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Synergistic effect of β-Bi2O3 and graphene/MWCNT in silicone-based polymeric matrices on diagnostic X-ray attenuation
摘要： The prolonged exposure of high-energy ionizing radiations during treatment of cancer/tumour and radiological examinations is hazardous to occupational workers and patients. Lead-incorporated composite materials are traditionally used as radiopaque fabrics, but are heavy, bulky and hence often cause inconvenience to users. Therefore, superior radiopaque protective wears that are preferably lead-free, light weight and flexible are being explored. Towards this goal, we study here the synergistic effect of graphene nanoplatelets and multi-walled carbon nanotube (MWCNT) on the X-ray attenuation property of polymer nanocomposites containing β-Bi2O3 nanofillers. The effect of graphene and MWCNT at different concentrations on Bi2O3-based polymer nanocomposites is studied to attain optimal compositions with respect to its X-ray attenuation property and thermal stability. Surface topography and surface roughness of the nanocomposite blocks are studied using an atomic force microscope (AFM). The effect of the density of polymer on the curing, thermal stability and X-ray attenuation property is also studied by using silicone polymers of density 1.7 (G1) and 1.04 g/cm3 (G2). The X-ray attenuation property of nanocomposites with G1 polymer matrix is found to be better than that of G2. The G1-based nanocomposite containing β-Bi2O3 and graphene is found to be better than the one with G1 polymer containing β-Bi2O3 and MWCNT. Thermal stability of multifiller nanocomposites is found to be better than the one without nanofillers. AFM topography images show a variation in surface roughness of nanocomposites with different fillers, which contributes to the different micro- and nano-structural architectures due to polymer–nanofiller interaction, thereby, affecting the X-ray attenuation of the nanocomposites. Our study shows that the multifiller nanocomposite containing β-Bi2O3 and graphene nanoplatelets offer greater potential for the development of efficient radiopaque fabric materials.
关键词： Nanofillers,Graphene,MWCNT,Nanocomposites,Bi2O3,X-ray attenuation
更新于2025-09-19 17:15:36
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Supersandwich Nanowire/Quantum Dots Sensitization Structure-Based Photoelectrochemical a??Signal-Ona?? Platform for Ultrasensitive Detection of Thrombin
摘要： A new photoelectrochemical (PEC) “signal-on” sensing platform based on photoactive material Bi2O3-ZnO and CdS quantum dots (QDs) sensitizer were fabricated for ultrasensitive determination of thrombin by constructing supersandwich nanowires. The CdS/ZnO/Bi2O3 sensitization structure with excellent energy level arrangement remarkably improved photoelectric conversion efficiency due to efficient separation of electron-hole. Moreover, the DNA supersandwich nanowire is ingeniously synthesized in one step by simple dislocation hybridization, which could carry a large amount of sensitized material CdS QDs. More importantly, with Exo III-assisted multiple amplification, the proposed “signal-on” platform demonstrated a detection range of 10 fM to 1 μM with the detection limit of 1.41 fM for thrombin. Impressively, the PEC platform can successfully detect human serum samples with good accuracy. Above all, the CdS/ZnO/Bi2O3 sensitization photoelectric biosensing platform by using DNA nanowire in combination with Exo III-multiple amplification open new sensitized amplification paths for supersensitive biosensing and bioanalysis.
关键词： photoelectrochemical,CdS quantum dots,signal-on,thrombin detection,Bi2O3-ZnO,supersandwich nanowires,Exo III-assisted multiple amplification
更新于2025-09-19 17:13:59
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Carbon Quantum Dots (CQDs) Decorated Bi2O3-x Hybrid Photocatalysts with Promising NIR-Light-Driven Photodegradation Activity for AO7
摘要： In this work, Bi2O3-x with surface oxygen vacancies was prepared through the NaBH4 reduction of Bi2O3. After that, carbon quantum dots (CQDs) were deposited onto the surface of the Bi2O3-x to obtain a series of the CQDs/Bi2O3-x composites. The HRTEM and XPS characterizations of the CQDs/Bi2O3-x composites suggest that the thickness of surface oxygen vacancies could be adjusted by changing the concentration of NaBH4 solution, and the intimate contact between CQDs and the Bi2O3-x is achieved. Acid orange 7 (AO7) was adopted as the target reactant for investigating the photocatalytic degradation activities of the CQDs/Bi2O3-x composites under simulated sunlight and NIR light irradiation. It is found that the photocatalytic activities of the samples are closely related to the concentration of NaBH4 and content of CQDs. The Bi2O3-x samples exhibit enhanced simulated-sunlight-driven photocatalytic activity compared with Bi2O3. Specifically, the optimal degradation efficiency of AO7 is achieved over the 3R-Bi2O3-x (concentration of NaBH4: 3 mmol/L), which is 1.38 times higher than the degradation AO7 efficiency over Bi2O3. After the decoration of the 3R-Bi2O3-x surface with CQDs, the simulated-sunlight-driven photocatalytic activity of the CQDs/Bi2O3-x composite could be further enhanced. Among the samples, the 15C/3R-Bi2O3-x sample reveals the highest photocatalytic activity, leading to an AO7 degradation percentage of ~97% after 60 min irradiation. Different from Bi2O3 and the 3R-Bi2O3-x, the 15C/3R-Bi2O3-x sample also exhibits near-infrared (NIR)-light-driven photocatalytic degradation activity. In addition, the intrinsic photocatalytic activity of CQDs/Bi2O3-x composite was further confirmed by the degradation of phenol under simulated sunlight and NIR light irradiation. The photocurrent response and electrochemical impedance spectroscopy (EIS) measurements confirm the efficient migration and separation of photogenerated charges in the CQDs/Bi2O3-x samples. The ?OH and h+ are proved to be the main reactive species in the simulated sunlight and NIR light photocatalytic processes over the CQDs/Bi2O3-x composites. According to the above experiments, the photocatalytic degradation mechanisms of the CQDs/Bi2O3-x composites under simulated sunlight and NIR light illumination were proposed.
