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In this work, bare and O‐doped g‐C3N4 nanosheets were synthesized. The results show that the structure of bare and O‐doped g‐C3N4 (OCN) nanosheets are layered and the absorption of visible light increases after O‐doping. Density function theory calculations demonstrate that the oxygen atom is replaced at the edge site of g‐C3N4. The reaction pathway of CO2 reduction to fuel/chemicals on the OCN surface is as follows: CO2→ HCOO→ HCOOH→ HCO + H2O→ H2CO→ H2COH→ H3COH→ CH3 + H2O→ CH4. The main product on the OCN and CN surfaces are methane and methanol, respectively. The Gibbs activation energy of CH3OH formation on the CN and OCN surfaces are 1.72 and 0.14 eV, respectively. The rate‐determining step on the OCN surface is HCOOH→ HCO + H2O, whereas on the CN surface is CH3OH formation from the H3CO intermediate. Therefore, the Gibbs activation energy on the O‐doped g‐C3N4 decreases for the methanol production in comparison with the bare g‐C3N4. In general, the O‐doping of g‐C3N4 improves the photocatalytic activity through the decrement in the band gap and enhances the reaction rate of CO2 conversion to fuels/chemicals. [ABSTRACT FROM AUTHOR]

In this work, bare and O‐doped g‐C3N4 nanosheets were synthesized. The results show that the structure of bare and O‐doped g‐C3N4 (OCN) nanosheets are layered and the absorption of visible light increases after O‐doping. Density function theory calculations demonstrate that the oxygen atom is replaced at the edge site of g‐C3N4. The reaction pathway of CO2 reduction to fuel/chemicals on the OCN surface is as follows: CO2→ HCOO→ HCOOH→ HCO + H2O→ H2CO→ H2COH→ H3COH→ CH3 + H2O→ CH4. The main product on the OCN and CN surfaces are methane and methanol, respectively. The Gibbs activation energy of CH3OH formation on the CN and OCN surfaces are 1.72 and 0.14 eV, respectively. The rate‐determining step on the OCN surface is HCOOH→ HCO + H2O, whereas on the CN surface is CH3OH formation from the H3CO intermediate. Therefore, the Gibbs activation energy on the O‐doped g‐C3N4 decreases for the methanol production in comparison with the bare g‐C3N4. In general, the O‐doping of g‐C3N4 improves the photocatalytic activity through the decrement in the band gap and enhances the reaction rate of CO2 conversion to fuels/chemicals. [ABSTRACT FROM AUTHOR]

In this study, graphene quantum dots (GQDs) have been incorporated into the g-C3N4/ZIF-67 heterojunction system as a photosensitizer to enhance photocatalytic conversion of CO2-to-CO. The GQDs are deposited onto the surface of g-C3N4/ZIF-67 using a simple water bath procedure. As expected, GQDs/g-C3N4/ZIF-67 presents outstanding performance in CO2 photoreduction. Among the GQDs/g-C3N4/ZIF-67 ternary photocatalysts, 7 GQDs-CN/ZIF-67 exhibits the best photocatalytic CO2 reduction ability with a CO yield of 51.71 μmol g−1, which is 5.05 and 1.87 times more than pristine g-C3N4 (10.24 μmol g−1) and g-C3N4/ZIF-67 (27.65 μmol g−1), respectively. This result shows that upon combination of GQDs with ZIF-67/g-C3N4, GQDs can be used as photosensitizers to improve the optical absorption capacity of the photocatalyst. Furthermore, GQDs serve as electron channels, facilitating the transport of photo-induced electrons from ZIF-67 to g-C3N4, which promotes photogenerated carrier separation efficiency. This study innovatively adds GQDs to the heterojunction and applies the prepared ternary composite to the CO2 photoreduction, which inspires a novel direction for the design of non-noble metal photocatalysts. [ABSTRACT FROM AUTHOR]

Heterogeneous photocatalysis is a promising technology for the degradation of environmental pollutants. In this work, g-C3N4 nanosheets were employed as a visible light photocatalyst to investigate the stability, kinetics and to understand the impact of humidity on the photocatalytic oxidation of nitric oxide (NO). Graphitic carbon nitride (g-C3N4) with unique physicochemical properties proves to be a promising photocatalytic material. Visible light active g-C3N4 nanosheets were successfully synthesized by thermal polycondensation of melamine followed by thermal exfoliation. Compared with the bulk carbon nitride, g-C3N4 nanosheets show significant NO removal efficiency (68%), followed by excellent stability after 5 cycles of photocatalytic oxidation under visible LED light illumination. Furthermore, photocatalytic oxidation of NO at various humidity levels revealed the significant role of humidity in photocatalytic NO removal. Finally, the initial uptake coefficients γ0,geo, and γ0,BET of NO on g-C3N4 nanosheets were determined to be 1.0 × 10− 5 and 1.58 × 10− 9, respectively, and were found to decrease with increasing humidity. It appears that the photocatalytic removal of NO happens primarily on the surface of the g-C3N4 nanosheet. Synopsis: The paper provides descriptive information on the visible light photocatalytic degradation of the priority pollutant NOx using g-C3N4-nanosheets supporting human health and environment policies. Highlights: NOx degradation efficiency was increased from 19.0% over bulk g-C3N4 to 68.0% over g-C3N4 nanosheets. High stability and repeatability after 5 cycles of photocatalytic oxidation were attained. Superior stability of g-C3N4 nanosheets after one year. The initial uptake coefficients γ0,geo and γ0,BET of NO on g-C3N4 nanosheets were determined at dry and several humidity levels. Effect of humidity on NO removal and initial uptake coefficients. [ABSTRACT FROM AUTHOR]

In this study, a Ti3C2 MXene@g-C3N4 composite powder (TM-CN) was prepared by the ultrasonic self-assembly method and then loaded onto a carbon nanofiber membrane by the self-assembly properties of MXene for the treatment of organic pollutants in wastewater. The characterization of the TM-CN and the C-TM-CN was conducted via X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and Fourier transform infrared spectrometer (FTIR) to ascertain the successful modification. The organic dye degradation experiments demonstrated that introducing an appropriate amount of Ti3C2 MXene resulted in the complete degradation of RhB within 60 min, three times the photocatalytic efficiency of a pure g-C3N4. The C-TM-CN exhibited the stable and outstanding photocatalytic degradation of the RhB solution over a wide range of pH values, indicating the characteristics of the photodegradation of organic pollutants in a wide range of aqueous environments. Furthermore, the results of the cyclic degradation experiments demonstrated that the C-TM-CN composite film maintained a degradation efficiency of over 85% after five cycles, thereby confirming a notable improvement in its cyclic stability. Consequently, the C-TM-CN composite film exhibits excellent photocatalytic performance and is readily recyclable, making it an auspicious eco-friendly material in water environment remediation. [ABSTRACT FROM AUTHOR]

[Display omitted] The extensive examination of hexagonal molybdenum carbide (β-Mo 2 C) as a non-noble cocatalyst in the realm of photocatalytic H 2 evolution is predominantly motivated by its exceptional capacity to adsorb H+ ions akin to Pt and its advantageous conductivity characteristics. However, the H 2 evolution rate of photocatalysts modified with β-Mo 2 C is limited as a result of their comparatively low ability to release H through desorption. Therefore, a facile method was employed to synthesize carbon intercalated dual phase molybdenum carbide (MC@C) quantum dots (ca. 3.13 nm) containing both α-MoC and β-Mo 2 C decorated on g-C 3 N 4 (gCN). The synthesis process involved a simple and efficient combination of sonication-assisted self-assembly and calcination techniques. 3-MC@C/gCN exhibited the highest efficiency in generating H 2 , with a rate of 4078 µmol g−1h−1 under 4 h simulated sunlight irradiation, which is 13 times higher than pristine gCN. Furthermore, from the cycle test, 3-MC@C/gCN showcased exceptional photochemical stability of 65 h, as it maintained a H 2 evolution rate of 40 mmol g−1h−1. The heightened level of activity observed in the 3-MC@C/gCN system can be ascribed to the synergistic effects of MoC-Mo 2 C that arise due to the existence of a carbon layer. The presence of a carbon layer enhanced the transmission of photoinduced electrons, while the MoC-Mo 2 C@C composite served as active sites, thereby facilitating the H 2 production reaction of gCN. The present study introduces a potentially paradigm-shifting concept pertaining to the exploration of novel Mo-based cocatalysts with the aim of augmenting the efficacy of photocatalytic H 2 production. [ABSTRACT FROM AUTHOR]

