Incorporation Of Gd Research Articles

Gadolinium-dominant monazite and xenotime: Selective hydrothermal enrichment of middle REE during low-temperature alteration of uraninite, brannerite, and fluorapatite (the Zimná Voda REE-U-Au quartz vein, Western Carpathians, Slovakia)

AbstractA hydrothermal quartz vein with REE-U-Au mineralization in the Zimná Voda (Gemeric Unit, Western Carpathians, Slovakia) is associated with contact metamorphism between Permian granites and host phyllites and metaquartzites. It contains unique REE minerals of the monazite and xenotime groups. Monazite-(Ce), monazite-(Nd), monazite-(Sm), and Gd-dominant monazite [“monazite-(Gd)”], along with xenotime-(Y) to Gd-dominant xenotime [“xenotime-(Gd)”] and Gd-rich hingganite-(Y) show heterogeneous compositions and reflect a strong fractionation trend toward the enrichment of MREE (Sm to Dy), particularly Gd. Here, the gadolinium abundance reported in “monazite-(Gd)” (≤23.4 wt% Gd2O3) and Gd-rich xenotime-(Y) to “xenotime-(Gd)” (≤28.7 wt% Gd2O3) and accompanied by Gd-rich hingganite-(Y) (≤15.8 wt% Gd2O3), is among the highest Gd concentrations ever reported in natural minerals. The Gd-richest compositions show the following formulas: (Gd0.31Sm0.24 Nd0.15Ce0.10La0.05Dy0.03Y0.03…)0.98PO4 [“monazite-(Gd)”], (Gd0.36Y0.32Dy0.13Sm0.08Tb0.05…)0.98 (P0.96As0.04)1.00O4 [“xenotime-(Gd)”] and (Y0.71Gd0.43Dy0.23Sm0.22Tb0.06Er0.04Nd0.06…Ca0.06)1.96 (☐0.87Fe0.132+)1.00(Be1.82B0.18)2.00(Si1.90As0.10)2.00O8(OH1.70O0.30)2.00 [hingganite-(Y)]. The MREE-rich monazites, xenotimes, and hingganite-(Y) precipitated in response to the alteration of primary uraninite, brannerite, and fluorapatite by low-temperature hydrothermal fluids of heterogeneous compositions on a microscale. These are responsible for the strong enrichment of individual MREE, especially Gd in the secondary minerals. This is accompanied by the advancing development of the W-type tetrad effect on REE through monazite species. The substantial incorporation of Gd into both REE-selective monazite and xenotime structures that are accompanied by LREE vs. HREE segregation indicates the possibility of differently sized REE3+ miscibility in REEPO4 solid solutions, as well as the stabilization of the Gd-rich orthophosphate structure by substitution of the remaining A-site cations with smaller HREE+Y in the xenotime-type, and/or larger LREE in the monazite-type structure.

Modulation of optical, photophysical and electrical properties of poly(3-hexylthiophene) via Gd:CdS nanoparticles

Herein, the impact of Gadolinium (Gd) doped cadmium sulphide (CdS) nanoparticles on the structural, optical, photophysical and electrical properties of poly(3-hexylthiophene) (P3HT) thin films have been investigated. The structural, morphological and vibrational properties of fabricated films were probed by measuring X-ray diffraction spectra, scanning electron microscope images and FT-Raman spectra, respectively. The absorption spectra of P3HT thin films was noted to be red shifted and energy bandgap slightly decreases with incorporation of Gd:CdS nanoparticles. The extinction coefficient (k), refractive index (n) and dielectric constants (εr, εi) of pure and hybrid films were extracted from spectroscopic ellipsometer data fitted by new amorphous dispersion model (for P3HT) and Adachi-New Forouhi dispersion model (for CdS) and noted that the optical constants decreases with increase of Gd:CdS nanoparticles concentrations. The photoluminescence intensity of P3HT/Gd:CdS films was quenched as compare to pristine P3HT, also an additional bands observed in hybrid films corresponds to emission from Gd:CdS nanoparticles. The average fluorescence life times of pristine P3HT thin films was evaluated to be 154 ps which drop to 109 ps for hybrid film, ascribes to formation of additional decay paths created due to Gd:CdS doping. The electrical resistivity (ρ) and mobility (μ) of P3HT films were measured from Hall Effect systems and noted to be decreases for hybrid films whereas charge carrier concentration (nC) and sheet resistance (RS) increases.

