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Industrial dye effluent causes significant risks to the environment. The present study was focused on photocatalytic degradation of the dye Direct Red 28 using a ternary composite of graphitic carbon nitride, TiO2, and polyorthoanisidine (g-C3N4/TiO2/POA), prepared by in-situ oxidative polymerization o- anisidine. The synthesized composite g-C3N4/TiO2/POA properties were characterized using different analytical techniques. X-ray diffraction (XRD) results revealed the prominent pattern of TiO2 and g-C3N4 in the composite peak at 2θ° while Fourier transform infrared (FTIR) results provided the confirmation peaks for g-C3N4/TiO2/POA and POA at 1,110 cm−1 and 1,084 cm−1 for C-O-C ether. Scanning electron microscopy (SEM) demonstrated an increase in the average size of the composite up to 428 nm. The energy-dispersive X-ray spectroscopy (EDX) spectrum provided the weight percentages of the C, O, and Ti in the composite were 8.5%, 45.69%, and 45.81%, respectively. The photocatalytic degradation of Direct Red 28 dye under UV irradiation using a composite showed that 86% Direct Red 28 dye was degraded by a 30 mg/L dose of g-C3N4/TiO2/POA in 240 min at pH 2. After four consecutive cycles, the utilized composite showed 79% degradation of Direct Red 28, demonstrating the stability and effectiveness of the g-C3N4/TiO2/POA photocatalyst. The high reusability and efficiency of the g-C3N4/TiO2/POA composite are due to increased light absorption range and reduced e−/h+ recombination rate in the presence of g-C3N4 and POA. [ABSTRACT FROM AUTHOR]

In this research, WO3, g-C3N4, and g-C3N4@WO3 nanocomposites were synthesized from Na2WO4.2H2O and urea precusors via the hydrothermal method in a strong acid medium. Physico-chemical characteristics of WO3, g-C3N4, and g-C3N4@WO3 nanocomposites were examined by means of XRD, Raman, FTIR, FE-SEM, BET, and UV-Vis spectroscopy. The produced materials were then applied for studying adsorptive removal of methylene blue (MB) as a model pollutant from aqueous solutions. The results showed that g-C3N4@WO3 nanocomposites were successfully synthesized, with a hexagonal shape and an average crystal size of in the range of 15.4–20.7 nm. The surface area (68.3 m2/g) of g-C3N4@WO3 nanocomposites was 2.37 times higher compared to sole WO3, and g-C3N4@WO3 composites were mesoporous materials with a typical average pore diameter of 4.5 nm. It was revealed that the MB adsorption process occurred extremely quickly, reaching equilibrium after only about 20 min, with a maximum uptake of MB of 190 mg/g which was significantly higher than other adsorbents. The adsorption process was followed the first-order-kinetics model and the adsorbent showed high durability in adsorbing MB, with a slight decline in adsorption efficiency after 4 cycles (from 98.7% to 95.9%). This research provides an easy method for producing high adsorption capacity nanocomposite which can be applied for efficient removal of MB from water. [ABSTRACT FROM AUTHOR]

Selective oxidation of benzyl alcohol under atmospheric oxygen is a sustainable route for the synthesis of benzaldehyde. The development of low-cost metal catalysts is a challenging research topic. Herein, supported vanadia catalysts on carbon nitride were prepared using vanadyl acetylacetonate as a precursor through a wet-impregnation method. The synthesized VO/eg-C3N4 were characterized by N2 adsorption–desorption, TG, XRD, FT-IR, XPS, UV–Vis, SEM, and O2-TPD. The eg-C3N4 material could disperse the vanadia species, and the distributions of vanadium cations (V5+/V4+) were largely dependent on the preparation temperature. In the selective oxidation of benzyl alcohol under atmospheric oxygen, the catalysts showed moderate catalytic activity. Under identical reaction conditions, the activity of VO/eg-C3N4 was higher than vanadia catalysts supported on SBA-15 and CNTs materials. [ABSTRACT FROM AUTHOR]

Graphitic carbon nitride (g-C3N4) is an intriguing nanomaterial that exhibits photoconductive fluorescence properties under UV–visible light. Dopamine (DA) coating of g-C3N4 prepared from melamine was accomplished via self-polymerization of DA as polydopamine (PDA). The g-C3N4 was coated with PDA 1, 3, and 5 times repeatedly as (PDA@g-C3N4) in tris buffer at pH 8.5. As the number of PDA coatings was increased on g-C3N4, the peak intensity at 1512 cm−1 for N–H bending increased. In addition, the increased weight loss values of PDA@g-C3N4 structures at 600 °C from TGA thermograms confirmed that the coating was accomplished. The band gap of g-C3N4, 2.72 eV, was reduced to 0.87 eV after five coatings with PDA. A pristine g-C3N4 was found to have an isoelectric point (IEP) of 4.0, whereas the isoelectric points of 1PDA@g-C3N4 and 3PDA@g-C3N4 are close to each other at 3.94 and 3.91, respectively. On the other hand, the IEP of 5PDA@g-C3N4 was determined at pH 5.75 assuming complete coating with g-C3N4. The biocompatibility of g-C3N4 and PDA@g-C3N4 against L929 fibroblast cell lines revealed that all PDA@g-C3N4 coatings were found to be biocompatible up to a 1000 mg/mL concentration, establishing that PDA coatings did not adversely affect the biocompatibility of the composite materials. In addition, PDA@g-C3N4 was screened for antioxidant potential via total phenol content (TPC) and total flavonoid content assays and it was found that PDA@g-C3N4 has recognizable TPC values and increased linearly with an increased number of PDA coatings. Furthermore, blood compatibility of pristine g-C3N4 is enhanced considerably upon PDA coating, affirmed by hemolysis and the blood clotting index%. Additionally, α-glucosidase inhibitory properties of PDA@g-C3N4 structures revealed that 67.6 + 9.8% of this enzyme was evenly inhibited by 3PDA@g-C3N4 structure. [ABSTRACT FROM AUTHOR]

This current study assessed the impacts of morphology adjustment of perovskite BiFeO3 (BFO) on the construction and photocatalytic activity of P-infused g-C3N4/U-BiFeO3 (U-BFO/PCN) heterostructured composite photocatalysts. Favorable formation of U-BFO/PCN composites was attained via urea-aided morphology-controlled hydrothermal synthesis of BFO followed by solvosonication-mediated fusion with already synthesized P-g-C3N4 to form U-BFO/PCN composites. The prepared bare and composite photocatalysts' morphological, textural, structural, optical, and photocatalytic performance were meticulously examined through various analytical characterization techniques and photodegradation of aqueous rhodamine B (RhB). Ellipsoids and flakes morphological structures were obtained for U-BFO and BFO, and their effects on the successful fabrication of the heterojunctions were also established. The U-BFO/PCN composite exhibits 99.2% efficiency within 20 min of visible-light irradiation, surpassing BFO/PCN (88.5%), PCN (66.8%), and U-BFO (26.1%). The pseudo-first-order kinetics of U-BFO/PCN composites is 2.41 × 10−1 min−1, equivalent to 2.2 times, 57 times, and 4.3 times of BFO/PCN (1.08 × 10−1 min−1), U-BFO, (4.20 × 10−3 min−1), and PCN, (5.60 × 10−2 min−1), respectively. The recyclability test demonstrates an outstanding photostability for U-BFO/PCN after four cyclic runs. This improved photocatalytic activity exhibited by the composites can be attributed to enhanced visible-light utilization and additional accessible active sites due to surface and electronic band modification of CN via P-doping and effective charge separation achieved via successful composites formation. [ABSTRACT FROM AUTHOR]

