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We present a significant advancement in the synthesis of carbon nitride framework (CN) using a rapid electric bunsen burner (EBB) method, achieving notable outcomes within a mere 10-min timeframe. The resulting material, designated as U10, exhibits amplified porosity and a semi-scrolling structure with a thickness measuring at 2.1 nm. In comparison to conventionally synthesized urea-derived carbon nitride (UCN) through a box furnace, the U10 demonstrates significantly heightened photocatalytic activity in both hydrogen (H 2) production and the removal of organic dye (methylene blue) from aqueous solutions. To ensure the robustness and reliability of this synthetic approach, two additional precursors were subjected to testing, and their rates of H 2 production were analyzed. The exceptional photocatalytic performance of the U10 material arises from its distinctive structural attributes and the synergistic influences of oxygen doping (O-doping) and the cyano (-CΞN) functional group, which are introduced during the rapid synthesis strategy. This innovative and streamlined strategy for synthesizing CN not only conserves energy and time but also significantly reduces production costs, rendering it a feasible method for the large-scale production of carbon nitride material. [Display omitted] • Developed a fast synthesis of defect-rich CN using a controlled EBB method. • Identified defect-rich CN with -CΞN groups and O, enhancing charge dynamics. • Improved charge transfer and electron-hole lifespan shown by light-dependent EPR. • Calculated thermodynamically stable structure using first-principle calculations. • Tracked intermediate products in fast CN synthesis initiated by urea. [ABSTRACT FROM AUTHOR]

Herein, three g-C3N4(MCN/TCN/UCN), obtained by the direct pyrolysis of melamine/urea/thiourea respectively, were introduced as supports to optimize the NH3-SCR activity of Ce-W-Ti catalyst. Compared to CWT-400-Air, CWT@g-C3N4(2)-300-N2 exhibits lower crystalline anatase TiO2 and larger specific surface area, which improves the dispersion of Ce/W/Ti species on catalysts surface. Furthermore, the introduction of g-C3N4 as supports also contributes to doping C/N elements into Ce-W-Ti catalyst and increases the Ce3+/(Ce3++Ce4+) and Oα/(Oα+Oβ) molar ratios on catalyst surface. These all are advantageous to the NH3-SCR activity. However, UCN shows better promotional effect than MCN and TCN. This might be mainly attributed to the loose and porous stacked layered fold structure of UCN, the larger BET surface area, higher dispersion of Ce/W/Ti species and moderate weak/medium-strong acid sites of CWT@UCN(2)-300-N2. At the same time, the influence of carbon nitride amount, calcination atmosphere and calcination temperature on the NH3-SCR activity of CWT@g-C3N4 catalyst were also investigated. [ABSTRACT FROM AUTHOR]

Photocatalytic (PC) CO2 reduction reaction (CO2RR) into value‐added oxygenated products is one of the most promising ways of solving climate warming change and energy crisis simultaneously. To reach higher selectivity and productivity of fuel products, it still remains great challenge in controlling both simultaneous sequential multi‐electron/proton shuttling through different transporting pathway, which determines the intermediates and final products. Consequently, a multifunctional nickel‐perylene‐carbon nitride nanosheet (NS‐P‐g‐C3N4‐Ni) are constructed rationally to strengthen the electron and proton transfer via different pathway at the same time through molecule‐level carbon backbone with excellent conductivity/charge capacity and proton transport via pendant functional group of ‐NH2 from water oxidation sites of Ni metal cluster on perylene skeleton. CO2 adsorption is enhanced and reduction energy is reduced by the complexation of N‐atom site of NS‐P‐g‐C3N4‐Ni and adjustment of co‐planarity, optimizing conduction band and band gap with energy controllable techniques. In situ FT‐IR/Raman/EPR spectra identified and verified the transformation of active intermediates (*CO2•−, *COOH and H*COO−) adsorbed on the NS‐P‐g‐C3N4‐Ni by complexation and highly selective production of formic acid (60%) is achieved. This work sheds light on the construction of effective well‐structured sites in photocatalytic CO2 reduction to produce value‐added products with higher selectivity and productivity. [ABSTRACT FROM AUTHOR]

The local atomic environments of single‐atom photocatalysts play a decisive role in determining the solar‐to‐hydrogen energy conversion efficiency. However, controllably modulating the microstructure of single‐atom sites to enhance catalytic activity and deeply understanding the structure‐property relationship remain great challenges. Herein, electron‐rich P atoms are introduced to accurately regulate the local coordination environment and electronic configuration of Fe single atoms and construct a unique asymmetrical FeN3P2 motif into carbon nitride (FeN3P2‐CN) for significantly improving the photocatalytic H2 evolution activity and stability. Specifically, in the absence of noble metal cocatalyst and photosensitizer, the FeN3P2‐CN achieves a remarkable H2 evolution rate of 2668.5 µmol g−1 h−1 under visible light irradiation (λ > 420 nm), more than 105 times higher than that of unregulated FeN4 sample. Systematic characterizations and theoretical calculations unveil that the FeN3P2 single‐atom sites not only significantly broaden the photoabsorption region and facilitate the charge separation and interfacial transfer, but also efficiently promote adsorption and activation of H2O. This work paves a promising pathway to design novel single‐atom photocatalysts at the atomic level for achieving highly efficient water‐splitting performance. [ABSTRACT FROM AUTHOR]

