Hexagonal Boron Nitride Nanoparticles Research Articles

Effects of temperature and concentration of nanoparticles on rheological behavior of hexagonal boron nitride/coconut oil nanofluid

In this work, a nano-lubricant composed of hexagonal boron nitride (hBN) nanoparticles suspended in pure coconut oil was developed using a two-step method that involved ultrasonic assistance. The synthesis was carried out at varying solid volume concentrations, ranging from 0.2% to 1.2%. X-ray diffraction and Transmission electron microscope techniques were utilized to conduct investigations into the structure and morphology of nanoparticles. These examinations reveal that the nanoparticles exhibit a hexagonal arrangement, with an average diameter measuring 40 nm. The viscosity of pure coconut oil/ hexagonal boron nitride (hBN) nanofluids was evaluated at temperatures ranging from 303 to 403 K. utilizing shear rates varying from 10 to 50 s−1. With the use of a rotational Anton Paar rheometer, the shear dynamic viscosity of the nanofluids was determined. The study focused on examining how the viscosity of pure coconut oil/ hexagonal boron nitride (hBN) nanofluids is influenced by variations in solid volume concentration and temperature. The results revealed that as the temperature increased, the viscosity of the nanofluids decreased. Conversely, when the quantity of nanoparticles was raised in the base fluid, the nanofluids demonstrated an increase in viscosity values. This study found that at a shear rate of 10 s−1, the nanofluid with a 1.0% solid volume concentration exhibits a viscosity 58% higher at 303 K compared to 403 K. Additionally, it was observed that when the concentration of nanoparticles increased from 0% to 1%, and the shear rate decreased from 50 to 10 s−1, the viscosity of the nanofluid increased by 32% at 303 K temperature. Furthermore, this study shows a significant impact of hexagonal boron nitride (hBN) nanoparticles in pure coconut oil as the prepared nanofluids with different nanoparticle concentrations demonstrated a relative viscosity higher than one.

Negatively charged boron-vacancy defect in hexagonal boron nitride nanoparticles

Fluorescent defects in two-dimensional (2D) hexagonal boron nitride (hBN) crystals have attracted a great potential in quantum information and sensing technologies. In particular, the negatively charged boron vacancy (VB−) center has shown spin-dependent fluorescence in 2D flakes or large hBN crystals, which can be manipulated at room temperature, enhancing the application scope of hBN in quantum technologies. In this work, we demonstrate the generation of this interesting spin defect in small hBN nanoparticles (NPs) with a size range of 10–50 nm. The obtained optical properties of the VB− showed a photostable photoluminescence peaked at 820 nm with a spin-lattice relaxation time (T1) of 17 μs and optically detected magneto resonance (ODMR) contrast of 10%. Achieving long T1 time and high ODMR contrast is crucial for effective quantum sensing using small hBN nanocrystals. The reported spin-optical properties of the generated VB− spin defect in hBN NPs are comparable to those created in bulk/flake hBN crystals. These results open the door for optimizing such spin-dependent defects in small hBN NPs for promising applications, especially in quantum sensing and biology.

Thermal properties analysis and thermal cycling of HITEC molten salt with h-BN nanoparticles for CSP thermal energy storage applications.

Molten salts are the operational fluid for most concentrated solar power (CSP) systems, which has attracted more attention among the scientific community due to the augmentation of their properties with the doping of nanoparticles. Hexagonal boron nitride (h-BN) nanoparticles were dispersed in HITEC molten salt to create a novel nanofluid and evaluate the h-BN nanoparticles' influence on HITEC thermophysical properties. The influence of nanoparticle concentration (0.1, 0.5, and 1wt.%) of h-BN and HITEC was studied in this research. HITEC and nano-enhanced HITEC molten salt (NEHMS) were characterized using energy-dispersive X-ray spectroscopy (EDX), field emission scanning electron microscopy (FESEM), and Fourier transform infrared spectroscopy (FT-IR). Specific heat capacity, latent heat, and melting temperature were assessed using differential scanning calorimetry (DSC). The maximum working temperature was evaluated with thermogravimetric analysis (TGA). The ideal nanoparticle concentration is 0.1 wt.% h-BN, which results in a 27% increase in heat capacity, a 72% increase in latent heat, and a 7% enhancement in thermal stability. The thermal cycling stability test proved the stability of the enhanced thermophysical properties. The material characterization revealed that the samples with improved thermophysical properties have a homogeneous dispersion of nanoparticles with minor nanoparticle agglomeration. The system advisor model (SAM) simulation comparison of the optimum sample with solar salt and HITEC salt revealed that using the optimum sample increases CSP plant efficiency by 0.4% and reduces power costs by 0.13¢/kWh.