关键词： photocatalytic,composites,oxygen vacancies,CQDs,Bi2O3
更新于2025-09-12 10:27:22
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Investigating the efficiency of α-Bismuth zinc oxide heterostructure composite/UV-LED in methylene blue dye removal and evaluation of its antimicrobial activity.
摘要： Heterostructured α-Bismuth zinc oxide (α-Bi2O3-ZnO) photocatalyst was fabricated by a facile and cost-effective, ultrasound assisted chemical precipitation method followed by hydrothermal growth technique. As synthesized α-Bi2O3-ZnO photocatalyst showed enhanced photocatalytic performance for the MB dye degradation in contrast to pure ZnO and α-Bi2O3. Light emitting diodes (UV-LED) were used in the experimental setup, which has several advantages over conventional lamps like wavelength selectivity, high efficacy, less power consumption, long lifespan, no disposal problem, no warming-up time, compactness, easy and economic installation. XRD study confirmed the presence of both the lattice phases i.e. monoclinic and hexagonal wurtzite phase corresponding to α-Bi2O3 and ZnO in the α-Bi2O3-ZnO composite photocatalyst. FESEM images showed that α-Bi2O3-ZnO photocatalyst is composed of dumbbell like structures of ZnO with breadth ranging 4-5 μm and length ranging from 10 to 11 μm respectively. It was observed that α-Bi2O3 nanoparticles were attached on the ZnO surface and were in contact with each other. Low recombination rate of photo-induced electron-hole pairs, due to the migration of electrons and holes between the photocatalyst could be responsible for the 100 % photocatalytic efficiency of α-Bi2O3-ZnO composite. In addition, photocatalyst was also observed to show the excellent antimicrobial activity with 1.5 cm zone of inhibition for 1 mg/L dose, against the human pathogenic bacteria (S. aureus).
关键词： Heterostructure,antimicrobial activity,Methylene blue,Photocatalyst,α-Bi2O3-ZnO,UV-LED,α-Bi2O3
更新于2025-09-11 14:15:04
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Effects of size on the phase stability and conductivity of double-doped δ-Bi2O3
摘要： Nano and micro (Bi2O3)1-x-y(Eu2O3)x(Er2O3)y (x = 0.1, 0.15, y = 0.05, 0.2) double-doped system materials are synthesized by exploiting solid-state synthesis techniques. When we use nano sized powders to synthesize the samples we call them nano; when we use micro sized powders, we call them micro. The thermal, structural, morphological and electrical properties of nano and micro structured electrolyte samples for solid oxide fuel cells (SOFCs) are characterized. As a result of XRD measurements, the face centered δ-Bi2O3 (cubic) phase is obtained for all nano samples. However, the mixed phase is obtained for some micro samples. The electrical measurements show that conductivity decreases when the amount of Er2O3 is increased. The principal conclusion of the study is that the size effect provides relatively good structural stability in intermediate temperature SOFCs (IT-SOFCs); also, the nano-Bi2O3 system has the lowest activation energy and demonstrates high electrical conductivity.
