Boron Carbon Nitride Research Articles

Comment on “A novel two-dimensional boron-carbon-nitride (BCN) monolayer: A first-principles insight” [J. Appl. Phys. 130, 114301 (2021)

Recently, Bafekry et al. [J. Appl. Phys. 130, 114301(2021)] reported their density functional theory results on the structural, phonon dispersion, elastic constants, and electronic properties of a BCN monolayer. The aforementioned theoretical work, however, includes erroneous results and discussions, as will be explained in this Comment.

Vacancy defects in monolayer boron carbon nitride for enhanced adsorption of paraben compounds from aqueous stream: A quantum chemical study

Paraben compounds have gained attention as emerging pollutants are a preservative in cosmetic and personal care products. In this work, the adsorption of paraben compounds (methylparaben, propylparaben and butylparaben) was studied on the monolayered boron carbon nitride (BCN) surface with B, C and N vacancies using first-principle density functional theory calculations. The electrostatic potential function on paraben compounds and BCN surface was calculated to understand the local electron density. Build-up of negative electrostatic potential was observed in the BCN surfaces with vacancy defects. The localization of electrons was studied using the electron localization function. The covalent nature of the bond was observed between the atoms of BCN surfaces. From the optimized geometries, it was clear that the paraben compounds were closest to the surface of the BCN surface with a B defect. The HOMO-LUMO distributions and the bandgap data were used to determine the quantum mechanical descriptors through Koopmans' approach. The adsorption energy of the paraben compounds with BCN surfaces was in the range of -0.50 to -0.20 eV, confirming the feasibility of the interactions. The recovery time values also supported the weak nature of interactions. The weak Van der Waals interactions during the adsorption of paraben compounds on the BCN surfaces (with and without vacancy) through the reduced density gradient plots and non-covalent interaction isosurface analysis. This study concluded that N vacancy enhanced the adsorption interactions between the BCN surface and paraben compounds.

A Highly Crystallized Hexagonal BCN Photocatalyst with Superior Anticorrosion Properties

AbstractA major challenge in the nitride‐based materials for photocatalytic oxidation reaction is their low stability under oxidizing and acidic environment. To solve these problems, highly crystallized hexagonal boron carbon nitride (BCN) with more homogeneous mixing of B, C, and N atoms is achieved by pyrolysis of precursor materials in the presence of NaOH as a crystallization promoter. The high crystallinity and chemical homogeneity features of the fabricated BCN reduce the structural defects and accelerate the interfacial charge transfer and separation, thus inhibiting the self‐oxidation and endowing it with a superior oxidation resistance. With these prominent advantages, the highly crystallized BCN exhibits markedly enhanced photocatalytic activity and long‐term anticorrosion stability under oxygen and self‐generated acidic condition, far beyond polycrystalline BCN. This work offers new insights into the catalyst design of crystalline BCN and demonstrates its great promise for solar energy applications.

Ordered Mesoporous Boron Carbon Nitrides with Tunable Mesopore Nanoarchitectonics for Energy Storage and CO2 Adsorption Properties.

Porous boron carbon nitride (BCN) is one of the exciting systems with unique electrochemical and adsorption properties. However, the synthesis of low‐cost and porous BCN with tunable porosity is challenging, limiting its full potential in a variety of applications. Herein, the preparation of well‐defined mesoporous boron carbon nitride (MBCN) with high specific surface area, tunable pores, and nitrogen contents is demonstrated through a simple integration of chemical polymerization of readily available sucrose and borane ammonia complex (BAC) through the nano‐hard‐templating approach. The bimodal pores are introduced in MBCN by controlling the self‐organization of BAC and sucrose molecules within the nanochannels of the template. It is found that the optimized sample shows a high specific capacitance (296 F g−1 at 0.5 A g−1), large specific capacity for sodium‐ion battery (349 mAg h−1 at 50 mAh g−1), and excellent CO2 adsorption capacity (27.14 mmol g−1 at 30 bar). Density functional theory calculations demonstrate that different adsorption sites (B—C, B—N, C—N, and C—C) and the large specific surface area strongly support the high adsorption capacity. This finding offers an innovative breakthrough in the design and development of MBCN nanostructures for energy storage and carbon capture applications.

