Variation Of Cell Parameters Research Articles

Synthesis and structure of carbonated barium and lead fluorapatites: Effect of cation size on A-type carbonate substitution

Substitution of carbonate has long been recognized in both synthetic and natural biologically and geologically precipitated forms of hydroxylapatite. Although the predominant substitution mechanism in all of the calcium members of the apatite group formed below 100 °C is substitution of carbonate for phosphate (B-type), small amounts of A-type substitution of carbonate in the channel sites also occur. The present study focuses on the effect of cation size on the type of substitution of carbonate in members of the apatite group. The barium and lead members offer a larger channel site, which potentially could stabilize A-type substitution. A series of carbonated barium and lead fluorapatites were synthesized in aqueous solution and characterized by powder X-ray diffraction, and infrared and Raman spectroscopy. Carbonate content was determined by combustion analysis. Unit-cell parameters derived from X-ray diffraction showed that, as carbonate content increased, the a -axis length decreased and the c -axis increased slightly for carbonated barium fluorapatites (CBaApF), whereas the lengths of both the a - and c -axes increased for CPbApF. The co-occurrence of two sets of peaks in the ν3 carbonate region of the infrared spectra of lead and barium carbonated apatites are strongly suggestive of both A- and B-type carbonate substitution. This interpretation is supported by Rietveld analysis of X-ray powder diffraction data, which confirms the presence of significant, but not dominant, A-type substituted carbonate ions. The variation in cell parameters as a function of carbonate substitution mode is discussed, and it is shown that B-type carbonate substitution need not be accompanied by a decrease in the a -axis in all apatites. The greater amount of A-type carbonate substitution in barium and lead fluorapatites compared to the their calcium homologs can be attributed to: (1) the less negative enthalpies of hydration of the barium and lead ions relative to that of calcium, and/or (2) the greater amount of space available for the relatively large carbonate ions in the channels defined by these large cations. Thus, the substitution modes can be controlled by either thermodynamic or kinetic considerations.

Structure, phase transition, and controllable thermal expansion behaviors of Sc(2-x)Fe(x)Mo₃O₁₂.

The crystal structures, phase transition, and thermal expansion behaviors of solid solutions of Sc(2-x)Fe(x)Mo3O12 (0 ≤ x ≤ 2) have been examined using X-ray diffraction (XRD), neutron powder diffraction (NPD), and differential scanning calorimetry (DSC). At room temperature, samples crystallize in a single orthorhombic structure for the compositions of x < 0.6 and monoclinic for x ≥ 0.6, respectively. DSC results indicate that the phase transition temperature from monoclinic to orthorhombic structure is enhanced by increasing the Fe(3+) content. High-temperature XRD and NPD results show that Sc(1.3)Fe(0.7)Mo3O12 exhibits near zero thermal expansion, and the volumetric coefficients of thermal expansion derived from XRD and NPD are 0.28 × 10(-6) °C(-1) (250-800 °C) and 0.65 × 10(-6) °C(-1) (227-427 °C), respectively. NPD results of Sc2Mo3O12 (x = 0) and Sc(1.3)Fe(0.7)Mo3O12 (x = 0.7) indicate that Fe substitution for Sc induces reduction of the mean Sc(Fe)-Mo nonbond distance and the different thermal variations of Sc(Fe)-O5-Mo2 and Sc(Fe)-O3-Mo2 bond angles. The correlation between the displacements of oxygen atoms and the variation of unit cell parameters was investigated in detail for Sc2Mo3O12.

