Two-dimensional g-C3N4 Research Articles

Ternary g-C3N4/Co3O4/CeO2 nanostructured composites for electrochemical energy storage supercapacitors

Extensive use of fossil fuels causes heavy discharge of carbon dioxide, depleting energy resources and this requires environmentally friendly and effective energy storage materials. Hybrid supercapacitors (HSCs) are recently developed as effective energy storage materials enabling high capacitance retention rate and quick charging. Herein, synthesis of two-dimensional g-C3N4 nanosheets supported onto three-dimensional flower-like Co3O4/CeO2 (CoCe) ternary synergistic heterostructures are developed as effective electrodes for hybrid supercapacitor applications. Addition of g-C3N4 produces substantial surface active sites, enabling its synergistic effect with CoCe to enhance electrochemical performance having exceptional conductivity. The CoCe/g-C3N4 ternary composite electrode exhibits a higher specific capacitance of 1088.3 F g−1 at 1 A g-1 with 96 % of recycling stability over 5000 cycles, which is ∼5.5 and ∼5 folds higher specific capacitance than the pristine g-C3N4 and CoCe electrodes. EIS analysis revealed that CoCe/g-C3N4 electrode offered reduced charge transfer resistance compared to pristine electrodes. The fabricated two-electrode HSC device displays outstanding retention after 10,000 cycles with an ultra-high specific capacitance of 119.8 F g−1, excellent energy density 37.4 Wh kg−1 and power density of 749.9 W kg−1. This research showcases the perspectives of CoCe/g-C3N4 ternary electrodes in hybrid supercapacitors and other renewable energy storage devices.

Indium oxide decorated graphitic carbon nitride/multiwalled carbon nanotubes ternary composite for supercapacitor applications

A hybrid ternary composite In2O3/g-C3N4/MWCNT (GCI) was synthesized by combining three-dimensional In2O3, two-dimensional g-C3N4, and one-dimensional MWCNTs employing a one-pot solvothermal method. The resulting In2O3/g-C3N4/MWCNTs composite leverages the combined benefits of the integration of different dimensionality materials and the synergy between its components. Integrating 1D, 2D, and 3-D materials can create hybrid structures with 3D architectures. It exhibits hierarchical porosity that provides better conductive pathways for ion transport and improves the rate performance. The distinct spatial structure of the composite with short ion diffusion paths maximizes the exposure of the active sites and enhances the conductivity, leading to superior energy storage performance. The electrochemical assessment of the In2O3/g-C3N4/MWCNTs composite exhibited a remarkable specific capacitance of 1081 F g−1 at 1 A g−1 with a commendable capacitance retention of 97.5 % at 3 A g−1 over 5000 cycles. An asymmetric supercapacitor fabricated using In2O3/g-C3N4/MWCNT//AC showcased a notable energy density of 57.5 Wh Kg−1 with an impressive power density of 2760 W Kg−1 at 1 A g−1. The outstanding electrochemical attributes of the fabricated device underscore the potential of the material for future applications in hybrid energy storage systems.

Manganese Oxide-Doped Graphitic Carbon Nitride-Based 2D Material as Nanozyme for the Colorimetric Sensing of Ascorbic Acid

Ascorbic acid is a key player in the human body, pharmaceutical industry, and food industry. It is involved in many physiological processes, and its deficiency or excess amount is linked to many pathological conditions, which makes it essential to monitor its concentration. In the current work, graphitic carbon nitride (g-C3N4) and manganese oxide-doped graphitic carbon nitride (g-C3N4@MnO2) were synthesized through the pyrolysis process. Various characterization techniques, including spectroscopic, diffraction, thermal, and imaging methods, were employed to analyse the material's structural, compositional, and morphological properties. The surface chemical state of the material through X-ray photoelectron spectroscopy confirmed that manganese was present in its tetravalent state, anchoring with nitrogen in the two-dimensional g-C3N4. The synthesized g-C3N4@MnO2 demonstrated intrinsic peroxidase-like activity visualized through the naked eye by the transformation of 3,3′,5,5′-tetramethylbenzidine (TMB) to oxiTMB and confirmed through a UV-Vis spectrophotometer. The detection of ascorbic acid was performed through the peroxidase inhibitory action of the analyte through a chromogenic substrate, which reduced the oxiTMB to a colorless form. Under the optimized conditions, the sensor system was able to detect the analyte in the linear range of 1 to 80µM with a 0.16μM LOD, 0.53µM LOQ, and an R2 value of 0.9982. The sensor system, along with its sensitivity and linearity, was very selective in the presence of various potential interfering species. The sensor was successfully employed for the sensing of ascorbic acid in real samples with excellent reproducibility. The proposed sensor can be used in diagnosis, pharmaceutical applications, and the food industry.