关键词： Solid electrolyte,IT-SOFC,Size effect,δ-Bi2O3,Nano-Bi2O3
更新于2025-09-10 09:29:36
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Controllable synthesis of flower-root shaped Bi2O3/Bi2MoO6 heterostructures as an efficient photocatalyst under visible light irradiation
摘要： In this article, Bi2O3/Bi2MoO6 composites were synthesized hydrothermally under optimized conditions, by adjusting pH, the concentration of polyvinylpyrrolidone (PVP (K30)) and reaction time. During the synthesis process, flower-root shaped zero-gap Bi2O3/Bi2MoO6 heterojunctions were successfully synthesized. The adopted samples were characterized by X-ray diffraction (XRD), Scanning electron microscope (SEM), Energy spectrometer (EDS), X-ray photoelectron spectroscopy (XPS), Diffuse reflectance spectra (DRS), Photoluminescence (PL), and Fourier transform infrared spectroscopy (FT-IR). The photocatalytic activity was measured under visible-light-irradiation (λ > 420 nm) by degrading tetracycline (TC), ciprofloxacin (CPFX) (antibiotics) and rhodamine B (RhB), methylene blue (MB) (dangerous dyes). The degradation results indicated that photocatalyst sample synthesized at pH 9.0, PVP (K30) 0.05 mol/L and 80 min reaction time (Sup-Bi2O3/Bi2MoO6) demonstrated highly efficient performance. The Sup-Bi2O3/Bi2MoO6 showed the highest apparent rate constant (Kapp) that’s 50% more than the samples prepared at ordinary conditions. Photocatalytic degradation order was i.e. RhB> TC> CPFX> MB, which depends on the polarity of the degrading medium.
关键词： Bi2O3/Bi2MoO6,Flower-root shaped,Heterojunction,Visible light irradiation,Photocatalyst
更新于2025-09-10 09:29:36
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Multiple charge carrier transfer pathways in BiOBr/Bi2O3/BiO0.67F1.66 ternary composite with high adsorption and photocatalytic performance
摘要： BiOBr/Bi2O3/BiO0.67F1.66 ternary composites were designed and prepared via a facile chemical precipitation method and their photocatalytic performances were assessed by degradation of rhodamine B (RhB) under visible light illumination. The highest activity was achieved over BiOBr/Bi2O3/BiO0.67F1.66 ternary composite with Br/F molar ratio of 1:1, which approximately degraded 98.61% of RhB after just 15min irradiation. Contrast to pure BiOBr, the enhanced photocatalytic performances of the ternary composites could be attributed to their larger specific surface areas and multiple charge carrier transfer pathways, which efficiently promoted separation of charge carriers. Besides, the formation mechanism of the composites was discussed in detail as well.
关键词： Bi2O3,Charge carrier transfer pathway,BiOBr,Ternary composite,BiO0.67F1.66
更新于2025-09-10 09:29:36
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Synthesis and photocatalytic activity of composite magnetic photocatalyst Mn <sub/>x</sub> Zn <sub/>1-x</sub> Fe <sub/>2</sub> O <sub/>4</sub> /α-Bi <sub/>2</sub> O <sub/>3</sub>
摘要： In this paper, a new magnetic photocatalyst MnxZn1-xFe2O4/α-Bi2O3 is synthesized by the dip-calcination technology, using manganese zinc ferrite as a magnetic substrate. It is beneficial to separate the composite from liquid solution under an extra magnetic field. This heterojunction of composite MnxZn1-xFe2O4/α-Bi2O3 presents remarkable photocatalytic activity and prominent photocatalysis for degradation of Rhodamine B (RhB), far exceeding the pure α-Bi2O3. Especially, the introduction of MnxZn1-xFe2O4 not only reduces the bandgap of photocatalyst α-Bi2O3, but also improves its response in the visible region. Importantly, the magnetic photocatalyst is capable of being used repeatedly, and the photocatalytic activity would remain above 90% after 3 cycles. Such an outstanding stability and retrievability of composite are mainly ascribed to the soft-magnetic material MnxZn1-xFe2O4, enhancing separation of photoinduced electron hole pairs. This work will replace the traditional semiconductor photocatalyst for a convenient recycling and removal of contaminants from wastewater in the future.
关键词： MnxZn1-xFe2O4,α-Bi2O3,photocatalytic activity,magnetic photocatalyst
更新于2025-09-09 09:28:46
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Facile photodeposition synthesis of novel Ag/4-Br/Bi2O3 composite photocatalyst
摘要： A novel Ag/4-Br/Bi2O3 composite photocatalyst was prepared by the hydrothermal and photodeposition method, and characterized by XRD, SEM, TEM and UV–vis analysis, respectively. The results indicated that the nanoparticles of Ag were successfully deposited on the surface of 4-Br/Bi2O3 composite. The as-prepared sample of Ag/4-Br/Bi2O3 showed higher photocatalytic activity than that of pure Bi2O3 or 4-Br/Bi2O3 through photodegradation of methyl orange(MO) under visible light. The enhanced photocatalytic activity could be attributed to the expansion of photoresponse range and the acceleration of carriers transmit caused by loading of Ag nanoparticles. Additionally, a possible photocatalytic mechanism of the Ag/4-Br/Bi2O3 composite was put forward.
关键词： Semiconductors,Ag/4-Br/Bi2O3,Photocatalyst,Composite materials
更新于2025-09-04 15:30:14