Boron Carbon Nitride Research Articles

Insights into electrochemical nitrogen reduction reaction mechanisms: Combined effect of single transition-metal and boron atom

Developing single-atom catalysts (SACs) for electrochemical devices is a frontier in energy conversion. The comparison of stability, activity and selectivity between various single atoms is one of the main research focuses in SACs. However, the in-depth understanding of the role that the coordination atoms of single atom play in the catalytic process is lacking. Herein, we proposed a graphene-like boron–carbon-nitride (BCN) monolayer as the support of single metal atom. The electrocatalytic nitrogen reduction reaction (eNRR) performances of 3d, 4d transition metal (TM) atoms embedded in defective BCN were systematically investigated by means of density functional theory (DFT) computations. Our study shows that the TM-to-N and B-to-N π-back bonding can contribute to the activation of N2. Importantly, a combined effect is revealed between single TM atom and boron atom on eNRR: TM atom enhances the nitrogen reduction process especially in facilitating the N2 adsorption and the NH3 desorption, while boron atom modulates the bonding strength of key intermediates by balancing the charged species. Furthermore, [email protected]3 possesses the highest electrocatalytic activity with limiting potential of −0.49 V, and exhibits a high selectivity for nitrogen reduction reaction (NRR) to ammonia compared with hydrogen evolution reaction (HER). As such, this work can stimulate a research doorway for designing multi-active sites of the anchored single atoms and the innate atoms of substrate based on the mechanistic insights to guide future eNRR research.

Single-step synthesis of efficient nanometric boron carbon nitride semiconductor for photocatalysis

Carbon-based materials have demonstrated great advantages over other metal-based photocatalyst materials. With the recent development in textile industries, residual commercial dyes discharged out as wastewater is a serious environmental concern. Herein, we have developed Boron Carbon Nitride nanosheets via thermal condensation (TBCN) and solvothermal route (SBCN). X-ray diffraction, X-ray photoelectron spectroscopy and Ultraviolet-Diffuse Reflectance Spectroscopy used to describe the surface optical properties of as-prepared samples. The results were compared to identify a facile single-step route for the synthesis of pure BCN photocatalyst materials thereby to avoid additional treatments for purification of the synthesised material. The optical bandgap of TBCN was estimated to 2.68 eV, resembling a typical semiconductor. XPS study revealed the presence of residual starting material as impurities in the as synthesised SBCN sample. Photodegradation of Malachite green, Acid green and Reactive blue dyes were carried out using the synthesised samples and the photoactivity of TBCN & SBCN were studied. The BCN photocatalyst after photodegradation was further characterized to understand the structural change of the material. Toxicological studies were conducted using the treated and untreated water by Mung bean (Vigna radiata L.). Based on the results, this study provides a facile single-step approach for the synthesis of BCN with great durability and stability which are promising for removal of textile dyes from wastewater.

Theoretical Calculation of Hydrogen Generation and Delivery via Photocatalytic Water Splitting in Boron-Carbon-Nitride Nanotube/Metal Cluster Hybrid.

Solar-driven water splitting is an appealing strategy to produce hydrogen energy. However, the non-negligible chance of reverse reactions due to a mixture of hydrogen molecules (H2) with oxygen species poses challenges for safe H2 collection and delivery, which hinders its applications. Using first-principles simulations, we propose a hybrid structure design where metal clusters of TM4 (TM = Au/Pt) are encapsulated in boron-carbon-nitride nanotube (BCNNT) decorated with CuN3 group. It can readily absorb ultraviolet-visible solar light to generate charge carriers. The energetic electrons and holes would be separately delivered to the reduction site of TM4 and the oxidation site of the BCNNT layer. Then, protons generated by water dissociation at the BCNNT layer will penetrate through BCNNT and consequently meet electrons at the TM4 site to be reduced into H2. As a selective sieve, BCNNT prevents oxygen species from going inside and H2 from crossing out so that H2 can be completely isolated. Further, the sufficient space of the tubular cavity endows the transportation feasibility of the produced H2 along the nanotube for collection. This proposed design combines photocatalytic hydrogen production and safe delivery, which may help in developing a practical solution for a photodriven hydrogen production.

