Bismuth Composition Research Articles

Electronic band structure and optical properties of BGaAsBi/GaAs using 16 band kp Hamiltonian

The numerical simulations of optical and electronic properties of BGaAsBi/GaAs quantum wells (QWs) are obtained by diagonalizing the 16-band kp Hamiltonian with distinct boron and bismuth compositions that exhibit multifaceted potential in 1.3–1.5 μm. It has been observed that under strain-relaxed conditions for a doping concentration of 12.5 % (B, Bi), the anticipated values of spin-orbit (SO) coupling energy (ΔSO) and the bandgap (Eg) are 302 meV and 0.952 eV, respectively. Additionally, strain interaction on band structure decreases the band gap from (Eg = 0.92eV–0.85eV), increasing dopant concentration from 8 % to 12.5 %. The consequence of incorporating both Bi and B impurity is a reduction in electron effective mass of BGaAsBi by ∼1.3 times concerning the host GaAs, enhancing the optical properties of BGaAsBi/GaAs quantum-confined heterostructures. Moreover, an increase in well-width introduced a red shift and reduced the peak amplitude of the gain spectra. In addition, for solar cell application, the onset of the fundamental absorption edge is depicted at an energy of about 0.96 eV. For laser applications, the optimum threshold current density and quality factor of BGaAsBi/GaAs quantum well achieved at room temperature are 1089 A/cm2 and 3653, respectively, at well width (w = 2.0 nm), cavity length (L = 0.5 mm), and average thickness of the active region (d = 45 nm). The variation in power density is studied with injected current density, while the quality factor is calculated with well width. The outcomes could be beneficial for future use in optical devices.

Novel FeOOH-decorated La-doped Bi4O5I2 microspheres for boosting photocatalysis-Fenton synergy degradation of emerging contaminants

Photocatalytic-Fenton synergistic degradation of pollutants in wastewater is considered a promising technology for environmental treatment. Herein, FeOOH quantum dots decorated La-doped Bi4O5I2 hybrids were prepared using an in-situ deposition strategy and applied for the removal of 2,4-dinitrophenylhydrazine. The FeOOH-1/La10-Bi4O5I2 sample exhibits the highest catalytic activity in degradation experiments, eliminating 93.8 % of 2,4-dinitrophenylhydrazine within 30 min at a reaction rate constant of 0.117 min−1. In addition, the impacts of several operational parameters on the catalytic activity were comprehensively examined, including H2O2 concentration, catalyst dosage, reaction solution pH and co-existing ions. In degradation process of 2,4-dinitrophenylhydrazine, the major reactive oxygen species are ·OH and ·O2–, with ·OH generated by Fenton reaction. Optical property characterization, cyclic voltammetry tests, and photoelectrochemical measurements confirmed that the FeOOH-1/La10-Bi4O5I2 composite has excellent light absorption capacity, abundant active centers, and excellent carrier separation efficiency. Finally, the degradation mechanism of FeOOH-1/La10-Bi4O5I2 composites for 2,4-dinitrophenylhydrazine is rationally discussed based on experimental and theoretical calculations. This study presents a fresh design idea for developing bismuth oxyhalide-based composites with high activity.

Construction of functionalized In-based metal organic framework/BiOCl1−xIx Z-scheme heterojunction for efficient photocatalytic degradation of tetracycline: Performance and mechanism

The environmental implications of antibiotics have drawn widespread attention. Numerous monomer-based bismuth oxide halide catalysts have been extensively studied to remove tetracycline (TC) from aquatic environments. Integrating bismuth oxide halide composites with In-based metal organic framework (NH2-MIL-68(In)) might potentially serve as a novel strategy. By meticulously adjusting Cl and I within the composite bismuth halide oxide (B-x), a suite of purpose built heterojunctions (NMB-x) were synthesized, which were engineered to facilitate the efficient photodegradation of TC in simulated and actual aquatic environments. The incorporation of Z-scheme heterojunctions yielded a significant enhancement in photocatalytic responsiveness and charge carrier separation. Notably, NMB-0.3 demonstrated remarkable TC removal efficiency of 88.52 ± 3.05%, which is 3.74 times of B-0.3 within 90 min. The apparent quantum yield was also increased from 8.97% (B-0.3) to 19.68% (NMB-0.3). The removal of TC from natural water bodies was also assessed. Moreover, the photocatalyst concentration, assessed using response surface method, was found to show influential factors on TC removal. In addition, density functional theory (DFT) simulations were employed to identify vulnerable sites within TC. Intermediates and pathways in the photodegradation of TC have also been inferred. Furthermore, a comprehensive environmental toxicity assessment of representative intermediates demonstrated that these intermediates exhibited significantly reduced environmental toxicity compared to TC. This study provides a new approach to the design strategy of efficient and environmentally friendly MOF-based photocatalysts.

