Boron Nanoparticles Research Articles

Development of Stable Boron Nitride Nanotube and Hexagonal Boron Nitride Dispersions for Electrophoretic Deposition.

Boron nitride nanotubes (BNNTs) represent a relatively new class of materials that provides alternative electrical and thermal properties to the carbon analogue. The high chemical and thermal stability and large band gap combined with high electrical resistance make BNNTs desirable in several thin-film applications. In this study, stable BNNT and hexagonal boron nitride (hBN) particle dispersions have been developed using environmentally friendly advanced oxidation processing (AOP) that can be further modified for electrophoretic deposition (EPD) to produce thin films. The characterization of the dispersions has revealed how the hydroxyl radicals produced in AOP react with BNNT/hBN and contaminant boron nanoparticles (BNPs). While the radicals remove the carbon contaminant present on BNNT/hBN and increase dispersion stability, they also oxidize the BNPs and the boron oxide produced, which, conversely, reduces the dispersion stability. The use of high- or low-powered ultrasonication in combination with the AOP affects the rate of the competing reactions, with low-powered sonication and AOP providing the best combination for producing stable dispersions with high concentrations. BNNT/hBN dispersions were functionalized with polyethyleneimine to facilitate EPD, where films of several micrometer thickness were readily deposited onto stainless steel and glass-fiber fabrics. BNNT/hBN films produced on glass fabrics by EPD exhibited a consistent through-thickness macroporosity that was facilitated by platelet and nanotube stacking. The film macroporosity present on the coated fabrics was suitable for use as separator layers in supercapacitors and provided improved device robustness with a minimal impact on electrochemical performance.

Elemental Boron Nanoparticles: Production by Ultrasonication in Aqueous Medium and Application in Boron Neutron Capture Therapy

A method for producing elemental boron nanoparticles with a size of less than 100 nm by ultrasonic dispersion in a liquid medium and subsequent cascade fractionation is described. The resulting boron nanoparticles were used as a target for boron neutron capture therapy (BNCT). According to the results of an experimental preclinical study of BNCT with the synthesized boron nanoparticles, neutron irradiation for 1 h of T98G human glioma cells pre-incubated in a medium with boron nanoparticles (10, 20, and 40 ppm in terms of boron-10 isotope) leads to a significant suppression of cell viability.

Cobalt–copper–boron nanoparticles as catalysts for the efficient hydrolysis of alkaline sodium borohydride solution

Developing non-precious metal catalysts with high activity is crucial for the extensive applications of the proton exchange membrane fuel cell (PEMFC). Herein, we have prepared cobalt–copper–boron (Co–Cu–B) nanoparticles by a modified chemical reduction route where Ni foam was used as an initiation medium for the efficient hydrolysis of alkaline sodium borohydride (NaBH4) solution. The influence of the synthetic condition (such as Cu2+ concentration, pH value and the concentration of reducing agent) on the catalytic activities has been explored. The catalytic hydrolytic tests reveal that the as-obtained Co–Cu–B nanoparticles with hollow spherical structure shows highly efficient catalytic activity, affording a hydrogen generation rate (HGR) of 3554.2 mLH2·gcatal.−1·min−1 under room temperature, and a lower activation energy of 52.0 kJ· mol−1, which overtakes the activities of previous reported most non-precious metal catalysts, even some precious catalysts. The kinetics results show that the catalytic hydrolysis process of alkaline NaBH4 solution is a zero-order reaction in view of the amount of Co–Cu–B catalyst, meaning that the reaction rate is independent of the catalyst amount. This study offers us a promising non-precious metal catalyst toward dehydrogenation from the hydrolysis of NaBH4 to further speed up the application steps.

