Ce-doped Sample Research Articles

Visible LED active photocatalyst based on cerium doped titania for Rhodamine B degradation: Radical's contribution, stability and response surface methodology optimization

In this study, cerium modified TiO2 catalyst was prepared and the performance on the photocatalytic degradation of Rhodamine B (RhB) in aqueous solution was evaluated. For the band gap engineering, three different percentages of Ce-doped TiO2 (3, 5 and 7 % mol) were synthesized using the simple, efficient, and low-cost sol-gel method. Structural, morphological, and optical analysis, performed by XRD-Rietveld, HRTEM, EDX, XPS and UV–Vis DRS techniques, indicate the formation of nanostructured Ce-doped TiO2 system with anatase phase and band gap in the visible range. Then, Ce-doping percentage, dose of photocatalyst and initial concentration of RhB effects on the removal efficiency were evaluated. The high removal efficiency of 70 % within 150 min was recorded under the condition of: 7 % Ce-doped TiO2 sample, 1.33 g L−1 of dose, and a concentration of RhB of 5 mg L−1. Additionally, a response surface methodology (RSM) was developed for stablish optimal degradation parameters when varying relevant factors for water treatment of real effluents: pH, NaCl, and Cu concentrations. The resulting model shows that the pH is the variable with the highest effect on the photodegradation. Finally, a scavenger study revealed that OH• radicals play a key role in the reaction; and, albeit TOC analysis reveals only 8.55 % of mineralization yield. Cycling study shows that the photocatalyst kept active after 3 cycles of reutilization. The present paper further examinates the parameters affecting Visible LED driven degradation of organic dye in water using Ce-doped TiO2 system and represents an advance in the comprehension of dye degradation with low use of energy.

Impact of Ce doping on the optoelectronic and structural properties of a CsPbIBr2 perovskite solar cell.

This paper provides a detailed analysis of pure CsPbIBr2 and 4% Ce-doped CsPbIBr2 perovskite films, emphasizing their structural, optical and photovoltaic properties. X-ray diffraction confirms a predominant cubic perovskite phase in both samples, with Ce doping leading to the increased crystal size (21 nm to 32 nm). UV-vis spectroscopy reveals a reduced bandgap energy (2.2 eV to 2.1 eV) with Ce doping. Dielectric constant analysis indicates the enhanced permittivity of the Ce-doped sample, crucial for solar-cell light trapping. Energy band structure analysis demonstrates improved photovoltaic cell performance with Ce doping, yielding higher open-circuit voltage, short-circuit current, and efficiency (9.71%) compared to pure CsPbIBr2 (8.02%). Ce doping mitigates electron-hole recombination, enhancing cell stability, electron affinity, and power output. This research underscores the potential of cost-effective, efficient, and stable CsPbIBr2 perovskite solar cells.

Enhancing Methyl Orange Degradation with Laser-Generated ZnO and Ce-Doped ZnO Nanoparticles

The presence of Methyl Orange, a hazardous organic compound typically found in industrial wastewater, presents a significant environmental challenge, necessitating the development of effective strategies for its removal to mitigate adverse impacts on aquatic ecosystems and human health. In this work, we utilized 60-watt continuous-wave (CW) and high-power CO2 laser with 10.6 μm wavelength to synthesize Zinc Oxide nanoparticles (ZnO NPs) doped with 1% Cerium (Ce) as photocatalyst at standard laboratory conditions through Laser-Assisted Chemical Bath Synthesis (LACBS) technique. The synthesized nanostructures were thoroughly characterized using UV–vis spectroscopy, field-emission scanning electron microscopy (FESEM), and X-ray diffraction (XRD) techniques. Subsequently, their efficiency in degrading Methyl Orange (MO) dye was evaluated under UV and sunlight irradiation. The findings revealed that the 1% Ce-doped ZnO sample exhibited enhanced photocatalytic efficiency under both UV and sunlight irradiation, as well as active adsorption capabilities in the absence of light. Notably, the most effective photodegradation performance was achieved under solar radiation, with an impressive 95% of MO dye degradation observed after just 90 min of exposure.

Cerium-Doped Iron Oxide Nanorod Arrays for Photoelectrochemical Water Splitting.