[Display omitted] Single-atom photocatalysts can modulate the utilization of photons and facilitate the migration of photogenerated carriers. However, the preparation of single-atom uniformly doped photocatalysts is still a challenging topic. Herein, we propose the preparation of Ni single-atom doped g-C 3 N 4 photocatalysts by metal vapor exfoliation. The Ni vapor produced by calcining nickel foam at high temperature accumulates in between g-C 3 N 4 layers and poses a certain vapor pressure to destroy the interlayer van der Waals forces of g-C 3 N 4. Individual metal atoms are doped into the structure while exfoliating g-C 3 N 4 into nanosheets by metal vapor. Upon optimization of Ni content, the Ni single atom doped g-C 3 N 4 nanosheets with 2.81 wt% Ni exhibits the highest CO 2 reduction performance in the absence of sacrificial agents. The generation rates of CO and CH 4 are 19.85 and 1.73 μmol g−1h−1, respectively. The improved photocatalytic performance is attributed to the anchoring Ni of single atoms on g-C 3 N 4 nanosheets, which increases both carrier separation efficiency and reaction sites. This work provides insight into the design of photocatalysts with highly dispersed single-atom. [ABSTRACT FROM AUTHOR]

In the present work, the surface of glassy carbon electrode (GCE) was modified with graphitic carbon nitride (g-C3N4) prepared from the freeze-dried dicyandiamide. The physiochemical properties and electrocatalytic ability of the g-C3N4 nanosheets have been well investigated. Differential pulse voltammetry (DPV) method was employed to determine bisphenol A (BPA) using the modified GCE. To obtain the conditions for maximum DPV response, the effects of experimental parameters, such as the solution pH and nano-sized modifier concentration, were investigated and optimized. The proposed BPA sensing assay indicated a linear range of 0.01 to 75.0 µM under optimal conditions, with a detection limit of 9.0 nM. The anti-interference investigations revealed that the presence of various organic and inorganic species did not hinder the accurate measuring of BPA. In addition, the presented modified electrode exhibited satisfactory results in terms of stability and reproducibility. The obtained results also confirm the efficacy of the g-C3N4 nanocatalyst for determination of BPA in different real samples (drinking water, milk and orange juice) with satisfactory recovery values (95.6–104.0%). The suggested assay provides a powerful sensing platform for the fast and sensitive analysis of BPA in food samples. [ABSTRACT FROM AUTHOR]

Positive phototropism enables plants to take advantage of sunlight more efficiently. However, positive phototropism of plant‐like photocatalyst has not been reported yet, which cause people's limited understanding on it. Therefore, developing new photocatalysts that can move toward the light source and thus speed up the photocatalytic process, is a great challenge. Herein, a biologically active photocatalyst (graphitic carbon nitride combined with algae microorganisms, g‐C3N4/alga) is reported first that can behave like green plants and move toward light source, leading to a great enhancement in photocatalysis. The photocatalytic degradation efficiency of the phototactic g‐C3N4/alga is improved up to 570% than that of pure g‐C3N4. The phototactic g‐C3N4/alga photocatalyst can effectively utilize the synergy of phototaxis of microalgae and photocatalytic activity of g‐C3N4 to promote the pollutant decomposition using sunlight. Imparting photocatalyst with positive phototropism will open a new door in photocatalysis field for clean energy production, pollutant treatment, and biomass conversion. [ABSTRACT FROM AUTHOR]

Herein, novel surface structure LaFeO3/nitrogen-deficient g-C3N4 nanocomposites (LaFeO3/g-C3N4-H) have been successfully synthesized by a two-step process. First, nitrogen-deficient graphitic carbon nitride (g-C3N4-H) was produced by thermally condensing melamine that had been treated with acetic acid as a precursor. After that, LaFeO3 was incorporated into the g-C3N4-H nanosheets. The as-prepared nanostructured materials were characterized by XRD, FT-IR, N2 adsorption–desorption experiments, FESEM, and TEM, demonstrating the formation of interfacial interaction and heterogeneous structure in LaFeO3/g-C3N4-H nanocomposites. Additionally, UV–vis diffuse reflectance spectra (DRS) and photoluminescence spectra (PL) have been used to assess the optical properties of the nanohybrids. The results show that the LaFeO3/g-C3N4-H nanocomposite was successfully produced with a reliable interfacial interface, and produced a good heterojunction relationship between g-C3N4-H and LaFeO3 which may significantly boost the photocatalytic activity as compared to prinstine g-C3N4 and LaFeO3. Phenol degradation under visible light irradiation was used to test the photocatalytic activity of LaFeO3/g-C3N4-H, and the results showed that 10%-LaFeO3/g-C3N4-H had significant photocatalytic activity and remarkable adsorption efficiency, with an overall removal rate of phenol up to 88% after 180 min of visible light irradiation. This study may present a novel method for developing highly efficient artificial photocatalytic systems. [ABSTRACT FROM AUTHOR]

In this study, nitrogen-doped carbon dots (NCDs) modified ultrathin carbon nitride (g-C 3 N 4) nanosheets were synthesized by a simple secondary calcination method, which realizes efficient photocatalytic hydrogen production. The secondary calcination process can not only thermally exfoliate g-C 3 N 4 into ultrathin nanosheets, but also uniformly anchor NCDs (∼3 nm) on the surface of g-C 3 N 4. The photocatalytic results manifested that a very small amount of NCDs (0.5 wt%) loading on g-C 3 N 4 could achieve a high photocatalytic hydrogen production rate (5.21 mmol g−1 h−1). The reasons for the enhanced photocatalytic activity were analyzed. The ultrathin g-C 3 N 4 nanosheets facilitated the migration of photogenerated carriers. Moreover, NCDs/g-C 3 N 4 exhibited enhanced visible light absorption owing to the up-conversion fluorescence effect of NCDs and the narrow band gap caused by the decoration of NCDs. Furthermore, NCDs as electron acceptors can promote carrier separation. This combination strategy provides a basis for the synthesis of inexpensive, metal-free, and efficient carbon-based photocatalysts. Nitrogen-doped carbon dots (NCDs) modified ultrathin carbon nitride (g-C 3 N 4) nanosheets were synthesized. The enhanced photocatalytic mechanism of NCDs/g-C 3 N 4 composites was analyzed. [Display omitted] • NCDs/g-C 3 N 4 nanosheets were synthesized by a simple secondary calcination method. • The ultrathin g-C 3 N 4 nanosheets (∼8 nm) facilitated the migration of carriers. • The modification of NCDs promotes light absorption and carrier separation abilities. • The H 2 production rate of g-C 3 N 4 loaded with 0.5 wt% NCDs reached 5.21 mmol g−1 h−1. [ABSTRACT FROM AUTHOR]

Membranes combined with nanoparticles are an excellent combination capable of successfully removing various contaminants, such as dyes from wastewater while using very little energy and decreasing pollution. The present study reports an efficient approach for Remazol Black 5 (RB5) dye removal using composite graphitic carbon nitride nanosheets (g‐C3N4), polysulfone (PSF), and polyvinylidene fluoride (PVDF) membranes. The membranes were prepared using the phase inversion method, with varying quantities of g‐C3N4 nanosheets ranging from 0.1%, 0.2% to 0.3%. The prepared g‐C3N4 nanosheets were characterized by FTIR, SEM analyses, and zeta potential measurements. FTIR and SEM studies, contact angle, water permeability, COD, and dye rejection measurements were used to characterize the g‐C3N4 nanosheets embedded in PSF and PVDF membranes. After the addition of 0.3 wt% g‐C3N4, the water flux of the 0.3 wt% g‐C3N4 embedded PSF membrane was the highest, whereas the water flux of the 0.3 wt% g‐C3N4 embedded PVDF membrane was the lowest. The ultrafiltration (UF) membrane's performance with g‐C3N4 embedded showed an RB5 rejection rate of more than 80% and a COD removal efficiency of more than 45%. The results of the experimental filtration showed that RB5 rejection reached maximum values of 91.3% for 0.1 wt% g‐C3N4/PSF, and 85.6% for 0.3 wt% g‐C3N4/PVDF. [ABSTRACT FROM AUTHOR]