Molten salt synthesis of carbon-doped boron nitride nanosheets with enhanced adsorption performance

Owing to their large specific areas, high thermal stability and chemical inertness, two-dimensional boron carbon nitride nanosheets (BCNNs) have captured much attention in recent years in the field of adsorption of pollutants. The formation of BCNNs via incorporating carbon into boron nitride (BN) can effectively improve the photoelectric and adsorption properties of the latter. In this work, carbon-doped BN (BCN) nanosheets were prepared at 1100 °C via a molten salt route using boric acid, melamine and glucose as the main starting materials. The effects of molten salt type and carbon doping level on the formation of BCN were investigated, and their isothermal adsorption properties in a methylene blue (MB) aqueous solution were evaluated based on the Langmuir and Freundlich models. The results indicated that using molten LiCl-KCl as a liquid medium was more favorable than NaCl-KCl to the formation of BCNNs. As-prepared BC0.4N sample possessed a sheet-like structure of about 10 nm thick and a specific surface area as high as 484 m2 g−1. Moreover, the adsorption test of MB demonstrated a high adsorption capacity of 249.04 mg g−1, which was about 14 times higher than that in the case of the pristine BN, and the kinetic rate constant value in the case of using BC0.4N is about ten times as high as that of BN following a pseudo-second-order model, suggesting that the as-formed BC0.4N nanosheets could be potentially used as a value-added effective adsorbent for future wastewater remediation.

Direct Assembly of 3D-BCN Microspheres as a Microsupercapacitor Electrode for Wearable Energy Storage.

Scalable and cost-effective fabrication of three-dimensional (3D) boron carbon nitride (BCN) microspheres was first demonstrated by hydrothermal and annealing methods. In particular, the specific surface area of 3D-BCN-4 reached 1390.12 m2 g-1 and had a high hierarchical pore structure. An all-printed solid-state flexible microsupercapacitor (MSC) based on 3D-BCN-4 microspheres as an electrode material was fabricated for the first time by a screen printing method, which also provided efficacious properties. The single MSC areal capacitance reached 41.6 mF cm-2. Furthermore, the remarkable mechanical flexibility was also achieved for the device with evidence that no obvious capacitance loss occurred even upon bending to 180°, and the device had a 93.3% capacitance retention after 1000 cycles. In addition, the maximum energy density reached 0.00832 mW h cm-2, and the highest power density was 2 mW cm-2. These results show the synthesis of 3D-BCN by a facile and effective method with excellent electrochemical performance, which should provide a promising direction to wearable energy storage devices.

Laser patterning of boron carbon nitride electrodes for flexible micro-supercapacitor with remarkable electrochemical stability/capacity

High performance, all solid-state planar micro-supercapacitor (MSC) with interdigitated Boron carbon Nitride (BCN) electrodes are fabricated via fast, scalable laser patterning technique. Heteroatom doping desirably enhances the electrochemical activity of carbon electrodes. This BCN based micro-supercapacitor showed comparatively very high specific capacitance of 72 mFcm−2 at a current density of 0.15 mAcm−2. Even at a high current density of 1 mAcm−2 device showed specific capacitance as high as 17 mFcm−2. It has demonstrated excellent electrochemical stability when tested up to 80000 cycles without any sign of further decay in capacity/efficiency. This device showed stable capacity even after bending at 150° angle, for 1500 times during cycling showing remarkable flexibility.

Work Function Extraction of BCN Thin Films from BCN/n-Si Heterojunction Devices

Boron carbon nitride (BCN) has gained attention due to its structural similarity to carbon and boron nitride. BCN compounds are known to combine excellent properties of B4C and BN, with properties being adjustable depending on elemental composition[1, 2]. BCN is a low-k material (k=2.13) and very high breakdown strength (~3.4 MV/cm). Additionally, the ability to control band gap by atomic composition and structure makes BCN films suitable for applications in electronic and optical devices[3].In this study, BCN/n-silicon heterojunctions are fabricated using RF sputtering technique. Work function of BCN thin films are extracted from I-V characteristics. I-V characteristics are obtained for operation at temperatures from 25 to 200 °C. Using this method, parameters such as barrier height, ideality factor, rectification ratio are investigated.