Industrial dye effluent causes significant risks to the environment. The present study was focused on photocatalytic degradation of the dye Direct Red 28 using a ternary composite of graphitic carbon nitride, TiO2, and polyorthoanisidine (g-C3N4/TiO2/POA), prepared by in-situ oxidative polymerization o-anisidine. The synthesized composite g-C3N4/TiO2/POA properties were characterized using different analytical techniques. X-ray diffraction (XRD) results revealed the prominent pattern of TiO2 and g-C3N4 in the composite peak at 2θ° while Fourier transform infrared (FTIR) results provided the confirmation peaks for g-C3N4/TiO2/POA and POA at 1,110 cm−1 and 1,084 cm−1 for C-O-C ether. Scanning electron microscopy (SEM) demonstrated an increase in the average size of the composite up to 428 nm. The energy-dispersive X-ray spectroscopy (EDX) spectrum provided the weight percentages of the C, O, and Ti in the composite were 8.5%, 45.69%, and 45.81%, respectively. The photocatalytic degradation of Direct Red 28 dye under UV irradiation using a composite showed that 86% Direct Red 28 dye was degraded by a 30 mg/L dose of g-C3N4/TiO2/POA in 240 min at pH 2. After four consecutive cycles, the utilized composite showed 79% degradation of Direct Red 28, demonstrating the stability and effectiveness of the g-C3N4/TiO2/POA photocatalyst. The high reusability and efficiency of the g-C3N4/TiO2/POA composite are due to increased light absorption range and reduced e−/h+ recombination rate in the presence of g-C3N4 and POA.

In recent years, the demand for micronano materials with superior microwave absorption capabilities has been on the rise, such as strong absorption capacity, lightweight, and wide frequency bandwidth, to tackle the issues associated with electromagnetic microwave (EMW) pollution. Here, the CuS/g-C3N4/Fe3O4 nanocomposite was fabricated using a simple mechanical stirring, hydrothermal treatment, and high-temperature calcination, composed of graphitic carbon nitride (g-C3N4), micron-sized flower-like copper sulfide (CuS), and iron oxide nanoparticles (Fe3O4). The CuS/g-C3N4/Fe3O4 nanocomposite has an excellent EMW absorption performance. The results show that the maximum reflection loss (RLmax) of the CuS/g-C3N4/Fe3O4 nanocomposite could achieve −41.2 dB at a frequency of 13.7 GHz with a thickness of 2.5 mm, corresponding to an ultrawide effective absorption bandwidth (RL < −10 dB) of 8.6 GHz (9.4–18 GHz). The excellent EMW properties of the CuS/g-C3N4/Fe3O4 nanocomposite are attributed to various mechanisms such as multidimensional multilevel scattering, interfacial polarization, and magnetic decay processes. The unique three-dimensional (3D) structure of the CuS/g-C3N4/Fe3O4 nanocomposite holds promise in providing ideas and solutions for the advancement of EMW technology in the future. [ABSTRACT FROM AUTHOR]

Formaldehyde is a pollutant that significantly affects the indoor air quality. However, conventional remediation approaches can be challenging to deal with low-concentration formaldehyde in an indoor environment. In this study, Photocatalysts of Ag/graphitic carbon nitride (g-C 3 N 4)/Ni with 3D reticulated coral structure were prepared by thermal polymerization and liquid phase photo-deposition, using nickel foam (NF) as the carrier. Experiments demonstrated that when the Ag concentration was 3%, and the relative humidity was 60%, the Ni/Ag/g-C 3 N 4 showed the maximum degradation rate of formaldehyde at 90.19% under visible light irradiation, and the formaldehyde concentration after degradation was lower than the Hygienic standard stated by the Chinese Government. The porous structure of Ni/Ag/g-C 3 N 4 and the formation of Schottky junctions promoted the Adsorption efficiency and degradation of formaldehyde, while the nickel foam carrier effectively promoted the desorption of degradation products. Meanwhile, the degradation rate was only reduced by 3.4% after 16 recycles, the three-dimensional porous structure extended the lifetime of the photocatalyst. This study provides a new strategy for the degradation of indoor formaldehyde at low concentrations. [ABSTRACT FROM AUTHOR]

Fluorescent graphitic carbon nitride (g-C3N4) doped with various heteroatoms, such as B, P, and S, named Bg-C3N4, Pg-C3N4, and Sg-C3N4, were synthesized with variable band-gap values as diagnostic materials. Furthermore, they were embedded within hyaluronic acid (HA) microgels as g-C3N4@HA microgel composites. The g-C3N4@HA microgels had a 0.5–20 μm size range that is suitable for intravenous administration. Bare g-C3N4 showed excellent fluorescence ability with 360 nm excitation wavelength and 410–460 emission wavelengths for possible cell imaging application of g-C3N4@HA microgel composites as diagnostic agents. The g-C3N4@HA-based microgels were non-hemolytic, and no clotting effects on blood cells or cell toxicity on fibroblasts were observed at 1000 μg/mL concentration. In addition, approximately 70% cell viability for SKMEL-30 melanoma cells was seen with Sg-C3N4 and its HA microgel composites. The prepared g-C3N4@HA and Sg-C3N4@HA microgels were used in cell imaging because of their excellent penetration capability for healthy fibroblasts. Furthermore, g-C3N4-based materials did not interact with malignant cells, but their HA microgel composites had significant penetration capability linked to the binding function of HA with the cancerous cells. Flow cytometry analysis revealed that g-C3N4 and g-C3N4@HA microgel composites did not interfere with the viability of healthy fibroblast cells and provided fluorescence imaging without any staining while significantly decreasing the viability of cancerous cells. Overall, heteroatom-doped g-C3N4@HA microgel composites, especially Sg-C3N4@HA microgels, can be safely used as multifunctional theragnostic agents for both diagnostic as well as target and treatment purposes in cancer therapy because of their fluorescent nature. [ABSTRACT FROM AUTHOR]

Graphitic carbon nitride (g-C 3 N 4) is a semiconductor polymeric photocatalyst with an attractive electronic band structure, a moderate band gap energy, facile synthesis, and functionalization which can be applied as a photocatalyst in the visible light of the spectrum. The main problem of the g-C 3 N 4 photocatalyst is the recombination of the photogenerated electron-hole pairs. The photogenerated electrons in the conduction band (CB) tend to return to the valence band (VB) with subsequent recombination which is unfavored for photocatalysis. It is difficult for a single-component photocatalyst to harvest a large portion of the sunlight spectrum, and simultaneously, possess a suitable spatial charge separation and efficient redox ability. Constructing a heterojunction aims to satisfy the above three factors in a photocatalyst heterojunction system. Constructing g–C 3 N 4 –based heterostructures can promote electron-hole pair separation through the charge transfer across the interface of the g-C 3 N 4 /semiconductor. In this review, the photocatalysis mechanism is discussed and several types of g-C 3 N 4 /semiconductor heterostructures including type II, Z-scheme, and S-scheme heterostructures are explained. Recent advances in different types of g–C 3 N 4 –based heterostructures have been addressed. The synthesis methods for mesoporous, 0D, 1D, and 3D g–C 3 N 4 and different modifications on this photocatalyst are reviewed. [Display omitted] • g-C 3 N 4 heterostructures are designed to improve charge carrier separation. • g-C 3 N 4 heterostructures increase the life time of electron and hole. • Type II, Z-scheme, and S-scheme heterostructures show different charge carrier path. • S-scheme heterojunctions are able to preserve the powerful photogenerated electrons and holes. • g-C 3 N 4 heterostructures improve the photocatalytic performance in pollutant degradation or H 2 production. [ABSTRACT FROM AUTHOR]