The rational design and development of highly-active photocatalytic materials for the degradation of dangerous chemical compounds, such as parabens, is one of the main research pillars in the field of photocatalysis. Graphitic carbon nitride (g-C3N4) is a 2D non-metal material and is considered one of the most promising photocatalysts, because of its peculiar physicochemical properties. In this work, porous g-C3N4 nanosheets (CNNs) were successfully prepared via thermal exfoliation of bulk g-C3N4 (CNB). A thorough physicochemical characterization analysis before and after the exfoliation process was performed, revealing the improved textural characteristics (surface area of 212 m2/g), chemical stability, and optical properties (wide band gap of 2.91 eV) of CNNs compared to the CNB. Then, both CNB and CNNs were comparatively assessed as photocatalysts for the degradation of methyl-, ethyl- and propylparaben (MP, EP, and PP), as well as of their mixture. CNNs with high surface area display superior photocatalytic performance under solar irradiation, offering > 95% degradation efficiency to all parabens, in contrast to the much inferior performance of CNB (< 30%). Several experimental parameters, involving catalyst concentration, initial concentration of parabens, and irradiation type were thoroughly investigated for the degradation of MP over CNNs. Moreover, various scavengers were employed to discriminate the role of different reactive species, revealing that superoxide anion radicals (·O2–) play a pivotal role in the degradation process, in contrast to hydroxyl radicals (·OH). The present results pave the way towards the facile synthesis of high surface area CNNs with improved textural and electronic characteristics, which can be applied in various environmental applications. [ABSTRACT FROM AUTHOR]

Developing polymer self‐lubricating composites is of great significance for reducing mechanical friction and wear. In this study, a hybrid of graphitic carbon nitride (g‐C3N4) nanosheets anchored carbon fiber (CF) was constructed through one‐step calcination method to enhance the tribological performance of polyimide (PI). The presence of g‐C3N4 improved the interfacial interaction of CF/PI composite by endowing CF surface with active sites and rough microstructure. Tribological test results demonstrated that CF/g‐C3N4/PI composite had outstanding antifriction and wear resistance, with friction coefficient and wear rate of 0.209 and 2.23 × 10−7 mm3/Nm, which were reduced by 21% and 73.52% compared to pure PI, respectively. This was mainly attributed to the enhanced interfacial interaction, which was conducive to the stress transferring from PI to CF/g‐C3N4 in sliding process. At the same time, the g‐C3N4 nanosheets could give the composite excellent self‐lubrication property by promoting the formation of transfer film. More importantly, the as‐proposed CF/g‐C3N4/PI composite still maintained good self‐lubricating performance in different sliding environment, with a friction coefficient of 0.132 in water environment and 0.049 in oil environment, suggesting it had a broad prospect in polymer self‐lubricating composite. In addition, the corresponding mechanism was discussed based on the analysis of worn surface of the composite and counterpart. [ABSTRACT FROM AUTHOR]

In this study, graphene quantum dots (GQDs) have been incorporated into the g-C3N4/ZIF-67 heterojunction system as a photosensitizer to enhance photocatalytic conversion of CO2-to-CO. The GQDs are deposited onto the surface of g-C3N4/ZIF-67 using a simple water bath procedure. As expected, GQDs/g-C3N4/ZIF-67 presents outstanding performance in CO2 photoreduction. Among the GQDs/g-C3N4/ZIF-67 ternary photocatalysts, 7 GQDs-CN/ZIF-67 exhibits the best photocatalytic CO2 reduction ability with a CO yield of 51.71 μmol g−1, which is 5.05 and 1.87 times more than pristine g-C3N4 (10.24 μmol g−1) and g-C3N4/ZIF-67 (27.65 μmol g−1), respectively. This result shows that upon combination of GQDs with ZIF-67/g-C3N4, GQDs can be used as photosensitizers to improve the optical absorption capacity of the photocatalyst. Furthermore, GQDs serve as electron channels, facilitating the transport of photo-induced electrons from ZIF-67 to g-C3N4, which promotes photogenerated carrier separation efficiency. This study innovatively adds GQDs to the heterojunction and applies the prepared ternary composite to the CO2 photoreduction, which inspires a novel direction for the design of non-noble metal photocatalysts.

In this study, a Ti3C2 MXene@g-C3N4 composite powder (TM-CN) was prepared by the ultrasonic self-assembly method and then loaded onto a carbon nanofiber membrane by the self-assembly properties of MXene for the treatment of organic pollutants in wastewater. The characterization of the TM-CN and the C-TM-CN was conducted via X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and Fourier transform infrared spectrometer (FTIR) to ascertain the successful modification. The organic dye degradation experiments demonstrated that introducing an appropriate amount of Ti3C2 MXene resulted in the complete degradation of RhB within 60 min, three times the photocatalytic efficiency of a pure g-C3N4. The C-TM-CN exhibited the stable and outstanding photocatalytic degradation of the RhB solution over a wide range of pH values, indicating the characteristics of the photodegradation of organic pollutants in a wide range of aqueous environments. Furthermore, the results of the cyclic degradation experiments demonstrated that the C-TM-CN composite film maintained a degradation efficiency of over 85% after five cycles, thereby confirming a notable improvement in its cyclic stability. Consequently, the C-TM-CN composite film exhibits excellent photocatalytic performance and is readily recyclable, making it an auspicious eco-friendly material in water environment remediation.

Graphitic carbon nitride (g-C3N4) has attracted extensive research interest in pollutants remediation. However, the photocatalytic activity of g-C3N4 was significantly limited by its small specific surface area. In this work, a green, high-energy ball milling method was used to fabricate g-C3N4 nanosheets. The structure, morphology, and optical properties of the prepared g-C3N4 nanosheets were characterized. The effect of ball milling parameters on the photocatalytic performance evaluated by Rhodamine B (RhB) and tetracycline (TC) was investigated systemically. Among the tested samples, the g-C3N4 sample milled with a 4 mL isopropanol solution at a rotation speed of 420 rpm, ball-to-powder weight ratio of 10:1, and milling time of 24 h exhibited the highest RhB degradation efficiency of 91.4% and TC degradation efficiency of 70.2%. The enhanced photocatalytic activity after ball milling was ascribed to the increase in specific surface area and efficient separation of electron–hole pairs. The trapping experiment indicated that holes and superoxide radicals were the main active species in the degradation reaction. Moreover, the photocatalytic degradation mechanism of organic pollutants on g-C3N4 nanosheets was also discussed in detail.

[Display omitted] • Multifunctional Mn/P-g-C 3 N 4 with enhanced magnetism and catalytic efficiency is prepared. • Mn/P-g-C 3 N 4 shows a magnetic moment and Curie temperature of 4.51 μ B and ∼ 800 K, respectively. • Mn/P-g-C 3 N 4 also displays outstanding catalytic performance in terms of low charge recombination rate, high specific surface area, and catalytic stability. • The coexistence of magnetic and semiconducting behavior at room temperature makes Mn/P-g-C 3 N 4 ideal for spintronics devices and as a photocatalyst. Manganese and phosphorus co-doped, graphitic carbon nitride (g-C 3 N 4) nanosheet (Mn/P-g-C 3 N 4) is prepared by facile and green calcination process of melamine (C 3 H 6 N 6), manganese chloride tetrahydrate (MnCl 2 ·4H 2 O), and ammonium dihydrogen phosphate ((NH 4)H 2 PO 4). The Mn/P co-doping significantly enhances magnetic values compared to pristine-g-C 3 N 4 , phosphorus-doped g-C 3 N 4 (P-g-C 3 N 4), and manganese-doped g-C 3 N 4 (Mn-g-C 3 N 4). We find that Mn/P-g-C 3 N 4 is a half-metallic ferromagnetic material having a magnetic moment and Curie temperature of 4.51 μ B and ∼ 800 K, respectively. The ultraviolet–visible (UV–vis) absorption spectrum of Mn/P-g-C 3 N 4 reveals superior absorption in broader wavelength compared to pristine-g-C 3 N 4 , P-g-C 3 N 4 , and Mn-g-C 3 N 4. The methyl orange degradation efficiency of Mn/P-g-C 3 N 4 photocatalyst is 94 %, which is three times more than that of pristine-g-C 3 N 4 (29 %) and more significant than the P-g-C 3 N 4 (46 %) and Mn-g-C 3 N 4 (58 %). Furthermore, density functional theory (DFT) calculation explains the origin of high magnetic behavior, the boosted photocatalytic efficiency of Mn/P-g-C 3 N 4 , and the essential material properties like structure, bandgap, the density of states (DOS), and atomic level interaction. This work may be helpful for reasonably designing ferromagnetic material for spintronics devices and boosting visible-light (VL) photocatalytic performance for environmental remediation. [ABSTRACT FROM AUTHOR]