In this work, a simple one-step hydrothermal method was employed to prepare the Ce-doped Fe2O3 ordered nanorod arrays (CFT). The Ce doping successfully narrowed the band gap of Fe2O3, which improved the visible light absorption performance. In addition, with the help of Ce doping, the recombination of electron/hole pairs was significantly inhibited. The external voltage will make the performance of the Ce-doped sample better. Therefore, the Ce-doped Fe2O3 has reached superior photoelectrochemical (PEC) performance with a high photocurrent density of 1.47 mA/cm2 at 1.6 V vs. RHE (Reversible Hydrogen Electrode), which is 7.3 times higher than that of pristine Fe2O3 nanorod arrays (FT). The Hydrogen (H2) production from PEC water splitting of Fe2O3 was highly improved by Ce doping to achieve an evolution rate of 21 μmol/cm2/h.

Preparation of magnetic core-shell Ce-doped zirconia and its As(III) adsorption properties

A new magnetic mesoporous As(III) adsorbent of Fe3O4@SiO2@Ce-ZrO2 was prepared by solvothermal and sol-gel method. The core-shell adsorbent presented a high specific surface area (168.2 m2/g) and fast magnetic separation performance (5.37 A·m2/kg). Compared with Fe3O4@SiO2@ZrO2, the Ce-doped sample exhibited 12%-23% increase in As(III) uptake over pH 3-11, which was mainly attributed to the formation of bimetal M—O—As complexes. The coexisted and weakened As(III) adsorption, Ca2+ worked oppositely, but the impact of Cl- and was negligible. The As(III) maximum adsorption capacity was 24.52 mg/g at 313 K with an initial As(III) concentration of 5 mg/L at pH 7, and its kinetics was well fitted by the pseudo-second-order model. Moreover, the adsorbent exhibited remarkable recyclability. It is suggested that Fe3O4@SiO2@Ce-ZrO2 is a promising adsorbent for the advanced treatment of As(III) contaminated wastewater.

Ce concentration dependence on scintillation properties of Ce-doped yttrium pyrosilicate single crystal

Yttrium pyrosilicate (Y2Si2O7) single crystals are successfully grown by the floating-zone method with 0.5–10.0% of Ce-doping concentration. X-ray diffraction patterns indicate a single phase of Y2Si2O7 without the impurity phase. The series photoluminescence (PL) and scintillation properties are systematically explored in this study, including PL emission, PL decay time, X-ray induced scintillation spectra, X-ray induced scintillation decay time, afterglow profile, and pulse height spectra. Ce-doped Y2Si2O7 is presented interesting properties including the intense emission band at 390 nm from Ce3+ 5d-4f transition on both PL emission contour maps as well as X-ray-induced scintillation spectra in all samples. The afterglow level at 20 ms after X-ray irradiation of the Ce-doped YPS is comparable with commercial scintillators such as CdWO4 and Tl-doped CsI. Under 137Cs (662 keV) γ-ray irradiation 137Cs (662 keV), the highest scintillation light yield of Ce-doped Y2Si2O7 is reach up to 17,200 ph/MeV for 2.0% Ce-doped sample.

Characterization of CaSiO3:Ce crystals for α- and X-ray detection

CaSiO3 crystals doped with 0.5%, 1.0% and 2.0% Ce were developed using the floating zone method, and the scintillation and thermally-stimulated luminescence (TSL) properties were evaluated. Under X-ray irradiation, the emission peaks due to the 5d–4f transitions of Ce3+ appeared at 360 nm in all the samples. Under 241Am 5.5 MeV α-ray irradiation, a clear full-energy peak appeared in all the samples, and the light yield of the 2.0% Ce doped-sample was 1040 ph/5.5 MeV-α. As a TSL dosimeter, the samples were very sensitive to X-rays and showed a good linear response from 0.1 to 1000 mGy, which was equivalent to the measurable sensitivity of commercial dosimeters for personal dose monitoring.