Photoluminescence performance of thulium doped Li4SrCa(SiO4)2 under irradiation of ultraviolet and vacuum ultraviolet lights

In this work, we synthesized Tm3+ doped Li4SrCa(SiO4)2 phosphors and investigated their photoluminescence properties under the excitation of ultraviolet and vacuum ultraviolet lights. The crystal structure analysis and variation of cell parameters confirm that Tm3+ ions have been successfully doped in the structure of Li4SrCa(SiO4)2 host by occupying the sites of Ca2+ with the coordination number of 6. The luminescence results suggest that Li4SrCa(SiO4)2:Tm3+ is a good blue-emitting phosphor when excited by ultraviolet and vacuum ultraviolet irradiations. In addition, it is observed that there is nearly no degradation for Li4SrCa(SiO4)2:Tm3+ after undergoing thermal and irradiation treatments. Possible mechanisms for the luminescence processes are proposed on the basis of the discussion of excitation and emission spectra. In particular, the emission color of Li4SrCa(SiO4)2:Tm3+ by excitation of 147 and 172nm irradiations is very close to the standard blue color, suggesting that it could be potentially applied in plasma display panels and mercury-free fluorescence lamps.

The numerical calculation of single-diode solar-cell modelling parameters

The accurate simulation of a photovoltaic solar cell requires the precise determination of modelling parameters specific to the device under study. For the case of the single diode model, five parameters must be determined; Iph, I0, Rs, Rsh, and n. Generally speaking these values may be calculated either by analytical or numerical methods. Although analytical approaches are simple and fast to carry out, the assumptions and simplifications they introduce in order to deal with the non-linear characteristics of a solar cell may result in modelling inaccuracies. In this study a new approach is presented to calculate all five parameter values numerically minimising assumptions and simplifications. The method proposed is based on solving the single diode current–voltage equation expressed using the Lambert W-function at five experimentally obtained points along the current–voltage curve. To solve the system of non-linear equations, the multi-dimensional variant of the Newton–Raphson method is applied. All necessary first order partial differential equations are provided in closed form. Experimental validation of the proposed method revealed an improvement in modelling accuracy over one commonly used analytical approach. Furthermore, using TRNSYS software to simulate the annual energy output we show that modelling photovoltaic systems with small variations in solar cell parameters can result in non-trivial variations in annual energy output highlighting the importance of their calculation.

Syntheses and characterization of two novel tetranuclear lead(II) clusters self-assembled by hydrogen bonded interactions.

BackgroundThe usage of polynuclear metal clusters as secondary building units (SBU’s) in designing of metal organic frameworks (MOF’s) is a field of current interest. These metal clusters have attracted a great deal of attention not only due to their interesting structural topologies but also due to promising physical and chemical properties. In this regard various d,f block (transition and lanthanide) metal clusters have been widely investigated so far. Less attention is paid to construction of heavy p-block Pb(II) clusters.ResultsTwo mixed ligand Pb(II) clusters have been synthesized with bipy(2,2’-Bipyridine), phen(1,10-Phenanthroline), quin (8-Hydroxy quinolinate) and 5-tpc (5-chloro thiophene 2-carboxylate). They have been characterized by elemental analysis, IR, TGA and X-ray crystallography. X-ray diffraction analysis reveals that the complexes [Pb4(quin)4(bipy)2(5-tpc)4] (1) and [Pb4(quin) 4(phen) 2(5-tpc)4] (2) are tetranuclear. The complexes show a slight variation in unit cell parameters, due to the replacement of bipy and the phen ligands. Both complexes contain two types of Pb(II) ions which differ in the coordination geometry around the Pb(II) ion.ConclusionsIn both complexes the four lead ions Pb1,Pb2, Pb1i and Pb2i lie on the same plane bridged by the 5-tpc anions. Pb1 and Pb2 of both complexes contain a 5-tpc and quin coordinated in a bidentate chelating bridging fashion. In addition the Pb2 and Pb2i ions alone contain a bipy and phen in a bidentate chelating fashion in (1) and (2) respectively. An additional notable feature in both of these complexes are the bridging ability of the quin oxygen which forms a network of coordination bonds in between the four Pb(II) ions. In both complexes the individual units are self-assembled by C-H---Cl/C-H---S hydrogen bonding interactions to generate 2-D aggregates.

