The characteristics of the X‐ray attenuation in electrospun nano(n)‐ and micro(m)‐Bi2O3/polylactic acid (PLA) nanofibre mats with different Bi2O3 loadings were compared as a function of energy using ...mammography (i.e. tube voltages of 22–49 kV) and X‐ray absorption spectroscopy (XAS) (7–20 keV). Results indicate that X‐ray attenuation by electrospun n‐Bi2O3/PLA nanofibre mats is distinctly higher than that of m‐Bi2O3/PLA nanofibre mats at all energies investigated. In addition, with increasing filler loading (n‐Bi2O3 or m‐Bi2O3), the porosity of the nanofibre mats decreased, thus increasing the X‐ray attenuation, except for the sample containing 38 wt% Bi2O3 (the highest loading in the present study). The latter showed higher porosity, with some beads formed, thus resulting in a sudden decrease in the X‐ray attenuation.
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•α, β, α/β Bi2O3 heterojunction-catalysts were synthesized by hydrothermal method.•α/β Bi2O3 porous nano flake shows synergistic degradation of RhB under sunlight.•Various operational ...parameters for photocatalysis were investigated.•Plausible mechanism of degradation of RhB was drawn.•99.6% removal of RhB is achieved in 180 min using 0.5 g/L photocatalyst at pH 3.
Nano particles of a few α/β Bi2O3 hetero-junctions of various compositions synthesized by one- pot hydrothermal method, exhibit exceptional and synergistic photo-catalytic activity for the degradation of Rhodamine-B in aqueous solution under natural sunlight. Pure α and pure β Bi2O3 are also synthesized by control post heating of synthesized hetero-junction. The nano-materials were characterized by diffraction (XRD), microscopic and spectroscopic techniques. The XRD reveals α-β phase hetero-junctions of Bi2O3 are made of α-Bi2O3 and β-Bi2O3 with average dimensions within 13–113 and 5–71 nm respectively and having band gap range of 2.4– 2.9 eV. The spectrophotometrically determined % degradation of the dye and associated rate constant on the best hetero-junction are increased by 4.5(/2.1) and 3.3(/1.2) times than these on pure α (/β). The effects of operational parameters and trapping agents have been analyzed. The maximum removal of the dye was achieved up to 99.6% in 3 h using 0.5 g/L photo-catalyst at pH 3. The reusability test shows that the photo-catalytic activity is retained excellently due to change in chemical nature of the catalyst from α -Bi2O3 to β-Bi2O3, Bi2O2CO3 and BiOCl. A suitable mechanism is proposed.
The aim of this study was to develop efficient anode materials for direct methanol fuel cell applications. The Ni foam was modified with Bi2O3 - acetylene black-rGO to increase catalytic activity ...toward methanol oxidation. The Bi2O3 was synthesized via a straightforward green technique. The characterization was achieved by using Fourier transform infrared spectroscopy and X-Ray diffraction analysis. The transmission electron microscope and field emission scanning electron microscope was utilized to evaluate the surface properties of catalysts, and energy-dispersive X-ray spectroscopy were employed to determine the chemical composition. Bi2O3 particles with diameters ranging from 15 to 75 nm were crystal structures in the (111), (220), (311), and (342) crystal planes. The performance of methanol electrooxidation in an alkaline medium was investigated using cyclic voltammetry, electrochemical impedance spectroscopy and chronoamperometry techniques. The surface coverage of the redox species was 2.04 × 10−5 mol g−1, and the diffusion coefficient ranged between 8.02 × 10−12 and 1.25 × 10−13 cm2 s−1. According to the obtained results, the Bi2O3 - acetylene black-rGO modification enhanced the electrocatalytic activity of Ni foam against methanol oxidation in an alkaline medium.
•This research aimed to produce effective anode materials for methanol fuel cells.•Facile method was used to generate composite electrocatalyst.•Bi2O3- acetylene black-reduced graphene oxide supported Ni foam used.
In this paper, Bi2O3-In2O3 heterostructure was designed and synthesized by a hydrothermal method. We first used this material for n-butanol sensing materials. In order to explore the potential ...application of the materials, their crystal structure, microstructure, and chemical state were characterized using XRD, TEM, and XPS. At the optimum operating temperature of 265 °C, the gas sensitive test shows that the response value of the composite containing 2.5 mol% Bi2O3 to 100 ppm n-butanol can reach 63, and the response time is only 3 s. Furthermore, the composite demonstrates excellent recyclable stability. The p-n heterogeneous structure and abundant active sites make the sensor have excellent gas sensing performance. The successful preparation of Bi2O3-In2O3 heterostructure contributes to the realization of more sensitive heterostructure n-butanol gas sensor.