Interface engineering of AgI/(P, K)-g-C3N4 novel S-scheme heterostructures as a highly efficient photocatalyst for RhB degradation

In this study, we developed an in-situ deposition method to load small-sized AgI nanoparticles as an oxidative photocatalyst (OP) onto phosphorus (P) and potassium (K) co-doped two-dimensional porous g-C3N4 (PK-CN-N) as a reductive photocatalyst (RP), forming an S-scheme heterojunction photocatalyst AgI/PK-CN-N. PK-CN-N achieved morphology control and element doping, leading to surface functionalization and heterostructure formation for the AgI/PK-CN-N photocatalyst. Notably, the 50AgI/PK-CN-N composite demonstrated an approximately 95 % removal efficiency for RhB within 30 minutes, 17.6 times higher than pure g-C3N4, surpassing most reported g-C3N4-based photocatalysts. The enhanced photocatalytic efficiency is attributed to the surface modification strategy and heterostructure formation of g-C3N4, which broadens the visible light response range, increases the number of active sites, improves the separation of photogenerated electron-hole pairs, and enhances REDOX capabilities. The band structure of the composite was elucidated through Mott-Schottky analysis and UV–vis DRS. The formation of the AgI/PK-CN-N S-scheme heterojunction and its charge transfer mechanism was confirmed through XPS, band structure analysis, KPFM, and EPR spectroscopy. Experimental data confirmed the presence of a strong and effective interface electric field between the two semiconductors, leading to band bending and accelerated charge separation. Additionally, the introduction of small-sized AgI semiconductors enhanced the exposure of the coupling interface, further improving catalytic performance. The reusability and lifespan of the catalyst were also analyzed, showing that after four cycles, the photocatalytic activity remained above 92 %.

Optimal Structure and Photocatalytic Performance of C3N4@TiO2 Composite by Controlling the Molar Ratio of Components.

Based on the heterogeneous composite design of C3N4 and TiO2, composite photocatalysts of C3N4@TiO2 (with varied molar ratios of C3N4 to TiO2) were synthesized by a water bath method to degrade RhB in wastewater. The composition, morphology, structure, and photocatalytic properties of the materials were assessed through a variety of characterization techniques. The results show that TiO2 nanoparticles are uniformly coated on two-dimensional g-C3N4 nanosheets, forming relatively dense heterostructures within the C3N4@TiO2 composite. Due to the synergistic effect derived from the heterogeneous component and appropriate proportion of C3N4 and TiO2, the light absorption range is extended, and the separation/transport performance of photon-generated carrier is improved. As a result, TCNT-3 (where the molar ratio of C3N4 to TiO2 is 1:1) presents remarkable photocatalytic performance, the degradation rate of which for 60 min is 99.8%, and the reaction rate constant is calculated to be 0.0872 min-1. Moreover, the degradation efficiency remains 94.4% after 5 cycles, indicating the superior cycle stability.

A cyclic durable all-solid-state battery constructed with LiBH4-based electrolyte with high ionic conductivity at room temperature