Strain dependent electronic and optical responses of penta-BCN monolayer

We report here, structural, dynamic, and mechanical stability in pentagonal boron carbon nitride (p-BCN) monolayer, a new member of direct bandgap two-dimensional (2D) semiconductor. The identified visible range bandgap with excellent mechanical strength allows it to be a promising candidate material in optoelectronics, nanomechanics, and optomechanical sensors. By employing density functional theory (DFT), we reveal a unique geometrical reconstruction with rigidity in B–N and C–N bond lengths with applied strain. These quasi-sp3 hybridized short and strong covalent bonding and unique geometry support the monolayer to possess extraordinary mechanical response. The desired bandgap is manipulated by loading the biaxial strain. Most importantly, our predictions on p-BCN show excellent optical response such as good static dielectric constant and refractive index, strong optical absorption (up to 1.08 × 105 cm−1 in VR and 7.01 × 105 cm−1 in UV) with small energy loss and reflectance both appearing in visible and ultraviolet regions (UV). The desired optical response along with the blue and red shift is demonstrated by tailoring with tensile and compressive strain. The predicted strong optical anisotropy provides it’s application in polarized photodetection.

Thermal-fluctuation gradient induced tangential entropic forces in layered two-dimensional materials

Recent studies on nanomechanical devices based on low-dimensional nanomaterials have revealed several different types of thermal fluctuation gradient induced tangential entropic forces (TEFs), including expulsion force, edge force, thermophoretic force, nanodurotaxis force, etc. While all these forces originate from thermal fluctuation gradients, they can take different forms for different problems and have been treated case-by-case in the literature. Here, we develop a unified theoretical framework for TEFs in layered low-dimensional materials. In particular, we derive explicit analytical solutions for TEFs in layered two-dimensional materials and validate them with molecular dynamics simulations for various bilayers composed of graphene, graphyne, hexagonal-boron nitride (h-BN), boron-carbon-nitride (BCN), and double walled nanotubes. We present also approximate solutions to TEFs in hetero- or substrate-supported-bilayers based on a solution-guided machine learning (SGML) technique. The developed concept for TEFs is unique to nanomechanical systems and may serve as one of the founding pillars of nanomechanics.

Synthesis of three-dimensional boron carbon nitrogen/reduced grapheme oxide broccoli as electrode material for flexible micro-supercapacitors

Scalable and cost-effective production of micro-supercapacitor (MSC) materials is crucial for the extensive application of MSCs. Thus, the two dimensional (2D) boron carbon nitride (BCN) nanosheet is first transformed into three dimensional (3D) BCN microsphere and incorporated with grapheme oxide (GO) nanosheet to construct 3D BCN/ rGO broccoli materials by a simple way. Then the 3D BCN/rGO broccoli as electrode materials are applied to MSCs through the two methods of screen printing and laser engraving. Finally, the BCN/rGO broccoli as electrode materials in MSCs by screen printing show an excellent specific capacitance of 72.2 mF cm−2 at a current density of 0.1 mA cm−2. The excellent power density and energy density is up to 1175 mW cm−2 at the current density of 2.5 mA cm−2 and 11 mWh cm−2 at a 0.1 mA cm−2. MSCs by laser engraving exhibit better performance than screen printing that the specific capacitance is up to 179 mF cm−2 which is owe to the further reduction of GO by laser. Furthermore, the 3D BCN/ rGO broccoli materials based MSCs also exhibit remarkable mechanical flexibility and cycle stability. It has been found that the capacitance reduction is negligible after bending up of device to 180° and 95% capacity retention was obtained even after 10,000 cycles. These results demonstrate the synthesis of BCN/rGO broccoli provides distinctive insights into new material toward developing flexible coplanar symmetric micro-supercapacitors, thus promoting the application of MSCs based on 3D BCN/ rGO broccoli electrode.

Molten Salt Assisted Synthesis of Boron Carbon Nitride Nanosheets for Enhanced Photocatalytic Activity of Silver Phosphate

Thin 2D boron carbon nitride nanosheets (BCNNS) possess high thermal and chemical stability as well as tunable electronic properties, but the lack of effective synthesis methods hinders their practical application. Herein, a facile and efficient approach for the synthesis of large-area boron carbon nitride nanosheets in molten KCl–NaCl salt media has been proposed. A Single precursor compound, ethylenediamine bisborane, was first heated to 1000 °C in KCl–NaCl salt melts and then held for only two minutes to produce BCNNS. Benefiting from the effective solvation of precursors and reduced surface energy in liquid salt melt, the lateral size of resultant BCNNS can reach up to 12 microns. The as-prepared products are subsequently used as a co-catalyst with silver phosphate (Ag3PO4) for degradation methyl orange under simulated sunlight. Due to the improved electronic property and interfacial effect of BCNNS, the photocatalytic performance of Ag3PO4 was significantly improved. The photodegradation rate increased from 0.369 min−1 of Ag3PO4 to 1.006 min−1 of BCN/Ag3PO4 composite with only 0.6 wt% BCNNS loading, a 2.73-fold higher value than that of pure Ag3PO4.