Photocatalysis technology is green and sustainable for reduction of nitrobenzene to aniline. However, the photocatalytic activity of pure carbon nitride is limited by the high photogenerated carrier recombination rates. Carbon nitride nanosheets (CNN) were prepared by prepolymerization and high temperature calcination and cadmium sulfide (CdS) nanoparticles were in situ grown between the layers of carbon nitride for facilitating the separation and transfer of charges. As a result, the optimal composite catalyst (CdS/CNN‐2) exhibited superior photocatalytic activity with nitrobenzene reduction rate of 83 % within 60 min. This work presents an effective strategy for designing catalysts for the photocatalytic reduction of nitrobenzene. [ABSTRACT FROM AUTHOR]

This study presents a comprehensive evaluation of catalytic ozonation as an effective strategy for indigo dye bleaching, particularly examining the performance of four carbon-based catalysts, activated carbon (AC), multi-walled carbon nanotubes (MWCNT), graphitic carbon nitride (g-C3N4), and thermally etched nanosheets (C3N4-TE). The study investigates the efficiency of catalytic ozonation in degrading Potassium indigotrisulfonate (ITS) dye within the constraints of short contact times, aiming to simulate real-world industrial wastewater treatment conditions. The results reveal that all catalysts demonstrated remarkable decolorization efficiency, with over 99% of indigo dye removed within just 120 s of mixing time. Besides, the study delves into the mechanisms underlying catalytic ozonation reactions, elucidating the intricate interactions between the catalysts, ozone, and indigo dye molecules with the processes being influenced by factors such as PZC, pKa, and pH. Furthermore, experiments were conducted to analyze the adsorption characteristics of indigo dye on the surfaces of the materials and its impact on the catalytic ozonation process. MWCNT demonstrated the highest adsorption efficiency, effectively removing 43.4% of the indigo dye color over 60 s. Although the efficiency achieved with C3N4-TE was 21.4%, which is approximately half of that achieved with MWCNT and less than half of that with AC, it is noteworthy given the significantly lower surface area of C3N4-TE. [ABSTRACT FROM AUTHOR]

In the recent years, piezocatalysis process is attracting extensive attention as an emerging technology to remove persistent organic pollutants. Its advantage is that it relies on mechanical energy and is independent of electricity and light source, unlike electrocatalysis or photocatalysis processes. In this research, 2H-MoS2/g-C3N4 heterojunction materials were successfully fabricated via the hydrothermal method and utilized as piezocatalyst in the treatment of Rhodamine B. This material exhibited a highly efficient piezo-catalyst effect, with the piezo-response amplitudes of 78.8 mV, almost doubled compared to 39.8 mV of 2H-MoS2. The degradation of Rhodamine B by ultrasonic irradiation could reach 75.4% only after 5 s and then 94.9% in 60 s without light assistance. This ultra-rapid degradation rate is attributed to the electron–hole pairs and transfer of the charge-carriers on the surface of 2H-MoS2 and g-C3N4 via S-scheme heterojunction model, which was confirmed by density functional theory study. The piezo-catalytic ability of the material can still be improved for better treatment of other organic pollutants in aqueous environment. [ABSTRACT FROM AUTHOR]

The present study focuses on the elaboration of magnetic nanocomposites by the in situ incorporation of magnetite (Fe3O4) nanoparticles (NPs) with spherical and nanoflower-like morphologies in graphitic carbon nitride (g-C3N4) sheets using two different synthetic routes. Nanomaterials are characterized by TEM, SEM, XRD, FTIR, BET, zetametry, vibrating sample magnetometry, and UV–vis absorption spectroscopy. The decoration of the carbon nitride matrix with the magnetic NPs enhanced optical and textural properties. The influence of the morphology of the magnetic NPs on the adsorptive and photocatalytic properties of the nanocomposites under different pH conditions (4.5, 6.9, and 10.6) was assessed from batch tests to remove methylene blue (MB) from aqueous solutions. In extreme pH conditions, the nanocomposites exhibited lower or equivalent MB removal capacity compared to the pure g-C3N4. However, at neutral medium, the nanocomposite with incorporated Fe3O4 nanoflowers showed a significantly higher removal efficiency (80.7%) due to the combination of a high adsorption capacity and a good photocatalytic activity in this pH region. The proposed nanocomposite is a promising alternative to remove cationic dyes from water by magnetic assistance, since no pH adjustment of the polluted effluent is required, reducing costs and environmental impact in the dyeing industry. [ABSTRACT FROM AUTHOR]

Graphitic‐carbon nitride (g‐C3N4), a metal‐free two‐dimensional layered semiconductor material, holds great potential for energy conversion, environmental remediation, and sensing. However, the limited solubility of g‐C3N4 in conventional solvents hinders its widespread application. Improving the dissolution of g‐C3N4 in the liquid phase is highly desired but challenging. Herein, we report an innovative approach to dissolve g‐C3N4 using ZnCl2 molten salt hydrates. The solubility of g‐C3N4 in the solution reaches up to 200 mg mL−1. Density functional theory (DFT) results suggest that ZnCl+H2O is the key species that leads to charge redistribution on g‐C3N4 surface and promotes the dissolution of carbon nitride in the solution. Furthermore, through dilution, the dissolved carbon nitride can be effectively recovered while maintaining its intrinsic chemical structure. The resultant regenerated C3N4 (r‐C3N4) exhibits nanobelt morphology and demonstrates a substantially improved photocatalytic activity in H2O2 production. The rate of H2O2 production over the r‐C3N4 reaches 20,228 μmol g−1 h−1, which is 6.2 times higher than that of pristine g‐C3N4. This green and efficient dissolution route of g‐C3N4 offers an effective approach for its diverse applications. [ABSTRACT FROM AUTHOR]