Oxygen vacancies and defects tailored microstructural, optical and electrochemical properties of Gd doped CeO2 nanocrystalline thin films

In this study, the authors present a pure and Gadolinium (Gd) doped CeO2 nanostructures, successfully elaborated onto the glass and Indium Tin Oxide (ITO) coated glass substrates under optimized parameters. A spray pyrolysis method was used at a temperature of 450 °C, with simultaneous incorporation of Gd at various concentrations (0, 2, 4, 6, 8 at. %) as a dopant. Different techniques for characterization were used to study the Gd impact on the microstructural, the morphological, the optical and the electrochemical behaviors of the CeO2 material. The XRD patterns shows that Gd3+ ions are inserted at the Ce4+ ion sites in the cubic fluorite structure network of CeO2 nanocrystals (NCs). Raman spectroscopy and UV–Vis–NIR have been utilized to study the defect structure and optical behaviors in these NCs. Broadening and Peak asymmetry of Raman active mode are attributed to the existence of Ce3+ and oxygen vacancy, which have been changed with addition of Gd3+ ions in CeO2 NCs. The results of UV–Vis–NIR spectroscopy show the variations of the optical gap energy with fluencies of Gd3+ due to the variations of particles sizes of NCs. Cyclic voltammetry results show that the ion storage capacities (ISC) of CeO2 thin films are increased with Gd doping. This research paper reports on the fluencies of Gd doping in CeO2 nanocrystals, to understand the role of oxygen vacancies and the impact they have on the tailoring of the microstructural, optical and electrochemical behaviors of doped CeO2 nanocrystals for multiple applications such as, catalysts, oxygen transportation, ultraviolet fuel cells, and electrochromic devices etc.

Investigation on the Structural and Electrical Properties of ZnO Thin Films Co-Doped with Rare Earth Gd and Al Prepared by Co-Sputtering Method

Undoped ZnO, Gd-doped ZnO, and (Al, Gd) co-doped ZnO thin films were synthesized using the co-sputtering technique on a glass substrate. XRD data confirmed all the films are hexagonal structures with dominant (002) diffraction peaks. There are no secondary phases or other peaks detected except for ZnO which proves well incorporation of Gd3+ and Al3+ ions into ZnO ions for Gd and (Al, Gd) co-doping ZnO thin films. The EDX analysis shows the composition of Al, Gd, Zn, and O for (Al, Gd) co-doped ZnO thin films considering the successfully doping of Gd and Al into ZnO structure by this deposition method. As compared with undoped ZnO and Gd-doped ZnO, the electrical properties of (Al, Gd) co-doped ZnO showing a good enhancement of carrier concentration (2.34 x 1026 m-3) and electrical conductivity (1.41 x 105 Ωm-1) whereas the resistivity is low about 7.11 x 104 Ωcm.