•We first used nanosheets of In2O3-Bi2O3 for n-butanol sensing materials.•In2O3-Bi2O3 nanosheets can rapidly detect n-butanol (3/60 s) at 265 °C.•The interfacial synergism of heterojunction and abundant oxygen vacancy greatly improve the gas sensitivity.
Rod-like α-Bi2O3 and tetrahedral γ-Bi2O3 particles have been controlled fabricated by a facile solution crystallization method, which was performed at a mild reaction condition without any ...surfactants and/or templates. By combining the results of X-ray powder diffraction, high resolution transmission electron microscope, scanning electron microscopy, X–ray photoelectron spectra, and UV-visible absorption spectra, the morphology and crystalline phase evolution of Bi2O3 was studied versus reaction time and reaction temperature. It is interesting to note that the phenomenon of α-Bi2O3 → γ-Bi2O3 → α-Bi2O3 transformation was found. The nanorod α-Bi2O3 phase formed in a short time, while α-Bi2O3 could transform to tetrahedral γ-Bi2O3 crystals upon enough reaction time. However, γ-Bi2O3 may transform into rod-shape α-Bi2O3 with further increasing the reaction time. Moreover, it can be deduced that high reaction temperature promoted the transformation from α-Bi2O3 to γ-Bi2O3, and then from γ-Bi2O3 to α-Bi2O3. The photocatalytic activities of Bi2O3 with different crystalline phases were evaluated by the photocatalytic degradation of rhodamine B as a model pollutant. The γ-Bi2O3, which exhibits lower electrons-holes recombination rate than that of α-Bi2O3, showed excellent photocatalytic activity as compared with the α-Bi2O3.
•The phase transformation of α-Bi2O3 → γ-Bi2O3 → α-Bi2O3 are found.•Nanorod α-Bi2O3 and tetrahedral γ-Bi2O3 can be controlled prepared at low temperature.•High reaction temperature promoted the transformation of α-Bi2O3 → γ-Bi2O3 → α-Bi2O3.•γ-Bi2O3 showed excellent photocatalytic activity as compared with the α-Bi2O3.
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•Part of α-Bi2O3 to γ-Bi2O3 phase transition constructed α-Bi2O3/BaTiO3/γ-Bi2O3.•A new interface contact was formed to provide anther channel of charge transfer.•Photocatalytic ...efficiency of norfloxacin and lomefloxacin increased sharply.•O2−, hole, and OH− were main active species for antibiotics degradation.•Double Z-type energy band enhanced photocatalytic activity.
Incomplete lattice transition in heterojunction preparation can generate another crystal phase to provide a new transfer channel of electrons and holes for enhancing photocatalytic activity. In this paper, the hydrothermal synthesis of BaTiO3 and α-Bi2O3 composite induced a part of α-Bi2O3 to γ-Bi2O3 lattice transition. Except for α-Bi2O3/BaTiO3 interface, a new BaTiO3/γ-Bi2O3 contact was formed to realize another transfer channel of the charge carriers. The removal efficiencies of norfloxacin and lomefloxacin using the optimal α-Bi2O3/BaTiO3/γ-Bi2O3 sample reached 93% and 95%, much higher than those of the pure phases and the diphasic heterojunction samples. After five times of cycle tests, the photodegradation efficiencies of these two antibiotics were above 90% and 91%, respectively, while the crystal structure of the sample unchanged to exhibit good structure stability. The superoxide radical (O2−), hole, and hydroxyl radicals (OH−) were the main active substances upon the antibiotics degradation. The photocatalytic enhancement mechanism was originated from the formation of a new Z-type energy band according to the surface and interface calculation. Finally, the analysis of mass spectrometry revealed the degradation processes of these two pollutants. These results provided a simple way to obtain efficient double interfaces heterojunction photocatalysts for removing antibiotic pollutants.