Enhancement of Flexural Strength by Slip Casting Cordierite Ceramics with h-BN Nanoparticles

In this study, we enhanced the flexural strength of cordierite ceramics by incorporating h-BN (hexagonal boron nitride) nanoparticles, facilitated by the slip casting process. Initially, commercial cordierite powder with an average particle size of 10 mm underwent a ball-milling process to reduce the size to 2.5 mm and simultaneously achieve a narrower particle size distribution. The resulting slurry, composed of 67% solid content, exhibited improved stability during the slip casting process for both pristine cordierite and the mixture containing 1 – 2 wt% h-BN nanoparticles. After sintering, the bulk material containing 2wt% h-BN nanoparticles demonstrated a remarkable flexural strength of 174.8 MPa, a significant improvement compared to the initial 119.5 MPa obtained without the addition of h-BN. It is worth noting that the introduction of h-BN nanoparticles did not induce substantial changes in dielectric constant and thermal conductivity, indicating that the desired mechanical enhancement did not compromise other crucial material properties. This research demonstrates a successful approach to concurrently optimize the flexural strength, dielectric constants, and thermal conductivity of cordierite ceramics. This breakthrough opens up new avenues for advanced applications in a wide range of fields, from electronics to aerospace, where high-strength, thermally stable materials are in demand.

Effects of using fireproof thermal management systems on the lifespan of battery cells

The current need, from the point of view of increasing the sustainability of electric vehicles (more and more present in the car market), makes the research in the field to be focused on the analysis of the factors that can lead to an increase electric vehicle batteries' lifespan. Since this is directly related to the temperatures reached during operation and the thermal gradients inside the battery packs, this paper presents the analysis of the cells' lifespan through artificial intelligence methods and techniques, evaluating the influence of the constructive and functional characteristics of two air-based hybrid thermal management systems (CHA - composite material + heat pipe + forced air convection and CTA - composite material + thermoelectric cooler + forced air convection). The construction of the thermal management system is a special and innovative one, being a composite material (epoxy flame-retardant resin and 2 wt% hexagonal boron nitride nanoparticles) chosen as the primary thermal energy dissipation element. The research was carried out experimentally on individual cells and on a battery module (consisting of 12 cylindrical Li-ion 18650 cells), the battery module being discharged at a rate of 3C with the temperatures recorded from 15 locations inside the battery module, which allows assessing the local and global influence of the thermal management systems. Predictions on the lifetime of the cells in the battery module were made using a convolutional neural network and showed that by using the proposed fireproof thermal management systems, the cells’ lifespan increases by 26.9 … 154.4% (depending on the implemented thermal management system and the location of the cell in the battery module).

Preparation of Ti4O7/h‐BN self‐supported ceramic photoelectrode and its photoelectrocatalytic performance for water purification