Photocatalytic dye degradation is an energy-saving, environmentally friendly and sustainable way of managing potentially toxic wastewater from the textile industry. PbTiO3 was prepared using a solid-state reaction method, and an optimal ratio of PbTiO3/TiO2/g-C3N4 photocatalyst was synthesized using the sol-gel method to test its ability to decompose organic dyes. Methylene blue (MB) was selected as a target dye to test the photocatalytic effects. SEM results showed that the synthesis of a PbTiO3/TiO2/g-C3N4 photocatalyst yielded a unique nano structure with many surface pores. UV-Vis analysis demonstrated that the novel composite photocatalyst had higher visible light absorption, and a reduced energy gap. Experimental results showed that of the samples tested, PTO/TO/CN 1.0 showed the best photocatalytic effect on the removal of MB. Under visible light, the removal rate of MB by PTO/TO/CN 1.0 was up to 98.79%. The novel PTO/TO/CN 1.0 photocatalyst exhibited relatively high MB adsorption and had a high photocatalytic ability. [ABSTRACT FROM AUTHOR]

Graphitic carbon Nitride (g-C3N4) is one of the most utilized graphitic materials in hydrogen (H2) production via photocatalytic water splitting. Thus, a detailed critical overview, updated with the most recent works, has been performed on the synthesis methods, modification techniques, characterization, and mechanisms of g-C3N4 and g-C3N4-based composite materials, with the aim of clarifying the optimum course towards highly efficient hydrogen-producing photocatalysts based on this promising material. First, the synthesis methods for different morphologies of pure g-C3N4 (bulk, nanosheets, nanotubes and nanodots) are critically analyzed in detail for every step and parameter involved, with special mention regarding the modification methods of g-C3N4 (doping and composite formation). Next, the most common results of g-C3N4 characterization, regarding structural, morphological, optical, and electrical properties, are presented and analyzed. Then, a detailed critical survey of the mechanisms, using g-C3N4 and g-C3N4-based composites during photocatalytic activity, is performed with a focus on their effect on their hydrogen production capabilities via water splitting. This review aims to provide a clear image of all aspects regarding the use of g-C3N4 for photocatalysis, as well as a comprehensive guide for research targeted towards this promising graphitic material.

Graphitic carbon nitride (g-C3N4) is an intriguing nanomaterial that exhibits photoconductive fluorescence properties under UV–visible light. Dopamine (DA) coating of g-C3N4 prepared from melamine was accomplished via self-polymerization of DA as polydopamine (PDA). The g-C3N4 was coated with PDA 1, 3, and 5 times repeatedly as (PDA@g-C3N4) in tris buffer at pH 8.5. As the number of PDA coatings was increased on g-C3N4, the peak intensity at 1512 cm−1 for N–H bending increased. In addition, the increased weight loss values of PDA@g-C3N4 structures at 600 °C from TGA thermograms confirmed that the coating was accomplished. The band gap of g-C3N4, 2.72 eV, was reduced to 0.87 eV after five coatings with PDA. A pristine g-C3N4 was found to have an isoelectric point (IEP) of 4.0, whereas the isoelectric points of 1PDA@g-C3N4 and 3PDA@g-C3N4 are close to each other at 3.94 and 3.91, respectively. On the other hand, the IEP of 5PDA@g-C3N4 was determined at pH 5.75 assuming complete coating with g-C3N4. The biocompatibility of g-C3N4 and PDA@g-C3N4 against L929 fibroblast cell lines revealed that all PDA@g-C3N4 coatings were found to be biocompatible up to a 1000 mg/mL concentration, establishing that PDA coatings did not adversely affect the biocompatibility of the composite materials. In addition, PDA@g-C3N4 was screened for antioxidant potential via total phenol content (TPC) and total flavonoid content assays and it was found that PDA@g-C3N4 has recognizable TPC values and increased linearly with an increased number of PDA coatings. Furthermore, blood compatibility of pristine g-C3N4 is enhanced considerably upon PDA coating, affirmed by hemolysis and the blood clotting index%. Additionally, α-glucosidase inhibitory properties of PDA@g-C3N4 structures revealed that 67.6 + 9.8% of this enzyme was evenly inhibited by 3PDA@g-C3N4 structure.

• Novel Ag-bridged Z-scheme 3D/3D g-C 3 N 4 /BiOI heterojunction was constructed. • 91.8% TC degradation was achieved with 0.4 g/L catalyst under visible light. • Z-scheme plasmonic heterojunction formation evolves efficient charge separation. • Four TC degradation pathways were proposed according to identified intermediates. • Plausible mechanism for the exceptional photocatalytic activity was put forward. Rational design and synthesis of highly efficient and robust photocatalysts with positive exciton splitting and interfacial charge transfer for environmental applications is critical. Herein, aiming at overcoming the common shortcomings of traditional photocatalysts such as weak photoresponsivity, rapid combination of photo-generated carriers and unstable structure, a novel Ag-bridged dual Z-scheme g-C 3 N 4 /BiOI/AgI plasmonic heterojunction was successfully synthesized using a facile method. Results showed that Ag-AgI nanoparticles and three-dimensional (3D) BiOI microspheres were decorated highly uniformly on the 3D porous g-C 3 N 4 nanosheet, resulting in a higher specific surface area and abundant active sites. The optimized 3D porous dual Z-scheme g-C 3 N 4 /BiOI/Ag-AgI manifested exceptional photocatalytic degradation efficiency of tetracycline (TC) in water with approximately 91.8% degradation efficiency within 165 min, outperforming majority of the reported g-C 3 N 4 -based photocatalysts. Moreover, g-C 3 N 4 /BiOI/Ag-AgI exhibited good stability in terms of activity and structure. In-depth radical scavenging and electron paramagnetic resonance (EPR) analyses confirmed the relative contributions of various scavengers. Mechanism analysis indicated that the improved photocatalytic performance and stability were ascribed to the highly ordered 3D porous framework, fast electron transfer of dual Z-scheme heterojunction, desirable photocatalytic performance of BiOI/AgI and synergistic effect of Ag plasmas. Therefore, the 3D porous Z-scheme g-C 3 N 4 /BiOI/Ag-AgI heterojunction had a good prospect for applications in water remediation. The current work provides new insight and useful guidance for designing novel structural photocatalysts for environment-related applications. [Display omitted] [ABSTRACT FROM AUTHOR]

In this study, unique hybrid structures were constructed between a Ce-based metal-organic framework (Ce-MOF) and graphitic carbon nitride (g-C 3 N 4) materials. In addition, the g-C 3 N 4 materials used for these heterostructures were prepared by five different methods, namely the conventional pyrolysis method, chemical exfoliation by a strong acid, activation by an alkaline hydrothermal treatment, melamine-cyanuric acid supramolecular assembly with a mechanochemical method, and by the solvothermally pre-treated method. The structural and morphological properties of the resulting g-C 3 N 4 sheets and their composites were characterized using scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared spectrometry (FTIR), thermogravimetric analysis-derivative thermogravimetry (TGA-DTG), diffuse reflectance UV–vis spectroscopy (UV–vis DRS) and N 2 sorption-desorption isotherms (BET). Finally, the photocatalytic performance of the composites was determined by following the photocatalytic degradation of methylene blue (MB) in an aqueous solution under UV–visible light irradiation. It was found that the photocatalytic efficiency of the Ce-MOF/g-C 3 N 4 ‒TS composite was significantly higher than that of their counterparts (Ce-MOF or g-C 3 N 4 ‒TS) for the photocatalytic degradation of MB. When employing the composite, UV light-induced degradation of MB yielded an efficiency of 96.5% after 120 min for a dye solution containing 10 mg/L MB. This corresponds to a 5-fold or 2-fold improvement of the rate constant (k) when compared to the Ce-MOF or g-C 3 N 4 , respectively. [ABSTRACT FROM AUTHOR]

