Carbon-doped BN Research Articles

From BN-Doped Molecular Carbon Scaffolds to BNC Sheets

In carbon nanoscience, the on-surface synthesis strategy emerged as a promising route to achieve structural control at the atomic scale. This approach might be applied to fabricate well-defined two-dimensional BN-substituted carbon nanomaterials with tunable electronic properties [1]. In this talk, I will review our activities on the self-assembly of BN-doped molecular precursors, including borazine [2] and BN-doped carbon scaffold [3], on noble metal supports. Temperature-induced dehalogenation and dehydrogenation reactions are applied to introduce intramolecular ring-closing and intermolecular coupling, e.g., yielding random BNC sheets, probed by low-temperature scanning tunneling microscopy and X-ray photoelectron spectroscopy. The potential transfer and characterization of such two-dimensional BNC materials in devices will be discussed.[1] Sánchez-Sánchez et al., ACS Nano 9, 9228 (2015)[2] Weiss et al., Adv. Mat. Interfaces, accepted, doi: 10.1002/admi.202300774[3] Schwarz et al., Chem. Eur. J. 24, 9565 (2018)

Nanostructured Carbon-Doped BN for CO2 Capture Applications.

Carbon-doped boron nitride (denoted by BN/C) was prepared through the pyrolysis at 1100 °C of a nanostructured mixture of an alkyl amine borane adduct and ammonia borane. The alkyl amine borane adduct acts as a soft template to obtain nanospheres. This bottom-up approach for the synthesis of nanostructured BN/C is relatively simple and compelling. It allows the structure obtained during the emulsion process to be kept. The final BN/C materials are microporous, with interconnected pores in the nanometer range (0.8 nm), a large specific surface area of up to 767 m2·g-1 and a pore volume of 0.32 cm3·g-1. The gas sorption studied with CO2 demonstrated an appealing uptake of 3.43 mmol·g-1 at 0 °C, a high CO2/N2 selectivity (21) and 99% recyclability after up to five adsorption-desorption cycles.

Alkali cations and H2 molecules on BN-doped carbon nanoflakes: Theoretical study

Non-covalent interactions of two cations (Li+ and Na+) and hydrogen molecules with coronene and hexagonal boron nitride models as well as their heterostructures (mBNC and pBNC) were studied by using a set of theoretical methods. It was shown that the shapes of boron nitride moieties in the graphene-like framework have a strong influence on the cation-π interactions. Decomposition of the interaction energy (Eint) was classified as consisting mainly of the inductive energy term (Eind), which is followed by the electrostatic term (Eel). Hydrogen adsorption, however, depends strongly on both these terms, and in the case of numerous adsorbed H2 molecules, the dispersion interactions (Edisp) are also of importance. The assessed hydrogen capacity of studied structures reaches 5.5 wt%. The present investigation explicitly shows that cation-π and, in some cases, hydrogen adsorption properties can be easily modified by a B and N atoms introduction in the carbon nanoflakes, and, hence, it establishes the route to the remarkable adsorbent materials.

BN-Doped Carbon Nanotubes and Nanoribbons as Nonlinear-Optical Functional Materials for Application in Second-Order Nonlinear Optics

Pure carbon-based nanomaterials with good π conjugation and thermal stability, e.g., nanotubes and nanoribbons, have long served as promising conjugated materials for application in second-order nonlinear-optical (NLO) devices but suffer from two inherent structural problems: weak polarity (or even nonpolarity) and high chemical reactivity ascribed to zigzag edge states. In the present work, boron nitride (BN) chains are used to divide carbon nanotubes and nanoribbons, forming a functional block to tune the electronic structure, and thus induce charge redistribution or modify the molecular energy gap for second-order NLO materials or integrated electronic materials. A balance between the electronic kinetic stability and second-order NLO properties is established by structural manipulation. The strong second-order NLO responses in the visible and near-infrared regions make these hybridized carbon-based molecules potential NLO materials for applications in biological nonlinear optics. The application of BN to tune the electronic structure of carbon nanomaterials paves a path for fabricating nanoelectronic and nano-NLO devices.