Synthesis, phase structure and microstructure of monazite-type Ce1−xPrxPO4 solid solutions for immobilization of minor actinide neptunium

Praseodymium was used as the surrogate for trivalent minor actinide neptunium, and a complete series of pure monazite-type Ce1−xPrxPO4 (x=0–1) solid solutions were successfully prepared by the solid state reaction. The effects of calcining temperature, holding time and Pr content on the structure of Ce1−xPrxPO4 solid solutions were investigated. The results show that although Pr6O11 (Pr23+Pr44+O11) exists two stabilized oxidation states, there has been no tetravalent praseodymium phosphate during the synthesis process. The optimized temperature for the synthesis of Ce0.8Pr0.2PO4 solid solution is more than 1100°C, and a hypothetical reaction mechanism is also proposed. Besides, the crystalline grains coarsen as the increasing of holding time. The linear variation of unit cell parameters and a gradual hypsochromic shift in the Raman spectra are observed with the increase of Pr content, indicating that cerium is progressively replaced by praseodymium and Ce1−xPrxPO4 solid solutions were prepared.

An I–V model based on time warp invariant echo state network for photovoltaic array with shaded solar cells

This paper proposes a new current–voltage (I–V) modeling approach for photovoltaic arrays based on time warp invariant echo state network (TWIESN). I–V characteristic model of a PV array is not only nonlinear and implicit, but also strictly dependent on material types, manufacturing process, ageing and environmental influence. Therefore, in this paper, TWIESN method is proposed to predict I–V characteristic curves of a PV array at any operating conditions, including partially shading conditions. I–V characteristic curves can be quickly obtained by only reading load voltage sequence, irradiation and temperature of each solar cell of the PV array without solving any nonlinear implicit equations that are necessary in conventional methods. The modeling approach based on TWIESN, obtained by using real operating data information of PV arrays, can really describe the dependency of solar cell on the dynamic variations of environment and cell parameters. Therefore, the method in this paper can accurately predict I–V characteristic for the PV array in operation, from different manufacturers, and of different material types. In addition, compared with conventional numerical methods, the time-consuming of the TWIESN model is very low. To verify the proposed TWIESN model, a KC200GT module and a KC200GT array are tested under different shading conditions. The comparison between the proposed model and the model based on back propagation (BP) network is made. Experiment results show the proposed TWIESN model is a simple, accurate, robust and effective model for PV modules and PV arrays at any operating conditions.

Structural, vibrational and dielectric study of Ni doped spinel Co ferrites: Co1−xNixFe2O4 (x=0.0, 0.5, 1.0)

Bulk samples of spinel ferrites with the compositional formula, Co1−xNixFe2O4 (x=0.0, 0.5, 1.0) were synthesized by a solid-state reaction route to discuss doping effect on the structural, vibrational and dielectric properties. The crystal structure and cell parameters were refined by the Rietveld analysis, infers that ceramics crystallized in single-phase cubic structure with Fd-3m space group. The variation in cell parameters with Ni substitution confirmed the partial substitution of the Co3+ by Ni3+ into the spinel CoFe2O4 structure. A blue shift in Ni doped CoFe2O4 ferrite has been observed as compared to parent CoFe2O4 from Raman scattering measurements. The dielectric constant (ε′) and loss tangent (tanδ) have been investigated as a function of composition and frequency in the frequency range 10Hz–1MHz. Porous ceramics are useful for microelectronics with lower value of dielectric constant.