Carrier mobility dependence of indium antimonide-bismide on carrier concentration, temperature, and bismuth composition grown on semi-insulating gallium arsenide substrate

We explore the impact of carrier concentration, temperature, and bismuth (Bi) composition on the carrier mobility of indium antimonide-bismide (InSb1−x Bi x ) material. Utilizing the molecular beam epitaxy method, we achieved high Bi composition uniformity. This method also enables the InSb1−x Bi x to be grown on semi-insulating GaAs substrate, effectively preventing parallel electrical conduction during Hall effect measurement. Our findings reveal that InSb1−x Bi x doped with silicon (Si) and tellurium (Te) consistently exhibit n-type conductivity. In contrast, InSb1−x Bi x doped with beryllium (Be) exhibit a transition from n to p type conductivity, subjected to the Be doping level and the measurement temperature. Based on these observations, we proposed an empirical model describing the dependence of InSb1−x Bi x electron mobility on carrier concentration, temperature, and Bi composition, specifically for Si and Te-doped InSb1−x Bi x samples. These insights gained from this study hold potential application in photodetector device simulations.

Structural, thermal, optical, morphological, electrical, and photocatalytic characteristics of silver-doped bismuth oxide synthesized by the green route

Herein, silver-doped bismuth oxide compositions with different dopant percentages (0 %, 3 %, 5 %, and 7 %) were synthesized at the nanoscale via the green route. The optical study and photoluminescence spectroscopic analysis proposed the bismuth oxide sample doped with 5 % Ag (ABO-5 %), owing to its lower band gap and lower charge recombination aptitude, as the most potential composition. The synergistic effect of nanotechnology and silver doping on the sample's thermal, optical, morphological, electrical, and photocatalytic properties was investigated in detail. X-ray and infrared spectroscopy tests on pure bismuth oxide (BO) and its most potential doped composition (ABO-5 %), show that silver ions took the place of the host metal ions (Bi3+ ions) and made the parent lattice's structure defective. Doping leads to a decrease in particle size, confirmed by morphological examination. Furthermore, it has been shown that adding an Ag dopant has a beneficial impact on improving electrical conductivity, as the ABO-5 % composition (2.3 × 10−3 Sm−1) possessed a higher specific electrical conductivity than the BO (6.7 × 10−4 Sm−1). These variations enhance the photocatalytic aptitude of the ABO-5 % composition and enable it to mineralize 92 % of Eosin Y (EY) dye within a short exposure time of 49 min under W-lamp illumination. ABO-5 % composition also showed superb stability and restrained 97.2 % EY dye mineralization efficiency after four reusability tests. The scavenging experiment identified the *OH radical as the most potent, while holes were shown to be the least effective in the EY dye degradation process. The new, environmentally friendly ABO-5 % composition would help with future progress in cleaning up the environment by using a photocatalyst.

Visible-light-driven photo-Fenton oxidation enhanced by Fe/Bi-nanocrystal phase transformation as a universal way for various organic pollutants mineralization

Emerging organic pollutants (EOPs), such as azoxystrobin (AZX) fungicide, have been an increasingly serious problem in aquatic environments. Here, a novel Fe/Bi-nanocrystal (bismuth ferrite polymorphism composites, BFPCs) driven a new photo-Fenton system in visible light (λ >420 nm) irradiation (LED/BFPCs/H2O2) remarkably accelerates hydroxyl radical (HO•) formation with excellent efficiencies of both AZX and other 18 EOPs (especially for AZX 100 % degradation rarely reported). The system outperforms in mineralization rate, saving H2O2 usage (85 %) and reaction time (50 %) compared to the alike Fenton-like system. A phenomenon in BFPCs crystal structure observed on the crystal phase transformation from FeO6 octahedron into FeO4 tetrahedron that implied/uncovered a new finding of crystal-phase restructuring for enhancing Fe3+/Fe2+ circulation in Fenton chemistry. The stability of crystal structure and chemical composition of BFPCs catalysts was evaluated by HAADF imaging coupling with EDX mapping at atomic level. The mechanism on AZX degradation pathway in LED/BFPCs/H2O2 system is proposed for the first time by monitoring HO• and its source, and intermediates at a control condition.