Cobalt single atom induced catalytic active site shift in carbon-doped BN for efficient photodriven CO2 reduction

Active site tuning in catalyst design is the key to improving the catalyst performance. Herein, we introduce single cobalt atoms into carbon-doped boron nitride (C-BN) and find, to our surprise, that the photocatalytic CO2 reduction site of C-BN shifts from CN3 to CB3. The catalyst Co/C-BN with new active sites exhibits excellent photocatalytic activity and selectivity of CO without adding sacrificial reagents, while the side reaction of hydrogen evolution is significantly inhibited. Theoretical calculations show that the introduced Co atom changes the spin density of the neighboring catalytic site, thus regulating the adsorption energy of the catalytic site for active intermediates (COOH*). Compared with CN3 site, CB3 in Co/C-BN shows superiority in CO* formation elementary step for the conversion of CO2 to CO, and inhibits the generation of adsorbed H2 in the competitive water-splitting reaction. This work provides valuable insights into the design of highly efficient catalysts in the future.

Carbon-doped boron nitride nanosheets as an efficient metal-free catalyst for the selective oxidation of H2S.

We report the first use of carbon-doped boron nitride (BCN) for H2S-selective catalytic oxidation. The obtained carbon-doped BN with an ultrathin layer structure exhibits outstanding H2S elimination and high S yield. In particular, BN doped carbon nanosheets display better catalytic performance than traditional catalysts, such as iron- and carbon-based catalysts. The findings of the present work shed a new light on metal-free catalysts for efficient catalytic removal of toxic H2S.

Modeling of BN-Doped Carbon Nanotube as High-Performance Thermoelectric Materials.

Ternary BNC nanotubes were modeled and characterized through a periodic density functional theory approach with the aim of investigating the influence on the structural, electronic, mechanical, and transport properties of the quantity and pattern of doping. The main energy band gap is easily tunable as a function of the BN percentage, the mechanical stability is generally preserved, and an interesting piezoelectric character emerges in the BNC structures. Moreover, C@(BN)1-xCx double-wall presents promising values of the thermoelectric coefficients due to the combined lowering of the thermal conductivity and increase of charge carriers. Computed results are in qualitative agreement with the little experimental evidence and therefore can provide insights on an atomic scale of the real samples and direct the synthesis towards increasingly performing hybrid nanomaterials.

Highly Efficient and Selective Carbon-Doped BN Photocatalyst Derived from a Homogeneous Precursor Reconfiguration

The modification of inert boron nitride by carbon doping to make it an efficient photocatalyst has been considered as a promising strategy. Herein, a highly efficient porous BCN (p-BCN) photocatalyst was synthesized via precursor reconfiguration based on the recrystallization of a new homogeneous solution containing melamine diborate and glucose. Two crystal types of the p-BCN were obtained by regulating the recrystallization conditions of the homogeneous solution, which showed high photocatalytic activities and a completely different CO2 reduction selectivity. The CO generation rate and selectivity of the p-BCN-1 were 63.1 μmol·g−1·h−1 and 54.33%; the corresponding values of the p-BCN-2 were 42.6 μmol·g−1·h−1 and 80.86%. The photocatalytic activity of the p-BCN was significantly higher than those of equivalent materials or other noble metals-loaded nanohybrids reported in the literature. It was found that the differences in the interaction sites between the hydroxyl groups in the boric acid and the homolateral hydroxyl groups in the glucose were directly correlated with the structures and properties of the p-BCN photocatalyst. We expect that the developed approach is general and could be extended to incorporate various other raw materials containing hydroxyl groups into the melamine diborate solution and could modulate precursors to obtain porous BN-based materials with excellent performance.

Theoretical analysis of the uptake of CO, CO2, and NO2 on pristine and BN-doped carbon nanocones

Ab initio simulations were performed to evaluate the use of pristine and BN-doped carbon nanocones as adsorption platforms or sensors of harmful gases CO, CO2, and NO2. The proposed models show good interaction energies, in the range of physisorption and chemisorption. Furthermore, the electronic properties and short recovery times, make the systems proposed (except the CNCB-NO2) good candidates for sensing or adsorption platforms of CO, CO2, and NO2.

Preparation of Chemically Structure-Controlled BN-Doped Carbons for the Molecular Understanding of Their Surface Active Sites for Oxygen Reduction Reaction

BN-doped carbons have been reported to exhibit higher oxygen reduction reaction (ORR) activities than single-atom-doped carbons. However, the structures of these BN-doped carbons as well as the mechanism underlying their catalytically active sites had not been elucidated. In the BN-doped carbons reported so far, B and N exist in a disordered manner within the carbon structure. Therefore, it is extremely difficult to determine the chemical structures of the active sites of these carbons. In this study, we prepared chemically structure-controlled BN-doped carbons by selectively introducing B–N–C moieties using a method based on organic molecular reactions. B and N in the prepared BN-doped carbons were mainly in the form of B–N–C moieties. The ORR catalyzed by these BN-doped carbons showed a higher number of transferred electrons, which was attributable to the electrochemical H2O2 reduction capability of the BN-doped carbon being enhanced by the BN doping. Furthermore, we prepared and evaluated BN-doped carbons with controlled amounts of B–N–C moieties and confirmed that there exists a strong correlation between the amount of B–N–C moieties and the ORR activity. These findings indicate that the B–N–C moieties in BN-doped carbons serve as the active sites for the ORR.

