Search Results (111)

Ecotribology focuses on both saving energy resources and reducing environmental pollution. Considering environmental concerns, water-based nanolubricants have gained significant attention over conventional oil-based ones. Non-ecotoxic and highly environmentally friendly nanoadditives were chosen for nanolubricant synthesis, especially considering their use at elevated temperatures. In this study, hexagonal boron nitride nanosheets (hBNNSs) and titanium dioxide nanoparticles (TiO₂ NPs) were used to prepare water-based lubricants with glycerol and surfactant sodium dodecyl benzene sulfonate (SDBS) in water under ultrasonication. An Rtec ball-on-disk tribometer was used to investigate the tribological performance of the synthesised water-based lubricants containing different nano-hBN/TiO₂ concentrations, with dry and water conditions used as benchmarks. The results indicated that the water-based nanolubricant containing 0.5 wt% hBN and 0.5 wt% TiO₂ exhibited the best tribological performance at both ambient (25 °C) and elevated (500 °C) temperatures. This optimal concentration leads to a reduction in the coefficient of friction (COF) by 72.9% and 37.5%, wear of disk by 62.5% and 49%, and wear of ball by 74% and 69% at ambient and elevated temperatures, respectively, compared to that of distilled water. Lubrication mechanisms were attributed to the rolling, mending, tribofilm, solid layer formation, and synergistic effects of hBNNSs and TiO₂ NPs. Full article

This study reported covalent organic frameworks (COFs) and their hybrid composites with two-dimensional materials, graphene oxide (GO), graphitic carbon nitride (g-C₃N₄), and boron nitride (BN), to examine their structural, textural, and gas adsorption properties. Material characterization confirmed the crystallinity of COF-1 and the preservation of framework integrity after integrating the 2D nanomaterials. FT-IR spectra exhibited pronounced vibrational fingerprints of imine linkages and validated the functional groups from the COF and the integrated nanomaterials. TEM images revealed the integration of the two components, porous, layered structures with indications of interfacial interactions between COF and 2D nanosheets. Nitrogen adsorption–desorption isotherms revealed the microporous characteristics of the COFs, with hysteresis loops evident, indicating the development of supplementary mesopores at the interface between COF-1 and the 2D materials. The BET surface area of pristine COF-1 was maximal at 437 m²/g, accompanied by significant micropore and Langmuir surface areas of 348 and 1290 m²/g, respectively, offering enhanced average pore widths and hierarchical porous strcuture. CO₂ adsorption tests were investigated showing maximum adsorption capacitiy of 1.47 mmol/g, for COF-1, closely followed by COF@BN at 1.40 mmol/g, underscoring the preserved sorption capabilities of these materials. These findings demonstrate the promise of designed COF-based hybrids for gas capture, separation, and environmental remediation applications. Full article

This work presents a high-performance novel photodetector based on two-dimensional boron nitride (BN) nanosheets functionalized with gold nanoparticles (Au NPs), offering ultra-broadband photoresponse from 0.25 to 5.9 μm. Operating in both photovoltaic and photoconductive modes, the device features rapid response times (<0.5 ms), high responsivity (up to 1015 mA/W at 250 nm and 2.5 V bias), and thermal stability up to 100 °C. The synthesis process involved CO₂ laser exfoliation of hexagonal boron nitride, followed by gold NP deposition via RF sputtering and thermal annealing. Structural and compositional analyses confirmed the formation of a three-dimensional network of atomically thin BN nanosheets decorated with uniformly distributed gold nanoparticles. This architecture facilitates plasmon-enhanced absorption and efficient charge separation via heterojunction interfaces, significantly boosting photocurrent generation across the deep ultraviolet (DUV), visible, near-infrared (NIR), and mid-infrared (MIR) spectral regions. First-principles calculations support the observed broadband response, confirming bandgap narrowing induced by defects in h-BN and functionalization by gold nanoparticles. The device’s self-driven operation, wide spectral response, and durability under elevated temperatures underscore its strong potential for next-generation broadband, self-powered, and wearable sensing and optoelectronic applications. Full article