Incoherent and coherent extreme ultraviolet emission from boron plasma

The search for reliable sources of incoherent and coherent extreme ultraviolet (XUV) radiation in different spectral ranges is an important task in laser physics. Here we report on the incoherent emission of XUV radiation in the region of 6 nm from boron plasma. The optimization of target ablation allowed the generation of XUV emission mainly originated from a single B IV transition (λ = 6.03 nm). We also demonstrate the generation of the 806 nm radiation harmonics up to the 55th order (λ = 14.6 nm) and of tunable near infrared radiation (1280–1400 nm) up to the 35th order (λ=38 nm), during the propagation of femtosecond pulses through boron plasma. The incoherent and coherent emissions from this target were compared and analyzed considering the influence of ionic transitions on the B IV emission and harmonic efficiency. We present different schemes of laser-plasma interaction (two-color pump of B plasma, generation of tunable harmonics in XUV range, formation of structured extended plasma, ablation of boron nanoparticles, laser-induced breakdown spectroscopy, overheating of boron targets, quasi-phase matching of plasma harmonics, etc.) during the ablation of boron-containing targets.

Preparation of boron nanoparticles by pulsed discharge of compacted powder

In this study, a low-cost and simple method for the preparation of B nanoparticles is described. Based on the pulsed wire discharge method, a large pulsed current was discharged through 10 mg of B micro-sized powder to form B nanoparticles in Ar gas. A small amount of Cu and C impurities was detected due to the material of the electrodes and the heat-shrinkable tube. The prepared B nanoparticles were of a crystalline phase and their sizes were estimated to be less than 100 nm. To the authors’ knowledge, this is the first realization of spherical crystalline B nanoparticles.

Synergetic Effects of Zinc, Boron, Silicon, and Zeolite Nanoparticles on Confer Tolerance in Potato Plants Subjected to Salinity

Salinity stress is a severe environmental stress that affects plant growth and productivity of potato, a strategic crop moderately sensitive to saline soils. Limited studies are available on the use of combined nano-micronutrients to ameliorate salinity stress in potato plants (Solanum tuberosum L.). Two open field experiments were conducted in salt-affected sandy soil to investigate plant growth, physiology, and yield of potato in response to soil salinity stress under single or combined application of Zn, B, Si, and Zeolite nanoparticles. It was hypothesized that soil application of nanoparticles enhanced plant growth and yield by alleviating the adverse impact of soil salinity. In general, all the nano-treatments applications significantly increased plant height, shoot dry weight, number of stems per plant, leaf relative water content, leaf photosynthetic rate, leaf stomatal conductance, chlorophyll content, and tuber yield, as compared to the untreated control. Furthermore, soil application of these treatments increased the concentration of nutrients (N, P, K, Ca, Zn, and B) in plant tissues, leaf proline, and leaf gibberellic acid hormone (GA3) in addition to contents of protein, carbohydrates, and antioxidant enzymes (polyphenol oxidase (PPO) and peroxidase (POD) in tubers. Compared to other treatments, the combined application of nanoparticles showed the highest plant growth, physiological parameters, endogenous elements (N, P, K, Ca, Zn, and B) and the lowest concentration of leaf abscisic acid (ABA) and transpiration rate. The present findings suggest that soil addition of the aforementioned nanoparticles can be a promising approach to improving crop productivity in salt-affected soils.

Ultrafine Ni-B nanoparticles for efficient hydrogen evolution reaction

AbstractThe search for active, stable, and cost-effective electrocatalysts for hydrogen evolution reaction (HER) is desirable, but it remains a great challenge in the overall water splitting. Here, we report the synthesis of nickel boron nanoparticles supported on Vulcan carbon (Ni-B) via a simple, yet scalable, two-step chemical reduction–annealing strategy. The results of the electrochemical measurements suggest that the overpotentials of Ni-B-400 are 114 and 215 mV (in 1 mol L−1 KOH) at current densities of 10 and 40 mA cm−2, respectively, indicating an exceedingly good electrocatalytic activity in the HER. More importantly, Ni-B maintains a current density of 7.6 mA cm−2 at an overpotential of 0.15 V for 20 h in the durability test. The excellent HER activity of Ni-B-400 is derived from the small particle size and the expanded lattice of Ni, which can optimize the hydrogen absorption energy and enhance the electrocatalytic properties.

Boron-Nanoparticle-Loaded Folic-Acid-Functionalized Liposomes to Achieve Optimum Boron Concentration for Boron Neutron Capture Therapy of Cancer.