AbstractThe construction of high‐efficiency self‐supported ceramic photoelectrode based on ideal semiconductor materials is essential for achieving effective degradation of pollutants by photoelectrocatalysis (PEC) technology. Herein, a Ti4O7/h‐BN composite ceramic photoelectrode with a unique microstructure was fabricated by a step‐by‐step calcination process and used in PEC water pollution remediation. The PEC activity of Ti4O7 ceramic photoelectrode could be enhanced by introducing hexagonal boron nitride (h‐BN) nanoparticles on the surface. The most optimized Ti4O7/h‐BN photoelectrode exhibited the decolorization rate of active brilliant blue KN‐R at about 97.79% in 30 min. The PEC activities could remain stable during five degradation cycles. The excellent photoelectrocatalytic performance of Ti4O7/h‐BN ceramic photoelectrode could be attributed to the low Tafel slope, low charge transfer resistance, large electrochemical active area, and excellent photo‐generated carrier separation efficiency. A type‐II heterojunction was formed between the Ti4O7 and h‐BN, which caused more effective carrier separation and enhanced the generation of dominant active species •O2− and h+. This work provided a mature synthesis strategy of Ti4O7/h‐BN self‐supported ceramic photoelectrodes with excellent practical application prospects to achieve superior PEC performance for water purification.

Investigating Friction and Antiwear Characteristics of Organic and Synthetic Oils Using h-BN Nanoparticle Additives: A Tribological Study

Friction and wear are two major elements that influence the life of a variety of equipment. According to estimates, as much as 30% of the energy used is dissipated as friction. However, this figure can be reduced by developing materials that enhance surfaces and apply lubricants appropriately. This study aims to analyze the impact of hexagonal boron nitride (h-BN) nanoparticles on the rheological and antiwear characteristics of four distinct oil varieties, namely Society of Automotive Engineers SAE-20W50, soybean, Polyalphaolefin PAO-4, and olive oils. The results of the tribological tests demonstrated a noteworthy enhancement in antiwear characteristics with the addition of 0.2 wt.% of h-BN nanolubricant. Among all nanolubricants, the maximum reduction in coefficient of friction (COF) and wear scar diameter was observed at 0.2 wt.% of h-BN in SAE-20W50 oil. Compared to the base oils, the wear scar diameter decreased by 17.93%, 8.80%, 22.65%, and 24.04% for (soybean oil and 0.2 wt.% of h-BN), (SAE20W50 and 0.2 wt.% of h-BN), (PAO4 and 0.2 wt.% of h-BN), and (olive oil and 0.2 wt.% of h-BN), respectively. Rheological test results indicated that with the addition of h-BN nanoparticles, the viscosity of the base oils significantly increased. The maximum viscosity was observed at 40 °C for SAE20W50 base nanolubricants, according to the rheological measurements.

Regulation and prediction of the dielectric constant and interfacial binding energy of surface modified hexagonal boron nitride/polyphenylene oxide@cyanate ester resin

AbstractParticulate‐filled materials with superior mechanical properties and wave permeability have received extensive research attention in the military industry. To elucidate the role of reinforcement in polymers, γ‐Aminopropyltriethoxysilane (APTES) is used to modify hexagonal boron nitride (h‐BN) nanoparticles, which are then filled into polyphenylene oxide@bisphenol A dicyanate ester composite, exhibiting a 1.46‐fold increase in flexural strength and a dielectric constant of 2.66 at 12 GHz. Finite element analysis is employed to design composite material models, successfully predicting the dielectric properties of composites at different frequencies and reinforcement filling levels. The change in the interface energy induced by the silane coupling agent is quantitatively calculated by molecular dynamics simulation, demonstrating that the modified nanoparticles are conducive to improving the flexural strength. Overall, the predicted dielectric and mechanical properties of composites can be utilized to screen for composites that possess excellent dielectric and mechanical properties, thereby greatly improving efficiency.Highlights A hexagonal boron nitride/polyphenylene oxide@cyanate ester is prepared. Finite element analysis is employed to predict the dielectric properties. The interface energy is calculated by molecular dynamics simulation. The resin has superior mechanical and dielectric properties.