Size controlling and tailoring the properties of Gd Zn1-O nanoparticles

In this study, we report on the successful synthesis and characterization (structural, optical, and magnetic properties) of Gd x Zn 1- x O nanoparticles ( x = 0.000, 0.005, 0.010, 0.030, 0.050, 0.075, and 0.100). Synthesis was carried out using the polymer precursor method (Pechini's method). X-ray diffraction patterns (XRD), FTIR and Raman spectra of all samples indicated the formation of the hexagonal wurtzite phase. No evidence of impurity phases was detected for samples with x ≤ 0.050. Additionally, analysis of the XRD data showed that the increase of the Gd-doping content leads to a tendency of particle size decrease, which is in good agreement with the observed transmission electron microscopy (TEM) micrographs. The UV–Vis spectra showed that the incorporation of Gd 3+ ions leads initially (for x ≤ 0.030) to a decrease and later on (for x > 0.030) in a reopening of the Gd x Zn 1- x O band gap. Magnetic measurements showed the coexistence of ferromagnetic (FM) and paramagnetic (PM) phases for the x = 0.010 sample at room temperature. However, for x > 0.010, only a PM phase is observed, which was attributed to the presence of intrinsic defects, such as oxygen vacancies. These defects may have their content increased by the insertion of low levels of Gd. The magnetic data ( χ ( T ) and M ( H ) ) were successfully fitted by the Curie-Weiss and Brillouin modified models, which showed the existence of antiferromagnetic (AF) interaction between Gd 3+ ions.

Modifying the magnetic response of magnetotactic bacteria: incorporation of Gd and Tb ions into the magnetosome structure.

Magnetotactic bacteria Magnetospirillum gryphiswaldense MSR-1 biosynthesise chains of cube–octahedral magnetosomes, which are 40 nm magnetite high quality (Fe3O4) nanoparticles. The magnetic properties of these crystalline magnetite nanoparticles, which can be modified by the addition of other elements into the magnetosome structure (doping), are of prime interest in a plethora of applications, those related to cancer therapy being some of the most promising ones. Although previous studies have focused on transition metal elements, rare earth (RE) elements are very interesting as doping agents, both from a fundamental point of view (e.g. significant differences in ionic sizes) and for the potential applications, especially in biomedicine (e.g. magnetic resonance imaging and luminescence). In this work, we have investigated the impact of Gd and Tb on the magnetic properties of magnetosomes by using different complementary techniques. X-ray diffraction, transmission electron microscopy, and X-ray absorption near edge spectroscopy analyses have revealed that a small amount of RE ions, ∼3–4%, incorporate into the Fe3O4 structure as Gd3+ and Tb3+ ions. The experimental magnetic characterisation has shown a clear Verwey transition for the RE-doped bacteria, located at T ∼ 100 K, which is slightly below the one corresponding to the undoped ones (106 K). However, we report a decrease in the coercivity and remanence of the RE-doped bacteria. Simulations based on the Stoner–Wohlfarth model have allowed us to associate these changes in the magnetic response with a reduction of the magnetocrystalline (KC) and, especially, the uniaxial (Kuni) anisotropies below the Verwey transition. In this way, Kuni reaches a value of 23 and 26 kJ m−3 for the Gd- and Tb-doped bacteria, respectively, whilst a value of 37 kJ m−3 is obtained for the undoped bacteria.

Structural, optical, and dispersive parameters of (Gd, Mn) co-doped BiFeO3 thin film

Nanocrystalline bismuth ferrite thin films co-doped with Gd and Mn were successfully fabricated via sol-gel spin coating method onto the corning glass substrate. The effect of Gd and Mn incorporation at A and B sites of bismuth ferrite perovskite on its structural, microstructural, and optical properties was studied systematically. The starting material for the synthesis of the samples was bismuth nitrate, ferrite nitrate, gadolinium nitrate and manganese acetate. These precursors were dissolved in 2-methoxy ethanol to prepare the sol, which was spin-coated at an optimized rate of 3000 rpm for 30 s on corning glass substrate. The samples were heated subsequently at 350 °C for 5 min on a hot plate in the open air and further annealed at 550 °C for 2 h at a muffle furnace for crystallization of the as-prepared thin film. X-ray diffraction analysis reveals the existence of distorted rhombohedral perovskite structure with preferred orientations along the (101) plane. The incorporation of Gd and Mn in bismuth ferrite perovskite was confirmed from Raman spectra measured at room temperature. Surface morphology and microstructural studies were carried out using Atomic Force Microscopy (AFM) and Field Emission Scanning Electron Microscopy (FESEM). Several optical parameters like bandgap energy, Urbach energy, Extinction co-efficient, Near Edge Absorption ratio were determined from Ultraviolet–Visible spectra of the film prepared. The variation of refractive index, permittivity, loss tangent as a function of wavelength were plotted and discussed. Real and imaginary parts of dielectric functions as a function of wavelength were reported. The correlation between the structural and the microstructural parameters with the optical parameters was investigated in this work.