Cobalt Single Atom Induced Catalytic Active Site Shift in Carbon-Doped Bn for Efficient Photodriven Co2 Reduction

Cobalt Single Atom Induced Catalytic Active Site Shift in Carbon-Doped Bn for Efficient Photodriven Co2 Reduction

Carbon-doped boron nitride nanosheets with adjustable band structure for efficient photocatalytic U(VI) reduction under visible light

Effectively separating uranium from aqueous solution is pivotal in the sustainable development of the nuclear industry and environmental protection. In this work, non-metal photocatalysts, carbon-doped BN (BCN) nanosheets were used to extract uranium by the photocatalytic reduction technique, and the doping in the form of carbon rings can regulate the bandgap and electronic structure by manipulating carbon amount. Benefiting from the porous structure and strong visible-light absorption, the U(VI) separation ratio of 97.4% could be achieved after 1.5-hour visible irradiation with an apparent rate value of 2.97 h−1 over BCN-80. Additionally, BCN-80 displayed good reusability and stability with the U(VI) separation ratio > 90% even after five cycles, and the enhanced U(VI) photoreduction was attributed to the synergistic effect of photoinduced electrons and formed ketyl radicals. This work demonstrates the great potential of BCN materials in U(VI) enrichment and will lay the foundation for further developing novel semiconductor photocatalysts.

Hierarchical porous carbon heterojunction flake arrays derived from metal organic frameworks and ionic liquid for H2O2 electrochemical detection in cancer tissue

The development of hierarchical nanostructure is demonstrated as an effective strategy to improve catalytic activity and stability of electrocatalysts. Herein, a novel leaf-like hierarchically porous heterojunction flake arrays (FAs), integrated graphitic N-doped carbon (NC) with amorphous B,N-doped carbon (BNC), has been designed and grown on flexible carbon fiber (CF) using metal-organic framework (MOF) FAs and green ionic liquids as precursors. The hierarchical heterojunction structure possesses micro- and nano-scaled pores, large surface areas, and exposed high-density catalytic active sites, which enhances electronic conductivity and offers accessible transport channels for effectively decreasing mass transport resistance. The results of discrete Fourier transform (DFT) calculations and experiments also suggest that the catalytic activity has been promoted by the heterojunction structure through narrowing the banding gap. Consequently, the resultant nanohybrid microelectrode exhibits remarkable electrochemical sensing performance towards H2O2 with a low detection limit of 50 nM, and a high sensitivity of 213 μA×mM-1×cm-2, as well as good anti-interference capability. The practical application of nanohybrid fiber microelectrode has been explored by real-time monitoring H2O2 released from live colon cells and surgically-resected fresh colon cancer tissue, which can provide important information for the identification of different types of cells as well as distinguish cancer cells from normal ones. We believe this research will pave the way towards the development of advanced carbon nanomaterials for application in the fields of electrochemistry, biosensing, and cancer diagnosis.

Feasibility of carbon-doped BN nanosheets as photocatalyst for degradation of 4-chloroguaiacol and ecotoxicity fate during indirect photochemical transformation

Although carbon-doped BN nanosheet (BCN) has been successfully synthesized and used, it has not been reported as a photocatalyst for the degradation of organic pollutants. In this study, 4-chloroguaiacol (4-CG) was selected as a representative substance to investigate the potential of utilizing BCN as photocatalyst for organic removal by use of computational simulation. The adsorption mechanisms, degradation mechanisms, and kinetics of 4-CG with the presence of different catalysts were determined. The adsorption energy of 4-CG on BCN was 10.71 kcal mol−1, and the ΔG≠s of initial reactions of 4-CG with OH were also reduced onto the BCN substrate. The band gap of BCN was 1.54 eV. Our computations depicted that the doping of aromatic carbon into BN narrows bandgap, and retains well catalytic performance and adsorption properties. Therefore, BCN nanosheet is a promising photocatalyst for organic pollutants removal. Possible degradation pathways of 4-CG and aquatic toxicity assessment during degradation were also carried out. More toxic products would be formed and the transformation products were still harmful to three trophic levels of aquatic organisms (fish, green algae, and daphnia).