Pure and Ce-doped spinel CuFe2O4 photocatalysts for efficient rhodamine B degradation

Wastewater management is becoming a serious issue worldwide. To enhance the reuse of wastewater, one has to remove toxic pollutants present in it. High amount of dye is present in wastewater, and to remove these dyes is the large scope of this research. Herein, we report production of pure and Ce-doped copper ferrite via hydrothermal route. The synthesized nanoparticles were collected and analyzed by basic characterization techniques. The bandgap energy calculated for pure, 1% Ce, and 2% Ce-doped CuFe2O4 was found to be 2.77, 2.57, and 2.36eV, respectively. Reduction in bandgap was attributed to the doping element. The shape and size of pure and Ce-doped products were investigated using a scanning electron microscope. Agglomeration was observed in the pure copper ferrite sample. In the Ce-doped sample, agglomeration was clearly reduced and the 2% Ce-doped CuFe2O4 sample showed growth of small nanoparticles. They showed complete growth and were arranged in a uniform manner without agglomeration. The surface area of the 2% Ce–CuFe2O4 sample was found to be 65.89 m2/g with 7.02 nm pore diameter. The photocatalytic activity of the prepared material was observed for rhodamine B degradation. The pure and catalyst-added dye was exposed under visible light. The samples were tested for UV. The efficiency obtained for pure dye solution, pristine CuFe2O4-added, and 1% Ce and 2% Ce-doped CuFe2O4-added dye solutions were 48%, 50%, 66%, and 88% within 2 h of irradiation. The 2% Ce-doped CuFe2O4 sample showed excellent photocatalytic activity as the bandgap and morphology were enhanced by doping an appropriate ratio of Ce ions.

Photoluminescence and scintillation properties of Ce-doped SrY2O4 single crystals

Photoluminescence (PL) and scintillation properties of Ce:SrY2O4 single crystals were investigated. The PL quantum yield (QY) of the 2 % Ce-doped sample was the highest, and it decreased in the high Ce concentrations samples. The undoped SrY2O4 single crystal exhibited a broad emission band at 380 nm due to host defects, and the scintillation decay time constant was about 4.2 μs. The pulse height spectrum of 137Cs γ-rays using the undoped SrY2O4 single crystal revealed the scintillation light yield of 830 photons/MeV.

Photocatalytic Reduction of Cr(VI) on a 3.0% Au/Sr0.70Ce0.20WO4 Photocatalyst.

Herein, a 3.0%-Au/Sr0.70Ce0.20WO4 sample was prepared for the photocatalytic reduction of the Cr2O72– ion. The photocatalyst was characterized by X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy, and ultraviolet–visible diffuse reflectance spectra. The Sr0.70Ce0.20WO4 sample presented a photocatalytic reduction activity that is better than those of the Ce-doped sample and the intrinsic sample. Thereafter, different metal elements, Cu, Ag, Au, and Pt, were used as cocatalysts, which were loaded on the Sr0.70Ce0.20WO4 sample. The 3.0%-Au/Sr0.70Ce0.20WO4 photocatalyst showed optimal photocatalytic reduction activity in a 8 vol % methanol solution (pH = 7) under visible light irradiation. The kinetic constant of the optimal one is 0.0039 min–1, which is 1.86 times that of the Sr0.70Ce0.20WO4 sample. The photocatalyst is stable enough after a 24 h photocatalytic experiment.

Theoretical and experimental investigation of magnetic properties of iodine and cerium Co-doped Bi2Te3 nanoparticles

A long-range magnetic order in the topological insulator (Bi2Te3) achieved a great interest by the doping of magnetic elements on to Bi and Te-sites. The magnetic moments can be introduced by adding trivalent rare-earth elements such as Ce and I. In this report, Bi2Te3, Ce0.2Bi1.8Te3, and Ce0.2Bi1.8Te2.9I0.1 nanoparticle were synthesized by the novel low-temperature double solvent sol-gel technique. The co-doped nanoparticles were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), high-resolution transmission electron microscopy (HRTEM), physical properties measurement system (PPMS), and vibrating sample measurement system (VSM). The VSM studies showed that the magnetization (M) of pure Bi2Te3 sample was successfully increased by adding iodine onto the Ce-doped sample (Ce0.2Bi1.8Te2.9I0.1). For in-depth analysis, PPMS results revealed that the as-synthesized samples exhibit paramagnetic nature which then exchange into antiferromagnetic behavior after substituting Ce I onto Bi2Te3, at a varying temperature range from 0 to 400K. The density functional theory (DFT) was also performed to understand the exchange-biased phenomenon for as-synthesized samples. Moreover, the experimental results can predict that the magnetic samples synthesized by the novel double solvent sol-gel method can provide magnetic materials with large remnant magnetization compared with the pure Bi2Te3.