Unveiling the effect of Gd–Co co-substitution in the enrichment of structural and dielectric properties of SrBaMn based magnetic oxide

Nano-crystalline Gd–Co substituted X-type hexagonal ferrites having formula SrBaMn2-xCoxGdyFe28-yO46 (where x = 0–1, y = −0.1) were synthesized employing sol-gel route. X-ray diffraction technique verified the formation of pure phase X-type ferrites for all samples. Crystallite size was reduced from 27.49 to 24.52 nm with Gd–Co concentration, which is favorable for attaining an appropriate signal-to-noise ratio in electronic devices. Lattice constants (a, c), bulk, and X-ray density slightly increased owing to the large ionic radius and density of Gd3+ ions than Fe3+ ions. Fourier transform infra-red spectroscopy displayed absorption bands in the lower wavenumber range (482-584 cm−1). The higher absorption bands (482-584 cm−1) are due to metal-oxygen vibration octahedral and tetrahedral sites. The influence of Gd–Co on dielectric properties such as dielectric constant, tangent loss, ac conductivity, and Q-value on frequency and composition were investigated in the frequency region of 1 MHz–3 GHz. The incorporation of Gd–Co resulted in the enhancement of dielectric properties of as-prepared X-type materials desired in electromagnetic devices operating at microwave frequencies. Electric modulus analyses indicated the contribution of grain boundary towards resistance.

Synthesis of hierarchical structured Gd doped α-Sb2O4 as an advanced nanomaterial for high performance energy storage devices

Bimetallic oxide nanostructures (NS) of Gdx: α-Sb2O4 (x = 5, 8, 10 wt.%) emerged as novel electrode material for batteries as they exhibit large specific capacity and cyclic stability. Crystal structure of Gd: α-Sb2O4 NS investigated by X-ray diffraction (XRD) patterns and identified as mixed orthorhombic phase. Surface chemical composition, binding energies of the metal oxides and incorporation of Gd into α-Sb2O4 NS analysed by XPS (X-ray photoelectron spectral) studies. Microstructure analysis reveals that distinctive flower/flake like arrays with agglomeration. Morphology, structure and physical/chemical properties of the resulting nanostructure were analysed by SEM (scanning electron microscopy), SEM-EDX (scanning electron microscopy-energy dispersive X-ray), BET (Brunauer-Emmett-Teller), XPS, UV-Visible and XRD studies. Electrochemical performances of Gdx: α-Sb2O4 (x = 10 wt.%) in 6 M KOH aqueous solution dipped in three electrode system evaluated by CV (cyclic voltammetry), GCD (galvanostatic charge-discharge) and EIS (electrochemical impedance spectroscopy) measurements. The as-synthesized NS exhibited higher specific capacitance of 958 mAh/g at a current density of 0.15 A/g and excellent cyclic stability with 86.5% capacitive retention after 1000 cycles. Distinctive flower/flake like structure, large surface area, and abundant active sites of Gdx: α-Sb2O4 NS could be the reason for significant increase in charge transfer and storage. In brief this work offers facile method to synthesize Gdx: α-Sb2O4 NS are promising electrode materials for potential applications in high performance super capacitor.

Bifunctional Paramagnetic and Luminescent Clays Obtained by Incorporation of Gd3+ and Eu3+ Ions in the Saponite Framework.

A novel bifunctional saponite clay incorporating gadolinium (Gd3+) and europium (Eu3+) in the inorganic framework was prepared by one-pot hydrothermal synthesis. The material exhibited interesting luminescent and paramagnetic features derived from the co-presence of the lanthanide ions in equivalent structural positions. Relaxometry and photoluminescence spectroscopy shed light on the chemical environment surrounding the metal sites, the emission properties of Eu3+, and the dynamics of interactions between Gd3+ and the inner-sphere water placed in the saponite gallery. The optical and paramagnetic properties of this solid make it an attractive nanoplatform for bimodal diagnostic applications.