Properties of impurity-bearing ferrihydrite III. Effects of Si on the structure of 2-line ferrihydrite

Siliceous ferrihydrites are abundant nanoparticles in natural environments. Although it is well known that the physical properties of ferrihydrite are affected when formed in the presence of silicate oxoanions (SiO44−), the structure of siliceous ferrihydrites (SiFh), and the speciation of Si within these nanosolids are not well understood. In this study we evaluate the effects of Si (at concentrations ranging from 5 to 40mol% Si) on synthetic ferrihydrite precipitates using structural data derived from synchrotron-based high energy X-ray scattering and pair distribution function (PDF) analysis, in combination with X-ray absorption near edge structure (XANES) spectroscopy, and transmission electron microscopy (TEM). Silicate oxoanions have a major effect on Fe(O,OH)x polyhedral polymerization and ferrihydrite particle growth, illustrated by the formation of smaller, poorly crystalline, structurally disordered/strained ferrihydrite nanocrystallites. Variation in Fh unit-cell parameters is suggested to arise from substantial particle size-induced structural disorder. As a result of this significant size-dependent structural disorder, it was not possible to identify evidence for Si4+ for Fe3+ substitution in these samples based on unit cell parameter variations or refinement of different structural models. Principal component analyses (PCA) and linear combination fits carried out on the PDFs suggest that iron partitions between several phases (e.g., ferrihydrite and an Fe-bearing amorphous silica phase (Amorph. SiO2+Fe)) in these co-precipitates. A mechanism of co-precipitation is proposed, in which silicate binds to Fe polymers and Fh particles, thus inhibiting particle growth at low Si content. At higher Si content, SiO44− polymerization traps significant Fe, and we suggest that the occurrence of this second Fe pool limits further the availability of Fe required for ferrihydrite particle development. Such Si-ferrihydrite co-precipitates are expected to be more stable in natural environments with respect to reductive dissolution or transformation, and to impact the bioavailability of Fe(III).

Microstructure and ionic conductivity of SrTiO3 heterogeneously doped YSZ composite ceramics

To improve the ionic conductivity of ZrO 2 stabilized by 8 mol% of Y 2 O 3 (8YSZ), the SrTiO 3 heterogeneously doped 8YSZ composite ceramics with different volumetric fractions of SrTiO 3 were prepared through powder sintering at 1400 °C and 1450 °C in air. The phase compositions, microstructures, electrical conductivities and ion transference numbers of the composites were investigated by X-ray diffraction, scanning electron microscopy, complex impedance and Hebb–Wagner polarization method, respectively. The composite ceramics only consist of cubic YSZ and SrTiO 3 . The deviations of the typical diffraction peak positions in XRD spectra and the variations in unit cell parameters of both SrTiO 3 and YSZ in composites have occurred due to the elemental inter-diffusion between both phases. The grain boundaries between these two heterogeneous phases do not exhibit any presence of a segregated impurity phase, and the heterogeneous doping of SrTiO 3 can suppress the growth of YSZ grains at higher doping levels. The apparent conductivities of the composites show a peak at 5 vol.% of SrTiO 3 addition. The activation energies for the oxygen ion transport of 8YSZ doped with 0–15 vol.% of SrTiO 3 all fall into the range of 101.71–104.93 kJ/mol. The ion transference numbers of the composites with 1–15 vol.% of SrTiO 3 are all higher than 0.99, demonstrating that the electrical conductivity is almost pure ionic in nature. By analyzing the effects of SrTiO 3 additions on the normalized conductivities of the composites, the SrTiO 3 /YSZ heterogeneous interfacial effects on the conductivity improvement can be proposed. • SrTiO 3 heterogeneously doped 8YSZ composites are prepared by sintering in air. • Elemental diffusions between SrTiO 3 and YSZ occur after powder sintering. • The SrTiO 3 /YSZ heterogeneous interface can enhance the conductivity of composites. • Electrical conductivities of YSZ doped with 1–15 vol.% of SrTiO 3 are ionic in nature.