ABSTRACT Biomimetic heterogeneous catalysts were prepared by immobilization of meso‐tetrakis(4‐carboxyphenyl)porphyrinatomanganese(III) acetate (MnTCPP) and meso‐tetrakis(4‐carboxyphenyl)porphyrinatoiron(III) chloride (FeTCPP) on graphitic carbon nitride (g‐C3N4) nanosheets. The anchored catalysts were characterized by various techniques such as scanning electron microscopy, thermogravimetric analysis, powder X‐ray diffraction, ultraviolet visible, photoluminescence, flame atomic absorption, and Fourier transform infrared spectroscopy. The thermogravimetric analysis demonstrated that the prepared catalysts were thermally stable up to almost 350°C, exhibiting high thermal stability. In the following, the catalytic efficiency of the prepared nanocatalyst was also investigated for the oxidation of various olefins with hydrogen peroxide (as a green oxidant) and the effect of various parameters which may affect the catalytic efficiency was optimized. The maximum conversion (100% for α‐methylstyrene and 97% for cyclooctene) was obtained in the presence of MnTCPP@C3N4. The Mn porphyrin nanocatalyst shows higher catalytic efficiency compared to the Fe porphyrin. [ABSTRACT FROM AUTHOR]

Photocatalysis is an efficient technology for the degradation of pollutants. However, there is still much room for improvement in its degradation efficiency. In this study, a pyrrolic N‐rich g‐C3N4 (PN‐g‐C3N4) framework was synthesized with transition metal M (M=Fe, Co, Ni, Cu, Cr, and Mn) atomic sites coordinated onto it. Then, a series of single atomic metals M anchored to PN‐g‐C3N4 (M/PN‐g‐C3N4) are constructed for peroxodisulfate activation. Their order of catalytic activity follows Fe>Cr>Ni>Cu≈Co>Mn, in particular the degradation rates of the TCH for Fe‐PN‐g‐C3N4 are 3.74 times higher than that of undoped PN‐g‐C3N4. These carefully regulated pyrrolic N‐rich Fe sites demonstrate outstanding performance in degrading organic pollutant. As an exemplary model, the Fe/PN‐g‐C3N4 catalyst efficiently drives the catalytic oxidation of TCH through Fenton‐like reaction under visible light, showcasing exceptional cycle stability and a broad effective pH range of 3.0–11.0. The synergy between photocatalysis and Fe doped catalysis results in increased generation and separation of charge carriers, along with the cyclic transformation of the Fe3+/Fe2+ couple. This combination significantly enhances the Fenton‐like performance, making it a highly effective process for pollutant degradation. [ABSTRACT FROM AUTHOR]

Photogenerated carriers transfer and separation from the substance itself to produce spatial isolated electron-hole pairs is crucial for the utilization of composite photocatalysts in the field of photocatalytic hydrogen (H 2) evolution. Herein, novel oxygen-doped porous graphitic carbon nitride (g-C 3 N 4) micro-sheets decorated with Ag 2 MoO 4 have been fabricated by a facile calcination method followed by in situ deposition strategy. The physicochemical properties of the obtained Ag 2 MoO 4 /OC 3 N 4 composites were characterized via SEM, TEM, EDS, XRD, N 2 adsorption-desorption, XPS, UV–vis DRS, PL, transient photocurrent response, and EIS, as well as DFT calculation. In addition, the effects of Ag 2 MoO 4 content, type of scavengers, pH value of reaction solution and dosage of scavenger on photocatalytic H 2 production were investigated. The results show that the modification of ammonium acetate thermal polymerization with urea could enhance the porosity of g-C 3 N 4 and its specific surface area. The Ag 2 MoO 4 nanoparticles are highly dispersed on the OC 3 N 4 surface, reducing the charge transfer resistance at their interfaces. The OC 3 N 4 photocatalyst achieves H 2 yield of 8629.11 μmol/g over 2 h, which is about 1.46 times higher than that of C 3 N 4. The H 2 production amount over the optimal Ag 2 MoO 4 /OC 3 N 4 composite photocatalyst (50 mg) is further enhanced to 16619 μmol/g, which is 1.93 and 180 times higher than that of OC 3 N 4 and Ag 2 MoO 4 , respectively. The S-scheme charge transfer mechanism of Ag 2 MoO 4 /OC 3 N 4 is proposed based on the DFT calculation. This work provides a facile and easy strategy to develop g–C 3 N 4 –based photocatalysts through adjusting chemical composition and photocatalytic properties. [Display omitted] • Oxygen-doped porous g-C 3 N 4 decorated with Ag 2 MoO 4 was fabricated. • Elemental sliver was generated in the photocatalytic H 2 evolution process. • Ag 2 MoO 4 /OC 3 N 4 /Pt system exhibited an excellent performance of H 2 evolution. • Construction of S-scheme mode improved the separation and transfer of carriers. [ABSTRACT FROM AUTHOR]

Carbon nitrides can form coordination compounds or metallic oxides in the presence of transition metals, depending on the reaction conditions. By adjusting the pH to basic levels for mild synthesis with metals, composites like g-C3N4-M(OH)x (where M represents metals) were obtained for nickel (II) and manganese (II), while copper (II) yielded coordination compounds such as Cu-g-C3N4. These materials underwent spectroscopic and electrochemical characterization, revealing their photocatalytic potential to generate superoxide anion radicals—a feature consistent across all metals. Notably, the copper coordination compound also produced significant hydroxyl radicals. Leveraging this catalytic advantage, with band gap energy in the visible region, all compounds were activated to disinfect E. coli bacteria, achieving total disinfection with Cu-g-C3N4. The textural properties influence the catalytic performance, with copper's stabilization as a coordination compound enabling more efficient activity compared to the other metals. Additionally, the determination of radicals generated under light in the presence of dicloxacillin supported the proposed mechanism and highlighted the potential for degrading organic molecules with this new material, alongside its disinfectant properties. [ABSTRACT FROM AUTHOR]

