Bismuth Substitution Research Articles

Investigation of BSCCO Superconductors with Ga Substitution by Solid State Method

Samples of (Bi2-xGax)Sr2CaCu2O2 superconductors with varying Ga substitution levels (x=0, 0.06, 0.12, 0.20) were synthesized using the solid-state reaction method. The effects of partial substitution of bismuth and gallium elements on the BSCCO structure were investigated in terms of their electrical, magnetic, structural, and mechanical properties. X-ray diffraction (XRD) was used to determine the crystalline phases, and samples A and B exhibited sharp peaks, indicating well-crystallized material with no Ga2O3 phase. SEM images were used to obtain microscopic views of all samples, and the elemental compositions of each element were determined from EDX spectra. The critical temperature was calculated from R-t measurements, and Sample A exhibited the highest Tc at 96K. Magnetic properties were investigated for all samples, including magnetic hysteresis behavior and magnetic moment. The critical current density (Jc) values were calculated using the Bean model by utilizing magnetic hysteresis.

The effect of bismuth oxide substitution on physio-elastic properties of new formulation zinc borate glass system

The effect of bismuth oxide substitution on physio-elastic properties of new formulation zinc borate glass system

Structural and magnetic effect of bismuth substitution on Li-Co ferrite synthesized through microemulsion method

Li-Co spinal ferrites were synthesized in pure and doped form by substituting/doping a post transition metal, bismuth in varying concentrations using micro-emulsion technique. Effect of bismuth substitution was studied by investigating the structural and magnetic properties in detail. X-ray diffractometer results confirmed the creation of single phase along with a slight occurrence of orthophase in prepared ferrites. Average crystallite size increased from 14 to 28 nm by increase in bismuth concentration. SEM micrographs were in complete agreement with XRD results showing spherical to cubic grains which was a confirmation of cubic spinal structure. Average estimated grain size of 52 nm showing agglomeration was also a good testimony of XRD results. VSM technique was employed to study magnetic properties of prepared samples within applied magnetic field strength of -10,000Oe to 10,000Oe. Ms and Hc values were observed to be decreasing with increasing bismuth content. Lower Ms and Hc values made our newly synthesized material fit for transformer cores and induction purposes.

Oxide ion conductivity in doped bismuth gallate mullite type oxide, Bi2Ga4O9

Mullite-phase bismuth gallate (Bi2Ga4O9) was successfully synthesized with partial substitution of bismuth with alkaline-earth cation, Mg2+, Ca2+, Sr2+, and Ba2+. The effect of this substitution on the electrical conductivity was investigated. In this study, substitution with Ca2+ of Bi site was further studied for increasing the ionic conductivity as well as the phase stability in reducing atmospheres. Substitution with Ca2+ was found to be the most effective and with 12.5 mol% of Ca2+ as the optimized doping amount. Conductivity and stability in reducing atmospheres was increased down to pO2 ≤ 10−19 atm while keeping the conductivity of σ = 2.6 × 10−2 S·cm−1 at 973 K largely independent of oxygen partial pressure. Oxygen permeation analysis estimates 76% of theoretical oxygen permeation rate at 973 K suggesting main charge carrier is oxide ion. Partial electronic conductivity was measured with the ion blocking method. Oxide ion conductivity is dominated over wide pO2 range excepting for hole conduction at high pO2. Density functional theory (DFT) analysis on oxide ion diffusion route suggests oxygen hoping through lattice vacancy is main pathway for oxide ion conductivity in this doped Bi2Ga4O9. Despite the low oxide ion conductivity in Mullite-phase oxide, it was found that Ca doped Bi2Ga4O9 shows good oxide ion conductivity over wide pO2 range.

Effects of bismuth substitution on the structural and ionizing radiation shielding properties of the novel BaSn1-xBixO3 perovskites: An experimental study

In this study, BaSn1-xBixO3(0.00 ≤ x ≤0.20) polycrystalline perovskites are synthesized using the conventional solid-state reaction method for their utilization as materials for shielding against ionizing radiation. The Rietveld refinement of the room temperature X-ray diffraction (XRD) pattern revealed that all samples exhibited a cubic structure with Pm3‾m space group. To investigate the photon shielding properties of the prepared samples, the mass attenuation coefficient (MAC) was experimentally measured, and then the findings were benchmarked with the calculated results from the XCOM database. The obtained experimental results showed a reasonable correlation with the XCOM data, with relative differences in the mass attenuation coefficient ranging from 0.57% to 7.1%. Based on the measured MAC, different radiation shielding parameters such as the linear attenuation coefficient (LAC), half-value layer (HVL), mean free path (MFP), transmission factor (TF), and radiation protection efficiency (RPE) were calculated for all ceramics studied. These findings suggest that BaSn1-xBixO3(0.00 ≤ x ≤0.20) ceramic samples could be beneficial for use in shielding applications against ionizing radiation.