Investigating structural, magnetic and multiferroic properties of gadolinium substituted strontium hexaferrite (SrFe12-xGdxO19)

An economical and citrate precursor based sol-gel technique is employed for pure phase synthesis of Gd3+ substituted M-type strontium hexaferrite (SrFe12-xGdxO19) for x = (0.25 - 1.00). The XRD patterns reflected all prominent planes related to hexagonal symmetry (P63/mmc space group). The crystallite size and induced strains is determined using Williamson-Hall plot. Lattice constants (a) and (c) shows minor increments with Gd3+ concentration. Particle distributions in SEM micrograph agree with W-H plot analysis. FTIR analysis is in consistent with X-ray intensity results. The ‘Law of Approach’ to saturation is applied to estimate parameters such as, magnetization (Ms) of order 40.91 to 57.7 emu/g and retentivity (Mr) ranging from 26.3 to 32.5 emu/g. A remarkable increase in coercivity (HC) is observed with increasing Gd3+ composition, with a value of 2500 to 6310 Gauss. Moreover, incorporation of Gd3+ in SrFe12-xGdxO19 lattice hinders electrical leakage profitably to yield remanent (Pr) and coercive polarization (Pc) of order 0.19 μC/cm2 and 17 kV/cm respectively. Thus sol-gel method proves to be useful in synthesizing nanomaterials of enhanced physical properties along with it being cost effective. Therefore, we are reporting tuning of magnetic and multiferroic properties of SrFe12O19 due to crystal strain mediated by Gd3+ doping at Fe3+ site.

Influence of Substrate Rotational Speed on the Structural and Optical Properties of Sputtered Gd-Doped ZnO Thin Films

Rare-earth element of gadolinium (Gd) were successfully doped into zinc oxide (ZnO) using dual sputter source of DC and RF sputtering. The substrate rotation speed was controlled from 1 rpm to 9 rpm to investigate their effects on the properties of the films in order to achieve a great feature of thin film. XRD profiles confirmed the c-axis orientation with structure of ZnO hexagonal wurtzite. No peaks related to secondary phases were observed. The intensity of dominant peak showed increment upon improvement of substrate rotation speed. The incorporation of Gd into ZnO structure was further confirmed by composition element form EDX with average atomic percentage of 3 at. % for all the films. Surface topology from AFM images showed the grain size has increased with the higher speed of substrate rotation. Gd-doped ZnO thin films indicated good transparency with an average transmittance above 90 % regardless of substrate rotation speed. The bandgap has a slight decrease from 3.06 eV to 3.03 eV with an increment speed of rotational substrate. These findings further imply that the substrate rotation speed has a significant influence on the structural and optical properties of the sputtered thin films.

Defect–defect magnetic coupling in Gd doped GaN epitaxial films: A polarization selective magneto-photoluminescence study

Here, we have carried out a magnetic field dependent polarization selective photoluminescence (PL) study at 1.5 K on Gd-doped GaN epitaxial layers grown on c-SiC substrates, where the incorporation of Gd has been found to generate three types of defects, which results in bound excitonic features in low temperature PL spectra. The study reveals that the external magnetic field dependence of the spin-flip scattering rates for the three excitonic features shows an increasing tendency of saturation at high fields as the density of these defects increases in these layers. This suggests that the signals must be stemming from defects which are ferromagnetically coupled with each other. This is further confirmed by the study carried out on a GaN sample co-doped with Si and Gd, where defects are found to be ferromagnetically coupled, while the Si-donors do not.