Photoluminescence and scintillation properties of Ce-doped CaBr2 crystals

Ce-doped CaBr2 crystals were evaluated for photoluminescence (PL) and scintillation properties. The samples showed PL peaking at 370 and 400 nm and decay time constants of 22 ns, which were due to 5d–4f transitions of Ce3+ ions. The PL maximum quantum yield was 66.1% in the 1% Ce-doped sample upon excitation at 340 nm. Under X-ray irradiation, the samples showed an emission peak at 400 nm due to the 5d–4f transitions of Ce3+ ions. The 0.1% Ce-doped sample showed intrinsic emission at around 590 nm as well. From the scintillation decay curves, the two components with decay time constants of ∼20 and 200–400 ns were obtained. Their origins would be attributed to the 5d–4f transitions of Ce3+ ions and intrinsic emission, respectively. From the pulse height spectra, the light yield of the 0.1% Ce-doped sample was 50 ph/5.5 MeV-α.

Photoluminescence and scintillation characteristics of Ce-doped CaLaAl3O7 crystalline scintillators for detecting alpha particles

Undoped and Ce-doped CaLaAl3O7 crystals were synthesized by the optical floating zone method and photoluminescence and scintillation properties were evaluated. A broad peak at 420 nm due to the 5d-4f transitions of Ce3+ is observed from the Ce-doped samples based on the measurement of photoluminescence and scintillation spectra. The photoluminescence and scintillation decay time constants attributable to the 5d-4f transitions of Ce3+ are obtained in the Ce-doped samples. The 1.0% and 3.0% Ce-doped samples show relatively high scintillation light yields of 230–260 ph/5.5 MeV-α from pulse height analysis under irradiation of α-rays from 241Am. The best afterglow level is 160 ppm in the 3.0% Ce-doped sample among the present samples.

Scintillation properties of BaSiO3:Ce crystals by the floating zone method

We developed BaSiO3:Ce crystals with different Ce concentration of 0.5, 1.0 and 2.0 % using the floating zone method, and evaluated the PL, scintillation and ionizing radiation induced storage luminescence properties. Under X-ray irradiation, a broad emission band appears at around 400 nm due to 5d–4f transitions of Ce3+. The decay time constants are in a range of 43–47 ns, which is a typical time constant of 5d-4f transitions of Ce3+. Under 137Cs γ-ray irradiation, only the 1.0 % Ce-doped sample shows a photoabsorption peak, and the scintillation light yield is ∼1500 ph/MeV. The results of pulse height spectra and TSL glow curves demonstrates a complementary relationship between scintillation and ionizing radiation induced storage luminescence properties in this material.

Photoluminescence and scintillation properties of Ce-doped barium silicate glasses synthesized by the FZ method

This paper presents the results of photoluminescence and X-ray induced scintillation properties of xCe:33.3BaO-66.6SiO2 (x = 0, 0.05, 0.1, 0.5, 1.0, 2.0) glasses produced by the Floating Zone (FZ) method. We observed intense emission from 5d–4f transition of Ce3+ and the concentration quenching with the increase of Ce concentration in photoluminescence (PL) and scintillation properties. The lowest Ce-doped sample indicated the highest scintillation intensity in the X-ray induced scintillation measurement. The non-doped sample had the highest afterglow level, and the afterglow levels decreased with Ce addition amount. From these results, it was found to be in a trade-off relationship between the scintillation intensity the and afterglow characteristics in present samples.

Ce-concentration dependence in CaYAl3O7 single crystalline scintillators

0–3% Ce-doped CaYAl3O7 single crystals were grown by the optical Floating Zone method, and the photoluminescence and scintillation properties were measured. Except for the undoped sample, all the samples show photoluminescence and scintillation dominantly with a broad band around 380–520 nm due to the 5d-4f transitions of Ce3+. The decay curves are well-fitted by one or a sum of two exponential functions. The 1st and the 2nd components are due to the 5d-4f transition of Ce3+ and intrinsic luminescence in the host material, respectively. Suggested from the pulse height spectra under irradiation of γ-rays from 137Cs, the 0.3% Ce-doped CaYAl3O7 sample shows the highest scintillation light yield of 5400 ph/MeV among the present samples. The energy response exhibits proportional relationship between channel number and radiation energy in the dynamic range of 22–1408 keV.