LiBH4 has been considered as a promising solid electrolyte for lithium-ion batteries. However, the low ionic conductivity at room temperature has been the biggest challenge of LiBH4 solid-state electrolyte (SSE) toward practical solid-state batteries. In this work, a ternary electrolyte is designed and prepared by milling LiBH4 with LiNH2 and interfacially decorated with g-C3N4. It is revealed that the soft dispersed phase of two-dimensional g-C3N4 can build an effective transportation network in the composite electrolyte, thereby decreasing the interfacial impedance and reducing the energy barrier for lithium ion diffusion. The optimized SSE, LiBH4-2LiNH2-g-C3N4-10 % (LBN-CN-10 %), exhibits an ionic conductivity of 1.5×10−3 S cm−1, five orders of magnitude higher than that of the LiBH4 electrolyte at 30 °C. The LiIn symmetric cell with LBN-CN-10 % electrolyte delivers a low polarization of ∼89 mV over 10,000 h. When assembling with Li4Ti5O12 cathode, the all-solid-state battery exhibits excellent cycling over 1000 cycles at 30 ℃, achieving a breakthrough in the lifetime of solid-state batteries with LiBH4 -based electrolyte. Moreover, the all-solid-state battery with LiNi0.8Co0.1Mn0.1O2 cathode also delivers a discharge plateau at 3.0 V, revealing the high voltage withstanding of LBN-CN-10 % electrolyte. This work provides new options for the development and practical application of room-temperature hydride all-solid-state batteries.

Synergistic photocatalytic performance of MoO3:Cu/g-C3N4 heterojunction semiconductor for efficient crystal violet dye degradation: A sustainable approach for environmental remediation

A heterojunction semiconductor of MoO3:Cu in conjunction with g-C3N4 was fabricated using a green synthesis approach facilitated by leaves extract of Murraya paniculata. Numerous methods of characterisation, including XPS, FTIR spectroscopy, XRD, BET, HR-TEM, FE-SEM, EDAX, and UV–visible spectrophotometry were employed to analyse the materials. The results from XRD and HRTEM indicated the highly crystalline nanoparticles with a mean particle size of 5.42 nm for MoO3 nanomaterials with doping of 5.62 nm Cu particles. The two-dimensional g-C3N4 sheeted structure acted as a translucent layer, facilitating self-assembly on the spherical MoO3:Cu nanoparticles, thereby promoting efficient charge flow and enhancing the photodegradation capability of the heterojunction semiconductor. XPS analysis confirmed the presence of Mo, Cu, N, O, and C in the fabricated heterojunction. UV–Visible and PL spectra demonstrated the efficient suppression of exciton annihilation in the heterojunction semiconductor. Remarkably, the heterojunction exhibited a high photocatalytic degradation performance of 97 % for the photodegradation of Crystal violet (CV) dye. Additionally, the effects of pH and dose of catalyst on photodegradation, as well as the recyclability of the catalyst, were evaluated. Kinetic analysis revealed a pseudo first-order reaction with 0.617 min−1 rate constant, while scavenger experiments confirmed the involvement of h+ and .O2− as active species in the degradation process.

Sunlight degradation of tetracycline by Z-type BiOI/g-C3N4 photocatalyst synthesized via a simple two-step process: Response surface methods, degradation pathways, toxicity evaluation

A method combining grinding and hydrothermal treatments was utilized to densely load three-dimensional BiOI onto two-dimensional g-C3N4, thereby preparing a BiOI/g-C3N4 photocatalyst with a Z-type heterojunction. Under varying climatic conditions throughout the year, 10%BiOI/g-C3N4 photocatalyst degraded 92.26 % of tetracycline (TC) under sunlight exposure in summer (sunny days) in 150 min, whereas it only degraded 47.33 % of TC under sunlight exposure in winter (cloudy days). The degradation parameters for TC by 10%BiOI/g-C3N4 were optimized using Response surface methods, establishing the optimal conditions for TC degradation (pollutant concentration of 10.94 mg/L, catalyst dosage of 31.34 mg, pH of 4.02), resulting in a degradation efficiency of 95.63 % for TC under the specified conditions. Employing HPLC-MS/MS and 3D EEM techniques, the degradation of TC primarily occurs due to the cleavage of its CC double bonds and CN bonds triggered by free radical attacks, and small molecular acids are produced during the degradation process. The impacts of TC solution treatment on plants were investigated, and the oxidative stress indicators MDA, SOD, POD, and CAT were assessed. The results demonstrated a decrease in all four indicators in plants cultured in TC degradation product solution, further affirming the applicability of 10%BiOI/g-C3N4 in practical scenarios.

