Efficient removal of radionuclides on positively charged graphitic carbon nitride nanosheet membrane

Anti-freezing and antibacterial conductive organohydrogel co-reinforced by 1D silk nanofibers and 2D graphitic carbon nitride nanosheets as flexible sensor

Herein, a novel palladium‐doped graphitic carbon nitride nanosheet (g‐C3N4‐PdNPs) is reported. The prepared g‐C3N4‐PdNPs has a 6.7 and 14.0 times higher peroxidase‐like activity in comparison with pure Pd nanoparticles (PdNPs) and graphitic carbon nitride (g‐C3N4) nanosheets respectively, and can be stably stored for 3 months. The high peroxidase‐like activity make g‐C3N4‐PdNPs effectively catalyze H2O2‐mediation oxidization of 3,3,5,5′‐tetramethylbenzidine to generate a color change from colorless to blue under lower concentration level and shorter time. The g‐C3N4‐PdNPs can be used as peroxidase mimetic to develop sensitive and specific colorimetric method for the rapid detection of glucose in the serum, and to fabricate a simple and cheap portable test kit for instrument‐free visual detection of glucose in serum. The portable test kit possesses obvious advantages such as low‐cost, short detection time, tiny sample consumption, excellent specificity, and higher visual sensitivity. The visual detection limit of portable test kit is lower than the glucose concentration in the serum of a diabetic. Using portable test kit, the glucose in serum can be visually detected by bare eye observation within 30 min with only 30 µL serum consumption. The success of this study provided a potential approach for low‐cost and instrument‐free “see” diabetes in clinical early diagnosis.

Electrical charging of graphitic carbon nitride nanosheets (g-C4 N3 and g-C3 N4 ) is proposed as a strategy for high-capacity and electrocatalytically switchable hydrogen storage. Using first-principle calculations, we found that the adsorption energy of H2 molecules on graphitic carbon nitride nanosheets is dramatically enhanced by injecting extra electrons into the adsorbent. At full hydrogen coverage, the negatively charged graphitic carbon nitride achieves storage capacities up to 6-7 wt %. In contrast to other hydrogen storage approaches, the storage/release occurs spontaneously once extra electrons are introduced or removed, and these processes can be simply controlled by switching on/off the charging voltage. Therefore, this approach promises both facile reversibility and tunable kinetics without the need of specific catalysts. Importantly, g-C4 N3 has good electrical conductivity and high electron mobility, which can be a very good candidate for electron injection/release. These predictions may prove to be instrumental in searching for a new class of high-capacity hydrogen storage materials.

Preparation of choline sulfate ionic liquid supported on porous graphitic carbon nitride nanosheets by simple surface modification for enhanced catalytic properties

Simultaneously enhancing ionic conduction and mechanical strength of poly(ether sulfones)-poly(vinyl pyrrolidone) membrane by introducing graphitic carbon nitride nanosheets for high temperature proton exchange membrane fuel cell application

This study explores the tribological performance of microwave-assisted synthesized g-C3N4/MoS2 coatings. The two-dimensional transition metal dichalcogenide (TMD) nanosheet is getting prominence in the study of tribology due to its layered structure. The graphitic carbon nitride (g-C3N4) nanosheet was made using the calcination method and its nanocomposite with molybdenum disulfide (MoS2) was produced using a microwave-assisted method. The structure and morphology of the samples were characterized by some well-known methods, and tribological properties were studied by a pin-on-disc (POD) apparatus. Morphological analysis revealed that graphitic carbon nitride and molybdenum disulfide coexisted, and the layer structured MoS2 was well dispersed on graphitic carbon nitride nanosheets. BET analysis was used to determine the pore volume and specific surface area of the synthesized materials. The inclusion of MoS2 nanoparticles caused the composite’s pore volume and specific surface area to decrease. The reduction in g-C3N4 pore volume and specific surface area confirmed that the pores of calcinated graphitic carbon nitride were filled with MoS2 nanoparticles. The tribological property of g-C3N4/MoS2 nanocomposite was systematically investigated under different factors such as applied loads (5N to 15N), sliding speed (500 to 1000 mm/s) and material composition (uncoated, MoS2-coated, 9 wt.% of g-C3N4 and 20 wt.% of g-C3N4 in the composite). The optimal composite material ratio was taken 9%, by weight of g-C3N4 in the g-C3N4/MoS2 composite for a variety of levels of loads and sliding speeds. The results indicates that the incorporation of g-C3N4 in nanocomposites could reduce friction and improve wear life, which were better than the results with single MoS2. This study demonstrates a solution to broaden the possible uses of g-C3N4 and MoS2-based materials in the field of tribology.