Synthetic organic pigments from the direct discharge of textile effluents are considered as colossal global concern and attract the attention of scholars. The efficient construction of heterojunction systems involving precious metal co-catalysis is an effective strategy for obtaining highly efficient photocatalytic materials. Herein, we report the construction of a Pt-doped BiFeO3/O-g-C3N4 (Pt@BFO/O-CN) S-scheme heterojunction system for photocatalytic degradation of aqueous rhodamine B (RhB) under visible-light irradiation. The photocatalytic performances of Pt@BFO/O-CN and BFO/O-CN composites and pristine BiFeO3 and O-g-C3N4 were compared, and the photocatalytic process of the Pt@BFO/O-CN system was optimized. The results exhibit that the S-scheme Pt@BFO/O-CN heterojunction has superior photocatalytic performance compared to its fellow catalysts, which is due to the asymmetric nature of the as-constructed heterojunction. The as-constructed Pt@BFO/O-CN heterojunction reveals high performance in photocatalytic degradation of RhB with a degradation efficiency of 100% achieved after 50 min of visible-light irradiation. The photodegradation fitted well with pseudo-first-order kinetics proceeding with a rate constant of 4.63 × 10−2 min−1. The radical trapping test reveals that h+ and •O2− take the leading role in the reaction, while the stability test reveals a 98% efficiency after the fourth cycle. As established from various interpretations, the considerably enhanced photocatalytic performance of the heterojunction system can be attributed to the promoted charge carrier separation and transfer of photoexcited carriers, as well as the strong photo-redox ability established. Hence, the S-scheme Pt@BFO/O-CN heterojunction is a good candidate in the treatment of industrial wastewater for the mineralization of organic micropollutants, which pose a grievous threat to the environment. [ABSTRACT FROM AUTHOR]

In this study, iron oxide (Fe2O3)/graphitic carbon nitride (g-C3N4)/titanium dioxide (TiO2) nanofibers (NFs) were used as an additional layer on photoanode in dye-sensitized solar cells (DSSCs) to improve the photovoltaic performance of DSSCs. The nanofibers were prepared by electrospinning with double jets. The heterogeneous nanofiber composite mainly includes Fe2O3, g-C3N4, and TiO2. The Fe2O3/g-C3N4/TiO2 NFs were characterized by X-ray diffractometer (XRD), and the surface morphology was observed by a field emission scanning electron microscope (Fe-SEM). The electrochemical impedance spectroscopy (EIS) was applied to analyze the impedance of the cell. The incident photon current efficiency (IPCE) measurements were applied to determine the quantum efficiency, and ultraviolet-visible (UV-Vis) spectrophotometer was applied to observe the dye adsorption and absorption wavelength. To understand the performance of the modified photoanodes in DSSCs, we analyzed the photovoltaic parameters. The results suggest that the addition of Fe2O3/g-C3N4/TiO2 NFs is able to improve the conversion efficiency of the modified DSSCs to 4.81%. In addition, the efficiency under different illumination was also analyzed, and the highest conversion efficiency was 6.81% at 30 mW/cm2. [ABSTRACT FROM AUTHOR]

Cycloaddition of CO2 with epoxides is a sustainable and promising route in both CO2 conversion and synthesis of cyclic carbonates. The development of efficient heterogeneous catalysts for this process is a very important research topic. Herein, a series of ZrO2/g-C3N4 materials were prepared using dicyandiamide and ZrOCl2·8H2O as raw materials through simple thermal condensation and wet impregnation methods. The synthesized materials have been analyzed by N2 adsorption–desorption, XRD, TG, FT-IR, UV–vis, XPS, and NH3-TPD techniques. The loading of ZrO2 improved the surface area of g-C3N4 support and the chemical states of Zr on g-C3N4 depended on the preparation temperature. As heterogeneous catalysts, ZrO2/g-C3N4 demonstrated good catalytic activity in cycloaddition of CO2 with propylene oxide, and the maximum yield of propylene carbonate was 68% under 140 °C. Additionally, the catalysts also exhibited good recyclability and substrate generality. [ABSTRACT FROM AUTHOR]

In this study nitrogen-doped carbon quantum dots/graphitic carbon nitride nanosheet (CNQD) composites with different contents of nitrogen-doped carbon quantum dots (NCQDs; 2, 4, 6, and 8 wt%) were synthesized. The morphological, physicochemical, and photoelectrochemical properties were investigated using complementary methods such as scanning electron microscopy (SEM), powder X-ray diffraction (pXRD), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR), UV/Vis spectroscopy in diffuse reflectance (DRS), photoluminescence (PL), nitrogen physisorption (BET), photocurrent response, and electrochemical impedance spectroscopy (EIS). The photocatalytic activity of the synthesized materials was assessed during diclofenac (DCF) degradation in an aqueous solution under visible light irradiation. As a result, improved photocatalytic efficiency in DCF degradation was observed for all the CNQD composites compared with bulk graphitic carbon nitride (bCN) and nanosheet g-C3N4 (CNS). The fastest DCF degradation was observed for the 6 wt% NCQD on the surface of CNS (CNQD-6), which removed 62% of DCF in 3 h, with an associated k value of 5.41 × 10−3 min−1. The performance test results confirmed the contribution of NCQDs to enhancing photocatalytic activity, leading to an improvement factor of 1.24 over bCN. The morphology of the CNS and the synergistic interaction between NCQDs and CNS were essential elements for enhancing photocatalytic activity. The photoelectrochemical data and photoluminescence analyses showed the efficient migration of photoexcited electrons from NCQDs to the CNS. The reduced charge recombination rates in CNQD photocatalysts might be due to the synergistic interaction between NCQDs and CNS and the unique up-conversion photoluminescence properties of NCQDs. Further investigations revealed that the photogenerated superoxide radicals (•O2−) predominated in the degradation of DCF, and this photocatalyst had good reusability and toxicity reduction abilities. This work provides insight into the effects of NCQDs on the CNS surface to enhance its potential to remove emerging organic pollutants from water and wastewater. [ABSTRACT FROM AUTHOR]

Fluorescent graphitic carbon nitride (g-C3N4) doped with various heteroatoms, such as B, P, and S, named Bg-C3N4, Pg-C3N4, and Sg-C3N4, were synthesized with variable band-gap values as diagnostic materials. Furthermore, they were embedded within hyaluronic acid (HA) microgels as g-C3N4@HA microgel composites. The g-C3N4@HA microgels had a 0.5–20 μm size range that is suitable for intravenous administration. Bare g-C3N4 showed excellent fluorescence ability with 360 nm excitation wavelength and 410–460 emission wavelengths for possible cell imaging application of g-C3N4@HA microgel composites as diagnostic agents. The g-C3N4@HA-based microgels were non-hemolytic, and no clotting effects on blood cells or cell toxicity on fibroblasts were observed at 1000 μg/mL concentration. In addition, approximately 70% cell viability for SKMEL-30 melanoma cells was seen with Sg-C3N4 and its HA microgel composites. The prepared g-C3N4@HA and Sg-C3N4@HA microgels were used in cell imaging because of their excellent penetration capability for healthy fibroblasts. Furthermore, g-C3N4-based materials did not interact with malignant cells, but their HA microgel composites had significant penetration capability linked to the binding function of HA with the cancerous cells. Flow cytometry analysis revealed that g-C3N4 and g-C3N4@HA microgel composites did not interfere with the viability of healthy fibroblast cells and provided fluorescence imaging without any staining while significantly decreasing the viability of cancerous cells. Overall, heteroatom-doped g-C3N4@HA microgel composites, especially Sg-C3N4@HA microgels, can be safely used as multifunctional theragnostic agents for both diagnostic as well as target and treatment purposes in cancer therapy because of their fluorescent nature.