Microwave assisted synthesis of boron and nitrogen rich graphitic quantum dots to enhance fluorescence of photosynthetic pigments

Energy transfer between quantum dots and biomolecules is of interest due to high absorption capacity and high quantum efficiency of quantum dots. Amongst all types of quantum dots, graphene and graphitic quantum dots have great potential for energy transfer studies due to their high biocompatibility and low toxicity. In this study, a simple route to synthesize boron and nitrogen rich graphitic quantum dots (C-BN) and boron carbon nitride (BCN) quantum dots is demonstrated. Quantum dots were synthesized in a domestic microwave oven. Composition of quantum dots was controlled by tuning initial mole ratio of boron and nitrogen precursors. As molar ratio of boron precursor was increased, formation of C-BN quantum dots was favoured. C-BN quantum dots were mainly composed of boron and nitrogen (with around 10 % carbon) in their main composition, and sized around 2 nm with bright photoluminescence. To the best of our knowledge, this is the first study which proposes a bottom-up synthesis method to synthesize C-BN quantum dots based on domestic microwaves. Also, treating photosynthetic pigments with quantum dots resulted in 20 % enhancement of fluorescence of photosynthetic pigments at 670 nm, which demonstrates that C-BN and BCN quantum dots can be important constituents of artificial antenna systems for photosynthetic organisms.

A h-BCN for Electrochemical Sensor of Dopamine and Uric Acid

A hexagonal boron carbon nitride hybrid (h-BCN) is developed by in situ high-temperature solid-state reaction and subsequent chemical reduction with hydrazine. The XRD and TEM results show that the h-BCN features interlayered structures with two characteristic d-spacing of 0.33 and 0.21 nm. The obtained h-BCN exhibits significant electrochemical sensor for dopamine and uric acid. The cyclic voltammetric and amperometric experiments revealed a good linear relationship between current densities and concentrations of dopamine (DA) of 10-300 μM and uric acid (UA) of 10-500 μM, with high sensitivities of 0.14 μA/μM and 0.32 μA/μM and detection limits of 5 μM and 2 μM, respectively.

Boron Carbon Nitride (BCN) Nano-Coatings of Central Venous Catheters Inhibits Bacterial Colonization

Central line associated bloodstream infections (CLABSI) are commonly induced due to bacterial colonization of medical devices such as central venous catheters (CVCs) and is leading cause of concern due to increasing hospitalization duration, costs, and morbidity. This study evaluated the efficacy of boron carbon nitride (BCN) nano-coatings on CVC for antimicrobial activity. RF magnetron sputtering technique was utilized to deposit nano-coatings of BCN on CVCs. For comparison purposes, RF magnetron sputtered TiO2 nano-coatings were also investigated. Antimicrobial activity of nano-coatings was tested against gram-positive Bacillus cereus and gram-negative Escherichia coli bacterial cells. Nanoparticle coated and uncoated catheter surfaces were studied using FE-SEM and AFM to determine if the surface characteristics correlated with anti-adhesive effects of the bacteria. Biofilm formation on uncoated and BCN coated catheters was quantified using absorbance spectrophotometry.

Tribological behavior under high temperature of BCN films deposited by sputtering-PBII hybrid system

In this article, the results obtained from a study on the tribological behavior of boron carbon nitride (BCN) films under high temperature are reported. BCN films with different carbon concentrations (from 0 to 66.7 at%) were deposited by a sputtering-PBII hybrid system. The hardness and Young's modulus of the films were evaluated using a nanoindenter. The friction and wear behaviors of the films measured under room and high temperatures were characterized using ball-on-disk friction testing and an optical microscope. The element composition of the transfer layer formed on the ball and wear track surfaces was analyzed by scanning electron microscopy and energy dispersive X-ray spectroscopy. The results indicated that the nanohardness and Young's modulus of BCN films increased with increasing carbon concentration. A higher carbon concentration led to a lower friction coefficient when measured at room temperature. However, only the BC2.4N1.3 film showed a very low friction coefficient with a low specific wear rate when measured under high temperature. This behavior can be confirmed by the agglomerated debris and wear scars formed on the ball and wear track surfaces. Therefore, the BC2.4N1.3 film is a promising material as a protective coating to be applied in high temperature lubricating applications due to its good wear resistance and thermal stability.

Improved photoremoval performance of boron carbon nitride–pyromellitic dianhydride composite toward tetracycline and Cr(vi) by itself to change the solution pH

A series of boron carbon nitride–pyromellitic dianhydride (BCNPA) composites were successfully synthesized for the first time, where BCNPA3 exhibited the best adsorption and photodegradation performances for tetracycline (TC) under visible-light irradiation.

Molten salt assisted assembly growth of atomically thin boron carbon nitride nanosheets for photocatalytic H2 evolution.