The corrosion resistance of two multilayered metallic/ceramic coatings deposited from a 50:50 vol.% CrAl target, with a-CNx top layer deposited by High Power Impulse Magnetron Sputtering (HIPIMS) onto A11 tool steel was studied. The CrAl/CrAlN multilayer coatings with, and without a-CNx top layer, characterized by FE-SEM resulted in two different layers thicknesses of 1.5 and 1.2 µm, respectively. A glassy-like morphology was observed in the CrAl layer and in the CNx top layer, whereas the CrAlN layers exhibited a columnar morphology. XRD-analysis revealed a CrAlN FCC structure (111), accompanied of a Cr phase (110). Raman spectra for the CNx top layer, showed the characteristic peaks of G (Graphitic) and D (Disorder) for molecular vibrations in a-CNx containing thin films. Peaks were located between 1200 and 1700 cm−1. XPS results, on the other hand, showed the characteristic peaks for Cr, Al, N, present in both coatings. The deconvoluted peaks agreed with Cr2p3/2, Al2p, and N1s binding energies, respectively; besides; XRF analysis confirms the bulk chemical composition of these coatings. The electrochemical impedance, and potentiodynamic polarization tests in a 3.5 wt.% NaCl solution, displayed an improvement in the corrosion resistance for a-CNx top layer, and up to 15 times in Rp values compared to AISI A11 substrate. [ABSTRACT FROM AUTHOR]

Carbon nitrides, metal‐free semiconducting materials, have unique molecular structure and semiconducting properties which have inspired researchers to utilize them as photocatalysts for the sustainable production of hydrogen. However, they suffer from a few drawbacks including fast charge‐carrier recombination rate and low charge transfer efficiency owing to their amorphous and less conducting wall structure which remain as significant challenge for achieving breakthrough in photocatalytic water splitting. Herein, the study reports a supramolecular approach of coupling thiourea and trimesic acid for designing highly efficient C‐doped carbon nitride photocatalysts in which the π‐electron density is precisely manipulated. The developed C‐doped carbon nitride demonstrates the fine‐tuned band positions, the mitigated electron–hole recombination, and enhanced conductivity, resulting in the facilitation of significantly enhanced hydrogen generation through the photocatalytic water splitting under the solar‐simulated light. The position and distribution of C‐doping in the carbon nitride framework are characterized by using advanced analytical techniques such as X‐ray photoelectron spectroscopy, near‐edge X‐ray absorption fine structure spectroscopy, and electron paramagnetic resonance spectroscopy together with the first‐principles studies of the electronic structure and energetics of doping. The remarkable increase in photocatalytic hydrogen generation by using developed C‐doped carbon nitride brings one step closer to achieving a green hydrogen economy. [ABSTRACT FROM AUTHOR]

[Display omitted] In this work, Br, K-doped and cyano group-rich carbon nitride (CN) were prepared via pyrolysis of molten urea and 6-Bromopyridine-3-carbaldehyde, followed by re-calcination with potassium thiocyanate. The hydrogen peroxide (H 2 O 2) evolution and in situ tetracycline (TC) mineralization performances of the prepared samples were studied. The optimal sample could produce 9127 μmol g–1 h–1 H 2 O 2 from 10 vol% ethanol solution and air atmosphere, which was 10.9 times higher than that of pristine CN. With addition of 4 mg L–1 Fe2+ ions, 97.2% of TC (10 mg L–1) and 98.7% of total organic carbon were removed in 30 min under the actions of holes, hydroxyl and superoxide radicals. The high H 2 O 2 yield and TC mineralization ratio were attributed to the increased light absorption, efficient electrons-holes separation, enhanced surface O 2 adsorption (0.3878 mmol g−1), and accelerated conversion from Fe3+ to Fe2+ ions. Meanwhile, the system possessed good reusability in H 2 O 2 evolution and TC removal. It is expected that this work can provide new ideas to design CN-based photo-Fenton system to treat wastewater. [ABSTRACT FROM AUTHOR]

[Display omitted] The development of highly efficient oxygen evolution reaction (OER) catalysts based on more cost-effective and earth-abundant elements is of great significance and still faces a huge challenge. In this work, a series of transition metal (TM) embedding a newly-defined monolayer carbon nitride phase is theoretically profiled and constructed as a catalytic platform for OER studies. Typically, a four-step screening strategy was proposed to rapidly identified high performance candidates and the coordination structure and catalytic performance relationship was thoroughly analyzed. Moreover, the eliminating criterion was established to condenses valid range based on the Gibbs free energy of OH*. Our results reveal that the as-constructed 2FeCN/P exhibits superior activity toward OER with an ultralow overpotential of 0.25 V, at the same time, the established 3FeCN/S configuration performed well as a bifunctional OER/ORR electrocatalysis with extremely low overpotential ηOER/ηORR of 0.26/0.48 V. Overall, this work provides an effective framework for screening advanced OER catalysts, which can also be extended to other complex multistep catalytic reactions. [ABSTRACT FROM AUTHOR]

