Boron-doped Carbon Nitride Research Articles

Porous boron-doped graphitic carbon nitride-based label-free electrochemical immunoassay of vascular endothelial cadherin.

As a main connecting protein between endothelial cells, vascular endothelial cadherin (CD144) is involved in regulating vascular remodeling and maintaining vascular integrity. It is regarded as a marker of endothelial dysfunction and injury. Quantitative determination of CD144 is of importance in pathology research, diagnosis and treatment of vascular diseases. A label-free electrochemical method for the immunoassay of CD144 was developed in this work. CD144 antibodies were assembled on a glassy carbon electrode modified with porous boron-doped carbon nitride (B-GCN) and gold nanoparticles (AuNPs) in the presence of protein A. The binding of CD144 on the antibody-modified electrode induced serious steric hindrance, inhibiting the diffusion of ferri-/ferrocyanide from the bulk electrolyte to the electrode interface. The change of the differential pulse voltammetric response displayed a linear relationship with the concentration of CD144 between 0.500 and 400 ng mL-1. The new electrochemical sensor showed some good performances including good selectivity, high stability and satisfactory reproducibility. The cellular morphology observation and activity measurement showed that the dysfunction of vascular endothelial cells appeared in the presence of high-content NaCl. The electrochemical analysis reveals a positive correlation between the release amount of CD144 from the dysfunctional cells and the NaCl concentration in the growth medium.

Continuous synthesis of boron-doped carbon nitride supported silver nanoparticles in an ultrasound-assisted coiled flow inverter microreactor

Continuous synthesis of boron-doped carbon nitride supported silver nanoparticles in an ultrasound-assisted coiled flow inverter microreactor

Ultrasensitive photoelectrochemical sensor of oxytetracycline based on nano Au decorated nitrogen-deficient boron-doped carbon nitride nanosheets

As one of the emerging organic pollutants, oxytetracycline (OTC) has been used widely and presents a potential hazard risk to ecology and health. To achieve an ultrasensitive OTC detection, an effective photoelectrochemical (PEC) aptasensor based on nano Au decorated nitrogen-deficient boron-doped carbon nitride (Au/BCN) nanocomposites was developed. The initial carbon nitride was shortened band gap to improve light absorption to obtain the efficient photoactive BCN. Nano Au was decorated in BCN to further enhance light absorption because of its unique surface plasmon resonance effect, which favors improved detectability of the aptasensor. Meanwhile, nano Au acted as a bridge between BCN with aptamer to fix the aptamers via thiol-gold bonding. Under the influence of the holes oxidation mechanism, a wide linear range of 0.1–200 nM of OTC and a low detection limit of 0.05 nM was offered. The detection accuracy and feasibility of the proposed sensor indicated that the PEC aptasensor is a promising analytical method.

Boron and Sodium Doping of Polymeric Carbon Nitride Photoanodes for Photoelectrochemical Water Splitting.

Polymeric carbon nitride is a promising photoanode material for water-splitting and organic transformation-based photochemical cells. Despite achieving significant progress in performance, these materials still exhibit low photoactivity compared to inorganic photoanodic materials because of a moderate visible light response, poor charge separation, and slow oxidation kinetics. Here, the synthesis of a sodium- and boron-doped carbon nitride layer with excellent activity as a photoanode in a water-splitting photoelectrochemical cell is reported. The new synthesis consists of the direct growth of carbon nitride (CN) monomers from a hot precursor solution, enabling control over the monomer-to-dopant ratio, thus determining the final CN properties. The introduction of Na and B as dopants results in a dense CN layer with a packed morphology, better charge separation thanks to the in situ formation of an electron density gradient, and an extended visible light response up to 550nm. The optimized photoanode exhibits state-of-the-art performance: photocurrent densities with and without a hole scavenger of about 1.5 and 0.9mA cm-2 at 1.23V versus reversible hydrogen electrode (RHE), and maximal external quantum efficiencies of 56% and 24%, respectively, alongside an onset potential of 0.3V.