One-step thermal polymerization synthesis of P and K co-doped two-dimensional porous g-C3N4 photocatalyst with enhanced visible light photocatalytic activity for RhB

To improve the reaction rate of g-C3N4 for the photocatalytic degradation of RhB, we have synthesized P and K co-doped porous g-C3N4 using a simple one-step thermal polymerization technique. The 3-P/K-CN-N sample showed the highest photocatalytic activity for RhB degradation under visible light irradiation. The first-order kinetic equation for 3-P/K-CN-N had a reaction rate constant of 0.10601 min−1, which was 13.59 times higher than that of pure g-C3N4. The internal reasons for improving the catalytic activity of the 3-P/K-CN-N are the synergistic effects of heteroatom doping and morphology regulation. The co-doping of P and K reduces the band gap, broadens the response range of visible light, and promotes the separation efficiency of photogenerated carriers. The decomposition of NH4Cl and KH2PO4 together at high temperatures promotes the formation of porous g-C3N4 with a large specific surface area and numerous surface active sites. This effectively shortens the distance of photogenerated carriers migrating from the bulk phase to the surface. Furthermore, the stability and repeatability were examined. After four cycles, the catalyst degrading efficiency decreased by only 5 %. This research provides a new reference for the preparation of highly efficient and stable photocatalysts.

Construction of charge transfer channels inside h-BN/ g-C3N4 composites to enhance photocatalytic activity

Water resources are an indispensable part of life, but the current water pollution problem is facing serious challenges. In this article, two-dimensional g-C3N4 and h-BN used as raw materials, a series of h-BN/g-C3N4 (BCN) composite catalysts with varying mass by designed and synthesized using combination of simple solvent volatilization and high-temperature thermal polymerization method. The degradation rate of the BCN-2 catalyst was impressively 13.7 times higher than that of the bulk g-C3N4 when RhB was used as the target pollutants, demonstrating significantly enhanced photocatalytic performance compared to both bulk g-C3N4 and h-BN. The burst experiments on free radicals revealed that h+ and ∙O2− played a predominant role in the photocatalytic system. Moreover, the introduction of h-BN into g-C3N4 nanosheets modulated their microstructure, facilitating effectively hole migration channels and enhancing synergistically the separation efficiency of photogenerated electron-hole pairs. Consequently, the composites of h-BN/g-C3N4 with remarkably enhanced photocatalytic activity were obtained.

Hybrid HMX multi-level assembled under the constraint of 2D materials with efficiently reduced sensitivity and optimized thermal stability

The interfacial interaction between HMX molecules and coating materials is the key to the safety performance of explosives and has received extensive attention. However, screening suitable coating agents to enhance the interfacial effect to obtain high-energy and low-sensitivity explosives has long been a major challenge. In this work, HMX-PEI/rGO/g-C3N4 (HPrGC) composites were innovatively prepared by a multi-level coating strategy of two-dimensional graphite rGO and g-C3N4. The g-C3N4 used for desensitization has a rich π-conjugated system and shows outstanding ability in reducing friction sensitivity. The hierarchical structure of HPrGC formed by electrostatic self-assembly and π-π stacking can effectively dissipate energy accumulation under heat and mechanical stimulation through structural evolution, thus exhibiting a prominent synergistic desensitization effect on HMX. The results show that rGO/g-C3N4 coating has no effect on the crystal structure and chemical structure of HMX. More importantly, the perfect combination of g-C3N4 and rGO endows HPrGC with enhanced thermal stability and ideal mechanical sensitivity (IS: 21 J, FS: 216 N). Obviously, the new fabrication of HPrGC enriches the variety of desensitizer materials and helps to deepen the understanding of the interaction between explosives and coatings.