Photocatalysis-assisted removal of uranium has been proven as an effective method for the elimination of radioactive pollution from wastewater. In this work, carbon nitride materials were synthesized in potassium hydroxide (KOH) molten salt and applied to photocatalytic uranyl extraction. Obtained materials were confirmed to possess the triazine-s-heptazine structure by NMR, XPS and UV-Vis characterization, and exhibited a wider visible light absorption than graphitic carbon nitride (g-C3N4). The photocatalytic activity of the carbon nitride materials was tailored by varying the precursor mass fractions. The carbon nitride obtained at 80% melamine as precursor (K-CN-80) exhibited the highest photocatalytic extraction ability and its photocatalytic reaction rate is 6.6 times faster than that of g-C3N4. The influence of sacrificial agents was studied and the results showed that triethanolamine inhibited U(VI) photoreduction, but methanol can accelerate U(VI) photoreduction by consuming photogenerated holes. This unary KOH molten salt synthesis method has exceptional potential applications in the preparation of carbon nitrides, and the obtained products showed potential in extracting U(VI) from aqueous solutions for use in nuclear fuel industry and for U(VI) environmental pollution cleanup. [ABSTRACT FROM AUTHOR]

The key to designing photocatalysts is to orient the migration of photogenerated electrons to the target active sites rather than dissipate at inert sites. Herein, we demonstrate that the doping of phosphorus (P) significantly enriches photogenerated electrons at Ni active sites and enhances the performance for CO2 reduction into syngas. During photocatalytic CO2 reduction, Ni single‐atom‐anchored P‐modulated carbon nitride showed an impressive syngas yield rate of 85 μmol gcat−1 h−1 and continuously adjustable CO/H2 ratios ranging from 5:1 to 1:2, which exceeded those of most of the reported carbon nitride‐based single‐atom catalysts. Mechanistic studies reveal that P doping improves the conductivity of catalysts, which promotes photogenerated electron transfer to the Ni active sites rather than dissipate randomly at low‐activity nonmetallic sites, facilitating the CO2‐to‐syngas photoreduction process. [ABSTRACT FROM AUTHOR]

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Highly-crystallized carbon nitride (HCCN) nanosheets exhibit significant potential for advancements in the field of photoelectric conversion. However, to fully exploit their potential, a thorough understanding of the fundamental excitonic photophysical processes is crucial. Here, the temperature-dependent excitonic photoluminescence (PL) of HCCN nanosheets and amorphous polymeric carbon nitride (PCN) is investigated using steady-state and time-resolved PL spectroscopy. The exciton binding energy of HCCN is determined to be 109.26 meV, lower than that of PCN (207.39 meV), which is attributed to the ordered stacking structure of HCCN with a weaker Coulomb interaction between electrons and holes. As the temperature increases, a noticeable reduction in PL lifetime is observed on both the HCCN and PCN, which is ascribed to the thermal activation of carrier trapping by the enhanced electron–phonon coupling effect. The thermal activation energy of HCCN is determined to be 102.9 meV, close to the value of PCN, due to their same band structures. Through wavelength-dependent PL dynamics analysis, we have identified the PL emission of HCCN as deriving from the transitions: σ *–LP, π *– π, and π *–LP, where the π *–LP transition dominants the emission because of the high excited state density of the LP state. These results demonstrate the impact of high-crystallinity on the excitonic emission of HCCN materials, thereby expanding their potential applications in the field of photoelectric conversion. [ABSTRACT FROM AUTHOR]

Non-woven jute (NWJ) produced from carpet industry waste was oxidized by H2O2 or alkali-treated by NaOH and compared with water-washed samples. Changes in the structure of the NWJ, tracked by X-ray diffraction (XRD), showed that both chemical treatments disrupt hydrogen bond networks between cellulose Iβ chains of the NWJ fibers. Thereafter, nano-carbon nitride (nCN) was impregnated, using a layer-by-layer technique, onto water-washed jute samples (nCN-Jw), NaOH-treated samples (nCN-Ja) and-H2O2 treated samples (nCN-Jo). Analysis of the Fourier transform infrared spectroscopy (FTIR) spectra of the impregnated samples revealed that nCN anchors to the water-washed NWJ surface through hemicellulose and secondary hydroxyl groups of the cellulose. In the case of chemically treated samples, nCN is preferentially bonded to the hydroxymethyl groups of cellulose. The stability and reusability of prepared nCN-jute (nCN-J) samples were assessed by tracking the photocatalytic degradation of Acid Orange 7 (AO7) dye under simulated solar light irradiation. Results from up to ten consecutive photocatalytic cycles demonstrated varying degrees of effectiveness across different samples. nCN-Jo and nCN-Ja samples exhibited declining effectiveness over cycles, attributed to bond instability between nCN and jute. In contrast, the nCN-Jw sample consistently maintained high degradation rates over ten cycles, with a dye removal percentage constantly above 90%. [ABSTRACT FROM AUTHOR]

Constructing a heterojunction is an effective way to overcome the handicaps of single-component photocatalysts for the photocatalytic N2 reduction reaction (PNRR). However, the fundamental photophysical processes between two semiconductors with different nanostructures are still unclear. Drawing upon a combination of experimental observations and theoretical calculations, a series of binary nanohybrid photocatalysts of MoS2 (nanodot, monolayer, and few nanolayers) and carbon nitride are systematically evaluated as potential N2 reduction reaction photocatalysts. Owing to the atomically well-defined interfacial interaction between MoS2 and graphitic carbon nitride (GCN), charge accumulates in MoS2. Meanwhile, the electron density of MoS2 increases with the reduction of nanosize, thereby facilitating N2 adsorption on the Mo-edge and boosting the potential-determining step of the desorption of the NH3 molecule. Simultaneously, the MoS2 nanodot anchored on GCN manifests a compelling photothermal effect upon solar light irradiation and raises the temperature of the compound in situ, leading to efficient charge transfer and thereby enhancing the photocatalytic performance. Encouragingly, the final product reaches a high ammonia synthesis rate of 2.71 mmol h–1 g–1 at ambient conditions and an apparent quantum of 0.62% at 430 nm. Establishing the relationship between the nano-, electronic structure and PNRR performance of MoS2/GCN heterojunction materials provides valuable insights for their potential application in PNRR technology. [ABSTRACT FROM AUTHOR]