Graphitic carbon nitride/Barium hydroxide (g‐C3N4/Ba(OH)2) nanocomposites (NCs) are synthesized using chemical precipitation method. https://serc.carleton.edu/research%5feducation/geochemsheets/techniques/SEM.html images revealed nanoneedle‐like formation of Ba(OH)2 in addition to g‐C3N4 nanosheets. MTT assay confirmed that g‐C3N4/Ba(OH)2 NC exhibited more anticancer activity against MCF‐7 breast cancer cell line, compared to pristine Ba(OH)2 NPs. The % cytotoxicity of Ba(OH)2 NPs, g‐C3N4 (5 mg/mL) @ Ba(OH)2 NCs, g‐C3N4 (10 mg/mL) @ Ba(OH)2 NCs and g‐C3N4 (20 mg/mL) @ Ba(OH)2 NCs against MCF‐7 cell line was found to be 0.79 %, 22.77 %, 6.97 and 9.44 % respectively at the lowest dose of concentration 2 μg mL−1 after 24 h. At 64 μg/mL concentration, the cell viability in pristine Ba(OH)2 NPs and g‐C3N4 (10 mg/mL) @ Ba(OH)2 NCs were found to be 25 % and 6.38 % respectively. The corresponding IC −50 values Ba(OH)2 NPs: 3.71 μg/mL; g‐C3N4 (5 mg/mL) @ Ba(OH)2 NCs: 3.60 μg/mL; g‐C3N4 (10 mg/mL) @ Ba(OH)2 NCs: 3.26 μg/mL; g‐C3N4 (20 mg/mL) @ Ba(OH)2 NCs: 4.04 μg/mL are observed. The mechanism behind the killing of tumor cells by the synthesized nanocomposites is through the generation of reactive oxygen species (ROS). The hydroxyl radicals formation in the solution treated with nanocomposites is confirmed through Terephthalic acid assay. [ABSTRACT FROM AUTHOR]

Abstract Green energy generation is an indispensable task to concurrently resolve fossil fuel depletion and environmental issues to align with the global goals of achieving carbon neutrality. Photocatalysis, a process that transforms solar energy into clean fuels through a photocatalyst, represents a felicitous direction toward sustainability. Eco‐rich metal‐free graphitic carbon nitride (g‐C3N4) is profiled as an attractive photocatalyst due to its fascinating properties, including excellent chemical and thermal stability, moderate band gap, visible light‐active nature, and ease of fabrication. Nonetheless, the shortcomings of g‐C3N4 include fast charge recombination and limited surface‐active sites, which adversely affect photocatalytic reactions. Among the modification strategies, point‐to‐face contact engineering of 2D g‐C3N4 with 0D nanomaterials represents an innovative and promising synergy owing to several intriguing attributes such as the high specific surface area, short effective charge‐transfer pathways, and quantum confinement effects. This review introduces recent advances achieved in experimental and computational studies on the interfacial design of 0D nanostructures on 2D g‐C3N4 in the construction of point‐to‐face heterojunction interfaces. Notably, 0D materials such as metals, metal oxides, metal sulfides, metal selenides, metal phosphides, and nonmetals on g‐C3N4 with different charge‐transfer mechanisms are systematically discussed along with controllable synthesis strategies. The applications of 0D/2D g‐C3N4‐based photocatalysts are focused on solar‐to‐energy conversion via the hydrogen evolution reaction, the CO2 reduction reaction, and the N2 reduction reaction to evaluate the photocatalyst activity and elucidate reaction pathways. Finally, future perspectives for developing high‐efficiency 0D/2D photocatalysts are proposed to explore potential emerging carbon nitride allotropes, large‐scale production, machine learning integration, and multidisciplinary advances for technological breakthroughs.

Photocatalytic hydrogen (H 2) evolution is expected to be a promising approach to generating a clean energy source (H 2) with low carbon emissions, which is vital to solving environmental degradation and energy shortages. The critical challenge to designing highly efficient photocatalysts is the fast recombination of photo-generated carriers; thus, we select Ti 3 C 2 Cl 2 MXene with excellent metal characteristics to serve as a co-catalyst and combine with g-C 3 N 4. The Ti 3 C 2 Cl 2 /g-C 3 N 4 composites exhibit an enhanced photocatalytic hydrogen evolution activity (maximum 155.9 μmol h−1) while they hardly perform photocatalytic activities. The photoluminescence (PL) spectra shows that Ti 3 C 2 Cl 2 MXenes help boost the separation of photo-generated carriers of g-C 3 N 4 and finally strengthen the photocatalytic hydrogen evolution performance. The ultraviolet–visible (UV–vis) spectra illustrate that composites perform a strengthened light absorption, which fits well with the results in the hydrogen evolution experiment. Thus, we fabricated a highly efficient photocatalyst through a safer molten salt approach without hydrofluoric acid (HF). We believe this work will offer a safer approach to manufacturing catalysts decorated with MXenes for highly efficient photocatalytic H 2 evolution. [ABSTRACT FROM AUTHOR]

A photocatalyst of iron–porphyrin tetra-carboxylate (FeTCPP)-sensitized g-C3N4 nanosheet composites (FeTCPP@CNNS) based on g-C3N4 nanosheet (CNNS) and FeTCPP have been fabricated by in situ hydrothermal self-assembly. FeTCPP is uniformly introduced to the surface of CNNS. Only a small amount of FeTCPP is introduced, and the stacked lamellar structure is displayed in the composite. As compared with pure CNNS, the FeTCPP@CNNS composites exhibit significantly improved photocatalytic performance by the photodegradation of p-nitrophenol (4-NP). At the optimum content of FeTCPP to CNNS (3 wt%), the photodegradation activity of the FeTCPP@CNNS photocatalyst can reach 92.4% within 1 h. The degradation rate constant for the 3% FeTCPP@CNNS composite is 0.037 min−1 (4-NP), which is five times that of CNNS (0.0064 min−1). The results of recycling experiments show that 3% FeTCPP@CNNS photocatalyst has excellent photocatalytic stability. A possible photocatalytic reaction mechanism of FeTCPP@CNNS composite for photocatalytic degradation of 4-NP has been proposed. It is shown that superoxide radical anions played the major part in the degradation of 4-NP. The appropriate content of FeTCPP can enhance the charge transfer efficiency. The FeTCPP@CNNS composites can provide more active sites and accelerate the transport and separation efficiency of photogenerated carriers, thus further enhancing the photocatalytic performance. [ABSTRACT FROM AUTHOR]

Topics on effectively improving the photochemical CO2/benzene/NO oxidation conversion performances of g-C3N4 based materials via charge transfer and separation enhancement are still considered challenging, despite the growing popularity of applying these materials in a variety of energy conversion related applications. Based on the idea of nanoarchitectonics, a post-nanotechnology concept, WOx/Au-g-C3N4 heterostructures are synthesized using two-step thermal polymerization and solvothermal treatment methods in this paper. Small Au nanoparticles are incorporated in superior thin g-C3N4 via mechano-chemical pre-reaction and two-step thermal polymerization (treated at 500 and 700 °C). Enhanced photocurrent density is observed after incorporation of Au, which is also in good agreement with the photocatalytic activity (H2 generation and CO2 reduction) data. Layered WOx with abundant oxygen vacancies are further incorporated into Au-modified g-C3N4 nanosheets to form heterojunctions possessing excellent photocatalytic CO2 photo-reduction performances with CO and CH4 generation rate of 5.64 and 2.58 μmolg−1h−1, respectively, under full solar spectrum. The heterojunctions constructed via in-situ formation show direct Z-scheme charge transfer pathway with improved charge separation and transport efficiencies. These highly stable and recyclable hierarchical g-C3N4 hybrid nanostructures (WOx/Au-g-C3N4 heterojunctions) show outstanding conversion rate (88.1%) and selectivity (99.3%) for benzene to phenol conversion under full solar spectrum condition, as well as excellent NO removal rate (61%).