The aim of this study is to examine the effect of Bi2O3 concentration and particle size on Bi2O3 glass. The tested glasses had the composition of SiO2–Bi2O3–CaO–MgO–B2O3–K2O–Na2O–ZnO. Ordinary glass ...was compared with glasses with 10% Bulk Bi2O3, 10% Bi2O3 Nanoparticles (NPs), 20% Bulk Bi2O3, and 20% Bi2O3 nanoparticles. The mass attenuation coefficients (MACs) of all the investigated glasses were determined between 0.0595 MeV and 1.41 MeV. The results demonstrated that increasing the Bi2O3 content in the glass matrix improved their shielding capability, as well as showing that the NPs provided greater attenuation than the bulk Bi2O3 at the same concentration. The percent increase in the MAC between the bulk and nano Bi2O3 was also calculated and analyzed. From the MAC values, the LAC of the glass was determined and similar results were found compared to the MAC figure. The HVL and MFP of the glass were then analyzed and the results demonstrated that the glass with Bi2O3 NPs attenuated the same amount of photons at a smaller thickness, making the NP shield more effective. The heaviness of the samples illustrated that all the tested samples have a smaller weight than pure lead, making them more desirable. The attenuation factor of the glass (Att. Factor %) showed that increasing the Bi2O3 content in the samples and increasing the thickness of the shields both improve the shielding capability of the glass. Lastly, the dlead of the glasses was determined, indicating that the greatest reduction in thickness occurs near the K-absorption edge of bismuth. Overall, the glass with 20% Bi2O3 NPs demonstrated to have the greatest potential for radiation shielding applications.
Waste from various dyes as a result of industrial development is an important source of pollutants for water resources; These wastes are frequently carcinogenic, mutagenic and toxic to aquatic life, ...so treating wastewater is vitally important. Photocatalytic purification is a popular method because it can break down dye molecules and change them into non-toxic, small and harmless species. Moreover, utilizing the power of sunlight, this technology holds significant promise for enabling environmentally friendly, sustainable, and economically viable technologies. The non-toxic polymeric photocatalyst graphitic carbon nitride (gC3N4) is an n-type semiconductor. Its facile and economical synthesis, effective band structure, and stability make it a popular option for photocatalytic investigations. It is crucial to develop nanocomposites to boost the capacity of materials for photocatalysis. The objective of this study is to fabricate nanocomposites of graphitic carbon nitride from thiourea, incorporating varying ratios of bismuth oxide through thermal condensation. The aim is to employ these composites for the catalytic degradation of Methylene Blue (MB) and Rhodamine B (Rh B) dyes. The synthesized samples' morphological and structural characteristics were studied. Their photocatalytic activity against methylene blue and rhodamine B dyes has also been reported. The Bi2O3/gC3N4 heterostructured samples were prepared considering bismuth nitrate and thiourea at weight ratios of 0.125:10, 0.25:10, and 0.5:10. In the study, the Bi2O3/gC3N4 heterostructured sample with the lowest bismuth doping rate was seen to have the highest photocatalytic degradation efficiency. A remarkable degradation rate, reaching 98.83 % within 70 min for MB and 98.59 % within 60 min for RhB dye was observed. The enhanced photocatalytic activities of the synthesized composite can be attributed to the synergistic effect of the heterostructure developed between graphitic carbon nitride and bismuth oxide. As a result, this study has shown promise that Bi2O3/gC3N4 composite photocatalysts can be an effective material for removing dyes.
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•gC3N4 and Bi2O3/gC3N4 heterostructure photocatalysts were synthesized by thermal condensation method.•The synthesized Bi2O3/gC3N4 heterostructures have high photocatalytic activity under simulated sunlight.•The synergy of gC3N4 and Bi2O3 can positively affect the photocatalysis activity against MB and RB dyes.•Addition of Bi2O3 particles to gC3N4 reduced its yellowness.
The systematic investigation of the impact of Bi2O3 on the structural, spectroscopic, and radiation features of 15SiO2 - 75B2O3 - (10-x) MgO - xBi2O3, x= (0 ≤ x ≥ 10) glasses were studied. The ...increase in glass density as Bi2O3 content increase is due to the incorporation of Bi2O3 into the glass network. XRD patterns indicate an amorphous, glassy nature of the glasses. The optical absorption spectra suggest that as the content of Bi2O3 increases, the optical band gap (Eopt.) widens and the Urbach energy (Eu) decreases. It has been observed that the opposite trend between the (Eopt.) and (Eu). The radiation shielding characteristics of MgBi glasses have been evaluated through the assessment of several fundamental radiation attenuation variables. As Bi2O3 content increases would enhance properties like (HVL), (MFP), and (Zeq), especially at lower energy ranges. Adding Bi2O3 to the glassy system has a positive impact on enhancing its neutron attenuation ability. The MgBi-10 glass has the best shielding performance against fast neutrons. The MgBi-10 glass sample shows promising properties for optical and radiation shielding purposes.
•The glass system 15SiO2 - 75B2O3 - (10-x) MgO - xBi2O3, x= (0 ≤ x ≥ 10) in mol% was prepared.•The density increased from 2.88 to 4.97 g/cm3.•We observe the opposite trend between the (Eopt.) and (Eu).•The glass sample MgBi-10 exhibited the best properties.
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