Chemical Strain and Oxidation-Reduction Kinetics of Epitaxial Thin Films of Mixed Ionic-Electronic Conducting Oxides Determined by X-Ray Diffraction

X-ray diffraction, at high T's and switching between N2/air atmospheres, was used to compare the chemical expansion due oxygen non-stoichiometry variations between epitaxial films of different mixed ionic-electronic conductors: La0.6Sr0.4CoO3−δ(LSC), Ba0.5Sr0.5Co0.8Fe0.2O3−δ(BSCF), LaNiO3−δ(LNO), La2NiO4+δ(L2NO) and GaBaCo2O5.5+δ(GBCO) and La0.7Sr0.3MnO3−δ(LSM). LSC and BSCF show the largest relative change in the cell parameter Δc/c = +0.5%, while L2NO and GBCO show negative Δc/c = −0.2% and −0.1%, respectively. LNO and LSM show either reduced or negligible chemical expansions. In all cases the values correspond to their particular defect equilibrium and degree of charge localization. The oxygen surface exchange kinetics was also evaluated from in-situ time-resolved analyses of the cell parameter variations. LSC, LNO and GBCO films show fast oxygen reduction kinetics, kchem = 5·10−6, 3·10−6, and 2·10−7 cm/s at 700°C, respectively, in relative agreement with reported values, while BSCF films show much slower kinetics than expected, below kchem = 10−7 cm/s at 650°C, related to the degradation process observed in the films.

Some Structural Aspects of Ionic Conductivity in Co-Doped Ceria-Based Electrolytes

Abstract The sinters of co-doped ceria solid solutions with the formula of Ce0.85Sm0.15-x RxO1.9, where R = Y, Gd, Pr, Tb, Ox-0.15, were obtained from powders synthesised by Pechini method. The linear variation of cell parameter a vs. chemical composition was observed for Ce0.85Sm0:15-xRxO1.9, where R = Y, Gd, Tb, 0 &lt;x&lt;0.15 samples. However, the introduction of Pr3+ into Ce0.85Sm0.15-x PrxO1.9 caused a small deviation from linearity due to possible changes in the valence from Pr3+ to Pr4+. The determined values of oxide transference number tion for Ce0.85Sm0.15-xRxO1.9, R = Y, Gd in the temperature range 400-750°C and partial oxygen pressure from 10-6 to 1 atm were close to 1, which indicated that materials investigated exhibited practically pure ionic oxide conductivity. On the other hand, the introduction of Tb3+ or Pr3+ higher than x&gt;0.05 into solid solution Ce0.85Sm0.15-xRxO1.9, R = Tb, Pr caused a decrease in the ionic transference number tion below 1 due to an increase in partial electronic conduction. This fact limiting investigated co-doped terbia and samaria or samaria and praseodymia ceria-based solid solutions for the further application as oxide electrolytes in solid oxide fuel cells. The analysis of bulk and grain boundary values indicated that partial substitution of Sm3+ by Y3+ or Gd3+ caused slight improvements in the ionic conductivity of Ce0.85Sm0.15-xRxO1.9. The highest ionic conductivity was found for solid solution with chemical composition Ce0.85Sm0.1Y0.05O1.9. The selected co-doped ceria samples were tested as solid electrolytes in solid oxide fuel cells operating in the intermediate temperature range 500-750°C.

Chemical Strain Kinetics Induced by Oxygen Surface Exchange in Epitaxial Films Explored by Time-Resolved X-ray Diffraction

We have developed a new method to study the oxygen surface exchange kinetics in oxide materials in the form of epitaxial thin films by analyzing subtle cell parameter variations induced by changes in the oxygen stoichiometry of the material. The method consists of continuously analyzing the X-ray diffraction pattern of particular film reflections with a linear X-ray fast detector in a static position, while exposing the sample to sudden changes in the pO2 of the atmosphere at elevated temperatures. With this method, we have been able to follow cell parameter changes as small as 2.10–4 A in time intervals as short as 10 s in La2NiO4+δ epitaxial films and La2NiO4+δ/LaNiO3−δ bilayers. This method provides a simpler and contactless tool for dynamically analyzing oxygen surface exchange kinetics and diffusion in transition metal oxide compounds, and complements other currently used techniques such as Electric Conductivity Relaxation (ECR) and Isotopic Exchange depth profiling (IEDP). In addition, this method i...