Preparation of carbon/Fe-doped g-C3N4 and study on its photocatalytic hydrogen production performance

With the large consumption of non-renewable energy, energy shortage has become a major challenge to human society. Among many new energy production technologies, photocatalytic hydrogen production from water can be realized by using abundant solar energy as the driving force, and the conditions of hydrogen production are mild, green and pollution-free, it is considered one of the effective technologies to solve the current energy shortage crisis. The core of photocatalytic hydrogen production is photocatalyst, therefore, the study of efficient, stable and cheap photocatalysts has become a hot spot. Two-dimensional layered g-C3N4 has become an important photocatalytic material in recent years because of its suitable band gap, its response in the visible light band and its chemical and thermal stability. Due to the high rate of photogenerated electron-hole recombination and the slow rate of photoreaction of g-C3N4, the addition of [Fe2(HMOPIP)6]·8H2O·10OH to regulate g-C3N4 forming carbon/Fe-doped g-C3N4, it can reduces the recombination efficiency of photogenerated electron-hole and improves photocatalytic activity. Through hydrogen production experiment, we can see that, compared with g-C3N4, the carbon/Fe-doped g-C3N4 has better electron-hole separation ability and photocatalytic hydrogen production performance, with the hydrogen production rate of the carbon/Fe-doped g-C3N4 being approximately 5.92-fold higher than g-C3N4.

Flexible Triboelectric Nanogenerators based on Hydrogel/g-C3N4 Composites for Biomechanical Energy Harvesting and Self-Powered Sensing.

Flexible and stretchable triboelectric nanogenerators (TENGs) have been rapidly advanced owing to the demand for portable and wearable electronic devices that can work under universal or motional circumstances. While versatile materials can be applied in a TENG as dielectric materials, flexible and cost-effective electrodes are crucially important for the output performance of TENGs. Herein, we developed a poly(vinyl alcohol) (PVA) hydrogel TENG doped with a novel two-dimensional material, graphitic carbon nitride (g-C3N4), which could act as both a cost-effective flexible electrode and a positive dielectric for TENG with different morphologies. The measured peak-to-peak open-circuit voltage of the TENG reached 80 V at a dopant concentration of 2.7 wt % in single-electrode mode, which is far higher than that of the pristine PVA hydrogel TENG. As a demonstration of the application, the g-C3N4/PVA hydrogel TENG can be adopted as electronic skin to monitor the movement of the human body. Low-frequency mechanical energy-harvesting devices in different morphologies including discoid flake shape, tube shape, and spiral shape in the single-electrode mode or contact-separation mode have been designed, fabricated, and evaluated. All of these merits of the proposed hydrogel TENG after doping two-dimensional (2D) material g-C3N4 have demonstrated their promising potential for versatile applications in biomechanical energy harvesting and self-powered sensing.

Au/Ti3C2/g-C3N4 Ternary Composites Boost H2 Evolution Efficiently with Remarkable Long-Term Stability by Synergistic Strategies.

The use of novel two-dimensional MXene materials and conventional g-C3N4 photocatalysts to fabricate the composites for hydrogen evolution reaction (HER) has attracted much attention, for which there is plenty of room for the enhancement of hydrogen evolution rates particularly under visible light and photostability. Herein, g-C3N4 was modified by copolymerization of malonamide and melamine and used to fabricate the ternary composites of Au particles and Ti3C2 MXene, and based on the synergistic effect, the composites enhanced the hydrogen evolution rates by 2.1, 99.8, and ∞ times compared with the unmodified g-C3N4 under UV, simulated sunlight, and visible light illumination, respectively. Moreover, the composite exhibited a sustained hydrogen evolution capacity in the cycle test for up to 120 h. Theoretical calculations and experimental results indicated that the hot electrons of Au are injected into the modified g-C3N4 and transferred to Ti3C2 simultaneously along with the photogenerated electrons of the modified g-C3N4 and then further transferred to Au, forming a photogenerated electron transfer channel of Au and modified g-C3N4 → Ti3C2 → Au within the composite. Ti3C2 acts as a bridge for fast separation of photogenerated electrons and holes on Au and modified g-C3N4, playing a key role in the enhanced photocatalytic performance. In addition, the visible light absorption ability of Au also positively contributed to the enhancement of visible light photocatalytic performance by providing hot electrons. Therefore, the selection of suitable cocatalysts for the design of composites is a crucial research direction to improve the photocatalytic performance and photostability of photocatalysts.

