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Adsorption and photocatalytic oxidation of ibuprofen using nanocomposites of TiO2 nanofibers combined with BN nanosheets: Degradation products and mechanisms
摘要： This study investigated the adsorption and photocatalytic activity of TiO2-boron nitride (BN) nanocomposites for the removal of contaminants of emerging concern in water using ibuprofen as a model compound. TiO2 nanofibers wrapped by BN nanosheets were synthesized by electrospinning method. Characterization of the nanocomposite photocatalysts indicated the BN nanosheets improved the light absorbance and reduced the recombination of the photoexcited charge carriers (e- and h+). The photocatalytic oxidation products and mechanisms of ibuprofen by the TiO2-BN catalysts were elucidated using a multiple analysis approach by high performance liquid chromatography, ultraviolet absorbance, dissolved organic carbon, fluorescence excitation-emission matrices, and electrospray ionization–liquid chromatography–tandem mass spectrometry. The experimental results revealed that the photocatalytic oxidation by the TiO2-BN nanocomposites is a multi-step process and the interactions between ibuprofen molecules and the TiO2-BN nanocomposites govern the adsorption process. The increasing BN nanosheet content in the TiO2 nanofibers facilitated the breakdown of ibuprofen degradation intermediates (hydroxyibuprofen, carboxyibuprofen, and oxypropyl ibuprofen). Kinetic modeling indicated both adsorption and photocatalytic oxidation of ibuprofen by the TiO2-BN nanocomposites followed the first-order kinetic model. The photocatalytic oxidation rate increased with the increasing BN content in the nanocomposite catalysts, which was attributed to the enhanced light absorption capacity and the separation efficiency of the photoexcited electron (e-)-hole (h+) pairs. Multiple photocatalytic cycles were conducted to investigate the reusability and regeneration of the nanofibers for ibuprofen degradation.
关键词： adsorption,titanium dioxide boron-nitride nanocomposites,photocatalytic degradation mechanisms,degradation intermediates,photocatalytic oxidation
更新于2025-09-23 15:23:52
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Separation of boron from silicon by steam-added electron beam melting
摘要： Removal of boron from silicon is a tough task by traditional directional solidification and vacuum refining techniques, due to its large and inappropriate segregation coefficient and low saturated vapor pressure. At high temperature boron react with oxygen to form volatile boron oxides which can be evaporated. So, the removal procedure of boron from silicon melt is investigated by incorporating a small amount of water vapor above the melted surface. The results show that boron is oxidized to mainly form BO and evaporated with 28% removal efficiency by average. It is considered that oxygen atoms experience a series of physical and chemical processes, such as a chemical reaction in the bulk of the melt, evaporation from the melt surface, transportation across the gas phase and ionization due the electron beam, which is conducive to the continuous removal of boron.
关键词： Electron beam melting,Photovoltaic,Boron removal,Oxygen self-circulating path,Solar-grade silicon
更新于2025-09-23 15:23:52
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Functionalized Single-Atom-Embedded Bilayer Graphene and Hexagonal Boron Nitride
摘要： Single-atom-embedded bilayer graphene and two-dimensional hexagonal boron nitride are proposed in terms of first-principles calculations. In particular, a series of 68 different single atoms are embedded within bilayer graphene and boron nitride. It is revealed that the magnetic moment and bandgap behave differently depending on the atomic element used for doping where it becomes possible to form a magnet, conductor, semiconductor, or insulator. The electronic and geometrical properties of bilayer graphene and boron nitride are, in principle, able to be tailored and tuned, thereby expanding on how two-dimensional materials are functionalized and designed.