4D printing of shape memory polymer nanocomposites for enhanced performances and tunable response behavior

The emergence of four-dimensional (4D) printing introduces a novel approach to the design and manufacturing of high-performance multifunctional shape memory polymers (SMPs). Herein, two types of nanomaterials were blended or embedded into SMPs matrix to enable 4D printing of shape memory polymer composites (SMPCs) via photocuring. The incorporation of hexagonal boron nitride (HBN) nanoparticles enhanced the thermal stability and mechanical properties of SMPs, and accelerated their thermally responsive shape recovery speed. HBN nanoparticles also significantly improved the performance stability of SMPs, even after undergoing multiple shape memory cycles. Electrically responsive shape memory behavior in SMPCs was achieved by embedding a spray-coated polyaniline: polystyrene sulfonate /graphene (PANI: PSS/GR) electrothermal layer (ETL). The applied voltage, ETL resistance, HBN blend content, and sample thickness had a significant regulation effect on electrically responsive shape recovery behavior and shape recovery force. PANI: PSS improved adhesion between ETL and SMPCs matrix, filled the gaps between graphene platelets, which resulted in rapid, uniform, and stable heating upon energization. The presented electrically responsive gripper was capable of grasping objects of various shapes and sizes. This strategy broadens the potential applications of 4D printed SMPCs in challenging environments while propelling the advancement of 4D printing.

Analyzing the thermal potential of binary 2D (h-BN/Gr) nanoparticles enhanced lauric acid phase change material for photovoltaic thermal system application

Thermal energy storage as latent heat is an effective strategy to preserve the excessive energy available. In this aspect, fatty acid phase change materials (PCMs) are promising materials since they have a high latent heat, nontoxic, and little sub-cooling. However, their inherently low thermal conductivity severely restricts their applicability. Herein, hexagonal boron nitride (h-BN) and graphene (Gr) binary nanoparticles (NPs) are taken as nano-additives to enhance thermal conductivity of lauric acid (LA). The NPs added PCM known as nano-enhanced phase change material (NePCM) is prepared by two-step method for thermo-physical characterization. According to an optical performance investigation using ultraviolet-visible spectroscopy (UV–Vis); optimal composite LBG2% (LA with 3 % h-BN and 2 % Gr NPs) displayed 78 % reduction in transmissibility compared to base LA. Further, LBG2% composites exhibited elevated thermal conductivity of LA by 97 %. Additionally, differential scanning calorimeter (DSC) observed a slight variation in latent heat and melting temperature. Latent heat for composite LBG2% found to be as 176 Jg−1 with a reduction equal to NPs weight% as compared to base LA. Moreover, the preferred composite LBG2% displays chemical stability and thermal reliability after 500 heating/cooling cycles. The addition of LBG2% NePCM to a photovoltaic thermal system increased electrical and thermal efficiency to 9.41 % and 69 %, respectively, as compared to the photovoltaic thermal system alone, which was 7.1 % and 64 %. It can be concluded, the binary NPs enhanced composite LBG2% exhibited improved photoabsoprtion and thermal conductivity, along with thermal reliability and higher latent heat. The composite has significant application potential within the melting temperature range of 50 °C for employment in solar photovoltaic systems and other applications.

Optical Properties and Band Structure of Boron Nitride Langmuir Films

Purpose. Investigate the structural features of boron nitride films obtained by the Langmuir-Blodgett method. Observe fluorescence spectra and determine the band structure of the resulting coatings using optical methods.Methods. The deposition of Langmuir films was carried out using the KSV NIMA 2002 setup from the colloidal solution of ST BN/CHCl3. The study of optical properties was conducted using the SF 2000 spectrophotometer in spectral range 200 – 1100 nm and the confocal Raman microspectrometer OmegaScope AIST-NT with spectral resolution 3 cm-1. Surface morphology investigation was performed using the scanning probe microscope SmartSPM AIST-NT with standard silicon cantilevers NSA10, tip radius 7 nm. The band structure modeling of stabilized boron nitride nanoparticles was carried out using the MaterialsStudio 2020 software package with the CASTEP module.Results. The spectral characteristics of deposited film structures made of stabilized hexagonal boron nitride nanoparticles have been investigated. The hydrodynamic size of the nanoparticles was determined to be ~100 nm using optical methods, while the lateral size of the nanoparticles in Langmuir films was found to be 84.6 nm, calculated from the spectral peak at 1360 cm-1 with E2g symmetry, and 82.4 nm based on scanning probe microscopy data. Absorption and fluorescence spectra of colloidal particles were obtained, showing an unusually large Stokes shift of 105 nm and a quantum yield of 0.72. The bandgap width of the stabilized nanoparticles was measured using the Tautz method and ab-initio modeling, resulting in values of 5.79 eV and 5.46 eV, respectively. Conclusion. The study examines the surface morphology, optical properties, and band structure of the deposited Langmuir films made of stabilized boron nitride nanoparticles.