In this study, we have synthesized and characterized a pure boron nanoparticle containing asolectin phospholipid-based liposome construct prepared using a water-in-oil emulsion method, as a novel alternative agent for BNCT, which contain poly(maleic anhydride-alt-1-octadecene) (PMAO) and polyethylene glycol (PEG) on the surface, and Cy5 near infrared (NIR) fluorescent dye and boron nanoparticles in the core (3PCB). A tumor-specific targeting ligand, folic acid (FA), was conjugated to PEG to produce a folate-functionalized liposome (FA-3PCB) for improved targeted delivery and accumulation of boron in cancer cells. The liposomes showed an average diameter of 100-120 nm and zeta potential of -38.0±1.5 mV. Cellular uptake monitored by fluorescence microscopy confirmed the targeting capability of FA-conjugated liposomes. Accumulation of FA-conjugated liposomes in C6-brain tumor cells was much higher than that of non-FA conjugated liposomes under the same conditions. ICP-MS (Inductively Coupled Plasma Mass Spectrometry) quantification confirmed that boron accumulated in cancer cells to sufficient intracellular concentration for therapeutic benefit from BNCT. These liposomes show blood-brain barrier (BBB) crossing ability, low cytotoxicity, and excellent stability under physiological conditions. Thus, these liposomes are a promising new boron carrier for BNCT.

Ultrafine cobalt–molybdenum–boron nanocatalyst for enhanced hydrogen generation property from the hydrolysis of ammonia borane

The hydrolysis of ammonia borane (NH3BH3) is recognized as an efficient way of hydrogen generation if it can be effectively catalyzed. In this work, a series of cobalt–molybdenum–boron (Co–Mo–B) nanoparticles (NPs) on copper (Cu) foil are introduced as catalysts for NH3BH3 hydrolysis by electroless deposition method. The influence of the depositing pH value on the catalytic property is investigated by adjusting the pH value ranged from 10.5 to 12.0. By optimizing the value to 11, the ultrafine Co–Mo–B NPs with the grain size around 4.3 nm show the best catalytic property for NH3BH3 hydrolysis. The hydrogen generation rate reaches 5818.0 mL·min−1·g−1 when the hydrolysis temperature is 298 K. The thermodynamic tests show that the lower activation energy (Ea) is estimated to be 59.3 kJ·mol−1. It can be found that the catalytic property in this work overtakes that of partial non-precious metal NPs, and is even better than some precious metal NPs previously reported. The hydrolysis reaction of NH3BH3 catalyzed by ultrafine Co–Mo–B NPs is a non-spontaneous process. In addition, the cycling ability of the ultrafine Co–Mo–B NPs is also studied and the results demonstrate that the catalyst is a recyclable one toward the hydrolysis of NH3BH3 under mild reaction conditions.

Antibiofilm and Antimicrobial Activities of Silver Boron Nanoparticles Synthesized by PVP Polymer and Gamma Rays Against Urinary Tract Pathogens

In the present study gamma-rays induced eco-friendly synthesis of silver boron nanoparticles (AgB NPs) using PVP polymer as a stabilizing agent. Antimicrobial and antibiofilm activities of AgB NPs were examined against multidrug-resistant microbes that cause urinary tract infection (UTI). AgB NPs were characterized by UV–Vis, SEM/mapping images, EDX, HRTM, DLS, FTIR and XRD analysis. A proposed reaction mechanism was investigated. Data obtained from results indicated that AgB NPs production was dependent on silver nitrate and boric acid concentrations. HRTEM image displayed the anisotropic AgB NPs with a diameter of 85.25 nm. FTIR spectrum data shows that there is a continuous reduction of ions due to the oxidation of PVP. Ring opening was assigned by N–H bond formation. AgB NPs presented a great efficiency against Candida albicans (20.0 mm ZOI) followed by Escherichia coli (18.0 mm ZOI) and Staphylococcus aureus (16.0 mm ZOI). Additionally, AgB NPs were provided biofilm inhibition % as 87.0, 85.3, and 69.4% against S. aureus, E. coli, and C. albicans, respectively. Accordingly, due to AgB NPs properties such as encourages antimicrobial agent with continued-term stability; they must identify possible purposes within pharmaceutical and medical application in the UTI treatment.