With the rapid development of marine renewable energy, especially offshore photovoltaic systems, the problem of biofouling of photovoltaic equipment in the marine environment has become increasingly prominent. The attachment of marine organisms such as algae will significantly affect the photoelectric conversion efficiency of photovoltaic panels, thereby reducing the stability and economy of the system. In this study, a composite siloxane coating was designed and prepared. Methyltrimethoxysilane (MTMS) was used as the organosilicon component. The negative potential of the coating was significantly enhanced by incorporating hexagonal boron nitride nanosheets (h-BNNS). This negative potential and the negative charge on the surface of marine organisms, especially algae, would produce electrostatic repulsion, which can effectively reduce the attachment of organisms. The results show that the prepared coating exhibits excellent performance in anti-biofouling, adhesion, chemical stability, transparency, and self-cleaning properties. The transparency of the coating reached 92.7%. After immersion with Chlorella for 28 days, the coverage percentage on the coating surface was only 0.98%, while the coverage percentage on the blank sample was 23.25%. The corrosion resistance and salt resistance of the coating also ensure its stability in complex marine environments, and it has broad application prospects. Full article

Hexagonal boron nitride (h-BN) and boron nitride nanotubes (BNNTs) are emerging advanced nanomaterials with analogous structures to graphene and carbon nanotubes, respectively. However, little is known about what effect replacing carbon atoms with boron and nitrogen will have on the materials’ safety profile. This study’s aim was to first identify if multi-walled nanotubes of BN could produce a hazard profile similar to that evidenced already for multi-walled carbon nanotubes (MWCNTs) and secondly if the material when present in a sheet-like structure increases or decreases the hazard profile. Fish are aquatic organisms sensitive to boron compounds; however, the potential hazard following exposure to BN and especially when present in such nanostructures has not yet been investigated. An in vitro testing platform consisting of multiple cell lines of the rainbow trout, Oncorhynchus mykiss (RTH-149, RTG-2, RTL-W1 and RTgill-W1), was used in a first-hazard screening approach for cytotoxicity and to gain information on material–cellular interaction. Clear differences were evidenced in material uptake, leading to plasma membrane disruption accompanied with a loss in metabolic activity for BNNTs at lower exposure concentrations compared to h-BN. As in the case of carbon nanotubes, close attention must be given to potential interferences with assays based on optical readouts. Full article

Broad lateral size and thickness distributions impede the application of hexagonal boron nitride nanosheets (BNNSs) as friction modifiers in base oil, although they possess remarkable potential for lubrication performance promotion. In this work, a cascade centrifugation-assisted liquid-phase exfoliation approach was presented to prepare BNNSs from hexagonal boron nitride (h-BN) efficiently and scalably. Subsequently, they were ultrasonically dispersed into gas-to-liquid (GTL) base oil, and their lubrication performance promotion was evaluated by a four-ball tribotester. Tribological tests demonstrated that BNNS possesses excellent friction-reducing and anti-wear properties in GTL. Furthermore, the findings indicate that at a BNNS content of 0.8 wt.%, the system displayed the lowest COF and WSD. Particularly, with an addition of 0.8 wt.% BNNS into GTL, the AFC and WSD are reduced significantly by 40.1% and 35.4% compared to pure base oil, respectively, and the surface roughness, wear depth, and wear volume were effectively reduced by 91.0%, 68.5%, and 76.8% compared to GTL base oil, respectively. Raman, SEM-EDS, and XPS results proved that the outstanding friction-reducing and anti-wear properties of BNNS can mainly be ascribed to the presence of physical adsorption film and tribo-chemical film, which were composed of FeOOH, FeO, Fe₃O₄, and B₂O₃. Full article