Simultaneous adsorption of methylene blue and arsenic on graphene, boron nitride and boron carbon nitride nanosheets: Insights from molecular simulations

The occurrence of various pollutants in water bodies has become a serious concern. In this study, an attempt was made to find out the affinity of two-dimensional graphene (GRA), hexagonal boron nitride (h-BN) and hexagonal boron carbon nitride (h-BCN) towards the simultaneous adsorption of heavy metal (arsenic(III)) and organic dye (methylene blue) using molecular dynamics. The radial distribution functions obtained for the different systems showed that the OW-OW and OW-As pairs peaked around 3 Å whereas, for the As-As pair, the distribution showed a maximum at ~9 Å. The observations were consistent for all three nanosheets, irrespective of whether the adsorption occurred individually or simultaneously. The simultaneous adsorption was synergistic on all three nanosheets, of which the effect was maximum for graphene, indicating better efficiency for real wastewater treatment. Further, by integrating the radial distribution function, a coordination number of 12 was obtained for the arsenic(III) ions. The diffusion properties of water molecules during various adsorption interactions were studied by calculating the diffusion coefficients from the mean squared displacement curves. The density distributions were also examined to highlight how the water molecules surround the adsorbate ions. The orientation of the adsorbate molecules and their distance from the nanosheets were evaluated to propose a possible pathway by which the adsorption occurred. This study revealed that the potency of GRA for simultaneous adsorption of methylene blue and arsenic(III) was better than h-BN and h-BCN.

Defects-induced transition in low-temperature electrical properties of boron carbon nitride thin films

Defects-induced transition in low-temperature electrical properties of boron carbon nitride thin films

Tailoring Electron‐Riched Boron Sites in BCN for Nitrogen Fixation via Alternate Mechanism

AbstractThe electrochemical nitrogen reduction reaction (eNRR) is promising for achieving sustainable ammonia (NH3) production under mild conditions. However, it is still challenged by nitrogen activation and strong competition with the hydrogen evolution reaction. Here, it is revealed that fine‐tuning the local electron density of boron (B) sites at the boron carbon nitride (BCN) solid catalysts has significant effects on the eNRR activity and selectivity. The concentration of electron‐rich B sites at BCN catalysts are mediated by solid‐state reaction, where their electronic structures are confirmed by electron energy‐loss spectroscopy (EELS) and electron paramagnetic resonance (EPR). Over the density functional theory (DFT) calculations, the nitrogen (N2) activation and reduction at an electron‐riched B site is through an alternate pathway with the determining‐step energy of only 0.92 eV. The optimized BCN5 catalyst with the highest ratio of electron‐riched B sites achieves an outstanding NH3 production rate of 29.3 µg h−1 mg−1cat and the highest Faradaic efficiency of 39%.

Synthesis and Characterization of Free-Standing Boron Carbon Nitride Nanosheets (Bcnns) in Inductively Coupled Plasma

Synthesis and Characterization of Free-Standing Boron Carbon Nitride Nanosheets (Bcnns) in Inductively Coupled Plasma

Er-doping g-C3N4/boron carbon nitride quantum dots composites under visible light irradiation for tetracycline degradation

A series of Er-doping g-C3N4/boron carbon nitride quantum dots (ErCN/BCNQDs) is synthesized for the first time. The prepared ErCN/BCNQDs are used for the degradation of tetracycline (TC) under visible light and results show that the degradation rate of ErCN/BCNQDs photocatalyst can reach 93%. The materials were characterized by XRD, SEM, TEM, EDS, mapping, UV–Vis DRS and PL spectra. The significant photocatalytic ability can be attributed to the doping of Er and the introduction of BCNQDs, which increases the number of effective photogenerated electrons and holes, inhibiting the binding of photogenerated carriers.