Atomic-level boron carbon nitride nanosheets (BCNNS) have been prepared by a molten salt assisted assembly growth strategy, which effectively promotes the solvation of precursors, minimizes the surface energy and prevents the aggregation of layers. The as-synthesized BCNNS have atomic layered thickness and large lateral size, and show enhanced visible light H2 evolution activity compared to bulk BCN.

Enhanced and selective photocatalytic reduction of CO2 by H2O over strategically doped Fe and Cr into porous boron carbon nitride

Strategic doping of metals and non-metals into a photocatalyst can help in tuning the band gap and alignment of band structure.

Study on boron and fluorine-doped C3N4 as a solid activator for cyclohexane oxidation with H2O2 catalyzed by 8-quinolinolato ironIII complexes under visible light irradiation

This paper discloses that boron and fluorine-doped carbon nitride (C3N4BF), as a solid activator, can efficiently accelerate the relatively inert 5,7-dichloro-8-quinolinolato iron(III) complex (FeIII(Qb)3) to photo-catalyze the oxidation of cyclohexane to cyclohexanol and cyclohexanone by hydrogen peroxide (H2O2) in acetonitrile (MeCN) under visible light irradiation and achieve 25.87 % cyclohexane conversion, which is almost twice as high as without it and obviously higher than the results obtained using ordinary C3N4 as an activator or under thermo-catalysis. Furthermore, its such activation effect on FeIII(Qb)3 photocatalysis is also observed in the H2O2-involved oxidation of other substrates such as toluene, ethylbenzene, benzyl alcohol and thioanisole. UV–vis and PL spectra, photocurrent transient measurements and theoretical calculations support that C3N4 and especially C3N4BF can form strong π-π stacking interactions with FeIII(Qb)3, thus inducing a weakly structural distortion of FeIII(Qb)3 and enhancing its photo-reductive activation via capturing the photo-generated electrons of the activator. As a result, the synergistic catalytic effect of FeIII(Qb)3 with C3N4/especillly C3N4BF can significantly accelerate the above thermo-/especially photo-oxidations.

Synthesis of hierarchical porous BCN using ternary deep eutectic solvent as precursor and template for aerobic oxidative desulfurization

Abstract Boron carbon nitride (BCN) has exhibited superior aerobic catalytic performance in oxidation reactions. Herein, the hierarchical porous BCN catalyst was synthesized using a ternary deep eutectic solvent (DES) composed of boric acid, urea and choline chloride as the precursor and template. The as-prepared BCN exhibited impressive catalytic performance in oxidative desulfurization of fuel. Under the optimized conditions, the BCN catalyst can reach 98.4% sulfur removal in 4 h and recycle 5 times with a little activity decrease. Experimental results revealed that the excellent catalytic activity was found to be originated from an improved electron delocalization. Combined with the density functional theory (DFT), the improved electron delocalization increased the electronic density of the BCN, promoting the activation of dioxygen. This strategy provides a novel approach for the design of high-performance catalyst in oxidative desulfurization.

Forming a B[sbnd]B bond in boron carbon nitride composite: A way for metal free electrocatalyst for oxygen reduction reaction in alkaline medium

Unmanageable of oxygen electrochemistry on cathode side of fuel cells creates a major hindrance to designing a cell device. Effectively, Platinum alone cannot afford the oxygen reduction reaction (ORR) due to several worries such as unaffordable cost, stability, scarcity and intermediate tolerance etc. that would hurdle the development of fuel cell technology. In order to demonstrate similar efforts, we discuss a synthesis of boron carbon nitride (BCN) nanosheets and its composite by thermal and solvothermal method respectively. The BCN nanosheets also show the formation of a homonuclear BB bond, which are important for enhancing oxygen affinity. Since the chemistry of BB bond involves higher bond energy, more reactivity or unusual gas adsorption behavior, thus making such sites promising towards stronger electrophilic interactions such as oxygen adsorption followed by its reduction. As synthesized BCN exhibits an interesting onset potential of ∼0.94 V in electroreduction of oxygen. More importantly, upon composite formation with carbon black, BCN shows further enhancement in the ORR kinetics with an onset potential of 1.01 V and a current density of 5 mA/cm2, which is very much comparable with Pt/C. An interesting phenomenon of activating O2 reduction using BCN has been systematically studied to unravel noble metal-free electrocatalysis.

