Bismuth Oxide Research Articles

Exploring the potential of bismuth-containing silicate borate glasses for optoelectronic devices and radiation protection

This study studied novel bismuth silicate borate glasses with different bismuth oxide (Bi2O3) concentrations for their optical and γ-radiation shielding capabilities. The glass samples were characterized using UV–Vis–NIR spectroscopy to determine their optical properties, including the optical absorption spectra, absorption edge, and optical band gaps. The FLUKA algorithm was used to determine the radiation shielding parameters in the energy range of 0.01–15 MeV. The results revealed that the optical absorption edge and intensity were influenced by the Bi2O3 concentration, with the highest absorption observed in the sample with 35 mol% Bi2O3. The direct and indirect optical band gaps decreased with adding Bi2O3 up to 15 mol%, then increased at 25 mol%, and then reduced to the lowest value at 35 mol%. The system's crystallite size grew as the amount of Bi2O3 in the sample increased, as revealed by XRD. With increasing Bi2O3 content, it was discovered that the mass attenuation coefficient (μm) and radiation shielding effectiveness rose. The effective atomic number (Zeff) values increased as Bi2O3 content grew. T0.5 values of the glass samples increased as the energy increased and decreased as the Bi2O3 concentration increased. These findings suggest that prepared glasses with high Bi2O3 concentrations have potential applications in radiation shielding and optoelectronics.

Removal of congo red and malachite green from aqueous solution using ternary GO/Bi2O3/MgO materials by co-precipitation method

The present work describes the preparation of Bismuth oxide and magnesium oxide modified with graphene oxide (GO/Bi2O3/MgO) using the co-precipitation method for the elimination of malachite green (MG) and congo red (CR) dyes from aqueous solution. The synthesized GO/Bi2O3/MgO materials were analyzed by using FTIR, SEM, XRD, EDX and EDS. The batch experiment was aimed to investigate the adsorption process by varying various parameters of optimum value for CR and MG dye adsorption such as adsorbent dosage was 100 mg, contact time was 30 min, stirring speed was 250 rpm, initial dye concentration was 30 mg L−1 and pH was 6.5. From experimental data, we concluded that for elimination of MG and CR dye with higher coefficient value (R2) was best fitted with the Langmuir isotherm model. The maximum adsorption capacity was observed to be 45.454 mg/g for MG and 58.823 mg/g for CR, respectively. The mechanism of the adsorbent and both the dyes were explained by electrostatic interaction, π-π interaction, and hydrogen bonding. To check the stability of the GO/Bi2O3/MgO materials, we performed the reusability study using various solvents like methanol, ethanol, water, sodium hydroxide and acetone. Among various solvents, NaOH has shown maximum desorption of both dyes.

Comprehensive analysis of physical, mechanical, thermal and attenuation characteristics of NaF - B2O3 – Bi2O3 - Sm2O3 glasses for gamma radiation shielding applications

A glass system with the nominal composition 10NaF - (89-x)B2O3 - xBi2O3 - 1Sm2O3 (where x = 15, 20, 25, 30, and 35 mol%) has been fabricated by the melt quenching technique. Densities increased from 3.598 to 4.726 g/cm³ and a corresponding rise in molar volume from 35.880 to 44.089 cm³/mol. The decrement in oxygen packing density (OPD = 75.250–61.239 mol/cm3) and increment in oxygen molar volume (13.289–16.329 cm3/mol) indicate an expansion of the glass structure with the Bi3+ ions. Young's modulus decreases from 58.974 to 41.685 GPa as the concentration of Bi2O3 increases from 15 to 35 mol%. The linear attenuation coefficient (LAC) shows an increasing trend, demonstrating improved attenuation ability with a higher molar concentration of Bi₂O₃. As the Bi₂O₃ concentration increases in the glass matrix, the effective atomic number (Zeff) increases from 61.214 to 72.116 at 59.54 keV, and from 15.829 to 25.988 at 662 keV. The half-value layer (HVL) decreases as bismuth oxide is introduced into the glass matrix, and prepared glasses exhibit lower values than Hematite-Serpentine Concrete, Ilmenite-Limonite Concrete, Basalt-Magnetite Concrete, Ilmenite Concrete, RS253, 55B2O3:20BaCO3:19.5ZnO:5Bi2O3:0.5Dy2O3, RS 323, LSGB1, and LSGB2 shielding materials. The mean free path (MFP) values reduced from 0.094 to 0.053 cm at 59.54 keV, and from 2.958 to 2.073 cm at 662 keV with the Bi2O3 concentration. Consequently, the prepared glass can be reliable for gamma radiation shielding applications.