In recent years graphitic carbon nitride (g-C3N4) has been considered the most popular candidate for replacing graphene and other similar materials in various applications. The g-C3N4 has unique electronic and mechanical properties, huge photoluminescence in the wide optical region, and promising properties in energy conversion and storage, water splitting, etc. Here we show a simple method of bulk g-C3N4 (BCN) synthesis using thermal polymerization of melamine and ultrathin 2D g-C3N4 nanosheets (NCN) prepared by ultrasonic exfoliation of BCN in water. The g-C3N4 samples were tested with XRD, FTIR, Raman, luminescence spectroscopy, and N2 adsorption at 77 K. We characterize its photocatalytic properties in H2 evolution by direct water splitting. We utilize the low-cost 10 W white LEDs photoreactor with visible light and flow conditions. In the water-splitting reaction, we found that the NCN were about 5 times more reactive than the primary BCN sample. [ABSTRACT FROM AUTHOR]

The 0D-Ag/2D-g-C3N4/3D-TiO2 nano-composite materials were fabricated by simple and mass production method. It involves the combination of incipient wetness impregnation and thermal spreading techniques. By changing the order of impregnation and thermal spreading, silver nanoparticles with "on-top" and "embedded" morphologies could be selectively controlled. The thermal spreading followed by impregnation (TS-IM) leads to the "on-top" structure [Ag/g-C3N4/TiO2] while, the reverse order (IM-TS) produces the embedded silver nanoparticles [g-C3N4/Ag/TiO2]. The 16%Ag/g-C3N4/TiO2 (TS-IM) sample exhibited the best performance due to the presence of very small and highly dispersed silver nanoparticles over g-C3N4/TiO2 sample. The loading of silver not only doubled the specific capacitance but also stabilized the recycling performance against deactivation. This study reveals easy and performance tunable synthesis of Ag/g-C3N4/TiO2 nano-composite materials towards energy-storage applications. [ABSTRACT FROM AUTHOR]

In this work, a novel dual Z-scheme Bi 2 WO 6 /g-C 3 N 4 /black phosphorus quantum dots (Bi 2 WO 6 /g-C 3 N 4 /BPQDs) composites were fabricated and utilized towards photocatalytic degradation of bisphenol A (BPA) under visible-light irradiation. Optimizing the content of g-C 3 N 4 and BPQDs in Bi 2 WO 6 /g-C 3 N 4 /BPQDs composites to a suitable mass ratio can enhance the visible-light harvesting capacity and increase the charge separation efficiency and the transfer rate of excited-state electrons and holes, resulting in much higher photocatalytic activity for BPA degradation (95.6%, at 20 mg/L in 120 min) than that of Bi 2 WO 6 (63.7%), g-C 3 N 4 (25.0%), BPQDs (8.5%), and Bi 2 WO 6 /g-C 3 N 4 (79.6%), respectively. Radical trapping experiments indicated that photogenerated holes (h+) and superoxide radicals (•O 2 −) played crucial roles in photocatalytic BPA degradation. Further, the possible degradation pathway and photocatalytic mechanism was proposed by analyzing the BPA intermediates. This work also demonstrated that the Bi 2 WO 6 /g-C 3 N 4 /BPQDs as effective photocatalysts was stable and have promising potential to remove environmental contaminants from real water samples. [Display omitted] [ABSTRACT FROM AUTHOR]

Improved graphitic carbon nitride (g‐C3N4) was synthesized through a unique one‐step cost‐effective technique involving a dynamic gas bubbling phenomenon using ammonium chloride (NH4Cl) as a bubbling agent. An extensive investigation was carried out to optimize the weight ratio of NH4Cl and melamine during the thermal pyrolysis process. Here, we report an improved form of g‐C3N4 namely "expanded g‐C3N4" with increased interlayer distance and remarkable volume expansion. The surface area of this improved version has notably increased leading to higher photocatalytic efficiency as compared with its counterpart, an synthesized without adding NH4Cl. Synthesized photocatalyst materials were further used to study the Rhodamine B photodegradation under visible light. It was observed that the expanded g‐C3N4 showed a 2.4 times higher photodegradation rate than its counterpart and degraded 94% of the dye in just 30 min. [ABSTRACT FROM AUTHOR]

Organic field-effect transistor (OFET) gas sensors based on conjugated polymer films have recently attracted considerable attention for use in environmental monitoring applications. However, the existing devices are limited by their poor sensing performance for gas analytes. This drawback is attributed to the low charge transport in and the limited charge–analyte interaction of the conjugated polymers. Herein, we demonstrate that the incorporation of graphitic carbon nitride (g-C₃N₄) into the conjugated polymer matrix can improve the sensing performance of OFET gas sensors. Moreover, the effect of graphitic carbon nitride (g-C₃N₄) on the gas sensing properties of OFET sensors based on poly(3-hexylthiophene) (P3HT), a conjugated polymer, was systematically investigated by changing the concentration of the g-C₃N₄ in the P3HT/g-C₃N₄ composite films. The obtained films were applied in OFET to detect NO gas at room temperature. In terms of the results, first, the P3HT/g-C₃N₄ composite films containing 10 wt.% g-C₃N₄ exhibited a maximum charge carrier mobility of ~1.1 × 10−1 cm2 V−1 S−1, which was approximately five times higher than that of pristine P3HT films. The fabricated P3HT/g-C₃N₄ composite film based OFET sensors presented significantly enhanced NO gas sensing characteristics compared to those of the bare P3HT sensor. In particular, the sensors based on the P3HT/g-C₃N₄ (90/10) composite films exhibited the best sensing performance relative to that of the bare P3HT sensor when exposed to 10 ppm NO gas: responsivity = 40.6 vs. 18.1%, response time = 129 vs. 142 s, and recovery time = 148 vs. 162 s. These results demonstrate the enormous promise of g-C₃N₄ as a gas sensing material that can be hybridized with conjugated polymers to efficiently detect gas analytes. [ABSTRACT FROM AUTHOR]

Volatile organic compounds (VOCs) pose significant health risks when inhaled or ingested in large quantities. Metal oxide-based solid-state gas sensors are commonly utilized for VOCs detection, including methanol, however their high operating temperature and selectivity are both biggest challenges. In this context, graphitic carbon nitride (g-C 3 N 4) has emerged as a promising alternative for VOCs sensing due to its superior sensing properties. In this work, Cu and Ag doped g-C 3 N 4 was synthesized via the polycondensation method for VOCs sensing applications. All the samples showed a selective response to methanol at room temperature. Notably, the Ag/g-C 3 N 4 sensor exhibited a significantly enhanced response (~27.5) compared to both undoped g-C 3 N 4 (~3.58) and Cu/g-C 3 N 4 (~9.82) sensors towards 200 ppm methanol. The Ag/C 3 N 4 based sensor showed rapid response (21 s) and recovery (17 s) times, along with excellent short-term and long-term stability. It was found that Ag/C 3 N 4 sensor exhibited a good response to humidity levels ranging from 9 % to 93 % RH, without any significant variation observed when deposited on the ceramic and flexible polyimide substrates. Further, considering its practical applicability, the Ag/C 3 N 4 sensor showed successful detection of alcohol in human breath, highlighting its potential for real-world applications. [Display omitted] [ABSTRACT FROM AUTHOR]

[Display omitted] • Remarkable pharmaceuticals conversion using carbon nitride immobilized on a film. • Photocatalytic performance evaluated in total recirculation and dead-end regimes. • Carbonate anions and low turbidity effect enhance removal in natural waters. • EEM fluorescence spectroscopy coupled with PARAFAC used to quantify conversion. The validation of immobilized photocatalysts is a fundamental matter regarding the scaling-up process in the photocatalytic degradation of aqueous pollutants in natural surface waters. This work presents the comprehensive evaluation of graphitic carbon nitride (g-C 3 N 4, CN) immobilized onto a polymeric film (F) placed inside a continuous flow operation planar reactor for the removal of a mixture of pharmaceuticals (i.e. , venlafaxine, citalopram, carbamazepine, tramadol, ketoprofen, and diclofenac, 3 μM each) under visible light. The resulting CN/F (8 mg of CN per cm2 of film and with significant preservation of optical and structural properties after more than 350 h of reuse) yielded the complete removal under total recirculation of all pharmaceuticals after 90 min under visible light, except for ketoprofen, probably ascribed to competition for photogenerated holes, as suggested by the proposed mechanism. Under dead-end continuous flow mode, the steady-state conversion averaged 67% in deionized water, increasing up to 76%, and 80% in natural surface waters obtained from the Douro River and the effluent from a wastewater treatment plant (Northwestern Portugal), respectively, related to the promotion effect of carbonates anions and organic matter. The assessment of excitation-emission matrix (EEM) fluorescence spectroscopy coupled with parallel factor (PARAFAC) analysis further demonstrated the removal (ca. 50%) of the protein- and humic-like substances contained in the collected wastewater, thus evidencing the continuous flow mode performance of the immobilized photocatalyst for real environmental applications. [ABSTRACT FROM AUTHOR]