RF Sputtered Boron Carbon Nitride (BCN) Thin Films for Biological Applications

Boron carbon nitride (BCN) films have achieved attention owing to their crystal structure and unique properties. BCN compounds are expected to combine excellent properties of diamond, B4C and BN with their properties adjustable depending on their composition and structure[1]. B-C-N ternary compounds has been reported previously for biological applications [2-5]. In this study, we investigate RF sputter deposited BCN films for biological applications. Bacterial contamination in biomedical field has several adverse effects. BCN coating may interfere with bacterial adhesion and reduce bacteria colonization. BCN films are deposited by reactive sputtering of B4C target in presence of nitrogen. Bacteria colonies are grown on BCN thin films and incubated for 24 hours. [1] A. Prakash, S. D. Nehate, and K. B. Sundaram, "Boron carbon nitride based metal-insulator-metal UV detectors for harsh environment applications," Optics letters, vol. 41, no. 18, pp. 4249-4252, 2016. [2] W. Yang, P. Thordarson, J. J. Gooding, S. P. Ringer, and F. Braet, "Carbon nanotubes for biological and biomedical applications," Nanotechnology, vol. 18, no. 41, p. 412001, 2007. [3] A. Bianco, K. Kostarelos, C. D. Partidos, and M. Prato, "Biomedical applications of functionalised carbon nanotubes," Chemical Communications, no. 5, pp. 571-577, 2005. [4] S. H. Mir, V. K. Yadav, and J. K. Singh, "Boron–Carbon–Nitride Sheet as a Novel Surface for Biological Applications: Insights from Density Functional Theory," ACS Omega, vol. 4, no. 2, pp. 3732-3738, 2019. [5] G. Ciofani, S. Danti, G. G. Genchi, B. Mazzolai, and V. Mattoli, "Boron nitride nanotubes: biocompatibility and potential spill‐over in nanomedicine," Small, vol. 9, no. 9‐10, pp. 1672-1685, 2013.

Properties of IN X-750/BNi-2/SAF 2205 joints formed by transient liquid phase bonding

The microstructure of the bonding area consisted of several distinct zones based on the bonding parameters. At temperature of 1050 °C, the isothermal solidification was completed after 60 min, while at 1100 °C it was completed after 30 min. The only γ-Ni solid solution was observed in the solidified zone. Samples with incomplete isothermal solidification showed a continuous eutectic structure in the centerline of the solidified zone. This eutectic structure produced due to the solidification of the remaining melt and consisted of three phases i. e. Ni3B, Cr2B, and γ-Ni solid solution. Two diffusion affected zones were seen on both sides of the solidification zone. These zones consisted of secondary phases such as (Fe,Cr)2B and boron carbon nitride. By increasing the time and temperature, the microhardness profile became more uniform owing to the removal of these eutectic structures. The maximum shear strength belonged to the bonded specimen at 1100 °C for 45 min, which is due to the fully isothermal solidification, the removal of brittle eutectic phases and more uniform microstructure of the bonding zone. The reason for increasing the shear strength with increasing temperature was the reinforcement of the bonding zone by the solution hardening owing to the inter-diffusion of the alloying elements.

Enhanced photocatalytic performance of boron and phosphorous co-doped graphitic carbon nitride nanosheets for removal of organic pollutants

In this work, the photocatalytic activity of graphitic carbon nitride is improved by co-doping of non-metal elements and morphologic regulation. We introduce B and P elements into the carbon nitride skeleton and meanwhile decrease the thickness by a thermal etching route. The obtained B, P co-doped nanosheets (BPCNNS) has narrow bandgap (2.61 eV) to utilize more visible light, and its ultrathin morphology promotes the separation and migration ability of photo-generated charges. Accordingly, the BPCNNS sample shows enhanced photocatalytic activity for removal of Oxytetracycline (OTC) and Rhodamine B (RhB) in comparison with the un-doped, single element doped and co-doped bulk samples. ∼70% OTC was removed after 120 min and RhB was completely decomposed in 60 min under visible light irradiation by the BPCNNS photocatalyst. Furthermore, the high cycling reusability and stability of the BPCNNS photocatalyst are demonstrated. This work suggests the activity of graphitic carbon nitride can be synergistically enhanced by introducing multiple dopants and morphologic control. Also, it provides a potential photocatalyst to efficiently purify wastewater containing different organic pollutants.