A study on solubility of bismuth cations in nickel cobalt ferrite nanoparticles and their influence on dielectric and magnetic properties

In this work, a low temperature (∼600 °C) solution combustion technique is employed for the synthesis of Ni0.5Co0.5BixFe2-xO4 (NCBFO, where x = 0.0, 0.05, 0.1, 0.15, & 0.2) nanoparticles with crystallite size variation of 17–22 nm. The X-ray diffraction (XRD) technique is used to confirm the formation of cubic spinel phase of Bi3+ doped (for x ≤ 0.05 samples) nickel–cobalt ferrite (NCFO) nanoparticles. The increase in bismuth substitution (x > 0.05) results in the formation of the Bi2O3 along with the NCFO structure, which results in the reduction of binding energy and is confirmed by the XRD and X-ray photoelectron spectroscopy (XPS) techniques. From the Raman spectra, the change in the intensities of the peaks is observed due to the variation of Bi3+ in NCFO matrix. Due to increasing cation concentration and electronegativity, the FTIR absorption band shifts toward the lower wave numbers. Dielectric measurements were carried out to examine the charge transport behavior and electric conduction mechanism. The FESEM images shows the non-magnetic bismuth atoms are diffused into the NCFO nanoparticles. From the vibrating sample magnetometer (VSM) analysis, it is observed that saturation magnetization, remanent magnetization, coercivity and squareness ratio are found to be maximum for x = 0.15 NCBFO sample. The high coercivity (Hc = 916.8 Oe) for the x = 0.15 sample indicates the hard ferromagnetic behaviour of the samples.

Bismuth Substitution in HSbOI with Positively-charged Oxide Clusters

We synthesized a Bi-substituted solid solution in [H10.7Sb32.1O44][H2.1Sb2.1I8O6][Sb0.76I6]2·25H2O (HSbOI), a recently discovered acid catalyst with positively charged clusters. Up to 5% of the antimony sites were substituted, resulting in an enlarged lattice and a smaller bandgap. EXAFS measurements show that the Bi cations are selectively located in the octahedral cluster. However, the Bi-substitution deteriorated catalytic properties, implying the potential of modifying characteristics of surface protons in large clusters. Bi-substituted solid solution in [H10.7Sb32.1O44][H2.1Sb2.1I8O6][Sb0.76I6]2·25H2O (HSbOI), a recently discovered acid catalyst with positively charged clusters, has been synthesized. The Bi cations are exclusively positioned in the small octahedral clusters, resulting in an enlarged lattice and a smaller bandgap. The alterations in the catalytic properties imply strong interactions among the three distinct types of clusters.

Effect of aliovalent bismuth substitution on structure and optical properties of CsSnBr3

Aliovalent substitution of the B component in ABX3 metal halides has often been proposed to modify the band gap and thus the photovoltaic properties, but details about the resulting structure have remained largely unknown. Here, we examine these effects in Bi-substituted CsSnBr3. Powder X-ray diffraction (XRD) and solid-state 119Sn, 133Cs and 209Bi nuclear magnetic resonance (NMR) spectroscopy were carried out to infer how Bi substitution changes the structure of these compounds. The cubic perovskite structure is preserved upon Bi-substitution, but with disorder in the B site occurring at the atomic level. Bi atoms are randomly distributed as they substitute for Sn atoms with no evidence of Bi segregation. The absorption edge in the optical spectra shifts from 1.8 to 1.2 eV upon Bi-substitution, maintaining a direct band gap according to electronic structure calculations. It is shown that Bi-substitution improves resistance to degradation by inhibiting the oxidation of Sn.

Effect on structural, morphological, electrical and optical properties of GdMnO3 nanoparticles induced by bismuth substitution

Effect on structural, morphological, electrical and optical properties of GdMnO3 nanoparticles induced by bismuth substitution

A highly efficient bismuth substitution induced A-site ordered layered perovskite electrode for symmetrical solid oxide fuel cells

A-Site substitution with bismuth promotes the oxygen vacancy formation in layered perovskite electrodes, which further enhances the electrochemical performance of symmetrical solid oxide fuel cells.