Traditional approaches to constructing thermally conductive networks typically necessitate costly equipment and intricate processes, rendering them unsuitable for mass production and commercialization. Here, we propose a facile strategy to construct highly oriented boron nitride/polyacrylate pressure-sensitive adhesive frameworks by a calendering process. A UV light-based bulk polymerization method is adopted to prepare the pressure-sensitive adhesives (PSAs), which makes the preparation process solvent-free and volatile organic compound (VOC)-free, and environmentally friendly compared to emulsion and solvent-based pressure-sensitive adhesives. This simple, economical and scalable method provides new ideas and ways for the preparation of advanced thermal conductive networks. The highly oriented and flexible m-BNNSs/polyacrylate pressure-sensitive adhesive composites (m-BNNSs/PSAs-Ori) exhibited a significantly high thermal conductivity (TC) of 0.9552 W/(m·K) at 25 wt% filler content. Significantly, m-BNNSs/PSAs-Ori composites showed a better thermal response than the single-layer thermally conductive pressure-sensitive adhesive. Moreover, the composites also possess excellent electrical insulation and mechanical properties. This exploration not only provides a reasonable design scheme for thermal interface materials, but also promotes the practical application of polyacrylate pressure-sensitive adhesive composites in thermal management. Full article

Due to the depletion of hydrocarbon resources worldwide, intensive research is being conducted to identify alternative energy carriers. Hydrogen has emerged as a promising candidate due to its high energy density and environmentally friendly nature. However, large-scale implementation of hydrogen energy is hindered by the lack of safe, efficient, and cost-effective storage methods. Among the various materials studied for solid-state hydrogen storage, boron nitride (BN)-based compounds have attracted significant attention owing to their high thermal stability, tunable morphology, and potential for physisorption-based storage. This review focuses on recent advances in the synthesis, functionalization, and structural optimization of BN-based materials, including nanotubes, nanosheets, porous frameworks, and chemically modified BN. Although other boron-containing hydrides such as LiBH₄, Mg(BH₄)₂, and closo-borates are briefly mentioned for comparison, the primary emphasis is placed on BN-related systems. This paper discusses various modification strategies aimed at enhancing hydrogen uptake and reversibility, offering insights into the future potential of BN-based materials in hydrogen storage technologies. Full article

Recent findings have demonstrated that the desalination and purification of contaminated water and the separation of ions and gases, besides solutions to other related issues, may all be achieved with the use of membranes based on artificial nanoporous materials. Before the expensive stages of production and experimental testing, the optimum size and form of membrane nanopores could be determined using computer-aided modeling. The notion that rectangular nanopores created in a multilayered hexagonal boron nitride (h-BN) membrane in a way that results in different inner lining atoms would exhibit unique properties in terms of the water penetration rate is put forth and examined in the current study. Nanopores in boron nitride sheets can be generated with the inner lining of boron atoms (B-edged), nitrogen atoms (N-edged), or both boron and nitrogen atoms (BN-edged). In this study, we compared the three different inner-lined nanopores of boron nitride nanosheets to a comparable-sized graphene nanopore and evaluated the water conduction. Full article

Two-dimensional (2D) hexagonal boron carbon nitride (h-B_xC_yN_z) has garnered a lot of interest in the last two decades because of its remarkable physical and chemical characteristics. Because of the carbon atoms, it has a smaller gap than its cousin, boron nitride, and is hence more appropriate for a wider range of applications. In the frame of density functional theory, we discuss the structural, electronic, and magnetic properties of mono Ti-doped and Co-doped BC₆N (Ti/Co-BC₆N) at different sites of substitutional doping (Ti/Co) in the BC₆N monolayer. The mono substitutional doping at the B (Ti_B/Co_B), N (Ti_N/Co_N), and two different C (C1 (Ti_C1/Co_C1), C2 (Ti_C2/Co_C2)) sites, are investigated. The position of the Ti/Co dopant is an important parameter that changes the electronic state, magnetic moment, and adsorption activity of the pristine BC₆N nanosheet. We find that the adsorption of the gases NO, NO₂, CO₂, NH₃, N₂, and O₂ is significantly improved on the doped sheet at all doped positions compared to the adsorption on the pristine structure. The Ti/Co-BC₆N can adsorb NO and NO₂ better than CO₂ and NH₃. Ti_C1-BC₆N and Ti_B-BC₆N are the best doped sheets for adsorbing NO and NO₂, respectively. The CO₂ and the N₂ molecules are moderately adsorbed at all doped positions as compared to the other adsorbed molecules. Ti-doped sheets can adsorb the CO₂, NH₃, and O₂ better than the corresponding Co-doped sheets. We also study the adsorption of molecular hydrogen on our single-atom Ti/Co-doped systems, as well as on 4-atom Ti and Co clusters embedded in the BC₆N sheets. We show that the cluster-embedded sheets can adsorb up to four H₂ molecules. These novel findings are important for many applications of BC₆N, including spintronics, gas filtration, molecular sensing, and hydrogen storage. Full article