Numerous defects induced by exfoliation of boron-doped g-C3N4 towards active sites modulation for highly efficient solar-to-fuel conversion

Graphitic carbon nitride (CN) has emerged as a highly promising material in the photocatalysis field. However, its bulk structure suffers from a lack of active sites, limiting its practical application. Herein, a boron-doped CN (BCN) was prepared by a green gas-blowing-assisted thermal polymerization and then subjected to different exfoliation processes in order to delaminate the layered structure and tune the surface-active sites. A thorough comparative study shows that thermal exfoliation creates unsaturated nitrogen sites and induces the formation of interconnected layers that act as an electron diffusion channel for better charge transport. Furthermore, the thermally exfoliated BCN is rich in structural disorders that serve as dissociation defects for photoinduced charge carriers with a low exciton binding energy of 27 meV. Experimental results supported by theoretical calculations show that the nitrogen adjacent to boron is activated by the surrounding surface amino groups and the perforated texture to serve as an active adsorption site towards CO2 and H2O. Consequently, the exfoliated BCN acts as an outstanding bifunctional photocatalyst towards CO2 reduction into CO (40.41 μmol g−1 h−1) and prominent hydrogen evolution (4740 μmol g−1 h−1, 12.2% apparent quantum yield (AQY)).

Highly-efficient photocatalytic hydrogen evolution triggered by spatial confinement effects over co-crystal templated boron-doped carbon nitride hollow nanotubes

Hollow nanotube-like boron-doped carbon nitride for efficient photocatalytic hydrogen evolution.

Electron deficient boron-doped amorphous carbon nitride to uphill N2 photo-fixation through π back donation

The photocatalytic Nitrogen fixation to NH3 by using water as a protonation source is a requisite renovation for life. Albeit, the activation and adsorption of robust NN is the bottleneck in NH3 synthesis. Here, we report an amorphous-wrinkled hollow-tubular electron-deficient boron-doped carbon nitride (BCN) for improved photocatalytic N2 fixation via “σ donation and π back donation”. The electron-deficient B played synergetic roles to activate and stabilize the adsorbed N2 i.e. (i) It tunes the bandgap of CN for effective light absorption and charge transfer; (ii) The B-N coordination site polarizes chemisorbed N2 via electron pair acceptance; (iii) The filled sp2 orbital of B activates the N2 by π-back donation. Consequently, the photocatalytic performance of BCN-4 reaches 0.93mmolh−1g−1 with AQY of ∼13% (350 nm) and solar to NH3 conversion efficiency (SSCNH3) of 0.017%. The in situ DRIFT and DFT studies revealed that BCN exhibited spontaneous N2 adsorption and activation, followed by protonation of the adsorbed N2, with a negligible energy barrier.

A Tandem Reaction System for Inactivation of Marine Microorganisms by Commercial Carbon Black and Boron-Doped Carbon Nitride.

The Pureballast system, based on photocatalytic technology, can purify ships’ ballast water. However, the efficiency of photocatalytic sterilization still needs to be improved due to the shortcomings of the photocatalyst itself and the complex components of seawater. In this work, a tandem reaction of electrocatalytic synthesis and photocatalytic decomposition of hydrogen peroxide (H2O2) was constructed for the inactivation of marine microorganisms. Using seawater and air as raw materials, electrocatalytic synthesis of H2O2 by commercial carbon black can avoid the risk of large-scale storage and transportation of H2O2 on ships. In addition, boron doping can improve the photocatalytic decomposition performance of H2O2 by g-C3N4. Experimental results show that constructing the tandem reaction is effective, inactivating 99.7% of marine bacteria within 1 h. The sterilization efficiency is significantly higher than that of the single way of electrocatalysis (52.8%) or photocatalysis (56.9%). Consequently, we analyzed the reasons for boron doping to enhance the efficiency of g-C3N4 decomposition of H2O2 based on experiments and first principles. The results showed that boron doping could significantly enhance not only the transfer kinetics of photogenerated electrons but also the adsorption capacity of H2O2. This work can provide some reference for the photocatalytic technology study of ballast water treatment.

Insights into the photocatalytic peroxymonosulfate activation over defective boron-doped carbon nitride for efficient pollutants degradation

The metal-free graphitic carbon nitride is a promising photocatalyst for peroxymonosulfate (PMS) activation towards water decontamination, but bearing low efficiency due to its electronic structure and surface chemistry. Herein, the non-metallic element boron was adopted for catalyst development. The boron dopants and defects were simultaneously introduced by potassium borohydride, resulting in an excellent activity towards PMS activation. The dominant reactive oxygen species was singlet oxygen, which was determined to originate from PMS activation over photo-induced holes initiated by an electron transfer process. Calculations based on density functional theory revealed that at excited states, due to the dopants and defects, the electron-hole distribution was altered from an even population to a significant separation, which was beneficial for photocatalytic performance. Besides, the engineered electronic structure weakened the catalyst resistance to charge transfer, enabling easier electron transfer between the catalyst and the PMS. Moreover, the strengthened and enlarged positive electrostatic potential areas on heptazine rings oriented the electron transfer process from the negatively charged PMS to the catalyst, facilitating the generation of singlet oxygen. These findings provide underlying mechanism insights into the contribution of dopants and defects to catalytic performance on persulfate-based photocatalytic water treatment.