Effect of h-BN nanoparticles incorporation on the anti-corrosion and anti-wear properties of micro-arc oxidation coatings on 2024 aluminum alloy

Micro-arc oxidation (MAO) coatings are recognized for their protective capabilities, yet their inherent porosity and defects limit broader applications. In this study, we aimed to rectify these limitations and enhance their performance by integrating hexagonal boron nitride (h-BN) nanoparticles into the MAO coatings. This work investigates the influence of h-BN concentration on the structure and properties of MAO coatings on 2024 aluminum alloy substrate. The results indicate that h-BN integration diminishes porosity and roughness, while improving hardness, adhesion, and corrosion and wear resistance. The corrosion current density (Icorr) of the most effective composite coatings is approximately 1% of the 2024 aluminum alloy substrate and 10% of undoped MAO coatings. Wear tests demonstrate the significant self-lubricating effect of the h-BN distributed in the coating, with the coefficient of friction (COF) of the most abrasion-resistant coating after h-BN doping being 67% of the undoped coating. During MAO, h-BN is uniformly incorporated into the coatings via diffusion and electrophoretic migration. The two-dimensional structure of h-BN in the coatings effectively blocks micro-defects, delays corrosive substance penetration, and enables self-lubrication. Conversely, excessive h-BN concentrations can instigate agglomeration and performance degradation. Optimum corrosion resistance is achieved with an h-BN concentration of 2.5 g/L, while the best wear resistance is attained at 10 g/L. The study suggests that h-BN-doped MAO coatings present substantial potential for applications necessitating high corrosion and wear resistance in aluminum alloys.

Evaluation of the mechanical properties and corrosion behavior of hBN-Zn composite coatings on the weathering steel

Mechanical tests were conducted and analyzed to investigate the efficacy of Zinc-based coating methods enhanced with hexagonal Boron Nitride (h-BN) nanoparticles. Various methods are employed to deposit these coatings, including Zinc electroplating, Zinc hot-dip, and Zinc-rich coat (ZRC). Different parameters, such as plating time, temperature, voltage, pH, and concentrations of additives, are carefully selected during the process. The introduction of h-BN nanoparticles at varying concentrations into a Zinc- based coating significantly enhanced mechanical properties and performance measures. This improvement was achieved through the diffusion and dispersion of the nanoparticles within the coating. Furthermore, the incorporation of h-BN nanoparticles has exhibited notable enhancements in corrosion resistance when subjected to a 3.5% (NaCl) solution. The best microhardness and adhesion strength values can be achieved by increasing the h-BN concentration (1.5 to 2.5) wt.% in the plating baths. For instance, electroplating with h-BN at a concentration of 15.75 g/l yields a microhardness of 606.7 HV and an adhesion strength of 14.48 MPa. Similarly, hot dip galvanizing with h-BN at a concentration of 2.0% results in a microhardness of 542.1 HV and an adhesion strength of 10.28 MPa. Lastly, when using h-BN at a concentration of 2.5% in ZRC, the microhardness and adhesion strength values obtained are 557.8 HV and 8.5 MPa, respectively. The incorporation of h-BN nanoparticles resulted in a significant improvement and augmentation of the thickness of the coating exhibited the least amount of porosity and the most uniform dispersion when compared to other Zinc composite coatings, namely Zinc electroplating (with a thickness of 97 µm of h-BN at a concentration of 21 g/l), Zinc hot dip (with a thickness of 144 µm of h-BN at a concentration of 2.5%), and ZRC (with a thickness of 123 µm of h-BN at a concentration of 2.5%). Moreover, the utilization of Tafel extrapolation curves and corrosion analysis has demonstrated that Zinc- based coating techniques, when reinforced with the incorporation of h-BN, exhibit significantly improved corrosion current densities (icorr) and corrosion rates (CR). Zinc electroplating technique with h-BN at a concentration of 15.75 g/l yields current density and corrosion rate values of 0.72 µA/cm2 and 0.00659 mpy, respectively. Similarly, Zinc hot dip with a 2.0% h-BN concentration results in current density and corrosion rate values of 3.5 µA/cm2 and 0.032 mpy, while ZRC with a 2.5% h-BN concentration exhibits values of 5.2 µA/cm2 and 0.04758 mpy. OM, SEM, XRD, and EDS mapping analysis were used to characterize the Zinc composite coating's grain structure, grain size, nanoparticle distribution, and chemical composition. The coating matrix contained Zinc and h-BN nanoparticles without impurities. h- BN in the composite coating does not affect grain size. As nucleation sites, h-BN nanoparticles can reduce porosity and refine grains after integration. SubjectsMaterials Chemistry; Corrosion-Materials Science; Surface Engineering-Materials Science.