Verteporphin loaded g‐C3N4 represents a multifunctional therapeutic platform for synchronous cancer imaging and treatment through the synergistic effect of phototherapy and chemotherapy. A biocompatible nanocarrier using g‐C3N4 nanosheets for high loading and anticancer activity of photosensitizer drug verteporfin (VP) is designed. The drug encapsulation efficiency (%) of optimized mannose functionalized g‐C3N4 formulation was observed to be 68.5 % for 5 mg of nanocarrier. It was found that 63.3 % and 81 % of the total bound drug was released from the nanocarrier at pH 5.4 and pH 1.2 respectively after 48 h. Under neutral conditions (pH 7.4), 45.2 % of the drug was released from the nanocarrier in the first 48 h. The % cytotoxicity of the free drug, the drug loaded nanocarrier against human breast cancer cell line (MCF‐7) was found to be 91.47 % and 91.23 % respectively at the dose of 40 μg/mL and 5 mg/mL after 48 h. IC50 values also manifest the significantly lower cytotoxicity of drug loaded nanocarriers (IC50=0.195 mg/mL) as compared to free‐drug (IC50=0.156 μg/mL). For mannosylated graphitic carbon nitride (g‐C3N4), verteporfin and man‐g‐C3N4@VP the values of mean ± std. deviation were found to be 4.14±2.46; 55.39±2.76; 63.27±1.74 respectively. Terephthalic acid assay confirmed formation of hydroxyl radicals in the solution treated with nanocarrier. This study suggests that g‐C3N4 is a promising use in drug carrier, cancer diagnosis and therapy. The combined effects of the high efficacy of ROS generation under UV light irradiation, low toxicity, and bio‐compatibility highlight the potential of verteporphin loaded g‐C3N4 for PDT. [ABSTRACT FROM AUTHOR]

Graphitic-C 3 N 4 is the prime photocatalyst for solar energy conversion applications owing to its inexpensive, non-toxic, low gap energy, chemical and thermal stability. Herein, a rGO/NiFe 2 O 4 -g-C 3 N 4 (RNC-3) hybrid heterostructure photocatalyst was fabricated to realize the effective charge carrier transfer and efficient solar fuel (H 2) generation. The photocatalytic H 2 generation activity was evaluated under solar light irradiation in the presence of triethanolamine (TEOA) as a hole scavenger. The optimized co-catalysts loadings are 15 wt% and 3 wt% for NiFe 2 O 4 and rGO, respectively. The results obtained show that RNC-3 hybrid heterostructure is an efficient and stable photocatalyst towards water-splitting and presented H 2 generation activity of 11,817 μmolg-1h-1, approximately ∼4 and 76 times higher than NiFe 2 O 4 -g-C 3 N 4 and g-C 3 N 4 nanosheets, respectively. Notably, the solar-to-hydrogen (STH) conversion efficiency of 2.44% was achieved, prominently surpassing many reported g-C 3 N 4 -based materials. This outstanding performance can be related to the substantial band gap reduction from 2.75 to 2.48 eV and significant PL quenching was observed after the incorporation of NiFe 2 O 4 and rGO, which dramatically improved charge carrier separation and transfer, thereby enhancing the photocatalytic performance. Furthermore, RNC-3 exhibits convenient magnetic recovery, practical reusability, and high activity, making it a potential visible-light responsive photocatalyst for efficient water-splitting applications. [ABSTRACT FROM AUTHOR]

Metal-free catalyst for photocatalytic production of H2O2 is highly desirable with the long-term vision of artificial photosynthesis of solar fuel. In particular, the specific chemical bonds for selective H2O2 photosynthesis via 2e− oxygen reduction reactions (ORR) remain to be explored for understanding the forming mechanism of active sites. Herein, we report a facile doping method to introduce boron-nitrogen (B-N) bonds into the structure of g-C3N4 nanosheets (denoted as BCNNS) to provide significant photocatalytic activity, selectivity and stability. The theoretical calculation and experimental results reveal that the electron-deficient B-N units serving as electron acceptors improve photogenerated charge separation and transfer. The units are also proved to be superior active sites for selective O2 adsorption and activation, reducing the energy barrier for *OOH formation, and thereby enabling an efficient 2e− ORR pathway to H2O2. Consequently, with only bare loss of activity during repeated cycles, the optimal H2O2 production rate by BCNNS photocatalysts reaches 1.16 mmol·L−1·h−1 under LED365nm irradiation, increasing nearly 2∼5 times as against the state-of-art metal-free photocatalysts. This work gives the first example of applying B-N bonds to enhance the photocatalytic H2O2 production as well as unveiling the underlying reaction pathway for efficient solar-energy transformations. [ABSTRACT FROM AUTHOR]

Efficiently constructing nanostructured Z-scheme heterojunctions with good interface contact is a desired route to optimize the photocatalytic property of the materials. In this work, novel 0D/1D/2D Z-scheme silver/silicon carbide/graphitic carbon nitride (Ag/SiC/CN) photocatalysts were prepared from Ag nanodots loaded on SiC nanofibers/CN nanosheets (SiC/CN) composite, using the calcination and chemical reduction routes. The Ag/SiC/CN composite with an optimal 3% Ag loading dose performs the best H 2 evolution rate of 2971 μmol g−1 h−1, which is approximately 8.8, 1.5 and 4.5 times compared to CN, SiC/CN and 3% Ag/CN, respectively. Besides the Ag/SiC/CN composite presents a high apparent quantum efficiency (7.3%) and outstanding photo-corrosion resistance stability. The Ag nanodots are served as efficient carriers transfer center and cocatalyst to construct Z-scheme heterojunction interface, which can help to generate more photo-generated carries, shorten the electron transmission distance and increase the electron transfer rate, certifying that 0D/1D/2D Z-scheme photocatalytic system is high-efficiency and has great advantages in photocatalytic applications. • A novel 0D/1D/2D Ag/SiC/g-C 3 N 4 nanoheterojunction photocatalyst was constructed. • Z-scheme system and multipurpose Ag nanodots conduce to enhance the property. • Ag/SiC/g-C 3 N 4 exhibits enhanced H 2 production activity and great cycling stability. • A detailed photocatalytic mechanism is illustrated for the activity improvement. [ABSTRACT FROM AUTHOR]

Graphitic carbon nitride (g-C3N4) has received much interest as a visible-light-driven photocatalyst for degrading pollutants such as organic dyes and antibiotics. However, g-C3N4 bulk activity could not meet expectations due to its rapid recombination of photogenerated electron–hole pairs and low specific surface area. In our study, melamine was thermally treated one-step in the presence of NH4Cl to produce g-C3N4 nanosheets. The characterizations of surface morphology and optical properties of all g-C3N4 samples were investigated by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectrum (XPS), transmission electron microscopy (TEM), and UV–visible diffuse reflectance spectroscopy. Compared to bulk g-C3N4, g-C3N4 nanosheets demonstrated excellent photocatalytic activities, with approximately 98% RhB removal after 210 min of visible light irradiation. Furthermore, the effect of catalyst dosage, pH, and RhB concentration on the removal percentage dye of g-C3N4 nanosheets was also investigated. h+ and •O2− species were demonstrated as the key reactive species for the RhB. Besides, ECN exposed a tetracycline degradation efficiency of 80.5% under visible-light irradiation for 210 min, which is higher than BCN (60.8%). The improved photocatalytic activity of g-C3N4 nanosheets is due to the restriction of the recombination of photogenerated electrons/hole pairs, as provided by photoluminescence spectra and Nyquist plot. As a result, our research may offer an effective approach to fabricating g-C3N4 nanosheets with high photocatalytic activity and high stability for environmental decontamination. [ABSTRACT FROM AUTHOR]

The development of efficient H2O2 sensors is crucial because of their multiple functions inside and outside the biological system and the adverse effects that a higher concentration can cause. This work reports a highly sensitive and selective non-enzymatic electrochemical H2O2 sensor achieved through the hybridization of Co3S4 and graphitic carbon nitride nanosheets (GCNNS). The Co3S4 is synthesized via a hydrothermal method, and the bulk g-C3N4 (b-GCN) is prepared by the thermal polycondensation of melamine. The as-prepared b-GCN is exfoliated into nanosheets using solvent exfoliation, and the composite with Co3S4 is formed during nanosheet formation. Compared to the performances of pure components, the hybrid structure demonstrates excellent electroreduction towards H2O2. We investigate the H2O2-sensing performance of the composite by cyclic voltammetry, differential pulse voltammetry, and amperometry. As an amperometric sensor, the Co3S4/GCNNS exhibits high sensitivity over a broad linear range from 10 nM to 1.5 mM H2O2 with a high detection limit of 70 nM and fast response of 3 s. The excellent electrocatalytic properties of the composite strengthen its potential application as a sensor to monitor H2O2 in real samples. The remarkable enhancement of the electrocatalytic activity of the composite for H2O2 reduction is attributed to the synergistic effect between Co3S4 and GCNNS. [ABSTRACT FROM AUTHOR]