Gas-phase self-assembly: Converting 2D graphitic carbon nitride into 1D nanotubes for improved photocatalytic tetracycline degradation

Achieving precise control and optimization of structure and composition is paramount for advancing photocatalyst performance. In this study, we successfully synthesized nitrogen-defect and boron-doped one-dimensional g-C3N4 nanotubes (BCNNT) with a tube diameter of approximately 100 nm using a one-step gas-phase self-assembly strategy. Intriguingly, the introduction of boric acid induced a transformation from a two-dimensional g-C3N4 structure to a one-dimensional tubular form. The physicochemical properties and photocatalytic performance of BCNNT were found to be influenced by the quantity of boric acid employed. The as-synthesized BCNNT exhibited notable advantages, including enhanced visible light absorption, a 0.1 eV reduction in the band gap, 5.1 times increase in photocurrent density, effective suppression of electron-hole recombination, and significant improvement in mass transfer compared to pure g-C3N4. Consequently, the first-order kinetic constant of BCNNT increased by 73.7 %, resulting in nearly 80 % degradation of tetracycline (TC) within half an hour. The boron doping played a crucial role in reducing the surface energy required for nanotube formation during synthesis, a key factor in their structural development. Both density functional theory (DFT) calculations and experimental studies confirmed that the Lewis acid site B enhanced tetracycline adsorption, while nitrogen-deficient sites suppressed electron-hole recombination, thus accelerating photocatalytic degradation rate. This research provides a novel perspective on fabricating tubular g-C3N4 structures and compositions, offering insights for improving the kinetics of photocatalytic reactions.

Spontaneous adsorption effect of graphitic carbon nitride nanosheets to improve sintering behavior of yttria-stabilized zirconia microbeads

Yttria-stabilized zirconia (YSZ) is a ceramic material in which the zirconium dioxide structure is stabilized at room temperature by adding yttrium oxide. However, the YSZ formed by the thick film process on a pre-sintered dense substrate suffers from sintering problems such as different sintering shrinkage rates due to phase transitions and thermal conductivity. This in turn can lead to de-bonding, cracking, delamination, and abnormal growth. We prepared a spherical YSZ green body of approximately 38 μm diameter formed by an organic binder based on a sintered YSZ seed with 15 to 20 μm diameter. In addition, the application of two-dimensional g-C3N4 nanosheets that can be adsorbed on the surface and pores of the green body before the sintering process was evaluated. The YSZ green body with adsorbed surface-modified g-C3N4 nanosheets could be synthesized by stable spontaneous adsorption due to zeta-potential attraction onto the surface of zirconia particles in an aqueous solution. Consequentially, the formation of large grains due to abnormal grain growth was reduced as g-C3N4 was adsorbed. The spontaneous adsorption of nanosheets controls the surface diffusion mechanism by sequentially lowering the energy from a high surface energy in the initial stage of sintering. Uniform grain growth thus can be induced according to the activation energy level of the controlled surface diffusion.

Nanopore rigidity as an atomic descriptor of ion-transfer kinetics in sieving membranes: Insights from two-dimensional g-C3N4

Kinetics of ions play a crucial role in the performance of materials for a wide range of applications, including solid electrolytes, fuel cells, and sieving membranes. However, establishing a quantitative correlation between microscopic characteristics of a material and kinetics of conducting species inside remains a major challenge. Combining first-principles and metadynamics methods, we investigate sieving behavior of two-dimensional graphitic carbon nitride (g-C3N4) for various species (H+, Na+, K+, and Cl−). We reveal that mechanism of proton conduction changes with a pore size of carbon-nitrogen ring in g-C3N4: varying from a pure H+ transportation when crossing narrow pores into a dual pathways (via both H+ and hydronium ions H3O+) when transmitting across wide pores. We introduce a novel local descriptor, nanopore rigidity (C), to quantify the rigidity of a material and relate the dynamics of sieving species to mechanics of the pore. The kinetic barrier of an arbitrary intercalating ion (ΔGion) can then be obtained via ΔGion=Cδρ2+B with B being a residual barrier of the pore and δρ being the local strain of the pore induced by the conducting ion. The descriptor as a microscopic metric can be extended to other porous materials, allowing a screening for electrochemical energy transition materials.