Catalytic cycloaddition of CO2 is a practical strategy to synthesize cyclic carbonate and is also a sustainable route to utilize CO2. Graphitic carbon nitride (g-C3N4) is a typical solid base but showed limited activity in catalytic cycloaddition of CO2 due to its lack of acidic sites. Herein, acid–base bifunctional g-C3N4 materials were synthesized. The incorporation of Zr and Al cations into g-C3N4 induced the formation of acidic sites and meanwhile enhanced the basic strength. The characterization results revealed that metal cations might coordinate with nitrogen atoms of g-C3N4. As heterogeneous catalysts, the synthesized ZrxAlyO/g-C3N4 materials showed superior catalytic activity to ZrO2/g-C3N4 in the cycloaddition of CO2 with propylene oxide. Under optimal reaction conditions, the maximum yield of propylene carbonate reached 90%, and the catalysts were able to be recycled at least five times without any loss in catalytic activity. [ABSTRACT FROM AUTHOR]

We report on the investigation of graphitic carbon nitride (g-C3N4) for carbon dioxide (CO2) sensor applications. g-C3N4 is prepared by the thermal polycondensation of thiourea and sprayed onto a substrate with interdigitated electrodes. The resulting sensor device exhibited a high sensitivity to CO2 molecules of ~200 ppm, a high responsivity of ~730 ms at 40 °C and a full recovery time of 36 s. Furthermore, a set of various characterization measurements demonstrated the excellent stability of both the g-C3N4 nanosheets and the fabricated gas sensor device. Meanwhile, density functional theory (DFT) calculations for the bulk and monolayer models, based on tri-s-triazine, revealed the optoelectronic properties of g-C3N4 and the interaction energy with CO2, which is evaluated at −0.59 eV. This value indicates the very good affinity of g-C3N4 nanosheets to CO2 molecules. Our findings shed light on the potential for g-C3N4 to be used for the development of high-performing gas sensor devices. [ABSTRACT FROM AUTHOR]

As a prospective visible-light-responsive photochemical material, graphitic carbon nitride (g-C3N4) has become a burgeoning research hot topics and aroused a wide interest as a metal-free semiconductor in the area of energy utilization and conversion, environmental protection due to its unique properties, such as facile synthesis, high physicochemical stability, excellent electronic band structure, and sustainability. However, the shortcomings of high recombination rate of charge carriers, relatively low electrical conductivity and visible light absorption impede its practical application. Various strategies, such as surface photosensitization, heteroatom deposition, semiconductor hybridization, etc., have been applied to overcome the barriers. Among all the strategies, functional nanocarbon materials with various dimensions (0D∼3D) attract much attention as modifiers of g-C3N4 due to their unique electronic properties, optical properties, and easy functionalization. More importantly, the properties of these functional nanocarbon materials can be tuned by various dimensions and thus there will be a way to overcome the defects of g-C3N4 by choosing different dimensional carbon materials. Distinguishing from some present reviews, this review starts with the fundamental physicochemical characteristics of g-C3N4 materials, followed by analyzing the advantages of functional nanocarbon materials modifying g-C3N4. Then, we present a systematic introduction to various dimensional carbon materials.The design philosophy of carbon/g-C3N4 composites and the advanced studies are exemplified in detail. Finally, a nichetargeting summary and outlook on the major challenges, opportunities for future research in high-powered carbon/g-C3N4 composites was proposed.

Among the wide range of chemosensors, the development of fluorescent chemosensors has shown continued interest in the domains of chemistry, materials, biology, and ecology due to their simple operation, low cost, high sensitivity, specificity, live observation, and short response time. As a metal‐free and fluorescent chemosensor, graphitic carbon nitride (g‐C3N4) has emerged as a new research hotspot and received widespread interdisciplinary attention which is attributable to its favorable electrical band structure, high physicochemical stability, and "earth‐abundant" nature. This review summarizes the structure, synthetic methods, and various techniques for the modification of g‐C3N4. This review also covers the development of g‐C3N4 nanomaterials‐based sensors and their potential applications in a variety of fields. Furthermore, the comparative performance of various sensors, existing obstacles, and perspectives of g‐C3N4‐based nanomaterials are also outlined in detail. [ABSTRACT FROM AUTHOR]

Elemental doping has been widely adopted to enhance the photoactivity of graphitic carbon nitride (g-C 3 N 4). Correlating photocatalytic performance with experimental conditions could improve upon the current trial-and-error paradigm, but it remains a formidable challenge. In this study, we have developed machine learning (ML) models to link experimental parameters with hydrogen (H 2) production rate over element-doped graphitic carbon nitride (D-g-C 3 N 4). Material synthesis parameters, material properties, and H 2 production conditions are fed to the ML models, and the H 2 production rate is derived as the output. The trained ML models are effective in predicting the H 2 production rate using experimental data, as demonstrated by a satisfactory correlation coefficient for the test data. Sensitivity analysis is performed on input features to elucidate the ambiguous relationship between H 2 production rate and experimental conditions. The ML model can not only identify important features that are well-recognized and widely investigated in the literature, which supports the efficacy of the developed models but also reveals insights on less explored parameters that might also demonstrate significant impacts on photocatalytic performance. The method described in the present study provides valuable insights for the design of elemental doping strategies for g-C 3 N 4 to improve the H 2 production rate without conducting time-consuming and expensive experiments. Our models may be used to revolutionize future catalyst design. [Display omitted] • Hydrogen generation on element-doped g-C 3 N 4 was modeled by machine learning. • The developed model demonstrated high prediction accuracy of H 2 production rate. • The relative importance of controllable experimental conditions was ranked. • Preferred experimental conditions for each input feature was identified. [ABSTRACT FROM AUTHOR]

This research employed g-C3N4 nanosheets in the hydrothermal synthesis of TiO2/g-C3N4 hybrid photocatalysts. The TiO2/g-C3N4 heterojunctions, well-dispersed TiO2 nanoparticles on the g-C3N4 nanosheets, are effective photocatalysts for the degradation of monochlorophenols (MCPs: 2-CP, 3-CP, and 4-CP) which are prominent water contaminants. The removal efficiency of 2-CP and 4-CP reached 87% and 64%, respectively, after treatment of 25 ppm CP solutions with the photocatalyst (40TiO2/g-C3N4, 1 g/L) and irradiation with UV–Vis light. Treatment of CP solutions with g-C3N4 nanosheets or TiO2 alone in conjunction with irradiation gave removal efficiencies lower than 50%, which suggests the two act synergically to enhance the photocatalytic activity of the 40TiO2/g-C3N4 nanocomposite. Superoxide and hydroxyl radicals are key active species produced during CP photodegradation. In addition, the observed nitrogen and Ti3+ defects and oxygen vacancies in the TiO2/g-C3N4 nanocomposites may improve the light-harvesting ability of the composite and assist preventing rapid electron-hole recombination on the surface, enhancing the photocatalytic performance. In addition, interfacial interactions between the MCPs (low polarity) and thermally exfoliated carbon nitride in the TiO2/g-C3N4 nanocomposites may also enhance MCP degradation. [ABSTRACT FROM AUTHOR]