关键词： single atom,boron nitride,bandgap,graphene,functionalized graphene,magnetic moment
更新于2025-09-23 15:23:52
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Deeply subwavelength phonon-polaritonic crystal made of a van der Waals material
摘要： Photonic crystals (PCs) are periodically patterned dielectrics providing opportunities to shape and slow down the light for processing of optical signals, lasing and spontaneous emission control. Unit cells of conventional PCs are comparable to the wavelength of light and are not suitable for subwavelength scale applications. We engineer a nanoscale hole array in a van der Waals material (h-BN) supporting ultra-confined phonon polaritons (PhPs)—atomic lattice vibrations coupled to electromagnetic fields. Such a hole array represents a polaritonic crystal for mid-infrared frequencies having a unit cell volume of 10??λ?3 (with λ? being the free-space wavelength), where PhPs form ultra-confined Bloch modes with a remarkably flat dispersion band. The latter leads to both angle- and polarization-independent sharp Bragg resonances, as verified by far-field spectroscopy and near-field optical microscopy. Our findings could lead to novel miniaturized angle- and polarization-independent infrared narrow-band couplers, absorbers and thermal emitters based on van der Waals materials and other thin polar materials.
关键词： van der Waals material,near-field microscopy,phonon-polaritonic crystal,mid-infrared,hexagonal boron nitride,Bragg resonance
更新于2025-09-23 15:23:52
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Pd nanoparticle-decorated hydroxy boron nitride nanosheets as a novel drug carrier for chemo-photothermal therapy
摘要： A multi-stimuli responsive nanoagent, hydroxy boron nitride nanosheets and Pd nanohybrids (Pd@OH-BNNS), was studied. The well-dispersed hydroxy boron nitride nanosheets were prepared via a facile thermal substitution approach. Pd@OH-BNNS was endowed with a photothermal property after in situ formation of Pd nanoparticles on the surface of the nanosheets. Pd@OH-BNNS as a drug delivery carrier exhibited high loading capability for the anticancer drug doxorubicin. The release of doxorubicin from the nanohybrids was triggered by a decrease in pH, and increases in glutathione concentration and near-infrared irradiation. The faster release behavior of the nanohybrids under near-infrared irradiation was confirmed by a cellular uptake study. In addition, local hyperthermia was verified using an imaging test and an infrared thermal camera. Tumor growth was remarkably inhibited in mice after two weeks of treatment with Pd@OH-BNNS/doxorubicin injection, demonstrating the high efficacy of combining chemotherapy and photothermal therapy. The Pd@OH-BNNS as a drug delivery system exhibited good stability, low cytotoxicity and multi-stimuli responsiveness.
关键词： photothermal therapy,Pd nanoparticles,drug delivery system,hydroxy boron nitride,nanohybrids
更新于2025-09-23 15:23:52
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Synthesis, characterization and photophysical properties of meso-indole-boron-dipyrromethene derivatives and their cell imaging and viscosity sensing
摘要： Based on the molecular design and structural modification of boron-dipyrromethene (BODIPY), two new BODIPY derivatives with meso-substituted functional indole moieties were successfully prepared. These new compounds were characterized by NMR, HRMS and FTIR, exhibiting the different UV-vis and PL spectral phenomena because of their varied molecular structures in various solvents and different degrees of negative solvatochromism. Theoretical calculations and CV results show that the substituted NO2 group at 5-position of indole is favorable for increasing the oxidation potential of the molecules, while the NH2 group is the opposite. These two BODIPY derivatives have different sensitivities to pH changes, and can be appropriately applied as cell imaging materials due to their good physical chemical characteristics and excellent biocompatibility. In particular, the fluorescence characteristics of BODIPY derivative with the substituted NH2 group at 5-position of indole show a good solvent viscosity dependence, highlighting its potential application for testing the intracellular viscosity changes of the living cell in disease diagnosis.
关键词： meso-indole boron-dipyrromethene derivatives,photoluminescence,fluorescence characteristics,cell imaging,viscosity sensing
更新于2025-09-23 15:23:52
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A promising family of fluorescent water-soluble aza-BODIPY dyes for in vivo molecular imaging
摘要： A new family of water-soluble and bioconjugatable aza-BODIPY fluorophores was designed and synthesized using a boron-functionalization strategy. These dissymmetric bis-ammonium aza-BODIPY dyes present optimal properties for a fluorescent probe, i.e. they are highly water-soluble, very stable in physiological medium, they do not aggregate in PBS, possess high quantum yield and finally they can be easily bioconjugated to antibodies. Preliminary in vitro and in vivo studies were performed for one of these fluorophores to image PD-L1 (Programmed Death-Ligand 1), highlighting the high potential of these new probes for future in vivo optical imaging studies.