Correlated N/O anion orders in melilite phosphors

The N/O anion distributions in the melilite-type phosphor host material Y2Si3O3N4 and a Ce-doped sample Y1.5Ce0.5Si3O3N4 have been determined from powder neutron diffraction. Both materials have a highly ordered N/O distribution that is not changed significantly by the disorder introduced by Ce doping. This distribution evidences the presence of SiN3O and SiN2O2 tetrahedra and although these are not fully long range-ordered, local structural correlations follow simple connectivity rules that lead to an estimated residual molar entropy of R ln3. A broad range of N/O environments is found around 8-coordinate Y(Ce) sites which is expected to broaden their spectroscopic features.

Scintillation properties of xCe:30Rb2O-30BaO-10Al2O3-30P2O5 glasses

This paper presents the results of photoluminescence and X-ray induced scintillation properties of xCe:30Rb2O-30BaO-10Al2O3-30P2O5 (x = 0, 0.1, 0.5, 1.0, 5.0) glasses produced by the melt-quenching method. We observed the concentration quenching increasing with Ce concentration in PL and scintillation properties. The Ce-doped samples indicated intense luminescence and scintillation, and the 0.5% Ce-doped sample indicated the highest scintillation intensity. The afterglow levels of our samples were very low comparable to that of conventional CsI:Tl. Taking into account all the properties investigated here, the 0.5% Ce-doped sample showed the best performance as a scintillator among the present samples.

Complex Garnets: Microscopic Parameters Characterizing Afterglow

Light yield, time response, afterglow, and thermoluminescence of Ce-doped garnet scintillators and persistent luminescent materials are controlled by a complex interplay between recombination and trapping/detrapping processes. Extensive research has contributed to a good qualitative understanding of how traps, impurities, and the presence of Ce4+ affect the materials properties. In this work we present a quantitative model that can explain the thermoluminescence and afterglow behavior of complex garnets. In particular, the model allows the determination of capture rates and effective capture radii for electrons by traps and recombination centers in Lu1Gd2Ga3Al2O12:Ce garnet ceramics. The model relies on solving a set of coupled rate equations describing charge carrier trapping and recombination in garnet ceramics doped with Ce and also codoped with a known concentration of an intentionally added electron trap, Yb3+. The model is supported by analysis of a complete set of experimental data on afterglow, rise-time kinetics, and X-ray excited luminescence which show that thermoluminescence/afterglow are governed by trapping/detrapping processes following interactive kinetics with dominant recombination channel. The underlying reason for dominant recombination is the presence of a small fraction of Ce4+ (≈2 ppm in the 0.2% Ce-doped sample) which have a very high capture cross section (≈2.7 A effective radius) because of the Coulomb attractive nature of this recombination center. The quantitative insights on capture cross sections and concentrations of Ce4+ help to better understand the optical properties of Ce-doped garnet scintillators and persistent luminescent materials and serve in optimizing synthesis procedures by tuning the Ce3+/Ce4+ ratio by codoping with divalent cations and annealing in an oxygen-containing atmosphere.

X-ray induced luminescence properties of Ce-doped BaF2-Al2O3-B2O3 glasses

In this study, we have synthesized xCeF3-(30-x)BaF2-20Al2O3-50B2O3 (x = 0, 0.3, 1.0, 3.0, 5.0 and 10.0 mol%) glasses by the conventional melt-quenching method and then investigated the optical properties (transmittance spectra, photoluminescence (PL) spectra and PL decay times), scintillation properties under X-rays irradiation (scintillation spectra and scintillation decay times) and thermally-stimulated luminescence (TSL) properties (glow curves and dose response functions). The PL spectra of the Ce-doped samples consist of an intense emission band due to the 5d-4f transitions of Ce3+ ion peaking at 350–400 nm, and PL quantum yield value was 70.1%. The decay time of the latter emission slightly varied in a range of 32–36 ns depending on the Ce concentration. The Ce-doped samples have also shown strong scintillation under X-ray irradiation having a spectrum of an intense emission band. The peak position around 300–400 nm with the Ce3+ concentration, and the decay time ranged 19–44 ns. The scintillation light yield of 5.0% Ce-doped sample was the highest among the present samples, and the measured value was 1,800 ph/MeV under 137Cs γ-ray exposure.