A novel affinity peptide–antibody sandwich electrochemical biosensor for PSA based on the signal amplification of MnO2-functionalized covalent organic framework

This work describes a novel affinity peptide–antibody sandwich electrochemical strategy for the ultrasensitive detection of prostate-specific antigen (PSA). Herein, polydopamine-coated boron-doped carbon nitride (Au@PDA@BCN) was synthesized and used as a sensing platform to anchor gold nanoparticles and immobilize primary antibody. Meanwhile, AuPt metallic nanoparticle and manganese dioxide (MnO2)-functionalized covalent organic frameworks (AuPt@MnO2@COF) was facilely synthesized to serve as a nanocatalyst and ordered nanopore for the enrichment and amplification of signal molecules (methylene blue, MB). PSA affinity peptide was bound to AuPt@MnO2@COF to form Pep/MB/AuPt@MnO2@COF nanocomposites (probe). The peptide–PSA–antibody sandwich biosensor was constructed, and the redox signal of MB was measured with the existence of PSA. The fabricated sensor exhibited a linear response (0.00005–10 ng mL−1) with a low detection limit of 16.7 fg mL−1 under the optimum condition. Additionally, the sensor showed an excellent selectivity, ideal repeatability, and good stability for PSA detection in real samples. Furthermore, the porous structure of COF can enrich more MB molecules and increase the sensitivity of the biosensor. This study provides an efficient and ultrasensitive strategy for PSA detection and broadens the use of organic/inorganic porous nanocomposite in biosensing.

Carrier engineering of carbon nitride boosts visible-light photocatalytic hydrogen evolution

Carbon nitride, as one of the metal-free photocatalysts, has aroused wide attention due to its low cost, easy preparation, and excellent optical response. However, challenges of the high recombination rate of electron-hole pair hindered their potential applications. Here, boron-doped carbon nitride nanotubes were designed and prepared by a simple hydrothermal and calcination route. Compared with the bulk carbon nitride, the control strategy forms the ordered nanotube structure, which greatly improved their specific surface area, exposed more active sites, and enhanced the graphitization degree. The transient fluorescence lifetime of tubular carbon nitride is twice as long as that of pure carbon nitride. Furthermore, boron doping carbon nitride nanotubes exhibited a 1.5-fold increase in a lifetime over tubular carbon nitride, which acts a synergistic role with nanotube architecture to further increases the carrier concentration and hinder the recombination of photogenerated electron-hole. Under the irradiation of visible light, the amount of hydrogen evolution of the optimum photocatalyst has achieved 22.1 mmol g−1 h−1, which was 64 times that of the bulk carbon nitride and exhibited excellent stability. This work provides a promising strategy for the development of non-metallic doped carbon nitride nanotube photocatalysts for hydrogen evolution.

Constructing light-weight polar boron-doped carbon nitride nanosheets with increased active sites and conductivity for high performance lithium-sulfur batteries

Lithium-sulfur (Li-S) batteries are highly attractive as one of the most promising energy storage systems owing to their superior theoretical capacity, low cost and environmental compatibility. Nevertheless, the low utilization of active materials and detrimental shuttle reactions severely inhibit the practical application of Li-S batteries. Herein, a lightweight 2D boron doped g-C3N4 nanosheets (BCN) with abundant active sites and increased conductivity prepared by a facile route is introduced onto commercial separators to achieve high performance Li-S batteries. The prepared BCN displays a 2D thin layer nanosheet structure with a thickness of ～2.5 nm. The boron doping not only can increase surface area and improve electrical conductivity, but also chemically anchor more polysulfides due to the formed B-N bond, which can effectively minimize the shuttling of polysulfides through the synergistic effect of physical yield and chemical confinement. As a result, the assembled Li-S batteries employing BCN separators with multifunction display large discharge capacity of 1197 mAh g−1, high sulfur utilization and outstanding durability with a capacity decay rate of 0.09% per cycle at 1 C after 500 cycles, which are also supported by the density functional theory simulation. Additionally, the alleviated self-discharge behavior and good areal capacity (up to 6.4 mAh cm−2) at a high sulfur loading of the cell are also demonstrated. The exploration of BCN modified separator furnishes a viable way to construct high energy density and long lifespan Li-S batteries.