关键词： molecular Imaging,Fluorescent probes,boron functionalization,aza-BODIPY,Water-soluble fluorophores
更新于2025-09-23 15:23:52
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Unique Substitution Effect at 5,5′ Positions of a Fused Azobenzene-Boron Complex with N=N Double-Bond π-Conjugated System
摘要： The recent report illustrates superior optical properties, such as near infrared emission, from the polymers with the connection positions at 4,4′ positions in the fused azobenzene–boron complex (BAz). In this study, we initially demonstrate that further narrower band gap can be realized by the substituent effect with bromine groups at 5,5′ positions of BAz than that at 4,4′ positions. From the series of mechanistic studies, perturbation of the energy levels were rationally explained by the contribution difference between the inductive effect and the variable resonance effect which is correlated to the degree of electron distribution of molecular orbitals at the substituent positions. Moreover, it was found that unique electronic states, such as delocalized highest occupied molecular orbital and localized lowest unoccupied molecular orbital, should appear on the main chains of the BAz-containing copolymers with fluorene and bithiophene units according to the optical and electrochemical data and theoretical calculations. Taking advantage of property tunability and the dramatic low LUMO energy level (near ?4.0 eV) of the BAz unit, it can be said that BAz should be a conjugated building block favorable for building advanced optoelectronic devices.
关键词： azobenzene,boron,narrow band gap,conjugated polymer,low LUMO
更新于2025-09-23 15:23:52
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Molecular Functionalization of Planar Nanocrystalline and Porous Nanostructured Diamond to Form an Interface with Newborn and Adult Neurons
摘要： This article examines the ability of newly developed nanostructured porous boron-doped diamond (BDD) to form an interface with neural cells and the role of molecular functionalization by a polymer on this interface. Due to its high stability, biocompatibility, and electrical properties, BDD is a promising material for construction of neuroelectrodes. Nanostructuring and an increase in the surface specific area can further improve the sensitivity and performance of such electrodes. Here, porous BDD prepared in a multistep diamond deposition on a porous template consisting of a polymer and electrospun SiO2 fibers is examined. This work shows that this new material is biocompatible and does not exhibit any cytotoxicity on fibroblast cell lines. Further, this work shows that porous BDD supports regeneration of newborn and adult neurons when functionalized with poly-L-lysine.
关键词： nanocrystalline diamond,boron-doped diamond,enhanced surface area,neural interface,chemical functionalization
更新于2025-09-23 15:23:52
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Electrowetting on 2D dielectrics: a quantum molecular dynamics investigation
摘要： Electrowetting on dielectrics (EWOD) is widely used to manipulate the spreading of a conductive liquid on a dielectric surface by applying an electric field. 2D hydrophobic dielectrics are promising candidates for EWOD applications. In this study, extensive quantum molecular dynamics (MD) simulations are performed to investigate the electrowetting behavior of salty water on hexagonal boron nitride (h-BN) monolayer. The proximal adsorption of salt ions and the associated realignment of the dipole moments of interfacial water with the applied electric field are found to be the physical origin of the electrowetting behavior. At low salt concentration and low electric fields, the proximal adsorption and the realignment follow the applied electric field, and the cosine of the water contact angle (WCA) follows a quadratic dependence on the applied electric field. At high salt concentration and high electric fields, the proximal adsorption saturates, which restricts further realignment and causes a saturation of the WCA. This case study provides physical insights into the much debated mechanism that underlies the contact angle saturation (CAS) found in macroscopic electrowetting phenomena and also provides an avenue for further studies of electrowetting at the atomic scale.
关键词： hexagonal boron nitride monolayer,contact angle saturation,electrowetting on dielectrics,first-principles
更新于2025-09-23 15:23:52