In this study, a novel magnetic bucky gel (MBG) is synthesized and coupled with dispersive magnetic solid‐phase extraction for preconcentration and determination of trace levels of nitrite in various water samples. The MBG is prepared by dispersing magnetic graphitic carbon nitride nanocomposite (g‐C3N4@Fe3O4) in a choline chloride‐urea deep eutectic solvent (DES) (1:2, molar ratio). The DES acts as a disperser and surface modifier for g‐C3N4/Fe3O4 nanocomposites simultaneously and leads to superior uptake of the analyte in a shorter time. The sorbent is characterized by Fourier transform infrared spectroscopy, X‐ray diffraction, and field emission scanning electron microscopy. The NO2− determination is carried out by UV–vis spectrophotometry. Variable factors on preconcentration of NO2− including pH, composition of MBG, contact time, sample volume, eluent type, eluent volume, and elution time are optimized. Under optimum condition, the limit of detection is 1.56 µg L−1, the linear dynamic range extends from 5.14 to 900.00 µg L−1, the relative standard deviation (n = 5) and the preconcentration factor are 2.7% and 100, respectively. The method is successfully used for the preconcentration of NO2− ions in different water samples and gave recoveries between 89% and 103%. [ABSTRACT FROM AUTHOR]

The future challenges associated with the shortage of fossil fuels and their current environmental impacts intrigued the researchers to look for alternative ways of generating green energy. Solar‐driven water splitting into oxygen and hydrogen is one of those advanced strategies. Researchers have studied various semiconductor materials to achieve potential results. However, it encountered multiple challenges such as high cost, low photostability and efficiency, and required multistep modifications. The conjugated polymers (CPs) have emerged as promising alternatives for conventional inorganic semiconductors. The CPs offer low cost, sufficient light absorption efficiency, excellent photo and chemical stability, and molecular optoelectronic tunable characteristics. Furthermore, organic CPs also present higher flexibility to tune the basic framework of the backbone of the polymers, amendments in the sidechain to incorporate desired functionalities, and much‐needed porosity to serve better for photocatalytic applications. This review article summarizes the recent advancements made in visible‐light‐driven water splitting covering the aspects of synthetic strategies and experimental parameters employed for water splitting reactions with special emphasis on conjugated polymers such as linear CPs, planarized CPs, graphitic carbon nitride (g‐C3N4), conjugated microporous polymers (CMPs), covalent organic frameworks (COFs), and conjugated polymer‐based nanocomposites (CPNCs). The current challenges and future prospects have also been described briefly. [ABSTRACT FROM AUTHOR]

[Display omitted] This paper discusses the adsorption of metal single-atoms (SAs) on graphitic C 3 N 4 (gCN) multilayered surface models based on density functional theory (DFT) calculations. We systematically searched stable adsorption sites on gCN and showed that the cavity site is preferred for metal SAs. We also discussed the usefulness of several descriptors, such as the distance between the SA and gCN, charge donation (electron transfer), and atomic radius, for evaluating the SA adsorption energy, based on the linear regression method. In addition, the most stable adsorption energy for fifth- and sixth-row metals can be predicted using only the "group" descriptor of the periodic table. The group descriptor is closely related to the atomic radius, and hence the stability of fifth- and sixth-row metals is determined from the fit between the SA radius and the gCN cavity size. The study findings facilitate the development of various metal-dopant techniques for gCN-based applications. [ABSTRACT FROM AUTHOR]

Synthetic organic pigments from the direct discharge of textile effluents are considered as colossal global concern and attract the attention of scholars. The efficient construction of heterojunction systems involving precious metal co-catalysis is an effective strategy for obtaining highly efficient photocatalytic materials. Herein, we report the construction of a Pt-doped BiFeO3/O-g-C3N4 (Pt@BFO/O-CN) S-scheme heterojunction system for photocatalytic degradation of aqueous rhodamine B (RhB) under visible-light irradiation. The photocatalytic performances of Pt@BFO/O-CN and BFO/O-CN composites and pristine BiFeO3 and O-g-C3N4 were compared, and the photocatalytic process of the Pt@BFO/O-CN system was optimized. The results exhibit that the S-scheme Pt@BFO/O-CN heterojunction has superior photocatalytic performance compared to its fellow catalysts, which is due to the asymmetric nature of the as-constructed heterojunction. The as-constructed Pt@BFO/O-CN heterojunction reveals high performance in photocatalytic degradation of RhB with a degradation efficiency of 100% achieved after 50 min of visible-light irradiation. The photodegradation fitted well with pseudo-first-order kinetics proceeding with a rate constant of 4.63 × 10−2 min−1. The radical trapping test reveals that h+ and •O2− take the leading role in the reaction, while the stability test reveals a 98% efficiency after the fourth cycle. As established from various interpretations, the considerably enhanced photocatalytic performance of the heterojunction system can be attributed to the promoted charge carrier separation and transfer of photoexcited carriers, as well as the strong photo-redox ability established. Hence, the S-scheme Pt@BFO/O-CN heterojunction is a good candidate in the treatment of industrial wastewater for the mineralization of organic micropollutants, which pose a grievous threat to the environment.

This study presents the development and evaluation of a novel anti-corrosion coating based on ZIF-67 metal-organic framework decorated g-C 3 N 4 nanosheets with inbuilt benzotriazole (BTA) and cerium (Ce3+) corrosion inhibitors. The primary focus was on the synthesis of Ce-BTA@ZI@GN nanopigments and their integration into epoxy coatings to enhance the corrosion resistance of mild steel (MS) in marine environments. Comprehensive characterization techniques, including FTIR, XRD, XPS, BET, and UV–Vis analyses, confirmed the successful development of the nanopigments and their homogeneous dispersion within the epoxy matrix. The corrosion mitigation performance was assessed using electrochemical impedance spectroscopy (EIS), potentiodynamic polarization (PDP), and salt spray tests. According to the PDP findings, the corrosion rate (CR) of MS immersed in a solution containing the released BTA and Ce3+ inhibitors decreased by 50 % compared to a blank solution. EIS results indicated that the inclusion of BTA and Ce3+ inhibitors resulted in a nearly 5-fold improvement in total resistance compared to the blank/EP coating. Furthermore, salt spray tests conducted over 20 days demonstrated the exceptional anti-corrosion properties of the BTA@ZI@GN and Ce-BTA@ZI@GN nanopigments, highlighting their potential for long-term protection against corrosion in harsh marine conditions. These findings suggest that the developed coatings not only provide effective corrosion resistance but also offer self-healing properties, making them suitable for advanced protective applications in marine engineering. [Display omitted] [ABSTRACT FROM AUTHOR]

This study examines the electrochemical behaviour of a hybrid composite material of graphitic carbon nitride/Nickel ferrite/Polyaniline (g-C 3 N 4 /NiFe 2 O 4 /PANI) synthesized by hydrothermal method, coupled with in-situ polymerisation. The ensuing g-C 3 N 4 /NiFe 2 O 4 /PANI composite demonstrates superior characteristics for energy storage applications. Through a comprehensive analysis, we elucidate the combined effects of the distinct components, revealing improved electrochemical properties. The composite exhibits improved galvanostatic charge/discharge exhibiting a specific capacitance of 770 Fg−1 at 1 Ag−1 current density. This research underscores the perspective of the g-C 3 N 4 /NiFe 2 O 4 /PANI composite as a promising candidate for advanced energy storage systems. [Display omitted] [ABSTRACT FROM AUTHOR]