Synthesis of Highly Bright Oil-Soluble Carbon Quantum Dots by Hot-Injection Method with N and B Co-Doping.

Oil-soluble BN-doped carbon quantum dots (CQDs) were successfully prepared in a novel hot-injection method by using 1,2-Hexadecanediol as carbon precursor and surface passivation agent. The reaction time, temperature, and surface passivation agent were investigated by fluorescence measurements to understand the underlying evolution of CQDs. The doping of N and B were carried out by choosing suitable N and B source, evaluated by their fluorescence properties. The size, morphology and surface properties were observed by TEM, AFM and FTIR measurements. The quantum yields of CQDs were also calculated to investigate the enhanced fluorescence properties. The prepared oil-soluble BN-doped CQDs were easily dispersed into organic solvent, showing great potential to produce optical and sensing devices.

Carbon-doped BN nanosheets for metal-free photoredox catalysis.

The generation of sustainable and stable semiconductors for solar energy conversion by photoredox catalysis, for example, light-induced water splitting and carbon dioxide reduction, is a key challenge of modern materials chemistry. Here we present a simple synthesis of a ternary semiconductor, boron carbon nitride, and show that it can catalyse hydrogen or oxygen evolution from water as well as carbon dioxide reduction under visible light illumination. The ternary B–C–N alloy features a delocalized two-dimensional electron system with sp2 carbon incorporated in the h-BN lattice where the bandgap can be adjusted by the amount of incorporated carbon to produce unique functions. Such sustainable photocatalysts made of lightweight elements facilitate the innovative construction of photoredox cascades to utilize solar energy for chemical conversion.

Confinement induced binding in noble gas atoms within a BN-doped carbon nanotube

Confinement induced binding interaction patterns for noble gas atoms (Hen/m, Arn, Krn; n=2, m=3) atoms inside pristine and -BN doped (3, 3) single walled carbon nanotube (SWCNT) have been studied through density functional theory calculations. The kinetic stability for He dimer and trimer has been investigated at 100K and 300K through an ab initio molecular dynamics simulation. The positive role of doping in SWCNT in enhancing the nature of interaction as well as the kinetic stability of the said systems has been found.

C-doped boron nitride fullerene as a novel catalyst for acetylene hydrochlorination: a DFT study

Density functional theory calculations were used to investigate the mechanism of acetylene hydrochlorination separately catalyzed by un-doped B12N12 and carbon-doped BN fullerene (B12−nN11+nC (n = 0, 1)).

Length dependence of carbon-doped BN nanowires: A-D Rectification and a route to potential molecular devices

Based on the first-principles approach, electronic transport properties of different lengths of carbon-doped boron-nitrogen nanowires, capped with two thiols as end groups connected to Au electrodes surfaces, are investigated. The results show that rectifying performance and negative differential resistance (NDR) behaviors can be enhanced obviously by increasing the length. Analysis of Mülliken population, transmission spectra, evolutions of frontier orbitals and molecular projected self-consistent Hamiltonian of molecular orbital indicate that electronic transmission strength, charge transfer and distributions of molecular states change are the intrinsic origin of these rectifying performances and NDR behaviors.

Density functional calculations of structural and electronic properties of a BN-doped carbon nanotube

The attachment of a variety of nitrogen nucleophilic groups to BN-doped single wall carbon nanotubes (SWCNTs) was characterized by quantum mechanical calculations at the DFT-level. We found that the binding energies for all systems lie between −6.90 and −30.13 kcal/mol and are in the order guanidine > arginine > ammonia > imidazole > chitosan > pyridine > m-nitroaniline, which is analogous to the p K a. m-Nitroaniline and pyridine grafted tubes display a smaller energy gap, 0.252 and 0.347 eV, respectively, compared to an isolated BN-doped SWCNT, 0.430 eV. For the other cases, the energy gaps did not change significantly, which is in keeping with the results for the densities of states (DOS). In the cases of m-nitroaniline and pyridine, electron density is seen at the Fermi level of both SWCNTs and probe molecules when the DOS is split into these two contributions, different from the isolated probe molecules. Thus, m-nitroaniline and pyridine attached to BN-doped SWCNTs increase the conductivity of the system.