Photocatalytic Dinitrogen Reduction with Water on Boron-Doped Carbon Nitride Loaded with Nickel Phosphide Particles.

Photocatalytic N2 reduction with water by sunlight irradiation is a challenging issue toward sustainable energy society, but previously reported photocatalysts had suffered from low stability and low activity. We prepared a boron-doped carbon nitride (BCN) semiconductor powder loaded with nickel phosphide particles (Ni2P) as cocatalysts. The Ni2P/BCN catalyst, when photoirradiated in pure water by simulated sunlight under N2 flow, successfully produces NH3 at room temperature. The B doping leads to a positive shift of the valence band level and enhances water oxidation by the photoformed holes. The Ni2P particles efficiently receive the conduction band electrons of BCN, leading to enhanced charge separation of the photoformed hole and electron pairs, and behave as N2 reduction sites. Simulated sunlight irradiation of the catalyst in water stably generates NH3 with 0.010% solar-to-chemical conversion efficiency. This noble-metal-free system therefore shows a significant potential for N2 photofixation.

Metal free alkene hydrogenation by B-doped graphitic carbon nitride

Metal free hydrogenation of styrene under mild conditions employing boron-doped carbon nitride catalysts is reported.

Synthesis of Porous Boron-Doped Carbon Nitride: Adsorption Capacity and Photo-Regeneration Properties.

Carbon nitride (CN) with improved adsorption–degradation capacity was synthesized using B2O3 and CN via calcination. The pollutant removal capacity of this B2O3/CN (B-CN) was studied by a powder suspension experiment and added into concrete to evaluate the adsorption and degradation of methylene blue (MB). The characterizations of all samples indicate that B2O3 significantly affects CN, e.g., by increasing the CN specific surface area to 3.6 times the original value, extending visible light adsorption, and narrowing the band gap from 2.56 eV to 2.42 eV. Furthermore, the results show that B-CN composite materials have a higher MB-removal efficiency, with the adsorption capacity reaching 43.11 mg/g, which is about 3.3 times that of pristine CN. The MB adsorption process on B2-CN is mainly via electrostatic attraction and π–π interactions. In addition, B-CN added into concrete also has good performance. After five adsorption–degradation cycles, B-CN and photocatalytic concrete still exhibit a good regenerate ability and excellent stability, which are very important for practical applications.

One step synthesis of boron-doped carbon nitride derived from 4-pyridylboronic acid as biosensing platforms for assessment of food safety.

The rational design of heteroatom-doped C3N4 offers a great opportunity to optimize C3N4 performance. In this communication, we propose a facile method to fabricate layered-stacked B-doped C3N4 (BCN-800) ultrathin nanosheets via a one-step calcination route. The distinctive layered-stacked structure and the presence of B atoms provide an active attachment point for antibodies and antigens. In addition, the presence of C and N might aid stability and increase conductivity. When used for vomitoxin detection, the BCN-800-based electrochemical biosensor exhibits high sensitivity with a detection limit of 0.32 pg mL-1 and superior selectivity to other interfering agents.

Ionic liquid directed construction of foam-like mesoporous boron-doped graphitic carbon nitride electrode for high-performance supercapacitor

Carbon materials with controllable hierarchically porous structure and high doping level are expect to exhibit superior energy storage performance when used as electrode materials for supercapacitors. Herein, we report the preparation of a novel foam-like boron-doped carbon nitride material with hierarchically porous structure and high doping contents of nitrogen (21.45 ± 0.93 at%) and boron (6.46 ± 0.60 at%). Due to the unique compositional and structural features, this material exhibits high energy storage performance, including a large specific capacitance of ∼ 660.6 F g−1 at 0.1 A g−1 and a high capacitance retention after 10,000 cycles. This study can provide new ideas for the development of carbon based electrode materials with unique hierarchically porous structure and improved doping level.