Structural, Raman Spectroscopy, and Magnetic Ordering in New Delafossite-Type Oxide CuCr1−x Ti x O2 (0≤x≤0.1)

We investigated in this paper a new mixture +3/+2 B cations delafossites by the doping at Cr3+ sites in CuCrO2 by nonmagnetic cation Ti2+. Ceramics of CuCr1−xTixO2 (0≤x≤0.1) were prepared via solid state synthesis techniques in a controlled atmosphere of O2. The compound crystallized into the 3R delafossite phase with hexagonal structure. The slightly different size in B cations induced a slightly variation in unit cell parameters. We modulate the spin chirality by the effect of spin dilution for Ti2+ on the structural and magnetic properties of delafossite CuCrO2 having a S=3/2 antiferromagnetic triangular lattice (ATL).

Effect of post-deposition annealing on the growth of nanocrystalline TiO2 thin films and elastic anisotropy of rutile phase at different temperatures

Abstract In this work, predominant anatase and rutile nanocrystalline TiO 2 thin films deposited by DC reactive magnetron sputtering are annealed at different temperatures. Raman spectroscopy and XRD experiments suggest phase transformations to rutile at elevated temperatures. A sharp increase of rutile content of the films confirms rutile phase stability above 650 °C. The variations in unit cell parameters are attributed to the changes in microstrain and macrostrain present in the films. The Miller indices dependence of Young’s modulus of rutile nanocrystals is estimated on the basis of the Reuss approximation for polycrystalline aggregates. Young’s modulus shows strong anisotropy. The elastic anisotropy is introduced in the Williamson–Hall (WH) method for the estimation of isotropic stress and uniform deformation energy density. Microstrain decreases with increasing annealing temperature. Lattice microstrain of nanocrystalline rutile is anisotropic. Along a particular crystallographic direction, rutile transformed from anatase rich films exhibit lower microstrain.

Genome-wide association mapping of blood cell traits in mice

Genetic variations in blood cell parameters can impact clinical traits. We report here the mapping of blood cell traits in a panel of 100 inbred strains of mice of the Hybrid Mouse Diversity Panel (HMDP) using genome-wide association (GWA). We replicated a locus previously identified in using linkage analysis in several genetic crosses for mean corpuscular volume (MCV) and a number of other red blood cell traits on distal chromosome 7. Our peak for SNP association to MCV occurred in a linkage disequilibrium (LD) block spanning from 109.38 to 111.75 Mb that includes Hbb-b1, the likely causal gene. Altogether, we identified five loci controlling red blood cell traits (on chromosomes 1, 7, 11, 12, and 16), and four of these correspond to loci for red blood cell traits reported in a recent human GWA study. For white blood cells, including granulocytes, monocytes, and lymphocytes, a total of six significant loci were identified on chromosomes 1, 6, 8, 11, 12, and 15. An average of ten candidate genes were found at each locus and those were prioritized by examining functional variants in the HMDP such as missense and expression variants. These results provide intermediate phenotypes and candidate loci for genetic studies of atherosclerosis and cancer as well as inflammatory and immune disorders in mice.