Bismuth and Vanadium-Substituted Yttrium Phosphates for Cool Coating Applications.

Luminescent yttrium phosphate is engineered into an environmentally benign near infrared (NIR) reflective yellow pigment by the substitution of bismuth and vanadium metals in the host lattice. A series of YP(1-x)V x O4 (x = 0, 0.05, 0.1, 0.15, 0.2, and 0.4), Y(1-y)Bi y PO4 (y = 0.1 and 0.3), and Y(1-y)Bi y P(1-x)V x O4 (x = y = 0.2, 0.4, and 0.6) were prepared by the precipitation method. Secondary phase was noticed at x = 0.2 and y = 0.2 while substituting vanadium and bismuth, respectively, due to high ionic radii of the dopant ions. Co substitution of vanadium and bismuth in the YPO4 lattice enhanced both NIR reflectance and yellow color of all the fabricated materials. XPS spectra proved the presence of trivalent bismuth and pentavalent vanadium in Y0.4Bi0.6P0.4V0.6O4. Due to the substitution effect, a more defined morphology was noticed, which enhanced the scattering co-efficient of the fabricated materials; hence, the NIR reflectance of the materials was increased from 68% (YPO4) to 83% (Y0.4Bi0.6P0.4V0.6O4). Chemical and thermal stability test of Y0.4Bi0.6P0.4V0.6O4 confirmed the color and strength of the designed pigment. With good yellow hue (b* = +56.06), high NIR solar reflectance (R* = 83%), and good stability, Y0.4Bi0.6P0.4V0.6O4 can act as an environmentally benign cool yellow pigment.

Tuning the Properties of Praseodymium Cobalt-Zinc Ferrites by Substitution of Bismuth

This work carried out the study of Co0.5Zn0.5Bi0.4-xPr0.1Fe1.5+xO4 spinel ferrite series (x = 0,0.1, 0.2, 0.3 and 0.4) prepared via micro-emulsion route. Effects on structural, electrical, optical and morphology properties is studied by varying Bi concentration (x = 0,0.1, 0.2, 0.3 and 0.4). The characterization techniques employed included X-ray diffraction (XRD), scanning electron microscope (SEM), UV-visible spectroscopy and Fourier transform infrared spectroscopy (FTIR). XRD results confirmed the spinel structure having lattice parameter around 8.39 Å and particle size decreased from 30 nm to 41 nm with increasing Bi concentration. Fourier transform infrared spectroscopy (FTIR) revealed fingerprints of metal oxides band at 408-577 cm-1. Optical properties were studied UV-visible spectroscopy and Eg was found to vary from 2.83 eV to 2.59 eV. The scanning electron microscope (SEM) described the morphology of the samples. We then examine the results and the material's characteristics, as well as the areas in which it can be used.

Bismuth substitution at the strontium site in the magnetoplumbite-type Sr ferrite: Phase stability, structure, and magnetic properties

We report a phase diagram, structural and magnetic properties of magnetoplumbite-type (M-type) Sr1−xBixFe12O19 (0.0 ≤ x ≲ 0.3) synthesized under various oxygen potentials, pO2= 0–10 atm. A systematic composition analysis for single and polycrystalline samples reveals that Bi substitutes for the Sr site in SrFe12O19. Within a solubility limit of x ≈ 0.3, obtained by synthesis under pO2 = 0.01 atm, the Bi solubility is mostly determined by the reduction amount of Fe3+ to Fe2+ to compensate a charge imbalance. The Bi3+ doping results in lattice parameters, a and c, with trends different from those by La3+ doping, reflecting different spatial characters of La3+ and Bi3+ ions. However, a nearly identical linear decrease in the lattice-parameter ratio c/a indicates that Bi3+ can provide the function of La3+ in high-performance substituted M-type ferrites. The doping dependence of magnetic properties, particularly the saturation magnetization and the anisotropy field, are examined and compared between the Bi- and La-substituted cases.