Effects of functionalization and silane modification of hexagonal boron nitride on thermal/mechanical/morphological properties of silicon rubber nanocomposite

Hexagonal boron nitride (h-BN) nanoparticles could induce interesting properties to silicone rubber (SR) but, the weak filler-matrix interfacial interaction causes agglomeration of the nanoparticles and declines the performance of the nanocomposite. In this work, h-BN nanoparticles were surface modified using vinyltrimethoxysilane (VTMS) at different concentrations. Before silane modification, h-BN nanoparticles were hydroxylated using 5 molar sodium hydroxide. The nanoparticles were characterized to assess success of silane grafting. The pure and modified h-BN nanoparticles were applied at 1, 3 and 5 wt% to HTV silicon rubber (SR). The curing, thermal, mechanical and morphological properties and hydrophobicity of the nanocomposites were evaluated. The morphology of the SR nanocomposites was characterized using AFM and FE-SEM analysis. It was found that silane grafting on the h-BN nanoparticles improves crosslink density but declines curing rate index (CRI) of the SR nanocomposite (at 5 wt% loading content) by 0.7 (dN m) and 3.5%, respectively. It also increased water contact angle of the nanocomposites from 97.5° to 107°. The improved nanoparticle-rubber interfacial interactions caused better dispersion of h-BN nanoparticles in SR matrix (at 5 wt%) that enhanced the elongation at break, modulus at 300% and Tg of the SR nanocomposites.

Hekzagonal Boron Nitrür Nanopartikülleri Septik Sıçan Beyninde Nörodejenerasyonu Önler

Sepsis, which develops with the triggering of an uncontrolled inflammatory response, causes multiple organ damage and dysfunction. Neuroinflammation occurring in sepsis causes varying degrees of deterioration in the central nervous system. Hexagonal boron nitride (h-BN) nanoparticles composed of boron and nitrogen have potential biomedical applications and are well tolerated by animals. Research has indicated that h-BN nanoparticles exhibit antioxidative characteristics. Although the anti-inflammatory properties of the boron present in them, the effectiveness of h-BN nanoparticles on systemic inflammation or neuroinflammation is unknown. Thus, the aim of this research was to investigate the potential protective benefits of h-BN nanoparticles against inflammation induced by lipopolysaccharide (LPS) in rat brains. An intraperitoneal 5 mg/kg dose of LPS was used to induce sepsis in Sprague Dawley rats. h-BN nanoparticles were given at 50 μg/kg and 100 μg/kg concentrations 24 h before LPS injection. To assess the prophylactic effect of h-BN nanoparticles in sepsis-induced neurodegeneration, besides measuring pro-inflammatory, oxidative stress, and apoptosis markers in brain tissues, the cerebral cortex and hippocampus were also examined histopathologically. Our ELISA results show that h-BN nanoparticles inhibit inflammation in the brain as evidenced by the reduction in LPS-induced increase in tumor necrosis factor-alpha (TNF-α) and interleukin-1 beta (IL-1β) levels. h-BN nanoparticles diminished the oxidative stress index and lowered cytochrome c and caspase-3 levels, components of the intrinsic apoptotic pathway. Our histopathological analyzes demonstrated that neuronal and neuroglial damage in the cerebral cortex and hippocampus was also prevented by the treatment of h-BN nanoparticles. These results implicated that h-BN nanoparticles could have a neuroprotective effect against sepsis-induced neurodegeneration through their anti-inflammatory, antioxidant, and anti-apoptotic properties.