Boron doped graphitic carbon nitride with acid-base duality for cycloaddition of carbon dioxide to epoxide under solvent-free condition

The cycloaddition of CO2 and epoxides to yield cyclic carbonate under solvent-free conditions is an eco-friendly way to utilize CO2 in environmental science and green chemistry. In this paper, we report that boron doped carbon nitride (BCN) is highly active and selective for such reactions. BCN, especially if supported on mesoporous silica SBA-15 (i.e., B0.1CN/SBA-15), shows above 95% conversion and selectivity for cycloaddition of CO2 and styrene oxide (SO) to yield styrene carbonate (SC), even under solvent-free conditions. That is mainly due to the acid-base duality induced by B doping, which enables the co-activation of CO2 and epoxide. A mechanism based on acid-base duality is proposed, where CO2 is activated on the basic >NH sites and SO is on the acidic −B(OH)2 sites through a hydrogen bonding. The co-activated CO2 and SO react with each other to yield the SC. Density functional theory (DFT) calculations were conducted to support the mechanism, which show that the co-adsorption of CO2 and SO on BCN is energetically favorable and the reaction follows the Langmuir-Hinshelwood mechanism. The BCN with acid-base duality provides an option for cheap, green and efficient catalysts for CO2 utilization.

Achieving highly stable Li–O2 battery operation by designing a carbon nitride-based cathode towards a stable reaction interface

A ruthenium oxide nanoparticles@porous boron-doped carbon nitride electrode with high stability upon ORR/OER endows the lithium–oxygen batteries with improved cycle performance and energy efficiency.

Kinetics Improvement through Cathode Designing for Aprotic Li-O2 batteries

The rechargeable aprotic lithium-air (Li-O2) battery is a promising potential technology to provide a safe and cost-effective secondary battery with several times higher energy density than state-of-the-art Li-ion batteries, and thus attracting extensive interest over the past decade. Despite their great promise, putting the Li-O2 batteries into practise are hindered by a range of fundamental challenges [1-2]. The greatest problem is lacking of stable materials that could endure the attack from the intermediates and/or the products of oxygen reduction/evaluation reaction (ORR/OER) during the operation of Li-O2 batteries. For example, masses of works have proven that many kind of materials undergo serious side reactions during the operation of Li-O2 batteries, which induce the formation and accumulation of carbonates on cathode and eventually kill the batteries. Moreover, the intrinsic poor kinetics of Li/O2 chemistry, slow kinetics of ORR (2Li+ + 2e- + O2 → Li2O2) and significantly sluggish kinetics of OER (Li2O2 → 2Li+ + 2e- + O2), are also of significant influence on cell performances. To address these issues, cathode designing toward a stable interface with improved activity on ORR/OER is of great promise. Recently, by virtue of the material and structure design for air cathodes, optimization of the operation protocols, and adding soluble catalysts/redox mediators into the electrolytes, many reports have shown that Li-O2 batteries could be run for hundreds or even thousands of cycles with considerably large specific capacities [2]. In spite of the rapid progress made on improving their cyclic performance and reducing their voltage polarization, lots of work related to thermodynamics and kinetics of Li/O2 chemistry as well as cathode designing are still needed prior to the realization of Li-O2 batteries. The galvanostatic intermittent titration technique (GITT), which combines the transient and steady-state measurements, is a widely used tool to determine kinetic properties and thermodynamic data for a specific electrode [3]. In this report, the thermodynamic equilibrium voltages for Li-O2 reaction and overpotential variation was studied using GITT measurements, from which a zero voltage gap for the open circuit voltage (OCV) between charging and discharging, an asymmetrical polarization behavior at different current densities and temperatures, a continuous increase of overpotential during charging, as well as a negative temperature coefficient of the cell's thermodynamic equilibrium voltage were observed [4]. This work also gives a clue that the kinetics of Li/O2 reaction plays a major role on improving the performances of Li-O2 battery. Based on such clue, several kind of cathodes ranged from carbon based to carbon-free materials, such as MnO nanoparticles embedded N-doped carbon composites (MnO-m-N-C), Ru nanoparticles anchored carbon nanotubes with ionic liquid coating layer (Ru-IL-CNTs) and RuOx nanodots decorated mesoporous boron-doped carbon nitride (RuOx@m-BCN), have been developed for Li-O2batteries, all of which show positive effects on lowering charge overpotential and improving cycle performance and energy efficiency [5-7].