The Structural and Dielectric Properties of Bi3−xNdxTi1.5W0.5O9 (x = 0.25, 0.5, 0.75, 1.0)

A new series of layered perovskite-like oxides Bi3−xNdxTi1.5W0.5O9 (x = 0.25, 0.5, 0.75, 1.0) was synthesized by the method of high-temperature solid-state reaction, in which partial substitution of bismuth (Bi) atoms in the dodecahedra of the perovskite layer (A-positions) by Nd atoms takes place. X-ray structural studies have shown that all compounds are single-phase and have the structure of Aurivillius phases (APs), with close parameters of orthorhombic unit cells corresponding to space group A21am. The dependences of the relative permittivity ε/ε0 and the tangent of loss tgσ at different frequencies on temperature were measured. The piezoelectric constant d33 was measured for Bi3−xNdxTi1.5W0.5O9 (x = 0.25, 0.5, 0.75) compounds of the synthesized series.

Enhancing the thermoelectric performance of nanostructured ZnSb by heterovalent bismuth substitution

Eco-friendly Bi substituted ZnSb samples were prepared by a novel hydrogen decrepitation method, followed by consolidation using the cold pressing technique. The structural and morphological analysis of the samples have been carried out by XRD, FESEM and TEM. XRD analysis confirms the phase purity of the ZnSb sample. The presence of secondary phase of Bi was observed in the XRD patterns of Bi substituted Zn1-xBixSb (0.02 ≤ x ≤ 0.06) samples, probably due to low solid solubility limit of Bi in ZnSb alloy. FESEM and HRTEM images revealed the highly inter-connected grain structure and the grain sizes were in the range of 200 nm. The electrical resistivity and Seebeck coefficient values of Zn1-xBixSb samples were decreased compared to the pristine ZnSb sample. The power factor of Zn0.98Bi0.02Sb sample increased compared to pure sample. The thermal conductivity of Zn1-xBixSb alloys were increased with increasing Bi content (x). As a result, a high ZT of ~0.45 was achieved for Zn0.98Bi0.02Sb sample at 573 K compared to pure ZnSb (0.39). The experimental results demonstrated that bismuth substitution with optimum content is a promising approach to enhance the thermoelectric properties of ZnSb.

Influence of Bismuth Substitution with Nb, Y, and P Elements on the Electronic Structure of Vacancy Filled BiCuSeO-Based System for the Thermoelectric Application

Thermoelectric materials allow a direct conversion of waste heat into electric energy. Oxiselenide-based materials are promising candidates to be used within the temperature range between room temperature and 500°C. Specifically, p-type BiCuSeO is considered to be one of the most promising materials for these applications. However, the intrinsic properties of this compound are not sufficient for reaching an efficiency above 30%. There are numerous approaches to improve the heat-to-electricity conversion performance, such as element substitution, nanostructuring, vacancies implementation, and others. Usually, these approaches are applied individually, starting from the pure intrinsic material. Higher performance could, however, be reached by combining a few strategies simultaneously or in sequence. In the current work, yttrium, niobium, and phosphorous substitutions on the bismuth sites in already bismuth deficient Bi1-xCuSeO systems were investigated via density functional theory. The bismuth-deficient system was therefore used as the reference system for further introduction of substitutional defects. The results show an improved density of states near the Fermi level for all types of substitutional defects. The substitution with phosphorous showed a up to 40 meV (11%) decrease in the energy gap between conduction and valence bands at the highest substitution concentration. Doping with niobium led to the system changing from a p-type to an n-type conductor, which provides a possible route to obtain n-type BiCuSeO systems.

Utilisation of pyrochlore-typeoxideas catalyst in bioanode of coffee mac microbial fuel cell: Boost of electric voltage and reduction of wastes

ABSTRACT This study is a contribution to development of material based on transition metal oxides with application in electrochemical devices. A pyrochlore-like solid solution with general chemical formula Bi1.2Ce0.3Sb1.5CuO7 was synthesised. The pyrochlore structure was determined by X-ray powder diffraction. The pressed pyrochlore powder sample was analysed by scanning electron microscopy to show effect of substitution fraction of cerium and to determine its grain size and morphology. Energy dispersive of X-rays was performed to confirm effective substitution of bismuth for cerium. The EDX analysis was supported by X-ray photoelectron spectroscopy which also gave information on respective oxidation states of cations. Several modes of vibration due to metal-oxygen bonds of pyrochlore-like material were studied by Fourier-transform infrared spectroscopy. The results suggested that this compound contained major component of pyrochlore and minor component of CeO2. The dielectric measurements carried out at frequency 1 MHz in temperature range –40°C–90°C proved that pyrochlore compound possessed dielectric constants ranging between 12 and 28. Furthermore, owing to its high electrical conductivity, synthesised material has been utilised as bioanode in a microbial fuel cell. This bio-electrochemical device converted organic wastes into electricity using microorganisms as biocatalysts. It displayed greater electron transfer from electroactive biofilm towards the bioanode by improving its electrical energy output. The presence of pyrochlore in electrode allowed a power density of 25 mW/m2. It was almost the same as that obtained with a graphite carbon modified by the conducting polymer polypyrrole. The MFC with pyrochlore solid oxide was advantageously more stable having longer lifetime and indicating its suitability to substitute the polypyrrole at the bioanode. Besides, the colour of the coffee mac leachate in the anolyte (anode compartment) became less dark, which means that the maximum chemical oxygen demand (COD) was removed and converted into electric energy.