B, P, and S heteroatom doped, bio- and hemo-compatible 2D graphitic-carbon nitride (g-C3N4) with antioxidant, light-induced antibacterial, and bioimaging endeavors

The synthesis of two-dimensional (2D) graphitic g-C3N4 and heteroatom-doped graphitic H@g-C3N4 (H: B, P, or S) particles were successfully done using melamine as source compounds and boric acid, phosphorous red, and sulfur as doping agents. The band gap values of 2D g-C3N4, B50@g-C3N4, P50@g-C3N4, and S50@g-C3N4 structures were determined as 2.90, 3.03, 2.89, and 2.93 eV, respectively. The fluorescent emission wavelengths of 2D g-C3N4, B50@g-C3N4, P50@g-C3N4, and S50@g-C3N4 structures were observed at 442, 430, 441, and 442 nm, respectively upon excitation at λ Ex = 325 nm. There is also one additional new emission wavelength was found at 345 nm for B50@g-C3N4 structure. The blood compatibility test results of g-C3N4, B50@g-C3N4, P50@g-C3N4, and S50@g-C3N4 structures revealed that all materials are blood compatible with <2% hemolysis and >90% blood clotting indices at 100 μg ml−1 concentration. The cell toxicity of the prepared 2D graphitic structures were also tested on L929 fibroblast cells, and even the heteroatom doped has g-C3N4 structures induce no cytotoxicity was observed with >91% cell viability even at 250 μg ml−1 particle concentration with the exception of P50@g-C3N4 which as >75 viability. Moreover, for 2D g-C3N4, B50@g-C3N4, and S50@g-C3N4 constructs, even at 500 μg ml−1 concentration, >90% cell viabilities was monitored. As a diagnostic material, B50@g-C3N4 was found to have significantly high penetration and distribution abilities into L929 fibroblast cells granting a great potential in fluorescence imaging and bioimaging applications. Furthermore, the elemental doping with B, P, and S of g-C3N4 were found to significantly increase the photodynamic antibacterial activity e.g. more than half of bacterial elimination by heteroatom-doped forms of g-C3N4 under UVA treatment was achieved.

Visible light-induced catalytic performance of composite photocatalyst synthesized with nanomaterials WO3 and two-dimensional ultrathin g-C3N4.

To improve the visible light-induced catalytic activities of Ultrathin g-C3N4 (UCN), a promising photocatalyst WO3/UCN (WU) was synthesized. Its visible light-driven photocatalysis performance was controllable by adjusting the theoretical mass ratio of WO3/UCN. We have calibrated the optimal preparation conditions to be: WO3/UCN ratio as 1:1, the stirring time of the UCN and sodium tungstate mixture as 9 h and the volume of concentrated hydrochloric acid as 6 mL which was poured into the mixture solution with an extra stirring time of 1.5 h. The optimal photocatalyst WUopt had porous and wrinkled configurations. Its light absorption edge was 524 nm while that of UCN was 465 nm. The band gap of WUopt was 2.13 eV, 0.3 eV less than that of UCN. Therefore, the recombination rate of photo-generated electron-hole pairs of WUopt reduced significantly. The removal rate of WUopt on RhB was 97.3%. By contrast, the removal rate of UCN was much lower (53.4%). WUopt retained a high RhB removal rate, it was 5.5% lower than the initial one after being reused for five cycles. The photodegradation mechanism was facilitated through the strong oxidation behaviors from the active free radicals ·O2-, ·OH and h+ generated by WUopt under the visible light irradiation.

Defects-enriched two-dimensional ultrathin g-C3N4/In2O3 nanoparticles for effective NO2 detection at room temperature

Rational integration of ultrathin two-dimensional(2D) graphitic carbon nitride(g-C3N4) nanosheets and indium oxide(In2O3) nanoparticles was implemented by hydrothermal and calcination. The optimized composites demonstrated an outstanding NO2 response of 1470 (5 ppm) and short response/recovery time (67/46 s). Moreover, the prepared composites displayed excellent reproducibility, low detection limit (18 ppb), and satisfactory selectivity to NO2 at room temperature (RT). The gas sensing mechanism was also proposed and verified by the density functional theory calculation. The outstanding gas sensing properties might be due to the combination of heterojunction, enhanced specific surface, and enriched defects. This study gives a reference for designing sensing materials by forming heterojunctions between metal oxides and g-C3N4 for superior gas sensitivity and exploring the manufacture of advanced gas sensors.