Bismuth Determination by Controlled-Potential Coulometry: Developing a Highly Accurate Procedure based on GET 176

In this work, we develop a procedure for reproducing the units of bismuth mass fraction in metallic bismuth and those of bismuth (III) mass concentration in bismuth nitrate solutions by controlled-potential coulometry based on the GET 176-2019 State primary standard of mass (molar, atomic) fraction units and mass (molar) concentration of components in liquid and solid substances and materials based on coulometry. The results obtained can be used when manufacturing certified reference materials (CRMs) for the composition of high-purity bismuth and CRMs for the composition of solutions of bismuth (III) ions directly traceable to GET 176-2019. These CRMs may find application in pharmacological, metallurgical, and nuclear industries.

Synthesis and study of bismuth(III) oxalates precipitated from mineral acid solutions

Bismuth oxalates of the compositions BiOH(C2O4), Bi2(C2O4)3·6H2O, Bi2(C2O4)3·7H2O, and Bi2(C2O4)3·8H2O were obtained by precipitation from bismuth solutions in perchloric, nitric, and hydrochloric acids with addition of oxalic acid. Compound compositions were confirmed by X-ray powder diffraction and chemical analysis, IR and Raman spectroscopy, and thermogravimetry. It has been shown that in the composition of bismuth(III) oxalate hydrates Bi2(C2O4)3· х H2O bismuth cation is coordinated by the oxygen atoms of carboxyl groups of oxalate ions and water molecules in the same way, and compositions, taking into account the structural features, are described by the general formula {[Bi2(C2O4)3(H2O)4]∙( x -4)H2O} n . Conditions for the oxidative thermolysis of BiOH(C2O4) and Bi2(C2O4)3·7H2O to yield the tetragonal modification of bismuth oxide β-Bi2O3 were determined.

Boosting electrocatalytic CO2 reduction to formate via carbon nanofiber encapsulated bismuth nanoparticles with ultrahigh mass activity

Electrochemical CO2 conversion is one of the most promising technologies to achieve carbon neutrality. However, it still suffers from some nonnegligible challenges on low production rate and unsatisfied current densities for potential large-scale applications. Herein, we prepare ultrasmall Bi nanoparticles uniformly encapsulated in the carbon nanofibers through electrospinning techniques, which is denoted as Bi/CNFs-900. Gratifyingly, this Bi/CNFs-900 catalyst demonstrates excellent performance and stability on CO2 electro-reduction in a broad potential window. Specifically, it can produce formate with a Faradaic efficiency over 90% and a high partial current density of –235.3 mA cm−2 at −1.23 V vs. RHE in a flow-cell. Furthermore, the confinement effect of carbon nanofibers largely restricts the severe aggregation of bismuth nanoparticles during synthesis as well as electrolysis procedure, which greatly increases the accessible active sites and decreases the actual mass fraction of bismuth composition. Consequently, Bi/CNFs-900 not only achieves ultrahigh mass activity of –1.6 A mgBi−1, but also possesses an unprecedented formate production rate of 4403.3 μmol h−1 cm−2. DFT calculations and in situ Raman spectroscopy further uncover the possible reaction mechanism for CO2 reduction toward formate. These results could provide an economical and industrial-viable strategy for the preparation of electrocatalysts in CO2 reduction.

Recent Development of Transition Metal Oxide Bismuth Vanadate Electrode Materials for Supercapacitor Applications: A Review

During the last decade, the supercapacitor, a replacement that may someday replace batteries, has sparked increased interest in energy-storage applications. For environmental and financial reasons, electrode materials with high energy and power density, and other electrochemical stability are vital to completing this critical duty. Numerous investigations on metal-based compounds and their composites have been conducted. Bismuth materials and composites stand out because of their redox behaviour, environmental friendliness, low toxicity charge storage capacity, and increased interest in employing them as energy storage for supercapacitor technology. In this article, we provide an overview of research on bismuth materials and their composites with a focus on energy storage applications and, more importantly, a focus on the study of their super capacitive performance, including specific capacitance, cycle stability, energy density, power density, and respective potential window and current density, as well as other electrochemical parameters.