Sonochemical Facile Synthesis of Bismuth Oxide Nanoparticles Using Citrus Lemon Extract and Its Catalytic Activity on Azo Dye Degradation

The synthesis of bismuth oxide nanoparticles through sono-cavitation using citrus lemon extract as a simple, eco-friendly and cost-efficient method was evaluated. The aqueous extract of citrus lemon acted as a bio-reducing and capping/stabilizing agent in the single-step biosynthesis of bismuth oxide nanoparticles. Different instrumental techniques have been used to characterize the biosynthesized bismuth oxide nanoparticles, including UV–vis spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray powder diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), Raman spectroscopy, X-ray photoelectron spectroscopy and energy-dispersive X-ray spectroscopy (EDS). UV–vis spectroscopy revealed the formation of stable bismuth oxide nanoparticles at λmax of 400 nm with a surface plasmon resonance (SPR) band. TEM revealed that the biosynthesized bismuth oxide nanoparticles were rod shaped with a particle size of 26 nm. A potential mechanism for the formation of bismuth oxide nanoparticles with the influence of sono-cavitation has been suggested based on the observed findings. These catalytic capabilities of the bio-synthesized bismuth oxide nanoparticles were then evaluated by degradation of toxic azo dyes under different laboratory conditions. The azo dye Congo red (CR) was effectively degraded to 86% within 30 min under optimum experimental conditions using 0.12 g/mL catalyst. Thus, the phytochemical citrus lemon offers a cheap and eco-friendly solution for the synthesis of catalytic nanoparticles to degrade highly toxic organic compounds such as azo dyes.Graphical

SRIM simulation of hydrogen ions interaction with bismuth oxide nanoparticles doped with rare earth elements

Simulation methods have received much attention across various fields in recent years. The rare-earth lutetium tantalate (LuTaO4) doped “Bismuth Oxide (Bi2O3) thin films were deposited onto polymer substrates using a SRIM program.” The SRIM program was used to calculate some physical characteristics of Bi2O3 films at energies between 1.0 MeV and 20 MeV. The “electronic and nuclear stopping powers” of LuTaO4, Bi2O3, C10H8O4, and LuTaO4/ Bi2O3/C10H8O4 samples were investigated. These findings show that rare earth doping may improve the performance of composite materials. The interaction of ion beams with matter can result in a wide variety of phenomena. The deposition of Bi2O3 films doped with LuTaO4 on C10H8O4 led to changes in the “electronic and nuclear stopping powers” and range in the materials. Published data were compared with the results obtained and the calculations parameters were provided.

Ultraviolet Grafting of Bismuth Oxide Enhances the Photocatalytic Performance of PVDF Membrane and Improves the Problem of Membrane Fouling.