Efficient solid-state dye-sensitized n-ZnO/D-358 dye/p-CuI solar cell

This paper describes the preparation and characterization of FTO/TiO2 dense layer/ZnO nanoporous layer/D-358 Dye/CuI hole collector/Cr-coated FTO and FTO/ZnO dense layer/ZnO nanoporous layer/D-358 Dye/CuI hole collector/Cr-coated FTO dye-sensitized solid-state solar cells. The variations of the solar cell parameters on the thickness of the TiO2 or ZnO dense layer are described. As the thickness (and hence the sheet resistance) of the TiO2 dense layer is increased, the conversion efficiency is gradually increased up to 2.6% at a sheet resistance of 370.0Ω/□ and beyond which it decreases. At this optimum thickness of the TiO2 dense layer, the best conversion efficiency is obtained when the thickness of the ZnO nanoporous layer is 15μm. Use of ZnO dense layer instead of TiO2 dense layer also shows the similar trend of variation of solar cell parameters as the thickness of the dense layer is increased. The best conversion efficiency of 3.2% is obtained when the sheet resistance of the ZnO dense layer is 2500Ω/□ and the thickness of the ZnO porous layer is 15μm.

Effects of BCO3 Addition on the Formation and Properties of the Bi-Based Superconductors

The effects of the BCO3 addition on the formation and properties of the Bi-based superconductors were studied. Phase identification, and structural and microstructural analyses were carried out using the powder X-ray diffraction method (XRD), scanning electron microscopy (SEM/EDX), AC magnetic susceptibility and resistivity measurements. The experiment results showed an increase of the superconducting phase content (BCO3) with x=0.01 and all samples doped with B contain the 2212 phase. In the BCO3 added samples (with x=0.01), the c lattice parameter decreased slightly from the nonadded sample showing the possibility of B incorporating into the crystal structure of the Bi-2212 phase. The variation in cell parameters is due to the difference in the ionic radii of B (0.2 A) and Ca (1.06 A). The SEM observation showed whisker grains, which are randomly distributed. The microstructural change is due to the addition of B. From the resistivity measurement, the \(T_{\mathrm{c}}^{\mathrm{onset}}\) was found to be increased by 4 K for the doped sample compared to the undoped sample. An improvement of the normal state conductivity is obtained with a small amount of the addition (0.01). In the normal state, all the samples exhibit a metallic behavior.

Study on effect of 1,3-dimethyl urea doping on optical properties of l-arginine phosphate monohydrate (LAP) single crystal

Pure and 1,3-dimethyl urea doped l-arginine phosphate monohydrate (LAP) crystals were grown by a solution growth technique from aqueous solution at a constant temperature. The effect of dopant on the optical properties, crystal structure and second harmonic generation (SHG) efficiency was studied. Dopant modifies the SHG efficiency of the LAP crystal at a greater extent. The SHG efficiency of 0.01mol% 1,3-dimethyl urea doped LAP crystal corresponds to 1.37 times more as compared to the pure LAP. Absorption and transmission were measured in the spectral range 190–1083nm. The increase in the optical transparency of the doped crystal is reported. The band gap of the grown crystals has been determined. The presence of the dopant in the doped crystals was confirmed qualitatively by the FT-IR spectroscopy. A slight variation in unit cell parameters has been reported. Thermal and dielectric study of the doped crystal has also been presented.

Effect of Co2+ Substitution in the Framework of Carbonate Intercalated Cu/Cr LDH on Structural, Electronic, Optical, and Photocatalytic Properties

In the present work, a series of Cu–Co/Cr ternary LDHs containing CO32– in the interlayer was prepared by coprecipitation method. To investigate the effect of divalent metal ions on the catalytic activity, we vaired Cu/Co atomic ratios, keeping constant the atomic ratio of Cu+Co/Cr (2:1). Several characterization tools, such as powder X-ray diffraction (PXRD), Brunauer–Emmett–Teller surface area, Fourier transform infrared spectroscopy, thermogravimetric analysis, transmission electron microscopy, and UV–vis diffuse reflectance spectroscopy, were employed to study the phase structures, textural, and optical properties of the samples. The PXRD of all samples showed the characteristic pattern of the hydrotalcite without any detectable impurity phases. The expected cell parameter variation was calculated assuming the Vegard’s law and proved the ideal atomic arrangement for the cations in the brucite layer. The shifting of the diffraction plane “d110” toward lower angle clearly indicates that Co2+ is substitu...