Potential Nematicidal Properties of Silver Boron Nanoparticles: Synthesis, Characterization, In Vitro and In Vivo Root-Knot Nematode (Meloidogyne incognita) Treatments

The purpose of this work is to evaluate the anti-nematode activity of silver boron nanoparticles (AgB NPs) synthesized by PVP polymer and gamma rays as a novel cost-effective and eco-friendly green method. AgB NPs were structurally identified by UV–Vis., XRD, HRTM, DLS, FTIR, SEM and EDX mapping analysis. A suggested reaction mechanism was considered. In-vitro and in vivo nematicidal potential of AgB NPs against root-knot Meloidogyne incognita was examined. HRTEM image exhibited spherical AgB NPs with a diameter of 29.55 nm. FTIR spectrum explains that there is a continuous reduction of ions due to PVP oxidation. AgB NPs possesses an encourage anti-nematode against M. incognita causing root-knot in the tomato plant. Treatment 3 exhibited the maximum mortality as 74.20% after 96 h. It also decreased root galls and egg masses numbers after 1 week of the infection (20.33 galls and 2.33 egg masses). Treatments 3 and 4 reduced the numbers of the 2nd stage juveniles, females and the developmental stages. Boron at the permissible limits was adjusted to be more than silver in the synthesized AgB NPs (to avoid the toxicity) for developing the resistance and immunity of the tomato plant. Therefore, AgB NPs may recognize potential targets within agricultural treatments.

Ultrahigh figure‐of‐merit of Cu2Se incorporated with carbon coated boron nanoparticles

AbstractCu2Se based thermoelectric materials are of great potential for high‐temperature energy harvesting due to their high‐temperature figure‐of‐merit (zT). For further development of Cu2Se, both engineering and mid‐temperature figure‐of‐merit need to be improved. In this work, we report that carbon‐coated boron (C/B) nanoparticles incorporation can significantly improve both mid‐ and high‐temperature zT in Cu2Se. The nanoparticle inclusions can result in a homogeneous distribution of Cu:C:B interfaces responsible for both improvement of the Seebeck coefficient and significantly reduction in thermal conductivity. Ultrahigh mid‐ and high temperature thermoelectric performance with zT = 1.7 at 700 K and 2.23 at 1000 K as well as significantly improved engineering zT are achieved in the C/B incorporated Cu2Se with desirable mechanical properties and cycling stability. Our findings will stimulate further study and exploration for the Cu2Se based thermoelectric materials for broad applications in converting waste heat to electricity with competitive energy conversion efficiency.

Production and Characterization of Novel PEMFC Nanocomposite Membranes Including Boron Nanoparticles

Bu çalışmada, çeşitli stokiyometrik oranlarda hazırlanan nano hekzagonal bor nitrür (NhBN), fosforik asit (FA) ve Nafyon (NAF) içeren yeni nesil proton iletken nano kompozit membran (NKM) üretildi ve su tutma, metanol geçirgenlik ve iyonik iletkenlik değerleri incelendi. NAF ağırlıkça %3-10 oranlarında NhBN ve molce %10-20 oranlarında FA ile karıştırılarak NKM’lar hazırlandı. Metanol geçirgenliği ve su tutma testleri sonuçlarına göre, hidrofobik NhBN parçacıklarının membranların su tutma ve metanol geçirgenliğini azaltırken FA’in su tutma özelliği ve metanol geçirgenliğini arttırdığı gözlemlendi. Maksimum proton iletkenliği, nem içermeyen ortamda 150°C'de, molce %20 FA ve ağırlıkça %3 NhBN içeren NKM için 0.056 S/cm olarak ölçüldü.