High fire hazard, including heat release and toxic volatile production, has been the bottleneck in expanding the application of polystyrene (PS). Here, a heteroatom doping strategy is adopted to strengthen the flame-retardant effect of graphitic carbon nitride (g-C3N4) on PS. It is observed that the doped g-C3N4 fillers (PCN-1, PCN-2, PCN-3, BCN-1, BCN-2, BCN-3, PBCN-1, PBCN-2, and PBCN-3) show nanosheet-like morphologies, while common g-C3N4 presents bulky morphology. Also, the doped g-C3N4 fillers show higher thermal stability than common g-C3N4. Consequently, the doped g-C3N4 fillers show a better dispersion state in the PS matrix, benefiting the generation of an efficient barrier network. Cone results reveal that using the doped g-C3N4 fillers endows the polymer with a lower peak heat release rate, a peak smoke production rate, and a peak CO yield (PCOY). Typically, adding CN results in corresponding reductions of 7.2, 3.74, and 12.4%, respectively. By contrast, incorporating PCN-2 leads to decreases of 39.9, 23.0, and 53.2%, respectively. Thermogravimetric analysis/infrared spectrometry analysis indicates that the use of these additives contributes to the inhibition of the release of decomposed volatiles. Thus, it is firmly believed that utilizing heteroatom-doped g-C3N4 impairs the fire hazard of the polymer. [ABSTRACT FROM AUTHOR]

Creating cross‐linking to establish efficient inter‐chain charge‐transfer channels in carbon nitride represents a promising strategy for enhancing its photocatalytic capabilities. Molten salt‐assisted calcining has emerged as a method for preparing cross‐linked carbon nitrides. However, the precise influence of molten salts on the molecular structure of carbon nitride remains to be fully elucidated. Herein, we develop a KCl guided cross‐linking reaction to preliminarily reveal the formation mechanism of cross‐linking. The cross‐linking reaction is initiated by the pre‐coordination of amino groups with K+. Subsequent heating at high temperature converts the amino groups into chlorines. Then, dechlorination leads to the formation of cross‐linking. Thus, this cross‐linking reaction can be accurately described as a pre‐coordination‐induced, two‐step deamination reaction. The pre‐coordination step plays a pivotal role in the cross‐linking process. Sufficient pre‐coordination results in a relatively high cross‐linking degree of the as‐prepared CNK‐2. Consequently, CNK‐2 demonstrates a significantly enhanced photocatalytic H2O2 production, with a generation rate of 682 μmol L−1 h−1, about 59 times that of traditional carbon nitride. [ABSTRACT FROM AUTHOR]

The development and application of nuclear energy is often considered as a potential solution to meet the increasing energy demand. However, it is important to acknowledge that the utilization of nuclear energy resources and the treatment of nuclear waste pollution pose significant challenges that require careful consideration and management. Therefore, it is crucial to address the challenges of uranium pollution treatment and uranium resource recovery to ensure the sustainable development of nuclear energy. The technology of photocatalytic reduction has been found to have a synergistic adsorption reduction ability, which allows it to overcome the thermodynamic limitations of single adsorption removal. As a result, photocatalytic reduction technology is widely recognized as having great potential in the removal and recycling of uranium in nuclear waste liquid. One of the key factors for the effective application of this technology is the acquisition of a catalyst with high photocatalytic reduction ability. Nitride carbon materials are considered an ideal photocatalyst for photocatalytic reduction of U（Ⅵ） due to their excellent photochemical properties, excellent physicochemical adjustability, and good chemical stability. However, the pure g-C3N4 photocatalyst still suffers from its low separation efficiency of photogenerated charge carriers, which results in unsatisfactory photocatalytic activity. In recent years, research on modifying and applying carbon nitride has provided in-depth insights into the reduction of uranium through photocatalysis. Discussing the strategy of modifying C3N4, constructing heterojunction nanostructures, and utilizing them for the photocatalytic reduction of uranium, along with the mechanisms involved. This review summarizes the recent significant progress on the design of g-C3N4-based heterostructure photocatalysts and their special separation/transfer mechanisms of photogenerated charge carriers. On the one hand, according to the key steps of photocatalytic uranium reduction, modification strategies using g-C3N4 photocatalysts can be classified into the following groups: morphology modification, band-structure regulation, and heterostructure construction. Moreover, according to the different transfer mechanisms of photogenerated charge carriers between g-C3N4 and the coupled components, the g-C3N4-based heterostructure photocatalysts can be divided into the following categories: g-C3N4-based conventional Type-Ⅱ heterojunction, g-C3N4-based Z-scheme heterojunction, g-C3N4-based S-scheme heterojunction, and g-C3N4/metal heterostructure. We also focused on the structure-activity relationship between the modification of photocatalytic materials based on carbon nitride and their photocatalytic reduction performance for U（Ⅵ）, as well as the mechanism of their catalytic reduction removal. Finally, this section offers concluding remarks and prospects for exploring the challenges and opportunities faced by advanced carbon nitride-based photocatalytic materials in the removal of uranium pollution and the recovery of uranium resources. It also provides directions for future breakthroughs.