0D boron carbon nitride quantum dots decorated 2D Bi4O5I2 as 0D/2D efficient visible-light-driven photocatalysts for tetracyclines photodegradation

A series of 0D boron carbon nitride quantum dots (BCNQDs) modified 2D Bi4O5I2 (0D/2D Bi4O5I2/BCNQDs) composites were synthesized and applied to photodegradation of tetracyclines (TCs), including tetracycline (TC) and oxytetracycline (OTC). The Bi4O5I2/BCNQDs (1) (1 mL BCNQDs) composite exhibits the highest photocatalytic performance for TCs degradation. The degradation rate constants of TC and OTC by the optimal sample were 4.95 and 2.17 times that of Bi4O5I2, respectively. This can be attributed to the fact that the narrow bandgap Bi4O5I2 is the electron acceptor, and the oxygen-containing functional group with the negative charge on BCNQDs can promote the formation of photoexcited holes, which makes the effective separation of photoexcited carriers easier. Furthermore, the active substance (h+ and ·O2−) is the major active substance for TCs photodegradation. On this basis, the possible photocatalytic reaction mechanism of Bi4O5I2/BCNQDs (1) composite is proposed. This study provides a new idea for 0D/2D interface engineering of BCNQDs heterojunction.

Boron Carbon Nitride Semiconductor Modified with CeO2 for Photocatalytic Reduction of CO2 with H2O: Comparative Study

Boron carbon nitride (BCN) is an emerging metal-free catalyst for CO2 photocatalytic reduction. However, the fast electron-hole recombination as well as the weak absorption for ultraviolet-visible (UV-vis) light are still challenging for the activity upgrading of BCN. In this paper, a BCN/CeO2 heterostructure via N-O-Ce bonding was fabricated by a urea-assistant heat-precipitation technique and confirmed by XRD, FT-IR, SEM, TEM and XPS characterizations. For CO2 photoreduction with H2O as reducing agent, the BCN/CeO2 heterostructure delivered an obviously enhanced catalytic performance with CO yield of ca. 6-fold that of BCN. UV-vis diffuse reflectance spectrophotometer (DRS), electrochemical impedance spectroscopy (EIS) and transient photocurrent response measurements revealed that the electron-hole separation efficiency and charge transfer are efficiently promoted on CeO2/BCN heterostructure, along with the boosted light harvesting in visible and ultraviolet light range. Furthermore, based on the photo(electro)chemical and photocatalytic results, a possible CO2 photocatalytic reduction mechanism was proposed.

Electrical Characterization of Hydrogenated Boron Carbon Nitride Thin Films at Cryogenic Temperatures

Compounds in boron-carbon-nitrogen ternary triangle such as diamond (C), cubic boron nitride (c-BN), and boron carbide (B4C) have gained attention due to their covalent bonding, short bond lengths, low atomic mass[1]. These materials exhibit low dielectric values along with excellent mechanical and thermal strength. Boron carbon nitride (BCN) compounds are known to combine unique properties of boron carbide and boron nitride, with the properties being tunable with varying elemental composition and structure. These outstanding properties have made BCN attractive and finds multi-functional applications in anti-wear and protective coatings, supercapacitors, UV detectors, nanobiotechnology and nanomedicine[2]. BCN thin films also find opto-electronic applications in the harsh environments. While addition of small amounts of hydrogen has been proven beneficial for electrical and optical properties in BCN films, the electrical behavior of hydrogenated BCN films at low temperatures is not evaluated. Such evaluations will further expand the use of of hydrogenated BCN for extreme temperature applications.In this study, BCN thin films are deposited using RF magnetron sputtering with varying hydrogen/nitrogen gas flows. Substrate temperature is kept constant at room temperature. Dual target sputtering from B4C and BN targets is performed to deposit BCN thin films. I-V characterization is performed from room temperature to 70 K. The variation in resistivity with reactive gas flow rate at low temperature is reported.

In-situ synthesis of non-phase-separated boron carbon nitride for photocatalytic reduction of CO2

Non-phase-separated hexagonal boron carbon nitride (h-BCN) is an emerging type of promising metal-free photocatalyst, but the synthesis of this material remains quite challenging. Here, h-BCN without phase separation was obtained through a novel organic-inorganic hybrid precursor pyrolysis method using boric acid and ethylenediamine as raw materials. The resultant BCN-1 exhibited excellent photocatalytic activity for CO2 reduction, as confirmed by a CO generation rate of 13.97 μmol g−1 h−1 under visible light illumination with no co-catalyst or sacrificial agent. This rate was 9.4 times higher than that of g-C3N4 (2.1 μmol g−1 h−1) under the same experimental condition. The pre-existing C–N–B bond is essential for mediating the growth kinetics and diminishing the thermodynamically preferred C and BN phase-segregation structure, while ammonia is crucial for C–N–B bond fixation and pore formation during the pyrolysis process. This finding of a facile method for synthesizing non-phase-separated BCN has positive effects on the study of photocatalytic CO2 reduction by sustainable metal-free catalysts.