Schottky-functionalized Z-scheme heterojunction: Improved photoelectric conversion efficiency and immunosensing

Designing photovoltaic materials with good photoelectric activity is the crucial to boost the sensitivity of photoelectrochemical (PEC) biosensors. To meet this concern, a Schottky-functionalized direct Z-scheme heterojunction photovoltaic material was proposed by electrodeposition of gold nanoparticles on two kinds of bismuth oxyhalide composites surface (bismuth oxybromide and bismuth oxyiodide with different but matched band gaps) (depAu/BiOI/BiOBr). Specifically, synergistic effect was achieved through the direct Z-scheme heterojunction formed by BiOBr and BiOI as well as the gold Schottky junction, resulting in the enhanced light harvest and photoelectric conversion efficiency. Meanwhile, combined with sandwich immunotechnology, a “signal-off” PEC biosensor was fabricated for highly sensitive detection of carcinoembryonic antigen (CEA). In which, using depAu/BiOI/BiOBr modified glassy carbon electrodes both as the photoactive sensing interface and capture antibody loading matrix, polyethyleneimine copper complex encapsulated gold nanoclusters labeled detection antibody (Ab2-Au@PEI-Cu) as the quencher, the photocurrent decreased with the increasing target CEA introduced by sandwich immune reaction. The proposed smart PEC immunoassay platform exhibited a wide detection range (1.0 fg/mL-2.0 ng/mL) and a detection limit as low as 0.11 fg/mL with favorable selectivity and stability. In addition, this PEC sensing strategy can be easily extended for other tumor marker analysis, which offers a new perspective of using multiple bismuth oxyhalide as photoactive materials for early diseases diagnosis.

Bi0.5Na0.5TiO3–SrTiO3 lead-free piezoelectric composites with large strain under low driving fields

Lead-free (1-f)[0.73Bi0.5Na0.5TiO3–0.27SrTiO3]–f[0.75Bi0.5Na0.5TiO3–0.25SrTiO3] composites were synthesized using a conventional solid-state reaction method. The f = 0.5 composites exhibited a giant unipolar strain of 0.176 % under an ultralow driving field of 2 kV/mm, corresponding to a high normalized strain of 880 pm/V. This value is comparable with that of other macro ferroelectric/relaxor composite materials under higher electric fields and even higher than those for commercial lead-based piezoceramic materials. We believe that these bismuth sodium titanate-based composites are extremely competitive in the practical applications of actuators at low electric fields.

Spark Plasma Sintering-Assisted Synthesis of Bi2Fe4O9/Bi25FeO40 Heterostructures with Enhanced Photocatalytic Activity for Removal of Antibiotics.

Bismuth ferrite-based heterojunction composites have been considered as promising visible-light responsive photocatalysts because of their narrow band gap structure; however, the synthetic methods reported in the literature were usually time-consuming. In this study, we report a facile and quick preparation of bismuth ferrite-based composites by the hydrothermal method, combined with spark plasma sintering (SPS), a technique that is usually used for the high-speed consolidation of powders. The result demonstrated that the SPS-assisted synthesized samples possess significant enhanced photoelectric and photocatalytic performance. Specifically, the SPS650 (sintered at the 650 °C for 5 min by SPS) exhibits a 1.5 times enhancement in the photocurrent density and a 3.8 times enhancement in the tetracycline hydrochloride photodegradation activity than the unmodified bismuth ferrite samples. The possible influence factors of SPS on photoelectric and photocatalytic performance of bismuth ferrite-based composites were discussed carefully. This study provides a feasible method for the facile and quick synthesis of a highly active bismuth ferrite-based visible-light-driven photocatalyst for practical applications.