The photocatalytic conversion of soluble U(Ⅵ) to insoluble U(Ⅳ) is regarded as an effective method for the separation of solution uranium. During the photocatalytic reactions, the design of photocatalyst plays a role. As a metal free polymer semiconductor, carbon nitride(CN) has attracted increasing attentions in photo-catalytic reduction of U(Ⅵ) under visible light irradiation due to its low cost, easy preparation, excellent physicochemical stability and adjustable structure. However, the application of carbon nitride in photocatalytic U(Ⅵ) reduction is limited by its low photocatalytic reduction efficiency, which is caused by the poor reactive sites low separation rate of charge carriers, and slow transport efficiency of electrons. This study aimed to evaluate the transformation of U(Ⅵ) in aqueous solution over Y-doped CN(YCN). YCN photocatalysts with different amount of Y3+ were prepared by in situ doping to modify the energy band structure and physicochemical properties of carbon nitride. It was revealed that the presence of Y3+ changed the in-plane periodic topology and inter-layer stacking structure of the tri-s-triazine unit of carbon nitride, resulting in the incomplete polymerization of the tri-s-triazine unit. The doping of Y3+ lead to the formation of porous structure in YCN, which increases the specific surface area and the active sites. Comparing with pristine CN, YCN showes enhanced absorbance for light and increases separation rate of charge carriers. The average fluorescence life is subsequently increased under light irradiation, which is 1.8 times for YCN2 than the pristine CN. The EPR spectra demonstrates that, compared to CN, significantly more \begin{document}$ · {\mathrm{O}}_2^- $\end{document} radicals and less \begin{document}$· {\mathrm{OH}} $\end{document} radicals are generated on YCN2 under light irradiation. The free radical trapping experiments verifies that \begin{document}$ · {\mathrm{O}}_2^- $\end{document} radicals act as the dominant reactive species for the reduction of U(Ⅵ) and the small amount of other radicals do not bring obvious influence. The enhanced generation of \begin{document}$ · {\mathrm{O}}_2^- $\end{document} radicals on YCN2 therefore provides favorable conditions for the photocatalytic reduction of U(Ⅵ). When using methanol as a sacrificial agent, it can remove about 95% of U(Ⅵ) within 20 min for the YCN2-containing system under light. The rate of the photocatalytic reduction of U(Ⅵ) on YCN2(0.112 min−1) is 5.3 times higher than CN(0.021 min−1). Analysis of the products reveals that water-soluble U(Ⅵ) is reduced in the photocatalytic reaction, with approximately 80% U(Ⅳ) and 20% U(Ⅵ). The soluble U(Ⅵ) is mainly reduced to insoluble UO2+x deposited on the surface of YCN by \begin{document}$ { · {\mathrm{O}}_2^- } $\end{document} radicals. This study improves the photocatalytic performance of CN for the reduction of U(Ⅵ) by Y3+ doping.

Double Z-scheme Bi 2 S 3 /S-CN/Bi 2 O 3 heterojunction hollow nanotubes with defective structure were synthesized and exhibited efficient photocatalytic amine oxidation owing to the synergistic of each component, hollow nanotube structure, and unique defect-transit double Z-scheme heterostructure. [Display omitted] The rational design of Z-scheme heterojunction hybrid photocatalysts is considered a promising way to achieve high photocatalytic activity. In this study, a dual Z-scheme heterojunction with bismuth sulfide (Bi 2 S 3) nanorods and bismuth oxide (Bi 2 O 3) nanoparticles anchored Sulfur-doped carbon nitride (S-CN) nanotubes (Bi 2 S 3 /S-CN/Bi 2 O 3) is designed and fabricated through the ordinal metal ion adsorption, pyrolysis, and sulfidation processes using supramolecular rods as precursor. Compared with pristine Bi 2 S 3 , Bi 2 O 3 , and CN, the dual Z-scheme tube-shaped Bi 2 S 3 /S-CN/Bi 2 O 3 catalyst exhibited a significantly improved photocatalytic activity in amine oxidation. The optimized Bi 2 S 3 /S-CN/Bi 2 O 3 nanostructure exhibits a 97.6 % benzylamine conversion and 99.4 % imine selectivity within 4 h under simulated solar light irradiation. The excellent activity of Bi 2 S 3 /S-CN/Bi 2 O 3 nanotubes can be attributed to the characteristic hollow defect band structure and efficient charge separation and transfer achieved by the dual Z-scheme charge transfer mechanism, which was systematically studied using electron spin resonance spectroscopy, Kelvin probe force microscope, and other techniques. The optimized dual Z-scheme heterojunction hybrid photocatalyst maintains the high oxidizing ability of Bi 2 S 3 and Bi 2 O 3 and the excellent reducing ability of CN, thereby significantly enhancing the photocatalytic activity. This research provides a facile and feasible synthesis strategy for designing dual Z-scheme heterojunctions with defect band structure to improve the photocatalytic activity. [ABSTRACT FROM AUTHOR]

Pyridinic nitrogen vacancy in carbon nitride for photo-self Fenton-like purification of organic contaminants. [Display omitted] • Carbon nitride with pyridinic nitrogen vacancy was successfully prepared. • Pyridinic nitrogen vacancy promotes charge transfer and activating O 2 into H 2 O 2. • Pyridinic nitrogen vacancy accelerates carbon nitride to adsorb organic contaminants. • Photo-self Fenton-like reaction for photocatalytic degradation of organics. This work reports a carbon nitride with pyridinic nitrogen-vacancy (N 2C V-CN), which purifies organic contaminants via an in-situ photo-self Fenton-like reaction. Experiments and calculations demonstrated that the nitrogen-vacancy induces lone-paired (LP) and symmetry-unpaired electrons, promoting the formation of low-energy LP-π hybridized orbitals and helping to overcome the pairing energy required for oxygen to accept electrons. Furthermore, the nitrogen-vacancy accelerates film and intra-particle diffusion rates of organic contaminants on N 2C V-CN, creating beneficial conditions for reactive oxide species to mineralize organic contaminants. Under sunlight and atmospheric oxygen, a photo-self Fenton-like reaction involving proton-coupled electron transfer occurred on the surface of N 2C V-CN. Furthermore, by integrating photocatalysis with flocculation, about 99.1 % suspended substance, 45.5 % chemical oxygen demand, and 38.4 % biological oxygen demand were reduced from polluted river-water. Constructing N 2C V-CN and understanding its crucial role offer theoretical and methodological insights into the in-situ purification of contaminated water bodies. [ABSTRACT FROM AUTHOR]