The composites of graphitic carbon nitride (g‐C3N4) doped with activated carbon (AC) were synthesized using the calcination method, and used as photocatalysts for the degradation of enrofloxacin in an aqueous system. The physical, morphology, and spectroscopic properties of the synthesized AC, bulk g‐C3N4, and AC/g‐C3N4 composites were characterized using x‐ray diffraction spectroscopy (XRD), Fourier transforms infrared spectroscopy (FTIR), Brunauer‐Emmett‐Teller method (BET), scanning electron microscopy, energy dispersive x‐ray mapping (SEM‐EDX‐mapping), transmission electron microscopy (TEM) with high resolution‐transmission electron microscopy (HR‐TEM), ultraviolet‐visible diffuse reflectance spectroscopy techniques (UV‐Vis DRS), photoluminescence spectroscopy (PL), and electron impedance spectroscopy (EIS). The AC/g‐C3N4 composites exhibited an extended visible light response and higher separation rate of photogenerated electron‐hole pairs compared to the bulk g‐C3N4. The 1 : 1AC/g‐C3N4 composite showed superior photocatalytic performance, nearly seven times higher than the bulk g‐C3N4 nanosheets, toward the degradation of enrofloxacin in aqueous solutions, under visible light irradiation. The high photocatalytic efficiency of AC/g‐C3N4 composites may be attributed to the role played by the significantly improved surface area, and the occurrence of high photoinduced charge separation, as revealed by the morphological and opto‐spectroscopic characterization of the synthesized composites, and photocatalysis experimental data. Furthermore, the AC/g‐C3N4 composites exhibited excellent recyclability and stability, making them potential candidates for use in environmental remediation. [ABSTRACT FROM AUTHOR]

[Display omitted] • Fabricating g-C 3 N 4 -MXene-12/Pebax MMM for simultaneous improvement of CO 2 permeability and selectivity. • MXene nanosheets were semi-oxidized to further prevent nanosheet stacking. • The fabricated membranes show excellent CO 2 capture capacity and surpass 2008 upper bound. • The membrane shows excellent stability during 100 h test. While mixed matrix membranes (MMMs) containing two-dimensional (2D) layered materials (such as, GO, g-C 3 N 4 and MXene, etc.) have revealed potential application prospects for gas separation applications, it still faces a serious challenge to enhance the performance of CO 2 separation. Owing to the structural defects of g-C 3 N 4 nanosheets produced during the exfoliation process, which has greatly reduced the gas selectivity. Herein, we describe the construction of g-C 3 N 4 -MXene/Pebax MMM composed by MXene modified the structural defects in g-C 3 N 4 nanosheets to surmount the low gas selectivity of g-C 3 N 4 membrane. However, the stacking of nanosheets on each other hinder the gas transport channels. The TiO 2 nanoparticles derived in-situ from MXene semi-oxidation can support an intermediate layer between g-C 3 N 4 nanosheet and MXene nanosheet to expand the gas transport channels. Eventually, a novel g-C 3 N 4 -TiO 2 @MXene/Pebax MMM was obtained that exhibited maximum CO 2 permeability of 1673.69 Barrer in separation of CO 2 /CH 4 , CO 2 /N 2 selectivity of 45.13, and CO 2 /CH 4 selectivity of 47.76, exceeding the bond 2008 limit on Robeson. What's more, the MMM within 100 h (1 bar and 298 K) are measured to have outstanding separation performance. Overall, this concept offers a novel strategy to enhance CO 2 separation by MXene modified defects in g-C 3 N 4 nanosheets. [ABSTRACT FROM AUTHOR]

In this study, we report the development of a cost-effective and highly efficient bi-functional g-C3N4/ZnS/SnO2 ternary nanocomposite for electrochemical hydrogen evolution reaction (HER) and photocatalytic applications under sunlight irradiation. The nanocomposites were synthesized using a facile hydrothermal method, combining semiconducting ZnS and SnO2 nanomaterials with g-C3N4 nanosheets. Comprehensive characterization techniques were employed to analyze the structural, morphological, electrochemical, and photocatalytic properties of the synthesized nanocomposite. X-ray diffraction (XRD) analysis demonstrates that the g-C3N4, g-C3N4/ZnS, and g-C3N4/ZnS/SnO2 nanostructures exhibit excellent crystallinity, as evidenced by the sharp and well-defined peaks in the XRD patterns. Field emission scanning electron microscopy (FESEM) reveals the deposition of spherical ZnS nanoparticles and agglomerated SnO2 nanoparticles on g-C3N4 nanosheets, forming a ternary nanocomposite structure. The g-C3N4/ZnS/SnO2 ternary nanocomposite exhibits a high Brunauer–Emmett–Teller (BET) surface area of 118.123 m2 g−1 and an optical band gap of 2.88 eV. Electrochemical measurements show that the nanocomposite has enhanced catalytic activity for the HER, with a low Tafel slope of 92 mV dec−1 and an overpotential of − 0.372 V vs. RHE at 10 mA cm−2. Furthermore, the g-C3N4/ZnS/SnO2 ternary nanocomposite demonstrates excellent photocatalytic performance, exhibiting high degradation efficiency against methylene blue (MB) dye under sunlight exposure. The synergistic effects of the ternary nanocomposite structure, high surface area, and suitable optical properties contribute to the enhanced photocatalytic and electrocatalytic activities. The developed g-C3N4/ZnS/SnO2 ternary nanocomposite shows great potential as a cost-effective and highly efficient bi-functional material for sustainable energy applications of hydrogen evaluation and environmental remediation. [ABSTRACT FROM AUTHOR]

Fossil fuel depletion and environmental toxins have made photocatalytic H 2 production of paramount significance. A novel and unique technique for producing sustainable H 2 and valorizing biomass using infinite solar energy is biomass photoreformation. Nevertheless, this environmentally friendly method is usually linked to severe reaction circumstances, insufficient selectivity, and restricted biomass conversion. Here, we present a novel one-pot photoreformation technique over porous g-C 3 N 4 nanosheets surface-modified with Pd nanoparticles to convert d -glucose to H 2. By stacking the g-C 3 N 4 photocatalyst into a 2D nanosheet structure, some of its inherent drawbacks can be mitigated. Furthermore, the inclusion of noble metal nanoparticles in these g-C 3 N 4 nanosheet structures could significantly boost existing photocatalytic activity. The majority of solar radiation is composed of visible light, which makes up 45% of it, and ultraviolet light, which makes up 5%. Therefore, our focus has been on utilizing abundant visible light to facilitate biomass reformation. After 4 h of continuous irradiation, our composite photocatalyst exhibited exceptional visible light activity; its H 2 evolution was 1839.84 μmolg−1h−1, or about 27 times higher than that of undoped g-C 3 N 4 nanosheets. The effectiveness of three different Pd loadings on g-C 3 N 4 nanosheets for glucose reforming was examined. In the quest for an improved H 2 evolution visible light active photocatalyst, g-C 3 N 4 nanosheets made at various pyrolysis temperatures loaded with optimized Pd weight percentage were also examined. [ABSTRACT FROM AUTHOR]

The fabrication of graphitic carbon nitride (g-C 3 N 4) has received much attention for its superior photoelectronic properties, it remains a remarkable challenge with a feasible methodology. Herein, inspired by carburization, a novel method with carbon diffusion was proposed to prepare g-C 3 N 4 nanosheets (CNNS). The carbon diffusion was caused by the gradient difference in carbon concentration between the gaseous environment and the C15 (mild steel with low carbon content) during thermal polymerization. Eventually, the CNNS with approximately 1.5 nm thickness was successfully fabricated and exhibited larger surface area (98.08 m2 g−1), which was 15.42 times higher than that of bulk g-C 3 N 4 (BCN). In the evaluation of photocatalytic CO 2 reduction activity, the CH 3 OH formation rate over CNNS (2.10 μmol g−1 h−1) was 3.28 times greater than BCN. Meanwhile, the designed CNNS exhibited dramatic improvement on H 2 evolved rate (HER) of 2507.02 μmol g−1 h−1, which was 6.99 times higher than BCN. More importantly, the C15 possessed the advantage of 10 times recycled to use for the fabrication of CNNS accompanied by a moderate decrease of HER. Moreover, the density functional theory (DFT) calculations were carried out based on the results. This work highlights an ingenious tactic with carbon diffusion for preparing CNNS towards renewable solar energy conversion. Herein, we reported an inducing carbon diffusion strategy for fabricating g-C 3 N 4 nanosheets to realize effectively solar energy conversion. [Display omitted] [ABSTRACT FROM AUTHOR]