Tumor Eradication by Boron Neutron Capture Therapy with 10 B-enriched Hexagonal Boron Nitride Nanoparticles Grafted with Poly(Glycerol).

Boron neutron capture therapy (BNCT) has emerged as a treatment modality with high precision and efficacy of intractable tumors. At the core of effective tumor BNCT are 10 B carriers with facile preparation as well as advantageous pharmacokinetic and therapeutic profiles. Herein, the design and preparation of sub-10 nm10 B-enriched hexagonal boron nitride nanoparticles grafted with poly(glycerol) (h-10 BN-PG), and their application to cancer treatment by BNCT are reported. By virtue of their small particle size and outstanding stealth property, h-10 BN-PG nanoparticles accumulate efficiently in murine CT26 colon tumors with a high intratumor 10 B concentration of 8.8%IDg-1 or 102.1µgg-1 at 12h post-injection. Moreover, h-10 BN-PG nanoparticles penetrate into the inside of the tumor parenchyma and then are taken up by the tumor cells. BNCT comprising a single bolus injection of h-10 BN-PG nanoparticles and subsequent one-time neutron irradiation results in significant shrinkage of subcutaneous CT26 tumors. h-10 BN-PG-mediated BNCT not only causes direct DNA damage to the tumor cells, but also triggers pronounced inflammatory immune response in the tumor tissues, which contributes to long-lasting tumor suppression after the neutron irradiation. Thus, the h-10 BN-PG nanoparticles are promising BNCT agents to eradicate tumor through highly efficient 10 B accumulation.

Effect of Hexagonal Boron Nitride Nanoparticles Additions on Corrosion Resistance for Zinc Coatings of Weathering Steel in Rainwater

Zinc and its alloy coatings are commonly used to provide cathodic protection for weathering steel. However, the steel substrate corrodes faster than the Zinc coating because of the coating's negative corrosion potential. Many studies have examined Zinc and alloy coatings' resistance to corrosion. Hot-dip galvanizing, Electrodeposition, and Zinc-rich coat (ZRC) spray are just some of the methods that can be used to deposit such coatings. Commercially available 99.95 % pure Zinc oxide was used in the electroplating process in this investigation. Steel samples were plated in Zinc sulphate and Zinc oxide solutions and were controlled by different bath parameters such as voltage, current, pH, temperature, and coating time. The addition of hexagonal Boron Nitride (h-BN) nanoparticles has also shown significant improvements in corrosion resistance. However, Zinc-based coating techniques reinforced with h-BN incorporation show the best corrosion current density (Icorr) of Hot dip 2 % wt. (2.1 μA/cm2), ZRC 2.5 % wt., (4.4 μA/cm2), and electroplating 15.75 g/L (0.081 μA/cm2), which is an order of magnitude lower than coatings without h-BNs. The corrosion rates and current densities of Zn/h-BN coated layers were investigated in a controlled laboratory environment that mimicked natural conditions (Rainwater solution) by extrapolating polarization curves.