Two-dimensional graphitic carbon nitride (g-C3N4) nanosheets (GCNNs) have been considered as an attractive metal-free semiconductor because of their superior catalytic, optical, and electronic properties. However, it is still challenging to prepare monolayer GCNNs with a reduced lateral size in nanoscale. Herein, a highly efficient ultrasonic technique was used to prepare nanosized monolayer graphitic carbon nitride nanosheets (NMGCNs) with a thickness of around 0.6 nm and an average lateral size of about 55 nm. With a reduced lateral size yet monolayer thickness, NMGCNs show unique photo-responsive properties as compared to both large-sized GCNNs and GCN quantum dots. A dispersion of NMGCNs in water has good stability and exhibits strong blue fluorescence with a high quantum yield of 32%, showing good biocompatibility for cell imaging. Besides, compared to the multilayer GCNNs, NMGCNs show a highly improved photocatalysis under visible light irradiation. Overall, NMGCNs, characterized with monolayer and nanosized lateral dimension, fill the gap between large size (very high aspect ratio) and quantum dot-like counterparts, and show great potential applications as sensors, photo-related and electronic devices.

Graphitic carbon nitride nanosheet (CNS) represents an attractive candidate for solar fuel production. However, the abundant defects in CNS lead to serious charge recombination and limit the photocatalytic performance. Herein, the synthesis of a CNS-covalent organic framework (CNS-COF) nanosheet composite is presented for the first time. CNS with significantly reduced defects is first obtained by rationally tuning the thermal exfoliation conditions of bulk carbon nitride. Subsequent modification of the CNS with trace COF nanosheet through chemical imine bonding can not only passivate the surface termination of carbon nitride in the boundary region, but also establish strong electronic coupling between these two components. As a consequence, enhanced charge separation and photocatalytic activity are realized on the resulting CNS-COF nanosheet composite. Under optimum conditions, hydrogen is evolved at a rate of 46.4 mmol g-1 h-1 . This corresponds to an apparent quantum efficiency of 31.8% at 425 nm, which is among the best values ever reported for carbon nitride-based materials.

Removal of aspirin from aqueous solutions using graphitic carbon nitride nanosheet: Theoretical and experimental studies

We demonstrate random laser (RL) emission from rhodamine 610 using graphitic carbon nitride (g-C3N4) nanosheets synthesized using a thermal polymerization method as scatterers in a liquid suspension to provide feedback for the RL emission. To characterize RL action and its threshold value, we observed replica symmetry breaking that leads to a transition from a photonic paramagnet to a photonic spin glass for four concentrations of g-C3N4. Additionally, we applied a fast Fourier transform to the RL spectra to gain insights into the photon optical path lengths, which aids in evaluating the feedback mechanism. The photonic disorder introduced by the g-C3N4 nanosheets creates multiple scattering paths of different natures. An important aspect revealed by our experimental results is the existence of coherent feedback in the system. At the same time, localized optical modes are generated within each nanosheet due to intrinsic structural defects and surface states, providing a coherent feedback mechanism.

The unique structure and property of K+‐modified graphitic carbon nitride (K‐CN) nanosheets would be beneficial for developing advanced epoxy nanocomposites. However, the compatibility between K‐CN nanosheets and epoxy matrix is a big challenge. In this study, we demonstrate a new and effective method to improve the compatibility of K‐CN nanosheets and epoxy by using 1‐(oxiran‐2‐ylmethyl)‐1H‐indole (IN) as surface modifier through the cation‐π interaction between K+ on the surface of K‐CN nanosheets and indole group of IN. In addition, the covalent bond between epoxy group of IN and amino group of curing agent could be used to participate in the formation of the epoxy network. When the content of K‐CN nanosheets is 0.5 wt%, the tensile strength of prepared epoxy nanocomposites increases by 60.7% and extensibility of prepared epoxy nanocomposites increases by 53.4% compared to neat epoxy resin. In addition, the prepared epoxy nanocomposites are used as efficient reusable photocatalysts for degradation of methylene blue (MB). The efficiency of MB degradation is 98% within 60 min. This work opens up a new avenue to fabricate high‐performance epoxy nanocomposites with multifunctional properties for advanced engineering applications.

Few-layer graphitic carbon nitride (g-C3N4) nanosheets were fabricated and utilized as a saturable absorber for mode-locking in an Er-doped fiber laser with net normal dispersion. The g-C3N4/polyvinyl alcohol (PVA) hybrid-film-based saturable absorber has a modulation depth of 4.01% and a saturation intensity of 7.5 MW/cm2. By integrating g-C3N4-PVA mode-locker into the laser cavity, a mode-locked operation could be obtained. The achieved mode-locking pulse centered at 1530.3 nm has a pulse width of 530 ps. Its repetition rate is 40.8 MHz, and the corresponding signal-to-noise ratio is about 55 dB.

In situ fabrication of the Bi2O3–V2O5 hybrid embedded with graphitic carbon nitride nanosheets: Oxygen vacancies mediated enhanced visible-light–driven photocatalytic degradation of organic pollutants and hydrogen evolution

Au nanoparticles (AuNPs) were loaded on graphitic carbon nitride (g-C3N4) nanosheets prepared by ultrasonication-assisted liquid exfoliation of bulk g-C3N4 via green photoreduction of Au(III) under visible light irradiation using g-C3N4 as an effective photocatalyst. The nanohybrids show superior photocatalytic activities for the decomposition of methyl orange under visible-light irradiation to bulk g-C3N4, g-C3N4 nanosheets, and AuNP/bulk g-C3N4 hybrids.

Fluorescence sensing of chromium (VI) and ascorbic acid using graphitic carbon nitride nanosheets as a fluorescent “switch”