Green energy generation is an indispensable task to concurrently resolve fossil fuel depletion and environmental issues to align with the global goals of achieving carbon neutrality. Photocatalysis, a process that transforms solar energy into clean fuels through a photocatalyst, represents a felicitous direction toward sustainability. Eco‐rich metal‐free graphitic carbon nitride (g‐C3N4) is profiled as an attractive photocatalyst due to its fascinating properties, including excellent chemical and thermal stability, moderate band gap, visible light‐active nature, and ease of fabrication. Nonetheless, the shortcomings of g‐C3N4 include fast charge recombination and limited surface‐active sites, which adversely affect photocatalytic reactions. Among the modification strategies, point‐to‐face contact engineering of 2D g‐C3N4 with 0D nanomaterials represents an innovative and promising synergy owing to several intriguing attributes such as the high specific surface area, short effective charge‐transfer pathways, and quantum confinement effects. This review introduces recent advances achieved in experimental and computational studies on the interfacial design of 0D nanostructures on 2D g‐C3N4 in the construction of point‐to‐face heterojunction interfaces. Notably, 0D materials such as metals, metal oxides, metal sulfides, metal selenides, metal phosphides, and nonmetals on g‐C3N4 with different charge‐transfer mechanisms are systematically discussed along with controllable synthesis strategies. The applications of 0D/2D g‐C3N4‐based photocatalysts are focused on solar‐to‐energy conversion via the hydrogen evolution reaction, the CO2 reduction reaction, and the N2 reduction reaction to evaluate the photocatalyst activity and elucidate reaction pathways. Finally, future perspectives for developing high‐efficiency 0D/2D photocatalysts are proposed to explore potential emerging carbon nitride allotropes, large‐scale production, machine learning integration, and multidisciplinary advances for technological breakthroughs. [ABSTRACT FROM AUTHOR]

The analysis of glyphosate is essential to agricultural production, environment protection and public health. Herein, we proposed a fast and convenient “on-off-on” fluorescence platform for sensitive detection of glyphosate via Cu2+ modulated g-C3N4 nanosheets. The fluorescence of the system was quenched by Cu2+. With the presence of glyphosate, the fluorescence could be restored due to the formation of Cu2+- glyphosate complex. The proposed method was cost-effective with label-free and enzyme-free. Moreover, it exhibits high sensitivity with a low detection limit of 0.01 μg/ml. Furthermore, the proposed method has been successfully monitored glyphosate in real samples.

Applications of reduced graphene oxide (rGO) in epoxy (EP) anticorrosion coatings are hindered by its poor dispersibility and galvanic corrosion hazard with the metal matrix. With an excellent water dispersibility, the acid-treated g-C3N4 nanosheets (CNNS) can be physically combined with rGO through ultrasonic treatment so as to enhance the dispersion of rGO in waterborne epoxy. The structure and morphology of the new hybrids prepared by this simple ultrasonic treatment were characterized through FTIR, Raman, XRD, XPS, and TEM. The results show that the best anticorrosion performance of the coating is achieved in 0.5 M sulfuric acid when the mass ratio of CNNS and rGO in the hybrid is 1:5. Compared with the case of pure EP coating, the corrosion current density of the new hybrid decreases by one order of magnitude, and electrochemical impedance increases by nearly two orders of magnitude. The new CNNS@rGO hybrid prepared by a simple ultrasonic method has broad prospects in the field of waterborne epoxy resin anticorrosive coatings. [ABSTRACT FROM AUTHOR]

[Display omitted] • CuS/Ag 2 O nanoparticles on ultrathin g-C 3 N 4 nanosheets to obtain CuS/Ag 2 O/g-C 3 N 4. • CuS/Ag 2 O/g-C 3 N 4 exhibited a remarkable photocatalytic H 2 production of 1752 µmol.h−1.g−1 cat. • Recombination rate in g-C 3 N 4 was inhibited by photocatalytic and visible-light sensitizer of CuS/Ag 2 O. • The detailed mechanism of charge separation in ternary CuS/Ag 2 O/g-C 3 N 4 nanostructures have been elucidated. Ternary heterostructures play a crucial role in improving the separation of charge carriers and fast surface reaction kinetics, which in turn helps in understanding the effective photocatalytic water splitting performance. Herein, CuS/Ag 2 O nanoparticles were presented on a graphitic carbon nitride (g-C 3 N 4) surface to obtain CuS/Ag 2 O/g-C 3 N 4 material using facile hydrothermal and precipitation methods. Structural and morphological studies confirmed the presence of ternary nanostructures comprising CuS, Ag 2 O, and g-C 3 N 4 with nanoparticle and nanosheet morphologies. The as-synthesized CuS/Ag 2 O/g-C 3 N 4 exhibited a remarkable photocatalytic H 2 production of 1752 µmol.h−1.g−1 cat , which is considerably superior than those of CuS and g-C 3 N 4. The improved H 2 production performance which is due to the effective interfacial CuS/Ag 2 O/g-C 3 N 4 heterojunction interface and superior hole (h+) trapping capability of the CuS at the CuS/Ag 2 O/g-C 3 N 4 interface. This can efficiently enhance the lifetime of photoexcited charge carriers and enhance the electron density for the production of H 2. The optimum CuS/Ag 2 O/g-C 3 N 4 heterostructure remained stable after 8 successive experimental cycles, although with a slight change in the H 2 production rate. Therefore, this study offers a novel approach to exploit the efficacy through the synergetic effect of integrating CuS as the photocatalyst and Ag 2 O as the visible sensitizer, thus proposing a viable strategy of using earth-abundant material to enhance the conversion of solar energy to fuel. [ABSTRACT FROM AUTHOR]

In this paper, a Bi 4 V 2 O 11 /SWNT/g-C 3 N 4 S-scheme heterojunction photocatalyst was reasonably constructed to achieve efficient photocatalytic CO 2 reduction.This job is prospective to offer more empirical reference for the construction of higher activity g-C 3 N 4 photocatalytic materials. [Display omitted] • The ultrathin porous nanosheets have large specific surface area and more active sites. • Oxygen vacancies increase the adsorption capacity of CO 2. • SWNTs can increase the charge separation efficiency even further. • S-scheme heterostructure can increase the effectiveness of photogenerated carrier separation. • The Bi 4 V 2 O 11 /SWNT/g-C 3 N 4 S-scheme heterojunction catalyst has good photocatalytic performance. A novel Bi 4 V 2 O 11 /single-walled carbon nanotube (SWNT)/g-C 3 N 4 S-scheme heterojunction photocatalyst is prepared using an in situ solvothermal growth method. Heterostructures are constructed by coupling the defective semiconductor Bi 4 V 2 O 11 with ultrathin porous g-C 3 N 4 nanosheets. To improve the photocatalytic CO 2 reduction activity, oxygen defects are used to enhance electron capture and CO 2 adsorption, the S-scheme heterojunction is used to improve the separation efficiency of the photogenerated carriers and SWNTs are used to form high-speed electron transport channels. The experimental results indicate that the maximum CO formation rate of Bi 4 V 2 O 11 /SWNT/g-C 3 N 4 is 18.6 μmol h−1 g−1, which is 2.7 and 2.4 times that of the ultrathin porous g-C 3 N 4 nanosheets and Bi 4 V 2 O 11 heated for 15 h, respectively, and 3.4 times that of standard g-C 3 N 4. This work provides a vital reference point for the in situ construction of S-scheme heterojunctions with defects. [ABSTRACT FROM AUTHOR]

Bortezomib is a key agent for treatment of cancer; while, it is a very hazardous bioactive substance (for healthy tissues). Therefore, delivering this drug to the targeted cancerous cells by using a suitable carrier is required. Considering it, in this project, several nanosized sorbents containing α-phographene, g-X 3 N 4 nanosheets, and C 19 X fullerenes have been considered for a systematic investigation on the possibility of adsorption and delivering of Bortezomib as a proteasome inhibitor drug residue. The results have indicated that g-B 3 N 4 could be considered as a potential actuator (a nano-sized key) which considerably alters its form by adsorbing Bortezomib (for example in lower temperatures) and returns to its early structure by losing this drug after receiving energy (in relatively higher temperatures). Also, the E ads of α-phographene-Bortezomib system is −9.14 kcal mol−1 which show like some other cases, it might be used for delivering of this drug. Finally, our results confirm that α-Phographene has a relatively good drug recovery time for desorption of Bortezomib (5.13(10−6) s at 298.15 K and 2.78(10−6) s at the body temperature). [Display omitted] • Among all considered sorbents, the best semiconductor sensor for detection of Bortezomib residue is g-C 3 N 4 which releases two strong and consecutive signals at −0.20761 eV, and − 0.90201 eV. • The α-phographene nanosheet could receive Bortezomib in a certain condition, and release this anti-cancer drug in another controlled situation. • The g-B 3 N 4 nano segment might be considered as a potential actuator (or nano-sized key) which significantly changes its shape by adsorbing BZB (especially in lower temperatures) and returns to its early structure by losing BZB after receiving energy (at higher temperatures). [ABSTRACT FROM AUTHOR]