Effect of defects and oxygen vacancies on the RTFM properties of pure and Gd-doped CeO2 nanomaterials through soft XAS

This work primarily is an investigation of the electronic structure properties of pure CeO2 and $${Ce}_{1-x}{Gd}_{x}{O}_{2}$$ (x = 0.02, 0.04, 0.06, 0.08 and 0.10) Nanoparticles using the soft X-ray absorption spectroscopy were used to explore defects and vacancies. For this purpose, pure CeO2 and $${Ce}_{1-x}{Gd}_{x}{O}_{2}$$ (x = 0.02, 0.04, 0.06, 0.08 and 0.10) nanomaterials were synthesized using the co-precipitation method. The XAS spectra at Ce M4,5, O K-edge and Gd M4,5 absorption edges clearly indicated a decrease in the valence state of Ce ions from Ce4+ to Ce3+ with the formation of oxygen vacancy defects upon incorporation of Gd3+ ions in CeO2 nanolattice. The results show meagre and sparse segregations of additive Gd+3 ions to form secondary phases in the samples. The deconvoluted Ce M4,5 peaks and O K-edge peaks clearly showed the existence of both oxidation states of Ce ions, Ce3+ and Ce4+,and also indicated the formation of oxygen vacancy defects in all the samples. The presence of Gd3+ oxidation state of Gd ions in Gd+3-doped CeO2 samples was investigated through Gd M4,5 edges. Furthermore, the origin of ferromagnetism in pure CeO2 and Gd3+-doped CeO2 samples is explained using F-centre exchange mechanism mediated by defects and oxygen vacancies.

Biocompatible gadolinium-coated magnesium alloy for biomedical applications

The present study was aimed at the preparation of electrophoretic deposition of gadolinium oxide on anodized Mg alloy to enhance the implant surface properties. Gadolinium was electrophoretically deposited on anodized Mg and sintered at 250 °C for 1 h. The coating consists of micro- and nano-fissures on the surface. The coating’s thickness was increased to 9.8 µm, which is onefold higher than the anodized sample. The formed gadolinium oxide exhibited a cubic crystal structure. The apatite formation was initiated within 24 h of immersion in Earle’s solution, and the surface was in complete coverage with the apatite observed after 7 days of immersion. The corrosion rate had declined several folds and exhibited self-healing property. The incorporation of Gd3+ and F− ions in the apatite was observed from XPS analysis. The degraded products from the coating enhanced the proliferation rate and osteogenic gene expression. The bacterial colony count method confirmed that the coating possesses inherent antimicrobial activity.

High performance Gd-doped γ-Fe2O3 based acetone sensor

Pure and Gd-doped γ-Fe2O3 nanopowders with different amount of Gd (1, 3 and 5 at. %) were successfully prepared via a sol gel technique followed by drying in supercritical ethanol. The microstructural and morphological properties of the synthesized materials have been investigated by scanning and transmission electron microscopies (SEM and TEM), X-ray diffraction (XRD) and BET analysis. Optical measurements, through photoluminescence (PL) and UV–visible analysis, were also performed. The characterization results confirmed the incorporation of Gd into the γ-Fe2O3 matrix. Consequently, the pore size, BET surface area, optical band gap, electrical conductivity and photoluminescence of the Gd-doped γ-Fe2O3 nanopowders were strongly affected and were found to be dependent on their composition. Compared with pure γ-Fe2O3, Gd-doped samples display enhanced gas-sensing properties toward acetone. 3 at. % Gd-doped maghemite based gas sensor exhibited the higher response Ra/Rg = 31.2 (to 20 ppm of acetone), which is 30 times larger than that of pure γ-Fe2O3. Moreover, the sensor also possesses a good selectivity toward acetone and signal stability.