Photocatalytic membranes are crucial in addressing membrane fouling issues. However, the grafting amount of the catalyst on the membrane often becomes a key factor in restricting the membrane's self-cleaning capability. To address the challenge, this manuscript proposes a method for solving membrane fouling, featuring high grafting rates of bismuth oxide (Bi2O3) and acrylic acid (AA), significant contaminant degradation capability, and reusability. A highly photocatalytic self-cleaning microfiltration membrane made of polyvinylidene fluoride bismuth oxide and acrylic acid (PVDF-g-BA) was prepared by attaching nano Bi2O3 and acrylic acid onto the polyvinylidene fluoride membrane through adsorption/deposition and UV grafting polymerization. Compared with pure membranes and pure acrylic grafted membranes (PVDF-g-AA), the modified membrane grafted with 0.5% bismuth oxide not only improves the grafting rate and filtration performance, but also has higher self-cleaning ability. Furthermore, the degradation effect of this membrane on the organic dye methyl violet 2B under visible light irradiation is very significant, with a degradation rate reaching 90% and almost complete degradation after 12 h. Finally, after repeated filtration and photocatalysis, the membrane can still significantly degrade contaminants and can be reused.

Unassisted photoelectrochemical CO2-to-liquid fuel splitting over 12% solar conversion efficiency

The increasing need to control anthropogenic CO2 emissions and conversion to fuels features the necessity for innovative solutions, one of which is photoelectrochemical system. This approach, capable of yielding gaseous production progressively, is facing challenges for liquid fuels generation due to optical, electrical, and catalytic properties. This study employs a standalone photoelectrochemical setup, in which InGaP/GaAs/Ge photoanode is integrated with tin-modified bismuth oxide cathode to convert CO2 into liquid formic acid. In unassisted two-electrode assembly, setup exemplifies its operational durability for 100 h, during which it maintains an average Faradaic efficiency of 88% with 17.3 mmol L–1 h–1 of yield, thereby excelling in average solar-to-fuel conversion efficiency at 12% with 60% of electrical energy efficiency under one sun illumination. This significant performance is further associated with metal-semiconductor interface formation between tin and bismuth oxide, which bridges electronic structures and generates an electric field at their interfaces. This study outperforms conventional solar-driven systems in operational durability and liquid fuel production.

Microstructure, electrical and magnetic properties of MgFe2O4 sintered with (1-x)Bi2O3.xFe2O3 additives

In this research, liquid phase sintering of MgFe2O4 with a Bi2O3-Fe2O3 additive was studied. Initially, MgFe2O4 powder was synthesized at 1150 °C, then 3 wt% additive with (1-x)Bi2O3.xFe2O3 (x=0.00, 0.04, 0.08, 0.12) was added to the powder and sintered at 1050 °C. The x=0.04 sample showed the highest density of ∼4.40 g/cm3. Cubic spinel ferrite and phases containing bismuth oxide were formed in all samples, notably, only x=0.08 and x=0.12 samples consist hematite. Uniform microstructure was achieved for x=0.00 and 0.04 samples while other samples exhibited non-uniform porous microstructures. EDS analysis revealed uniform iron distribution in the grains of x=0.04 sample, unlike the x=0.00 sample. Impedance spectroscopy indicated increased electrical resistivity in x=0.04 compared to x=0.00. Saturation magnetization peaked at 18.5 emu/g for x=0.04, then decreased, while coercive force rose from 13.2 to 30.2 Oe with increasing x. The x=0.04 additive acted as the optimal sintering aid, improving electrical and magnetic properties.