Bismuth composition, thickness, and annealing temperature dependence of the spin Seebeck voltage in Bi-YIG films prepared using sol–gel solution and spin-coating method

We investigated the Bi composition, film thickness, and annealing temperature (Ta) dependence of the magnitude of the longitudinal spin Seebeck effect (LSSE) voltage in BixY3-x Fe5O12 (0 ≤ x ≤ 1.2) (Bi-YIG) films on a Si substrate, prepared using sol–gel solution and spin-coating methods. The Bi-YIG garnet films exhibited a polycrystalline structure, and the thickness of the film formed by the agglomeration of nanoparticles was approximately 50 nm. The LSSE coefficient (S) of the Bi-YIG/Pt (5 nm) films tends to increase with increasing Bi composition (0 ≤ x ≤ 0.8), and the value of the S at x = 0.8 is 1.7 times larger than that at x = 0. When the Bi composition is 0 ≤ x ≤ 0.8, the values of the saturation magnetization and resistivity are almost constant regardless of x, and the value of the Gilbert damping constant increases with increasing x, while the values of the spin mixing conductance and maximum Kerr rotation angle are tended to increase with increasing x. This result indicates that the increasing tendency of the S occurs because of the induced of effective spin current conversion in the Pt layer thorough Bi-YIG due to the enhancement of interface effect between the Pt and Bi-YIG by Bi substitution. In addition, a large S is obtained in Bi-YIG films annealed at Ta = 973 K because the films contained few cracks and smooth surface conditions.

Screen-printed bismuth telluride nanostructured composites for flexible thermoelectric applications

We herein report the results of a facile two-step surfactant assisted reflux synthesis of bismuth telluride (Bi2Te3) nanowires (NWs). The as-synthesised NWs had diameters ranging from 70 to 110 nm with a length varying between 0.4 and 3 µm and a preferential lattice orientation of (0 1 5) as determined by grazing incidence x-ray diffraction. We demonstrate for the first time that a solvent/binder paste formulation of N-methyl-2-pyrrolidone/polyvinylidene fluoride (PVDF) is suitable for screen-printing the Bi2Te3 NWs with the potential for the fabrication of flexible thermoelectric (TE) materials. The wt% of PVDF in the composite films was varied from 10% to 20% to identify the optimal composition with a view to achieving maximum film flexibility whilst retaining the best TE performance. The films were screen-printed onto Kapton substrates and subjected to a post-printing annealing process to improve TE performance. The annealed and screen printed Bi2Te3/PVDF NW composites yielded a maximum Seebeck coefficient −192 µV K−1 with a power factor of 34 µW m−1K−2 at 225 K. The flexible screen printed composite films were flexible and found to be intact even after 2000 bending cycles.

Photoactive bismuth silicate catalysts: Role of preparation method

The published papers highlight the photocatalytic properties of bismuth silicates, especially Bi2SiO5. Meanwhile, there is limited information on the formation of bismuth silicates that hinders the controlled synthesis of pure phases of bismuth silicates or composites on the basis thereof. The study is focused on the influence of preparation conditions on the interaction of initial reagents at each stage of synthesis taking into account the roles of solvent (water or ethylene glycol (EG)), precipitation agent, Si-containing component as well as the calcination procedure. The key role in these transformations is played by the stable Bi(III)–EG complex that participates in the Bi3+ reduction to metallic state under solvothermal conditions. The phase formation process is accomplished during the thermal treatment of the samples synthesized from EG solution. A four-phased composite material demonstrates the highest photocatalytic performance in photodegradation of Rhodamine B and phenol solutions via selective deethylation and mineralization processes, respectively.

Carbon quantum dots sensitized 2D/2D carbon nitride nanosheets/bismuth tungstate for visible light photocatalytic degradation norfloxacin

A novel carbon quantum dots (CQDs) sensitized 2D/2D carbon nitride nanosheets and bismuth tungstate composite (CQD-CNs/BWO) was successfully prepared via the facile hydrothermal method and used for the photocatalytic degradation of norfloxacin (NOR). During 120 min irradiation test, CQD-CNs/BWO exhibited 9 and 1.76 times higher photocatalytic activity than CNs and BWO, respectively. CQDs and constructed 2D/2D structure could not only improve the light harvesting but also promote the generation and separation of electron-holes. The existing inorganic ions in solution (e.g. bicarbonate ions, chlorine ions, and sulfate ions) could inhibit NOR degradation. Based on the electron spin resonance and free radicals inhibition tests, the holes and superoxide radicals rather than hydroxyl radicals were the main reactive species. The intermediates and possible pathways were proposed, and the antibacterial activity of the treated solution after the reaction was evaluated via bacteriostatic tests. The prepared composite material with high photocatalytic activity and stability is potentially effective for the degradation of antibiotics in wastewater.