Rh nanoparticles supported on porous hexagonal boron nitride nanorods with hierarchical structure for highly efficient hydroformylation of olefins

Hydroformylation would be a promising alternative for partial technological process in petrochemical industry because it is a 100% atom-economical route for large-scale production of aldehydes and alcohols from olefins and synthesis gas (H2 and CO). However, there are still a few problems such as cost-intensive recycling and harsh operating conditions etc. encountering in the ligand-modified cobalt and rhodium as homogeneous catalysts in practical applications. Responding to the challenges, to exploit heterogeneous catalysts especially supported catalysts is desired and needs to make more efforts. Here, porous boron nitride (p-BN) with hierarchical structure is designed through a facile thermal polymerization procedure for catalyst support. The p-BN possesses nanorod morphology assembled by numerous highly crystallized hexagonal boron nitride (h-BN) nanoparticles with the diameter of about 20 nm as building blocks, thereby forming abundant interparticle pores. The Rh nanoparticles are then supported on p-BN by an impregnation-borohydride reduction method using RhCl3 as metal precursor, and the obtained catalyst of Rh nanoparticle supported on p-BN (Rh/p-BN) is applied in hydroformylation of styrene. The high porosity and accessible boron acid sites arising from hierarchical structure of p-BN nanorods make Rh nanoparticles homogeneously disperse on the surface of p-BN nanorods and also keep the diameter about 5 nm without further aggregations. Just for this reason, Rh/p-BN exhibits excellent activity of styrene hydroformylation with the highest turnover frequency of styrene as high as 12000 h−1, in comparison with other supported catalysts using different catalyst supports. Besides the detailed investigation of the catalytic properties of Rh/p-BN under different reaction conditions, the recycle of Rh/p-BN is also conducted for five times during which there is no significant decrease in catalytic activity. The present findings indicates that the combination of catalyst support of p-BN and metal nanoparticle catalysts could be an attractive strategy for designing heterogeneous hydroformylation catalysts.

Betacoronavirus ve S. aureus'un hekzagonal bor nitrür ile etkileşimi

Investigations on advance effects of boron-containing compounds have gained attention the last decade. This study was carried out to investigate the effect of hexagonal boron nitride nanoparticles (BNNPs) on Bovine Coronavirus (BCoV) and Staphylococcus aureus (S. aureus) by different methods. First, biological effects of different BNNPs concentrations lower than 0.5 mg/mL examined on HRT-18 (Human Rectal Tumor) for 5 days. Different concentrations of hBN mixed with BCoV in liquid, on membrane or directly on cells and examined for differences of titers or replications. And also Bacterial Filtration Efficiency (BFE) test of hBN powders coated on polypropylene fabric by spray method was applied against S. aureus. The compound was found slightly toxic on the HRT-18 cell line by live cell counting, while no remarkable morphological difference was observed. BNNPs treatment with 0.025 or 0.3mg/mL concentrations did not reduce the infective titer and create no inhibitory effect on in vitro replication. Stability of virus titer after treatment of BNNPs coated fabric also indicated no antiviral efficiency. But hBN applied fabric formed a barrier of ≥90.3%, while non hBN applied fabric formed ≥64.6% barrier. The present study demonstrate that, BNNPs alone is not a good candidate for disinfectant or drug for BCoVs, while it could be valuable to use as coated fabric in the areas needing easy sanitation especially for S. aureus.

Simple Laser-Induced Hexagonal Boron Nitride Nanospheres for Enhanced Tribological Performance

Hexagonal boron nitride, as a layered material with a graphite-like structure, exhibits good mechanical, lubricating and oxidation resistance properties, and is thus expected to become one of the top choices for green lubricating oil additives. However, its poor dispersibility in oil and difficulties in preparing spherical particles when constructing hexagonal boron nitride limit its application. In this paper, spherical hexagonal boron nitride nanoparticles are constructed via a simple laser irradiation method. Under laser irradiation, raw irregular hexagonal boron nitride particles were reshaped into nanospheres via a laser-induced photothermal process and rapid cooling in a liquid-phase environment. Under the optimal concentration, the coefficient of friction and wear spot diameter decreased by 26.1% and 23.2%, and the surface roughness and wear volume decreased by 29.2% and 23.8%, respectively. The enhanced tribological performance is mainly due to the ball bearing, depositional absorption and repair effect of the spherical particles. This simple laser irradiation method provides a new method by which to prepare spherical hexagonal boron nitride lubricating oil additives.