(Invited) Mixing Elements in 2D Nanostructures Grown by Discharges in Liquids

The synthesis of nanosheets through discharges in liquid nitrogen is observed for certain metals when employed as electrodes [1,2]. Various metals have been examined, with bismuth, lead, or zinc showing a propensity to form nanosheets. Other metals, such as silver or indium, also exhibit sheet formation but with smaller aspect ratios (width/thickness). Mixing metals is not only interesting to create alloys with new properties but also to understand how discharges work to enable the synthesis of these objects.Recently, we demonstrated that these structures can be grown not only in liquid nitrogen but also in water. This is attributed to the discharge primarily originating from the metallic vapor emitted by the electrodes, a consistent process in both liquids, as confirmed by time-resolved optical emission spectroscopy.We showcased that a pre-treatment, involving chemical etching by a Nital solution, significantly enhances the efficiency of nanosheet production, increasing it from almost zero to nearly 100%. We successfully identified the growth mechanism of nanosheets in the case of bismuth electrodes. These structures grow on the cathode with ion assistance, collecting in the bubble formed during the discharge. Upon the collapse of the bubble, they transfer into the liquid phase. Interestingly, the number density of nanoparticles produced under these conditions is either null or too weak to be evaluated.It is feasible to incorporate two different elements into 2D nanostructures by utilizing two electrodes. We achieved a mixture of lead and bismuth oxide by using electrodes composed of the respective elements. This capability is likely associated with the similar melting points and miscibility of both elements. Nanosheets exhibit thicknesses around 5-10 nm for widths ranging in the tens of micrometers.We anticipate that a more comprehensive understanding of the synthesis of these alloys will pave the way for the production of alloyed nanosheets incorporating other elements.[1] A. Hamdan, H. Kabbara, C. Noël, J. Ghanbaja, A. Redjaimia, T. Belmonte, “Synthesis of two-dimensional lead sheets by spark discharge in liquid nitrogen”, Particuology 40 (2018) 152–159[2] H. Kabbara, J. Ghanbaja, C. Noël, T. Belmonte, “Nano-objects synthesized from Cu, Ag and Cu28Ag72 electrodes by submerged discharges in liquid nitrogen”, Materials Chemistry and Physics 217 (2018) 371–378

(Invited) Enhancing Stability for Elevated Temperature CO2 Electrolysis: Insights from Catalyst Development and Impact of Carbon Protection

While most lab-scale CO2 reduction experiments are conducted at ambient temperatures (20-25°C), maintaining such low temperatures at an industrial scale will become challenging due to joule heating. In our study, we pushed the boundaries further than the already existing systems, opting for a higher temperature of 85°C for CO2 reduction. This deliberate choice was made to accentuate the deviations from ambient conditions and explore their effects on CO2 electrolyzers.Our current emphasis at elevated temperatures focuses on catalyst development, specifically addressing stability issues induced by the increased temperature. Nevertheless, it was soon discovered that several modifications were required to the system, both in terms of cell materials and operational conditions (e.g. gaskets, pressure arrangements, GDE type, etc.) to allow stable operation at 85°C for extended duration and especially to avoid flooding. Prior research provided valuable insights into the multifaceted impacts of elevated temperatures on the electrochemical reduction of CO2, and proof they go beyond catalyst kinetics. With this in mind, we have synthesized a series of bismuth-related nano catalysts, including oxidized, metallic and carbon containing nanoparticles, and have quantitatively evaluated their activity, selectivity towards formate, and stability at 85°C. Preliminary observations suggest that catalysts without carbon exhibit high initial selectivity, but demonstrate diminished stability over a 24-hour timeframe compared to catalysts with a protective carbon layer. Specifically, we observed an initially high faradaic efficiency toward formate of 85% for commercial bismuth oxide nanoparticles, in contrast to 75% for bismuth nanoparticles with carbon. However, over a 24-hour timeframe, the carbon-free catalyst showed a 20% decrease in FE, while for the carbon-containing catalyst this drop was halved in the same timeframe.By evaluating the role of carbon additives (e.g. their oxidation state, pore size, surface area, hydrophobicity, etc.) our results yield valuable insights into the impact of carbon additives on stability and overall performance, especially at elevated temperature. These findings uncovered critical aspects for catalyst design, providing essential knowledge for future larger-scale applications. Moreover, we shed light on the required advancements and remaining challenges for elevated temperature CO2 reduction electrolysis, which we believe will become the predominant mode of operation for CO2 electrolysis in the future. Figure 1

Electrochemical CO2 Reduction in the Presence of Flue Gas Impurities: Effect of NOx, SOx and O2