Co‐Assembly of Gd(III)‐Based Metallosurfactant and Conjugated Polymer Nanoparticles in Organosilica Cross‐Linked Block Copolymer Micelles for Highly Efficient MRI and Fluorescent Bimodal Imaging

AbstractConformity of two biological imaging entities, magnetic resonance imaging (MRI) and fluorescence imaging, is achieved through co‐assembly of a Gd(III)‐based metallosurfactant, conjugated polymeric nanoparticles, and amphiphilic block copolymer F127 (PEO106PPO70PEO106) followed by crosslinking with organosilica. The cross‐linked micelles with a size around 100 nm exhibit outstanding dispersion stability in aqueous and phosphate buffered saline solutions, bright fluorescence emission, and high relaxivities, providing a new approach to synthesize highly efficient bimodal contrast agents. The relaxivities of the co‐assembled micelles are synergistically enhanced by incorporation of Gd(III) complexes with high hydration number (q = 3) and elongation of rotation correlation time to achieve r1 values up to 105.37 mm−1 s−1 (at 1.5 T), which is over 20 times that of clinically used MRI contrast agents and among the highest values of all the nanoparticular MRI contrast agents. The external PEO layer endows these micelles with very low cytotoxicity for both in vitro and in vivo imaging. Meanwhile, thanks to the enhanced permeability and retention effect originating from their nanoscale sizes, the bimodal contrast agents show a prolonged blood circulation time in vivo and targeted accumulation at tumor regions to display outstanding MRI imaging performance.

Structural and optical properties of gadolinium doped ZnTe thin films

ZnTe and Ga-doped ZnTe thin films were prepared onto glass and Te-doped GaSb substrates by thermal evaporation method under vacuum and their structural and optical properties were studied. XRD results show that for both substrates, the doping with gadolinium yield a reduction in the ZnTe lattice parameter. The optical band gap increases with incorporation of Gd into the ZnTe structure and the values obtained are 2.19 and 2.29 eV, respectively for glass and GaSb:Te substrates. The presence of defects due to Gd doping into ZnTe thin films is evidenced.

Concentration Effect of Gd3+ on the Structural, Optical and Spectroscopic Properties of NdVO4 Nanoparticles

Neodymium vanadate with concentration of gadolinium as 3% and 5% having general formulae GdxNd1-xVO4 where x = 0.03 and 0.05 was prepared by chemical route technique. The effect of concentration of gadolinium on the structural, optical and spectroscopic properties was explained by various characterization techniques. Powder X-ray diffraction study suggests tetragonal zircon structure; various parameters such as crystallite size, volume and X-ray density were calculated. A change in morphology with the change in concentration of gadolinium was observed through scanning electron microscopy. Ultraviolet absorption spectroscopy shows various transitions from ground state to various excited state within 4f shell, and variation in the optical band gap calculated by Tauc plot is due to the incorporation of Gd3+ ions.

Improved photocatalytic performance of Gd and Nd co-doped ZnO nanorods for the degradation of methylene blue

This paper reports the synthesis of pure ZnO, Gd and Nd co-doped ZnO nanorods based nanocomposites via simple hydrothermal method. Subsequently, the prepared photocatalysts were characterized using XRD, SEM/EDX, TEM, UV–visible and PL spectroscopy. The XRD results demonstrate that Gd and Nd ions were incorporated into ZnO lattice in the synthesized ZnO based nanocomposites and showed hexagonal wurtzite structure. The SEM and TEM results show that nanorods having nanoscale diameter and length were successfully synthesized by hydrothermal method. The UV–visible spectroscopy verified that the band gap of ZnO was reduced due to incorporation of Gd and Nd into ZnO photocatalyst. Similarly, Gd and Nd incorporation into ZnO was found effective to reduce the recombination of electrons and holes as confirmed by PL spectroscopy. Moreover, the prepared nanocomposites with various atomic ratios (0.5–2%) were tested for photocatalytic degradation of methylene blue (MB), under visible light irradiation. The highly efficient and optimized 1.5% Nd/ZnO nanocomposite demonstrated enhanced photocatalytic performance for the degradation of methylene blue compared to pure ZnO and other nanocomposites. Furthermore, the recycling results show that the 1.5% Nd/ZnO nanocomposites displayed good stability and long-term durability. These finding suggest that the ZnO based nanocomposite could be efficiently used in various energy and environmental applications.