[Display omitted] • MgZrO 3 @g-C 3 N 4 hybrid nanocomposite (MZCN) was created by ultrasonication technique to remove Rh B dye from contaminated water. • Characterization results exposed that the MZCN nanocomposite was successfully formed with high surface characteristic. • Based on the adsorption modelling, the maximum adsorption capability estimated was 370.8 mg/g. • Mechanism of the RhB adsorption occurred by van der Waal interaction between the aromatic rings of the dye and the graphene framework. Pristine graphitic carbon nitride (g-C 3 N 4) was synthesized by calcination of urea under elevated temperature. A blend of g-C 3 N 4 nanosheets and nanosized ZrO 2 and MgO precursors were used to prepare MgZrO 3 @g-C 3 N 4 hybrid nanocomposite (MZCN) then it was assessed for the adsorption of Rhodamine B (RhB) dye from aqueous solution. The X-ray diffraction analysis revealed the development of the monoclinic ZrO 2 , cubic MgO, and hexagonal graphitic carbon nitride phases. The energy diffraction X-rays (EDX), photoelectron electron, and Fourier transformed infrared (FT-IR) spectroscopy analyses collectively validated the formation of the presumed composite. An improved porosity with a surface area 35.86 m2.g−1 and pore volume 0.087 cm3.g−1 were determined by N 2 adsorption setup. The adsorption kinetics fitted well with the pseudo-first-order model (R2 > 0.99), which designated an adsorption process influenced by physisorption. The kinetics models investigations revealed a film diffusion control of the adsorption process. The adsorption equilibrium matched perfectly with the Langmuir isotherm model (R2 > 0.99) marking a maximum adsorption capacity of 370.8 mg g−1, demonstrating outstanding monolayer adsorption process. In addition, the Freundlich constant (n = 1.76) value is falling in the range 1–10 suggested a favorable adsorption of RhB onto the composite surface. The mechanistic enquiry suggested van der Waal, hydrogen bonds and π–π electron–donor interactions between the electron-rich RhB and the functional groups in the adsorbent's molecule. This work stipulates that MgZrO 3 @g-C 3 N 4 holds promise as efficient adsorbent for organic dyes from contaminated wastewater. [ABSTRACT FROM AUTHOR]

Graphitic carbon nitride (g-C 3 N 4) has attracted great interest in photocatalytic water splitting. However, the poor photogenerated charge carriers transfer and the insufficient driving force for oxygen evolution reaction limit its practical application. In this work, boron-doped g-C 3 N 4 nanosheets (BCNS) have been synthesized by calcining a mixture of g-C 3 N 4 and NaBH 4. The synthesized BCNS were then combined with Ti 3 C 2 MXene using electrostatic self-assembly to construct a 2D/2D BCNS/Ti 3 C 2 heterojunction. The resultant BCNS retained the original framework of g-C 3 N 4 , while the optimized band structure of BCNS induced prominently enhanced visible light absorption, accelerated charge carriers separation, and the increased driving force for water oxidation compared to pure g-C 3 N 4. Density functional theory further proved that BCNS can enhance the driving force for photocatalytic O 2 evolution. Moreover, the construction of 2D/2D face-to-face BCNS/Ti 3 C 2 heterojunction was carried out to further enhance photocatalytic performance due to the intimate contact interface and the accelerated separation and transfer of photogenerated charge carriers. As a result, the 2D/2D BCNS/Ti 3 C 2 hetrojunction exhibited a dramatically improved photocatalytic water-splitting performance compared to pristine g-C 3 N 4. This integrated engineering strategy, involving non-metal element doping and 2D/2D heterojunction construction, might provide a unique paradigm for the rational design of efficient photocatalysts for photocatalytic water splitting. [Display omitted] • The 2D/2D BCNS/Ti 3 C 2 heterojunction was established by the electrostatic self-assembly method. • B doping into the framework of CNS could effectively increase the driving force for water oxidation reaction. • The construction of 2D/2D BCNS/Ti 3 C 2 heterojunction could accelerate the separation and transfer of charge carriers. • The synergistic effect of B doping and Ti 3 C 2 introduction enhanced the photocatalytic water splitting performance. [ABSTRACT FROM AUTHOR]

It is well known that graphite-like carbon nitride (g-C 3 N 4) is a good photocatalyst for in-situ the production of H 2 O 2. However, how to activate H 2 O 2 generating the strong oxidizing ·OH is the key factor to affect the degradation of pollutants. In this paper, the layered g-C 3 N 4 nanosheets were prepared by using urea and H 2 O with different mass ratios and calcined in Muffle furnace by one-step synthesis method. The morphology, composition and structure of photocatalysts were analyzed, indicating that the as-prepared L-g-C 3 N 4 -7 had abundant edge regions in comparison with L-g-C 3 N 4 made by solid urea. The photocatalytic performance of g-C 3 N 4 nanosheets was investigated with atrazine (ATZ) as the target pollutant in water. The results revealed that the prepared L-g-C 3 N 4 -7 exhibited the best photocatalytic activity in visible light (λ ≥ 420 nm). The degradation of 1.0 mg/L ATZ reached over 96% after 3 hours and the photocatalytic degradation rate constant (k) was 6.8 times than that of L-g-C 3 N 4 photocatalyst. In addition, under the same conditions, the H 2 O 2 production of L-g-C 3 N 4 -7 was 4.5 times than that of L-g-C 3 N 4 photocatalyst. Based on the capture experiments of free radicals, it was found that the contribution rate of ·OH in L-g-C 3 N 4 -7 photocatalytic increased to 17 % compared to 4 % of L-g-C 3 N 4 photocatalyst during the degradation of ATZ. The ·OH quantitative experiment indicated that the L-g-C 3 N 4 -7 photocatalyst could obviously activate H 2 O 2 to generate ·OH and the amount of ·OH was 2.5 times than that of the L-g-C 3 N 4 photocatalyst. More importantly, a large amount of terminal-NH x (14.6 %) in L-g-C 3 N 4 -7 was measured by the XPS, FT-IR and zeta potential. The additive H 2 O 2 adsorption experiment in the dark was used to confirm terminal-NH x sites of L-g-C 3 N 4 -7 photocatalyst, which was beneficial to adsorb and activate H 2 O 2. The results illustrated that the L-g-C 3 N 4 -7 photocatalyst with rich edge regions and terminal-NH x had the characteristics of in-situ the activation of H 2 O 2 to generate ·OH. The findings suggest that designing and developing efficient g-C 3 N 4 photocatalysts pave a new avenue for activating in situ self-synthesizing H 2 O 2 and the removal of atrazine in water. [Display omitted] • The L-g-C 3 N 4 -7 photocatalyst with rich edge regions had a high efficiency in-situ activation of H 2 O 2 to produce ·OH. • The main reason for the degradation of ATZ in L-g-C 3 N 4 -7 photocatalyst was the increasing contribution of ·OH. • The terminal-NH x of L-g-C 3 N 4 -7 was the main adsorption and activation site of H 2 O 2. [ABSTRACT FROM AUTHOR]

A photocatalyst of iron–porphyrin tetra-carboxylate (FeTCPP)-sensitized g-C3N4 nanosheet composites (FeTCPP@CNNS) based on g-C3N4 nanosheet (CNNS) and FeTCPP have been fabricated by in situ hydrothermal self-assembly. FeTCPP is uniformly introduced to the surface of CNNS. Only a small amount of FeTCPP is introduced, and the stacked lamellar structure is displayed in the composite. As compared with pure CNNS, the FeTCPP@CNNS composites exhibit significantly improved photocatalytic performance by the photodegradation of p-nitrophenol (4-NP). At the optimum content of FeTCPP to CNNS (3 wt%), the photodegradation activity of the FeTCPP@CNNS photocatalyst can reach 92.4% within 1 h. The degradation rate constant for the 3% FeTCPP@CNNS composite is 0.037 min−1 (4-NP), which is five times that of CNNS (0.0064 min−1). The results of recycling experiments show that 3% FeTCPP@CNNS photocatalyst has excellent photocatalytic stability. A possible photocatalytic reaction mechanism of FeTCPP@CNNS composite for photocatalytic degradation of 4-NP has been proposed. It is shown that superoxide radical anions played the major part in the degradation of 4-NP. The appropriate content of FeTCPP can enhance the charge transfer efficiency. The FeTCPP@CNNS composites can provide more active sites and accelerate the transport and separation efficiency of photogenerated carriers, thus further enhancing the photocatalytic performance.