Electrochemically converting CO2 to valuable chemical products using renewable energy sources may present solutions to alter current increasing CO2 emission trends. Currently, electrolyzer research is almost exclusively done with pure CO2 streams that - in practice - would originate from carbon capture units that prevent CO2 release to the atmosphere [1]. The capture and purification steps are cost intensive processes which is why direct usage of flue gases that contain impurities is a highly interesting approach. For this reason, the performance of CO2 electrolyzers equipped with state-of-the-art Bi2O3 or Ag catalysts is investigated in this work with an impure CO2 feed stream containing SO2, NO or O2. The short-term effect of highly concentrated SO2 (10 000 ppm) and NO (8 300 ppm) impurities during CO2 electrolysis was previously described [2,3]. Our work [4] elaborates further on this matter through 20 h experiments with flue gas-like concentrations of 200 ppm SO2 or NO. The results show a stable operation without severe FE losses (remains >90%) and structural adaptations to neither Ag nor Bi2O3 by these impurities. The presence of oxygen in flue gas streams at concentrations of several percent is common and causes a major decrease in FE to the target products (CO or HCOO-) during electrolysis. This is a result of the competition between the ORR and CO2RR with the former occurring more preferentially. To overcome this, we have discovered two possible strategies, which allow high FE’s to CO2RR products even in the presence of oxygen. (1) By operating the electrolyzer at a sufficiently high overall current density, all of the O2 entering and reaching the electrode surface gets reduced, allowing the CO2RR to become the dominant reaction. Although this approach has a higher electricity penalty, the extra cost is negligible compared to the cost otherwise associated with the CO2 purification for CO2 streams with an O2 content below 3%. (2) Given that the ORR is mostly occurring at the carbon-based gas diffusion layers another approach to improve CO2RR efficiency in the presence of oxygen is to replace this conventional support with ultra hydrophobic PTFE membrane filters. Since they are inefficient oxygen reduction catalysts, CO2RR again takes up the major fraction of the applied current density. A downside of using PTFE is that an additional conductive layer is required in case the catalyst itself (e.g. for bismuth oxide) is not conductive enough. These results thus not only offer new insights into the impact of gaseous impurities during CO2 electrolysis, but also suggest a strategy to improve electrolyzer performance with O2-containing feed streams. Bibliography [1] Lee M.Y., Environ. Sci. and Technol.; DOI: 10.1080/10643389.2019.1631991[2] Luc W.; JACS, DOI: 10.1021/jacs.9b03215[3] Ko B., Nature Comm. DOI : 10.1038/s41467-020-19731-8[4] Van Daele S ., J. Appl. Catal. B, Environ.; DOI: 10.1016/J.APCATB.2023.123345 Figure 1

Designing Heterogeneous Catalysts for Microwave Assisted Selective Oxygenation

AbstractMicrowave dielectric heating is an emerging technology in heterogeneous catalysis. However, catalyst design in this field is not as well developed as when conventional heating is used. In this study the selective oxidation of propene to acrolein has been used as a model reaction to understand the how the properties of bismuth mixed metal oxide catalysts can be tuned for use in microwave assisted catalysis. The role of the dielectric properties, that are crucial to enable the catalyst to be heated in the microwave electric field, were determined using cavity perturbation methods. Catalysts with a very high loss tangent reached high temperatures leading to combustion products, whereas materials with a low loss tangent could not be heated and were inactive. Bi2MoO6 and BiVO4 both showed promising performance during an initial screening and were investigated further. For Bi2MoO6, a partial substitution of molybdenum with vanadium resulted in the formation of Bi1−X/3V1−xMoxO4, with a decrease in particle size and dielectric loss tangent, and the highest rate of acrolein production was found when x=0.6 at 15 W microwave power. Higher microwave power resulted in thermal runaway which decreased the activity of the catalyst.