Atomic-dispersed copper simultaneously achieve high-efficiency removal and high-value-added conversion to ammonia of nitrate in sewage

Environmentally friendly electrochemical reduction pathways from NO3− to NH3 or N2 have provided feasible strategy into the green production of ammonia or the treatment of nitrate wastewater. Here, we anchored single-atom Cu with boron carbon nitride on carbon nanotube (BCN@Cu/CNT), and achieved the efficient operation of electrochemical nitrate reduction reaction (NIRR). BCN@Cu/CNT can efficiently catalyze the selective conversion of high-concentration nitrate into high-value-added ammonia, where the ammonia yield rate and Faradaic efficiency are as high as 172,226.5 μg h−1 mgcat.−1 and 95.32% (at −0.6 V), respectively. BCN@Cu/CNT also shows the ability to efficiently remove low-concentration nitrates in sewage. Specifically, here only takes 5 h to nearly 100% (99.32%) eliminate NO3- (50 mg L−1) in sewage without any residual NO2−. The excellent catalytic activity and physicochemical stability of BCN@Cu/CNT for NIRR suggest the promising industrial application prospects, including the green production of ammonia and the purification of nitrate wastewater.

Accelerated charge transfer in well-designed S-scheme Fe@TiO2/Boron carbon nitride heterostructures for high performance tetracycline removal and selective photo-reduction of CO2 greenhouse gas into CH4 fuel

Designing and fabrication of smart hybrid multifunctional materials for energy/fuel production and environmental detoxification is indeed of great significance for sustainable development. Herein, we synthesized a new well-structured S-scheme heterostructure Fe@TiO2/Boron Carbon nitride (FT/BCN) with high performance tetracycline degradation and selective CO2 photo-reduction to CH4. Under visible light irradiation, 96.3% tetracycline was degraded in 60 min using best performing FT30/BCN sample with a high 83.2% total organic carbon removal in 2 h. The tetracycline degradation rate for FT30/BCN composite catalyst was ∼7 times than bare boron carbon nitride (BCN). The impact of reaction parameters as pH, presence of interfering electrolytes, light source and water matrix was also investigated. The FT30/BCN photocatalyst shows dramatic improvement in CO2 photoreduction as exhibited in 24.7 μmol g−1 h−1 CH4 and 2.4 μmol g−1 h−1 CO evolutions with optimal 91.1% CH4 selectivity. Pure BCN shows a poor 39.1% selectivity. Further, effect of alkali activation, CO2/H2O feed ratio, reducing agent and light source onto CH4 production and selectivity was also investigated. The CH4 evolution and selectivity was improved because of enhanced visible light absorption, high adsorption potential, charge carrier separation and high reducing power of photogenerated electrons induced by an effective S-scheme heterojunction between Fe@TiO2 and boron carbon nitride. An S-scheme (step-scheme) charge transfer mechanism is here operative both during tetracycline removal and CO2 reduction. The drug degradation route and photocatalytic mechanism for antibiotic removal and CO2 reduction was also predicted.

A novel two-dimensional boron–carbon–nitride (BCN) monolayer: A first-principles insight

The optical, electronic, and structural properties of a theoretically predicted new boron–carbon–nitride (BCN) two-dimensional monolayer have been explored using density functional theory calculations. The phonon dispersion, molecular dynamics simulation, the cohesive energy, and the Born criteria of elastic constant calculations of the BCN monolayer confirm its stability. The phonon spectrum illustrates an out-of-plane flexure mode with quadratic dispersion in the long-wavelength limit. The BCN monolayer is a semiconductor with a direct bandgap of 0.9 (1.63) eV determined via the Perdew–Burke–Ernzerhof (Heyd–Scuseria–Ernzerhof) functional. The same electron and hole effective masses and mobility values indicate the high recombination rate of electrons and holes. Meanwhile, the BCN monolayer can absorb ultraviolet radiation more effectively than visible light. Due to its interesting physical properties, the novel BCN monolayer could be a rather good candidate material for electro-optical applications.