Addition-omission of zinc, copper, and boron nano and bulk oxide particles demonstrate element and size -specific response of soybean to micronutrients exposure

Plant response to microelements exposure can be modulated based on particle size. However, studies are lacking on the roles of particle size and specific microelements in mixed exposure systems designed for plant nutrition, rather than toxicology. Here, an addition-omission strategy was used to address particle-size and element-specific effects in soybean exposed to a mixture of nano and bulk scale oxide particles of Zn (2 mg Zn/kg), Cu (1 mg Cu/kg) and B (1 mg B/kg) in soil. Compared to the control, mixtures of oxide particles of both sizes significantly (p < 0.05) promoted grain yield and overall (shoot and grain) Zn accumulation, but suppressed overall P accumulation. However, the mixed nano-oxides, but not the mixed bulk-oxides, specifically stimulated shoot growth (47%), flower formation (63%), shoot biomass (34%), and shoot N (53%) and K (42%) accumulation. Compared by particle size, omission of individual elements from the mixtures evoked significant responses that were nano or bulk-specific, including shoot growth promotion (29%) by bulk-B; inhibition (51%) of flower formation by nano-Cu; stimulation (57%) of flower formation by bulk-B; grain yield suppression (40%) by nano-Zn; B uptake enhancement (34%) by bulk-Cu; P uptake stimulation by nano-Zn (14%) or bulk-B (21%); residual soil N (80%) and Zn (42%) enhancement by nano-Cu; and residual soil Cu enhancement by nano-Zn (72%) and nano-B (62%). Zn was responsible for driving the agronomic (biomass and grain yield) responses in this soil, with concurrent ramifications for environmental management (N and P) and human health (Zn nutrition). Overall, compared to bulk microelements, nanoscale microelements played a greater role in evoking plant responses.

Spectroscopic Study on the Polymer Condensates Formed via Pyrolysis of Levitated Droplets of Dicyanamide-Containing Ionic Liquids.

To investigate the suitability of ionic-liquid-based hypergolic fuels as replacements for traditional hydrazine-based propellants, a 1-methyl-4-amino-1,2,4-triazolium dicyanamide ([MAT][DCA]) droplet, with and without hydrogen-capped boron nanoparticles, was acoustically levitated in argon and heated to successively higher temperatures by a carbon dioxide laser. At each temperature, in situ Fourier-transform infrared and near-infrared, Raman, and UV-visible spectra were recorded. The droplet became increasingly yellow before exploding at 400 K to produce a brown foam-like substance and dense smoke. The foam was subsequently studied ex situ by X-ray photoelectron spectroscopy, infrared diffuse-reflectance spectroscopy, and elemental analysis. The combined spectroscopic analyses suggest that the foam is formed by linking two or more melamine molecules to yield a combination of melem, melon, and possibly graphitic carbon nitride. At least 37 ± 3% of the [MAT][DCA] liquid was transformed into the stable, solid-state foam, which would be problematic for the use of such an IL-based hypergolic fuel in rocket engines. 1-Butyl-3-methylimidazolium dicyanamide ([BMIM][DCA]) did not explode and form the foam even at temperatures of up to 430 K. Elimination of the amino group (-NH2) during the decomposition of [MAT]+ to volatile products or the increased energy density provided by the additional nitrogen atom in the triazolium ring therefore seem to be required to produce the foam. The present results, provided by an original and accurate experimental technique, elucidate how the nitrogen content affects the stability of an ionic liquid and reveal potential hazards when implementing ionic liquids in bipropellant systems.

Optical excitations of boron and phosphorous doped silicon nanoparticles: A computational study

Discovery of tunable localized surface plasmon resonances (LSPRs) in boron (B) and phosphorous (P) doped silicon (Si) nanocrystals has opened exciting possibilities for Si-based plasmonics. Here, using computationally efficient time-dependent density-functional theory calculations, we investigate the optical response modulations of B- and P-doped Si NPs as a function of dopant locations (incorporated in the bulk, sub-surface, and surface regions) and nanoparticle size. More specifically, we show that the optical features of doped Si NPs are critically depend on the location of the dopant atom and a maximal spectral intensity enhancement can be achieved via surface doping. We believe that our theoretical findings would help in the emerging field of doped Si-based plasmonics.