Analysis of Microstructure and Mechanical Properties of Bismuth-Doped SAC305 Lead-Free Solder Alloy at High Temperature

SAC305 lead-free solder alloy is widely used in the electronic industry. However, the problems associated with the growth formation of intermetallic compounds need further research, especially at high temperatures. This study investigates the doping of Bismuth into SAC305 in the various compositions of 1, 2, and 3 wt.%. The microstructure in terms of intermetallic compound particles and mechanical properties was examined after thermal aging at temperatures of 100 °C and 200 °C for 60 h. The microstructure examination was observed using scanning electron microscopy, and the chemical composition of each alloy was confirmed with an energy dispersive X-ray. Tensile tests were performed to find the mechanical properties such as yield strength and ultimate tensile strength. The intermetallic compound’s phase analysis was identified using X-ray diffraction, and differential scanning calorimetry was done to study the temperature curves for melting points. Results showed that the addition of Bismuth refined the microstructure by suppressing the growth of intermetallic compounds, which subsequently improved the mechanical properties. The thermal aging made the microstructure coarsen and degraded the mechanical properties. However, the most improved performance was observed with a Bismuth addition of 3 wt.% into SAC305. Furthermore, a decrease in the melting temperature was observed, especially at Bismuth compositions of 3 wt.%.

Formation conditions of noble metal mineralization in sulfide cobalt-copper-nickel ores of Kamchatka (on the example of Annabergitovaya Schel ore occurrence)

The authors present research results, the purpose of which is to study the specifics of noble metal mineralization and its genesis in sulfide cobalt-copper-nickel ores of the Kamchatka nickel-bearing province. The paper is dedicated to one of its many ore occurrences called Annabergitovaya Schel (Annabergite Gap). The material composition of platinoid, silver, gold, bismuth and tellurium minerals, as well as sulfarsenides in the ores of this occurrence was investigated. Based on the data of mineral formation sequence and the use of geosensors, conclusions were drawn regarding the genesis of noble metal mineralization.
 Formation of platinoid minerals, silver and gold at the Annabergitovaya Schel ore occurrence is mainly associated with the epigenetic effect of post-ore granitoids on ore-bearing intrusion rocks of the Dukuk complex of the cortlandite-norite formation and on syngenetic ores. An early association of noble metal minerals is represented by sperrylite, irarsite, and rare unnamed phases of Pt + Ir + Te. Irarsite and Pt + Ir + Te phases were formed at the contact-metasomatic stage. Sperrylite can be assumed to be of magmatic origin. Silver sulfides and tellurides, silver and palladium bismuth tellurides, and native gold were formed at the late, hydrothermal-metasomatic, stage. The occurrence conditions of mineral parageneses, associated with noble metal mineralization, correspond to the formation of shallow-depth metasomatic rocks (5 km). Sub-developed quartz-feldspar metasomatites, associated with the formation of early platinoid arsenides and sulfarsenides, are in equilibrium with circumneutral solutions (pH of 4.5-6.5) at temperatures of 350-600 °C. Late hydrothermal association with Pd, Ag and Au minerals is close to propylites and was formed at pH values of 4.5-6.5 and temperature of 150-350 °C.

Enhancement of visible light photocatalytic activity of BiVO4 by polypyrrole modification

In this study, the different amounts of polypyrrole modified BiVO4 photocatalyst were synthesized by oxidative polymerization of pyrrole. The photocatalytic activity of polypyrrole and vanadate bismuth (PPy/BiVO4) composite was determined by photocatalytic degradation of Rhodamine B (RhB) under visible light irradiation. The results showed that PPy could not only affect the crystal structure and the morphology of BiVO4 photocatalyst, but also had a great influence on the photocatalytic activity of pure BiVO4. It was also found that PPy/BiVO4 with the highest photocatalytic activity when the doping amount of PPy was 5%, and the RhB degradation rate could reach 95.72%. This paper also discussed the possible mechanism of enhanced activity: the photogenerated holes in the valence band of BiVO4 can be directly transferred to the π orbital of PPy. At the same time, photogenerated electrons can be transferred to the conduction band of BiVO4, resulting in charge separation and stabilization, thereby effectively preventing the recombination of photogenerated electrons and holes.