Removal of Levofloxacin by Copper-Doped Bismuth Oxide Thin Films Under UV Light Irradiation

Removal of Levofloxacin by Copper-Doped Bismuth Oxide Thin Films Under UV Light Irradiation

Tailoring structural, thermal, and optical properties of Tm3+-doped borotellurite glasses through Bi2O3 incorporation for optical fiber construction

This research investigates the influence of bismuth oxide (Bi2O3) on the structural, thermal, and optical properties of thulium (Tm3+) ion-doped borotellurite glasses, aiming to optimize materials for optical fiber construction. Melt-quench method was employed for glass preparation. XRD spectra indicated that all the synthesized glass samples exhibit an amorphous structure. By methodically increasing the Bi2O3 content to 0.1 molar fraction, significant improvements were observed in the glass matrix. These improvements include increased optical band gaps and decreased Urbach energy, indicative of reduced structural disorder and enhanced homogeneity. which are crucial for minimizing optical losses in fiber optics. Infrared (IR) spectroscopy analysis revealed that this optimal Bi2O3 content leads to denser, more ordered glass structures with an increase in bridging oxygens and a reduction in non-bridging oxygens, contributing directly to the observed improvements in optical properties. Additionally, thermal analysis highlighted a notable enhancement in the thermal stability of the glasses, highlighting their suitability for enduring variable temperature conditions and ensuring durability in optical fiber infrastructure. The findings support for the potential of these doped borotellurite glasses in advancing the development of robust, high-performance optical fibers capable of withstanding environmental challenges.

Effect of Bi2O3 Particle Size on the Radiation-Shielding Performance of Free-Lead Epoxide Materials against Ionizing Radiation.

In this work, we studied the effect of bismuth oxide particle size and its attenuation capacity as a filler additive in epoxy resins. Six samples were prepared according to the amount of microparticles and nanoparticles in the sample and were coded as ERB-1, ERB-2, ERB-3, ERB-4, ERB-5, and ERB-6. One of the composite epoxies contained Bi2O3 microparticles at a 50:50 ratio (ERB-6) and was chosen as the control composite, and the number of microparticles (MPs) was gradually decreased and replaced by nanoparticles (NPs) to produce epoxy-containing Bi2O3 nanoparticles at a 50:50 ratio (ERB-1). The morphological and thermal characteristics of the studied composites were tested. The attenuation capability of the prepared composites, which is determined by the Bi2O3 particle size, was determined experimentally using a semiconductor detector, an HPGe-detector, and three different gamma-ray point sources (Am-241, Co-60, and Cs-137). The linear attenuation coefficient (LAC) of ERB-3, which contained 30% nanoparticles and 20% microparticles, had the highest value compared to the other composites at all the energies discussed, while the ERB-6 composite had the lowest value at all energies. The radiation-shielding efficiency (RSE) of the prepared samples was determined at all discussed energies; at 662 keV, the radiation-shielding efficiency values were 15.97%, 13.94%, and 12.55% for ERB-3, ERB-1, and ERB-6, respectively. The statistics also proved that the attenuation capacities of the samples containing a combination of nanoparticles and microparticles were much superior to those of the samples containing only microparticles or nanoparticles. A ranking of the samples based on their attenuation capacity is as follows: ERB-3 > ERB-4 > ERB-2 > ERB-1 > ERB-5 > ERB-6.

Preparation of Manganese-Doped Bismuth Oxide for the Photocatalytic Degradation of Methylene Blue