The photocatalytic performance and structural characteristics of nickel cobalt ferrite nanocomposites after doping with bismuth

Here, a novel bismuth-doped nickel-cobalt ferrite (Ni0.5Co0.5Bi0.1Fe1.9O4) was synthesized using a sol-gel auto-combustion approach. The impact of bismuth substitution on the nickel-cobalt ferrite structural characteristics was investigated relative to the nickel-cobalt ferrite without bismuth substitution (Ni0.5Co0.5Fe2O4) based on diverse technical options (e.g., scanning electron microscopy-equipped with an energy dispersive X-ray spectrometer, X-ray diffraction, physisorption, and Fourier-transform infrared spectroscopy). Bismuth doping increased the surface area without affecting pore size. The X-ray diffraction pattern confirmed a nano-ferrite cubic spinel structure of the catalyst. Photodegradation of Congo red (CR) was tested using these nickel-cobalt ferrite catalysts under visible light across varying reaction parameters (e.g., pH, catalyst loading, dye concentration, and reaction time). The photo-degradation efficiency for CR in aqueous medium was the highest (98%) at pH 3 with 0.2 g catalyst loading in 100 mL under visible irradiation to reinforce the role of nanostructures as a potent photocatalyst (QY = 2.79 × 10−7 molecule photon−1). The kinetic reaction rate of Bi-doped spinel ferrite (3.5 µmol g−1 h−1) was1.25 times higher than those undoped materials. This study experimentally proved that the bismuth-doped nickel-cobalt ferrite photocatalyst is an effective option for removing industrial dyes.

Rietveld Study of the Changes of Phase Composition, Crystal Structure, and Morphology of BiFeO3 by Partial Substitution of Bismuth with Rare-Earth Ions

BiFeO3 is an interesting material due to its multiferroic properties. It attracts attention due to its potential applications in spintronics and in microelectronics for data storage, among others. Single-phase bulk material from BiFeO3 is difficult to synthesize. The kinetics of perovskite phase formation most often leads to the presence of impurity phases. It has been shown that low levels of replacement of Bi with rare earth ions lead to stabilization of the perovskite phase. In the present work, Rietveld refinement of the crystal structure based on powder X-ray diffraction patterns was applied to study the influence of partial substitution of Bi by rare-earth (RE) elements with different ionic radii on structural and morphological properties of the ferrite phase. Substitution by large RE ions was found to preserve the rhombohedral symmetry of BiFeO3, whereas substitution by smaller RE ions led to the coexistence of two polymorphic perovskite phases with rhombohedral R3c and orthorhombic Pnma symmetries. The unit cell parameters as well as the interatomic distances and angles, not only around the A cation but also around the iron ions, were influenced by the substitution. The mean crystallite and particle size decreased with the decrease of ionic radius of substituting RE ion.

Enhancement of the spin Seebeck effect owing to bismuth substitution in thermoelectric generators fabricated from LPE Bi-substituted YIG films

Raising the thermoelectric voltage in spin thermoelectric generators is an important subject. We investigated the substitution of bismuth for yttrium to increase spin pumping at the paramagnetic metal and ferrimagnetic insulator (PM/FMI) interface, and tested bismuth-substituted iron garnet films grown by liquid phase epitaxy. Epitaxial Bi-substituted iron garnet films exhibit large growth-induced magnetic anisotropy perpendicular to the film surface. This anisotropy increases the magnetic damping α in the FMI; α also increases with increasing Bi content. We report the rise in voltage observed in a spin thermoelectric generator incorporating Bi-substituted YIG films grown by liquid phase epitaxy, and explain the origin of the voltage rise based on the results of FMR measurements.