ ion doping on CeO2 could be employed as effective chemical sensor for harmful metal ions in real water samples.
关键词： photoluminescence,lattice parameter,crystalline,doped Cerium oxide,oxygen vacancies,hydrothermal
更新于2025-09-11 14:15:04
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Role of oxygen vacancies in Co/Ni Substituted CeO2: A comparative study
摘要： Single phase Co/Ni substituted CeO2 nanoparticles reveal the importance of oxygen vacancies on the electronic properties of the materials. The effect of Co/Ni substitution on the structural, optical, and photoluminescence properties of CeO2 have been studied systematically. Lattice shrinks and hence strain increase owing to incorporation of Co/Ni in CeO2. Optical absorption analysis shows a red shift in band-gap with Co/Ni substitution. Photoluminescence studies reveals increase in defect concentration which causes quenching of PL emission. Vibration-modes at ~460 cm-1 in Raman spectra indicates incorporation of Co/Ni in CeO2 lattice whereas a broad peak appearing at ~ 540-640 cm-1 with substitution depicts the defects related to the increase in oxygen vacancy. X-ray absorption (XAS) studies show that Co/Ni substitution maintains local structure while Ce4+ → Ce3+ concentration increases to preserve the charge neutrality in lattice.
关键词： Oxygen vacancies.,Strain,Bandgap,Urbach energy,Cerium oxide
更新于2025-09-10 09:29:36