Graphitic carbon nitride (g-C 3 N 4) has been widely used to improve photoelectrochemical (PEC) activity owing to its outstanding photoresponse and strength. In this study, g-C 3 N 4 hollow tubes decorated with SnO 2 quantum dots were prepared by combining hydrothermal and post-annealing approaches. In particular, different characterization techniques such as Fourier transform infrared, photoluminescence, ultraviolet–visible, and X-ray photoelectron spectroscopies were employed to investigate the electrical and optical behaviors of the samples. The prepared samples exhibited considerable photoresponse and excellent PEC performance, producing hydrogen. Furthermore, the heterostructures among SnO 2 and g-C 3 N 4 encouraged carrier separation, improving the PEC ability. In addition, the applied voltage showed numerous effects on generating charge carriers for the anodes in a 0.1 M sodium hydroxide electrolyte. Therefore, the proposed approach is simple and effective and can be used to enhance the performance of the PEC activity. [Display omitted] • Synthesized a novel heterostructures of g-C 3 N 4 hollow tubes decorated with SnO 2 quantum dots • Achieved a highly stable structure of hollow tubes anchored with SnO 2 nanostructures • Heterostructures showed an improved light absorption ability of and higher electrochemical activity • g-C 3 N 4 /SnO 2 tubes exhibited a lowest resistance of 1.46 kΩ with a current density of 3.06 mAcm−2 [ABSTRACT FROM AUTHOR]

The photocatalytic degradation technique is one of the suitable ways of dealing with environmental pollutant decontamination. This study demonstrates the ability of graphitic carbon nitride (g-C 3 N 4) nanocomposites containing tellurium (Te) and molybdenum disulfide (MoS 2) to photocatalytically destroy organic cationic methylene blue (MB) dye, which is primarily used in the textile industry. Using the alkali treatment approach, layered graphitic carbon nitride (g-C 3 N 4) was created. Using MoS 2 and Te, several g-C 3 N 4 nanocomposites were created using ultrasonic calcination techniques. After the MoS 2 and Te were immobilized individually, the composites underwent a methodical characterization process utilizing a variety of instruments, including XRD and SEM. Using a 2D layered nano-g-C 3 N 4 substrate, the photo-catalytic degradation reaction of MB was observed, and a UV spectrophotometer was used to determine the absorbance of the MB dye. Using 0.2 % MoS 2 /g-C 3 N 4 and 5 % Te/g-C 3 N 4 , the photocatalytic degradation efficiency of the MB dye (10, 15, and 20 mg/L) solution was examined. In comparison to other produced nanocomposites, the 5 % Te/g-C 3 N 4 composite was shown to have the highest photocatalytic activity in terms of dye degradation ability, and about 100 % of the MB dyes were degraded in less than 60 minutes. As the concentration of MB increased, the dye degradation efficiency of g-C 3 N 4 nanocomposites steadily dropped, and the degradation rate of MB was around 1.5 mg/L. [Display omitted] • Graphitic Carbon Nitride (g-C 3 N 4) was synthesized by an alkali treatment approach. • The proposed g-C 3 N 4 composite was used for toxic methylene blue (MB) dye degradation. • The possible photo-catalytic charge transfer mechanism was determined and investigated. [ABSTRACT FROM AUTHOR]

The absence of stable and highly active non-precious metal electrocatalysts as a substitute to precious metal i.e., Pt (state-of-the-art) for methanol oxidation reaction in the application of direct methanol fuel cell considerably impedes the commercialization of these energy devices. In this work the electrocatalytic investigation of Fe-In MOF and its g-C3N4-based composites (i.e., 5–8 wt% g-C3N4@ Fe-In MOF) for methanol oxidation is reported. All the catalysts were prepared via solvothermal method. XRD, SEM, EDX, and FTIR were used to characterize the Fe-In MOF and its 5–8wt% g-C3N4 composites. In comparison to other prepared g-C3N4 based Fe-In MOF composites, the 7wt% g-C3N4 @ Fe-In MOF catalyst showed much greater electrochemical activity (i.e., 95.54 mA/cm2) and stability of 72.45% in 1 M NaOH and 3 M CH3OH. Due to graphitic carbon nitride specified high catalytic activity, intercalation, ion exchange, and redox properties. Further, the availability of iron (Fe) and indium (In) may also show a significant role in enhancing the electrocatalytic performance of 7wt% g-C3N4 @ Fe-In MOF over Fe-In MOF. They could be viewed as stable and economical electrocatalysts due to their numerous advantageous characteristics in structure, content, and nitrogen doping level. [ABSTRACT FROM AUTHOR]

[Display omitted] • Developed a novel hydrothermal method for synthesizing 3D-Fe 2 O 3 /2D-g-C 3 N 4 heterojunction materials. • Investigated structural changes with varying iron loading; optimal at 22 wt%. • Achieved effective encapsulation of 3D-Fe 2 O 3 by 2D-g-C 3 N 4 at 22 wt% loading, enhancing surface contacts. • Demonstrated high specific capacitance of 950 Fg−1 and robust recycling performance up to 2000 cycles. Designing heterojunction nanocomposites is crucial for optimizing supercapacitor electrodes. This study addresses the challenge by introducing a facile synthesis method for creating 3D-α-Fe 2 O 3 @2D-g-C 3 N 4 heterojunctions through a bulk carbon nitride-assisted hydrothermal process. During this process, the growth of ferric oxide particles coincides with the exfoliation and deposition of carbon nitride, leading to simultaneous structural changes in both iron oxide and carbon nitride phases. The resulting composite's properties strongly correlate with the iron oxide loading. Comprehensive characterization using XRD, FTIR, SEM-EDAX, XPS and TEM identified three distinct structures for α-Fe 2 O 3 /g-C 3 N 4 composites based on iron oxide loading: low, medium, and high. The medium-loaded sample demonstrated superior electrochemical performance, attributed to better interfacial contact and the formation of 3D-Fe 2 O 3 @2D-g-C 3 N 4 heterojunctions. This composite, with an optimized 22 wt% iron oxide loading, exhibited a maximum specific capacitance of 925.1 Fg−1 at 5 mVs−1 and 498.6 Fg−1 at 6 Ag−1 in charge-discharge analysis, with stable performance over 2000 cycles. Overall, this research presents an enhanced hydrothermal method for facile preparation of effective α-Fe 2 O 3 /g-C 3 N 4 heterojunction materials. [ABSTRACT FROM AUTHOR]

Mo-doped graphitic carbon nitride (Mo/g-C3N4) was successfully prepared by thermal condensation of a Mo/melamine precursor in a semi-closed alumina crucible at 550 °C without atmosphere. Thermogravimetric analysis (TGA) was used to evaluate the polymerization route of the precursor, and theoretical and experimental investigations revealed that the Mo species were likely dispersed and anchored to the pyridinic groups of g-C3N4. As a result, the obtained Mo/g-C3N4 displayed exceptional catalytic activity in the oxidative desulfurization of dibenzothiophene (DBT) with H2O2. The effects of catalyst dosage, O/S ratio, and temperature on the catalytic properties of Mo/g-C3N4 were investigated. The kinetic studies revealed a pseudo-first-order kinetic process for DBT oxidation with an apparent activation energy of 43.6 kJ mol−1. Experimental and theoretical evaluation of the Mo/g-C3N4 stability suggests that catalytically active Mo species are progressively leached from the g-C3N4 structure. The decrease in the Mo–N bond order after forming reactive peroxo-Mo(VI) groups was associated with catalyst deactivation. [ABSTRACT FROM AUTHOR]

Liquid-phase selective oxidation of alcohols to aldehydes using molecular oxygen as an oxidant is one of the most important transformations in organic synthesis and green chemistry. In this work, nitrogen-containing ordered mesoporous materials (NOMCs) were prepared and utilized as supports to load vanadia. The physical and chemical properties of the synthesized VxOy/NOMC materials were characterized by N2 adsorption–desorption, XRD, TEM, Raman, and XPS. The characterization results exhibited that NOMC could well disperse vanadia species and there was a steady interaction between V and N of NOMC. In selective oxidation of benzyl alcohol using oxygen as an oxidant, the synthesized VxOy/NOMC materials showed good and stable catalytic performance, affording a maximum yield of benzaldehyde up to 80% at 95 °C. [ABSTRACT FROM AUTHOR]