The current study describes a unique method for degrading methylene blue dye utilizing Mn-doped Bi2O3 nanoparticles (NPs) exposed to UV light. Bi2O3 nanoparticles (NPs) doped with Mn were produced using a hydrothermal process. Scanning electron microscopy (SEM), energy-dispersive X-ray analysis (EDX), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and were use to characterize the prepared nanoparticles. It was discovered that the band gaps of Mn/ Bi2O3 NPs are 2%, 3%, and 4%, respectively, and are 4.13 eV, 3.92 eV, and 3.77 eV. Functional group identification using Fourier transforms infrared spectroscopy (FT-IR). Mn-doped Bi2O3 nanoparticles were captured in SEM pictures at various magnifications, and the photos clearly display the particles' dual morphologies, cubic and cylindrical. The Mn-doped Bi2O3 particles were found to be crystalline, with mean diameters of 20 nm, according to the XRD data. The photodegradation efficiency of Mn/Bi2O3 at experimental dye concentrations of 2%, 3%, and 4% was determined to be 90.29, 91.6, and 93.16 percent, respectively, over a 150 minute time interval. At the ideal catalyst dosage of 0.2 g and concentration of 40 ppm, a high percentage of dye degradation was observed. Numerous metals have been doped into zinc oxides, although no work has documented doping of Bi2O3 with Mn. Additionally, it was utilized for the first time to look at the deterioration of methylene blue dye. Received: 11 May 2024 | Revised: 9 July 2024 | Accepted: 18 July 2024 Conflicts of Interest The authors declare that they have no conflicts of interest to this work. Data Availability Statement Data available on request from the corresponding author upon reasonable request. Author Contribution Statement Mansoor Jamal: Conceptualization; Gul Asimullah Khan Nabi: Methodology; Hao Sun: Software; Khair Ullah: Validation; Osama Ali Khattak: Formal analysis; Muhammad Kashif: Investigation; Salman Khan: Resources; Mohsin Alam: Data curation; Shah Hussain: Writing - original draft; Mati Ullah: Writing - review & editing; Seeqal Aleena: Visualization; Hameedul Haq: Supervision; Saira Umar: Project administration; Muhammad Atif: Project administration; Ijaz Hussain: Project administration; Aalia Masood: Project administration.

Ti-doped synergistic hollow thin-walled Bi2O3 nano-microspheres for efficient tetracycline hydrochloride photodegradation

Bismuth oxide (Bi2O3) has been extensively investigated in the fields of environmental photocatalysis, owing to its exceptional charge transport performance and remarkable resistance to photocorrosion. However, the limited absorption spectrum of light and rapid recombination of photogenerated charge results in a low quantum efficiency. Herein, an efficient photocatalytic system for tetracycline hydrochloride (TCH) photodegradation based on titanium (Ti)-doped hollow, thin-walled Bi2O3 with nano-microspheres is fabricated via a facile self-assembly strategy. It is shown that doping Ti in Bi2O3 can generate oxygen vacancies, in addition, the addition of Ti in the solvothermal process inhibits the conversion of Bi3+ to bismuth at high temperature, making the content of each component in the heterostructure controllable. The hybrid catalyst exhibits superior performance in visible-light-driven photocatalytic degradation of TCH (about 95.1 % degradation efficiency after 120 min) and excellent stability (up to 4 cycles) under visible light irradiation. The optimized catalyst exhibits excellent performance in visible light catalytic degradation, owing to the synergistic effect of high specific surface area, Bi plasma resonance effect and charge mobility. Moreover, the photocatalytic mechanism of Ti-Bi2O3 have been deeply analyzed through experimental investigation and DFT theoretical calculations. The findings contribute to the synthesis of efficient visible-light-driven Bi-based photocatalysts and to the understanding of photocatalytic degradation reactions.

Photocatalytic and antimicrobial activities of nanostructured bismuth oxide synthesis via the green route