The corrosion of metal substrates is closely associated with the permeability of the corrosive medium in which they are immersed. To enhance the protection of metal materials and improve anti-corrosion performance from an epoxy resin perspective, the diffusion path complexity can be increased and porosity reduced within the epoxy resin coating to effectively block the invasion of corrosive media. Simultaneously, reducing the affinity between the corrosive media and the epoxy resin coating makes it difficult for corrosive substances to adhere. Based on this principle, this study introduces two-dimensional boron nitride nanosheets (BNNS) and fluoropolymers-modified one-dimensional nano-silica (SiO₂) and organic tannic acid as fillers to jointly enhance the protective effect of waterborne epoxy-resin-based composites. Experimental results demonstrate that when the BNNS content is 0.5 wt.%, the 0.5-BNNS/WEP composite coating exhibits superior anti-corrosion performance, achieving an electrochemical impedance of 2.90 × 10⁷ Ω∙cm². Moreover, when BNNS is compounded with fluorinated SiO₂ or fluorinated tannic acid as fillers and incorporated into waterborne epoxy resin, the resulting composite coatings maintain excellent long-term anti-corrosion performance even after 20 days of salt spray testing. Full article

The electric field orientation method effectively promotes the orientation and arrangement of BN nanosheets, forming a thermal conduction network and enhancing the thermal conductivity of the composite material. In this study, microsecond pulsed electric field and direct current electric field were applied to induce the orientation and arrangement of BN nanosheets and improve the thermal conductivity of epoxy resin composites. Under a microsecond pulsed electric field of 50 Hz, 1.5 μs, and 8 kV/mm, the average orientation angle of BN nanosheets increased by 147.7%, and the thermal conductivity of the composite reached 0.352 W/(m·K), which is 1.84 times that of pure epoxy resin. In contrast, under a DC electric field of 70 V/mm, the average orientation angle of BN nanosheets increased by only 57.9%, while the thermal conductivity of the composite reached 0.364 W/(m·K), 1.91 times that of pure epoxy resin. The results indicate that the microsecond pulsed electric field primarily enhances the local orientation of the fillers to improve thermal conductivity, whereas the DC electric field mainly enhances the global arrangement of the fillers to achieve a similar effect. Additionally, thermogravimetric analysis and differential scanning calorimetry were conducted to evaluate the thermal properties of the composites. The results demonstrate that after BN nanosheets orientation and arrangement within the epoxy resin induced by both microsecond pulsed and DC electric fields, the composites exhibited a higher glass transition temperature and improved thermal stability. This study systematically explores the effects of microsecond pulsed and DC electric fields on filler orientation and arrangement, providing valuable insights for the fabrication of electric field-oriented composites. Full article