Simulation of the fate and transport of boron nanoparticles in two-dimensional saturated porous media

The wide production and application of engineered nanomaterials (ENMS) inevitably lead to their release in the groundwater environment. However, the release and transport of boron nanoparticles in the multi-dimensional subsurface remain largely unknown. In this work, a multi-dimensional numerical simulator for the transport of boron nanoparticles in the saturated porous media was first developed and validated. Hypothetical scenarios for the release of boron nanoparticles into a layered two-dimensional (2D) and heterogeneous 2D saturated porous media were then explored, and compared with the fullerene nanoparticles. The results demonstrated that the soil heterogeneity influenced the fate of nanoparticles, with high permeable layers and high aqueous-phase concentration. Besides, the boron nanoparticles tend to accumulate at the inlet zones, where it was closer to a nanoparticles source. Different layers of interface interaction also impact the concentration of nanoparticles. In general, the mobility and aqueous-phase concentration of fullerene nanoparticles were higher than those of the boron nanoparticles. In addition, the mobility of boron nanoparticles was found to be sensitive to release concentration, soil porosity and nanoparticle aggregate size.

Combustion Characteristics of Boron-HTPB-Based Solid Fuels for Hybrid Gas Generator in Ducted Rocket Applications

ABSTRACT Metal/metalloid particles as additives in polymeric fuels have been investigated since several decades, among which boron has been remaining the most attractive one due to its high energy density. In the present study, a low-cost screening instrument called opposed flow burner (OFB) is used to investigate the salient features of various boron-HTPB-based solid fuels to understand the major performance parameters such as burning efficiency and regression rate. Pure-HTPB (baseline solid fuel) and HTPB loaded with boron nanoparticles (nB) at various concentrations (5–40% by wt.) have been tested. In the OFB system, single gaseous oxygen (GOX) jet has been applied on the surface of the solid fuel pallet at oxygen mass flux (Gox) range of 20–57 kg/m2-s in order to compare the performance of various solid fuels. High-speed videography and UV–VIS spectroscopy have been employed to realize the burning process of fuel samples. Emission spectra obtained from the experiments clearly identify the gas-phase intermediate species (BO and BO2) of boron ignition/combustion. Several material characterization techniques such as field emission scanning electron microscope (FE-SEM), energy-dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), bomb calorimetry, and thermogravimetric analysis (TGA) have also been applied on pre- and post-burn samples to identify the physiochemical changes. The residual active boron content is found out to be almost negligible in fine-condensed combustion products whereas significant amount of un-burnt boron is present in the coarse ejected agglomerates.

Oxidation of a Levitated Droplet of 1-Allyl-3-methylimidazolium Dicyanamide by Nitrogen Dioxide.

Understanding the reaction mechanisms of ionic liquids and their oxidizers is necessary to develop the next generation of hypergolic, ionic-liquid-based fuels. We studied reactions between a levitated droplet of 1-allyl-3-methylimidazolium dicyanamide ([AMIM][DCA]), with and without hydrogen-capped boron nanoparticles, and nitrogen dioxide (NO2). The reactions were monitored with Fourier-transform infrared (FTIR) and Raman spectroscopy. The emergence of new structures in the FTIR and Raman spectra is consistent with the formation of functional groups including organic nitrites (RONO), nitroamines (R1R2NNO2), and carbonitrates (R1R2C=NO2-). Possible reaction mechanisms based on these new functional groups are discussed. The reaction rates were deduced at various temperatures by heating the levitated droplets with a carbon dioxide laser. We thereby determined an overall activation energy of 38.5 ± 2.3 kJ mol-1 for the oxidation of [AMIM][DCA] for the first time.

Liquid‐Phase Synthesis of Boron Isocyanates: Precursors to Boron Nanoparticles

AbstractThe practical application of boron isocyanates has been hindered by their extremely high sensitivity and reactivity toward air and moisture. A convenient synthetic method in a suitable liquid media is reported for practical utilization of boron isocyanates. According to NMR studies, the in situ generated boron isocyanates can be stored for at least one month under an inert atmosphere at −20 °C without noticeable decomposition. The boron tri(isocyanate) (B(NCO)3) was converted into boron nanoparticles by reduction with hydrogen under mild reaction conditions.