Photocatalysis for environmental cleanup is one of the potential applications of nanostructured materials with tailored optical, electrical, thermal, and structural properties. Green nanomaterial synthesis offers benefits over traditional chemical and physical methods in areas such as biocompatibility, sustainability, environmental impact, and energy consumption. Citrus sinensis leaf extract was used as a natural source of reducing, capping, and stabilizing agents in this study, which successfully reported the production of nanostructured bismuth oxide (NBO). The thermal, optoelectronic, and structural properties of the as-synthesized NBO sample were compared to those of a commercially available bulk bismuth oxide (BBO). Additionally, the morphology, composition, optical band gap, and electrical conductivity of the NBO sample were respectively examined through SEM, EDX, UV/Vis, and I–V analysis. The NBO showed exceptional photocatalytic aptitude as it mineralized the crystal violet (CV) dye and killed E. coli under visible-light irradiation. The superb photocatalytic activity of the NBO is attributed to its unique features, i.e., a large surface area (59.73 m2g-1), defective states (D-S) structure, visible-light-triggered band (2.23 eV), and good electrical conductivity (1.23 × 10−5 sm−1). These factors enhance the light-harvesting, charge-separation, electron-excitation, and charge transport properties of the NBO. Additionally, NBO retains 94.5 % photocatalytic activity after four cyclic runs. All of these feature work together to make the environmentally friendly NBO photocatalyst the leading contender for wastewater treatment applications.

Highly efficient CoFe LDO/α-Bi2O3/g-C3N4 heterojunction for photocatalytic elimination of antibiotic pollutants

Efficiently enhancing the photocatalytic activity of graphite carbon nitride (g-C3N4), a promising candidate for pollutants degradation, is of great importance but remains a challenge. Herein, bismuth oxide (Bi2O3) and layered double oxides (i.e. LDO) were applied to improve the photocatalytic performance of g-C3N4 by constructing a ternary CoFe LDO/α-Bi2O3/g-C3N4 heterostructure. Physicochemical characterization results indicate that CoFe LDO/α-Bi2O3/g-C3N4 exhibits large surface area, competitive visible-light harvesting ability and effective separation and transfer efficiency of the photogenerated carriers. Thus, CoFe LDO/α-Bi2O3/g-C3N4 demonstrates the excellent photocatalytic activity for Tetracycline (TC) degradation, achieving approximately 90% degradation within 60 min, and its apparent reaction rate (about 0.03919 min−1) is 1.78, 1.84 and 9.9 times higher than that of CoFe LDO/g-C3N4, α-Bi2O3/g-C3N4 and g-C3N4, respectively. The major active free radicals, namely •O2− and photogenerated h+, are largely responsible for the photocatalytic degradation of TC, as demonstrated by the radical trapping tests and electron spin resource (ESR) measurements. The feasible photocatalytic mechanism for degrading TC by the CoFe LDO/α-Bi2O3/g-C3N4 heterostructure is tentatively proposed.

Bismuth oxide effects on optical, structural, mechanical, and radiation shielding features of borosilicate glasses

Four glasses were synthesized using traditional melting and then the annealing process to study the possible enhancement effects of heavy metals like Bi2O3 on the borosilicate glass system for the composition ((50-x)B2O3–5SiO2–40MgO-xBi2O3 where x = 5, 10, 15, and 20). The structural features were investigated using Fourier-transform infrared (FT-IR) analysis and X-ray diffraction (XRD). Many physical and mechanical parameters have been studied. Optical absorption was measured for all samples to investigate direct and indirect transitions for optical band gap energy (Eg) and Urbach’s energy (EU) and extract various optical properties. The well-known Phy-X simulation was utilized to achieve the study’s goal of calculating the shielding parameters of various gamma energies. Based on XRD results, the amorphous nature of all samples was observed. Adding Bi2O3 instead of the B2O3 side improves the ionizing radiation shielding properties and glass transparency. For example, the MAC values at 15 keV increased from 34.75244 to 73.80841 cm2/g with adding Bi2O3. At the same time, the glass transparency rose from 62 % to 72 %. In contrast, adding Bi2O3 reduced the glass stability according to mechanical and structural properties results. For example, Young’s modulus reduced from 88.745 to 62.109 GPa with increasing Bi2O3. The packing density (Vt) also decreased from 0.606 to 0.468. Based on the results, the current glass is valid for use in a radiation shielding field.