To significantly improve the tribological performance of epoxy resin (EP), a novel h-BN/MoS₂ composite was successfully synthesized using spherical MoS₂ particles with lamellar self-assembly generated through the calcination method, followed by utilizing the “bridging effect” of a silane coupling agent to achieve a uniform and vertically oriented decoration of hexagonal boron nitride (h-BN) nanosheets on the MoS₂ surface. The chemical composition and microstructure of the h-BN/MoS₂ composite were systematically investigated. Furthermore, the enhancement effect of composites with various contents on the frictional properties of epoxy coatings was studied, and the mechanism was elucidated. The results demonstrate that the uniform decoration of h-BN enhances the chemical stability of MoS₂ in friction tests, and the MoS₂ prevents oxidation and maintains its self-lubricating properties. Consequently, due to the protective effect of h-BN and the synergistic interaction between h-BN and MoS₂, the 5 wt % h-BN/MoS₂ composite exhibited the best friction and wear resistance when incorporated into EP. Compared to pure EP coatings, its average friction coefficient and specific wear rate (0.026 and 1.5 × 10⁻⁶ mm³ N⁻¹ m⁻¹, respectively) were significantly reduced. Specifically, the average friction coefficient decreased by 88% and the specific wear rate decreased by 99%, highlighting the superior performance of the h-BN/MoS₂-enhanced epoxy composite coating. Full article

Hexagonal boron nitride (h-BN) has emerged as a promising dielectric material for protecting metallic substrates such as copper and steel under ambient conditions. The layered structure of h-BN offers significant potential in preventing the oxidation and corrosion of these substrates. Due to their impermeability, boron nitride nanosheets (BNNSs) do not form a galvanic cell with the underlying metals, enhancing their effectiveness as protective coatings. BNNSs are both thermally and chemically stable, making them suitable for coatings that protect against environmental degradation. Additionally, BNNSs have demonstrated excellent fire resistance, hydrophobicity, and oxidation resistance when applied to wood, functioning as a binder-free, retardant coating that remains effective up to 900 °C in air. This review focuses on the anti-corrosion properties of BNNSs, particularly on copper and steel substrates, and discusses various methods for their application. This article also discusses future perspectives in this field, including the innovative concept of wooden satellites designed for short- and long-term missions. Full article

Boron nitride nanostructures (BNNs), including nanotubes, nanosheets, and nanoribbons, are renowned for their exceptional thermal stability, chemical inertness, mechanical strength, and high surface area, making them suitable for advanced material applications. Metal–organic frameworks (MOFs), characterized by their porous crystalline structures, high surface area, and tunable porosity, have emerged as excellent candidates for gas adsorption and storage applications, particularly in the context of hydrogen. This paper explores the synthesis and properties of BNNs and MOFs, alongside the innovative approach of integrating BNNs within MOFs to create composite materials with synergistic properties. The integration of BNNs into MOFs enhances the overall thermal and chemical stability of the composite while improving hydrogen sensing and storage performance. Various synthesis methods for both BNNs and MOFs are discussed, including chemical vapor deposition, solvothermal synthesis, and in situ growth, with a focus on their scalability and reproducibility. Furthermore, the mechanisms underlying hydrogen sensing and storage are examined, including physisorption, chemisorption, charge transfer, and work function modulation. Electrochemical characterization techniques, such as cyclic voltammetry, electrochemical impedance spectroscopy, and galvanostatic charge–discharge, are used to analyze the performance of BNN-MOF systems in hydrogen storage and sensing applications. These methods offer insights into the material’s electrochemical behavior and its potential to store hydrogen efficiently. Potential industrial applications of BNN-MOF composites are highlighted, particularly in fuel cells, hydrogen-powered vehicles, safety monitoring in hydrogen production and distribution networks, and energy storage devices. The integration of these materials can contribute significantly to the development of more efficient hydrogen energy systems. Finally, this study outlines key recommendations for future research, which include optimizing synthesis techniques, improving the hydrogen interaction mechanisms, enhancing the stability and durability of BNN-MOF composites, and performing comprehensive economic and environmental assessments. BNN-MOF composites represent a promising direction in the advancement of hydrogen sensing and storage technologies, offering significant potential to support the transition toward sustainable energy systems and hydrogen-based economies. Full article