[Display omitted] Catalysts composed of nanocluster and single-atom (SA) were extensively used to enhance electrocatalytic water splitting performance, whereas study of their photocatalytic hydrogen (H 2) evolution activity was limited. Herein, carbon nitride (CN) decorated by ruthenium (Ru) cocatalysts existed as SA + cluster, cluster + nanoparticles (NPs), and NPs were prepared by impregnation and calcination processes. The correlation between existential form, content of Ru cocatalyst and H 2 evolution rate were carefully discussed. It was found that Ru NPs were favor for water molecule adsorption, whereas Ru SAs and clusters facilitated H 2 desorption. Theoretical calculations revealed that Ru clusters + NPs cocatalyst were beneficial for H* intermediate formation. Water splitting tests found that 1.07 wt% Ru NPs + cluster modified CN showed the highest H 2 evolution rate of 13.64 mmol h−1 g−1, which was 266.4 and 1.5 times higher than those of CN and Ru NPs (2.33 wt%) decorated CN, respectively. This work deeply reveals the influences of existential form of Ru cocatalysts on photocatalytic water splitting of CN, and provides thought in designing new cocatalysts to largely enhance H 2 evolution. [ABSTRACT FROM AUTHOR]

[Display omitted] Despite the excellent photocatalytic activity under visible light, graphitic carbon nitride (g-C 3 N 4) exhibits a high overpotential for hydrogen evolution. To address this issue, cocatalysts have been utilized to modify g-C 3 N 4. However, the use of high-performance cocatalysts typically involves noble metals such as platinum and palladium, which are cost-prohibitive for practical applications. Therefore, the development of efficient and cost-effective cocatalysts is crucial for advancing photocatalysis. In this study, we synthesized a new Ni-based cocatalyst, nickel thiocarbonate (NiCS 3), to enhance the photocatalytic hydrogen evolution reaction (HER) on g-C 3 N 4. The NiCS 3 /g-C 3 N 4 composite demonstrated a significantly increased hydrogen evolution rate of 951 μmol·h−1·g−1 under visible light, representing more than a 105-fold improvement compared to pure g-C 3 N 4. Theoretical calculations suggested that the enhanced performance in photocatalytic hydrogen production can be attributed to the generation of a built-in electric field within the composite, facilitating efficient charge carrier separation and migration. Additionally, the C site in NiCS 3 provides a favorable Gibbs free energy of adsorbed H* (Δ G H ∗ ). This work underscores the potential of NiCS 3 as a viable alternative to precious metals in photocatalytic hydrogen production using g-C 3 N 4. [ABSTRACT FROM AUTHOR]

Despite challenges still remain, simultaneous regulation of light absorption, carrier separation and efficient exposed active sites of carbon nitride for the photocatalytic production of hydrogen (H 2) are essential to help alleviate the energy crisis and achieve carbon neutrality. Using in-plane phenyl groups doping and interlayer sulfate groups modification, we demonstrated an eco-friendly and facile method for excogitating porous tubular graphitic carbon nitride (PhSO-TCN2.5). The PhSO-TCN2.5 has hollow tubular morphology with ultrathin pore walls, which offers more exposed active sites, shortened charge diffusion path and readily available diffusion channels. More importantly, the in-plane phenyl groups doping and interlayer sulfate groups modification enabled significant intense the visible light absorption, accelerated carrier transfer due to the electron transport channel between the interlayers. Meanwhile, PhSO-TCN2.5 possesses exceptionally adjusted band gap structure and more negative conduction band potential. Accordingly, the above synergistic effects contribute to the efficient photocatalytic efficiency in H 2 evolution to 8709.29 μmol g−1 h−1. In addition to the apparent quantum yield of 12.0% at 420 nm, that far exceeds the reported tubular and functional group-modified carbon nitride photocatalysts. This document offers guidance on designing and producing photocatalysts with high efficiency. [Display omitted] • g-C 3 N 4 with phenyl groups doping and sulfate groups modification is fabricated. • Intercalated sulfate groups facilitate the transfer and separation of charge carriers. • The tubular structure and phenyl groups contribute to improve the light absorption. • The photocatalytic H 2 evolution of PhSO-TCN2.5 is 8709.29 μmol h−1 g−1 and AQY is 12 %. • A possible photocatalytic mechanism is proposed. [ABSTRACT FROM AUTHOR]

In industrial production, the preparation of cubic boron nitride (cBN) under high temperature and pressure wastes a large amount of unreacted hexagonal boron nitride (hBN). This study aims to use this BN waste (wBN) as a raw material, composite it with g-C3N4 to construct wBN/g-C3N4 composites, and apply the composites in the field of photocatalysis. wBN/g-C3N4 composites were prepared by simple calcination using wBN and ammonium cyanide as raw materials. Results showed that a heterogeneous structure was formed in the composite photocatalyst, with a decrease in its bandgap width and a significant increase in its ability to absorb light. The simulated sunlight photocatalytic activity of composite photocatalysts was significantly better than that of single wBN or g-C3N4. The photocatalytic performance of B2 sample, composed of a 4:3 ratio of wBN and melamine in the raw materials, demonstrated the highest efficiency. Under simulated solar illumination, it was capable of degrading 99.3% of MB within 60 min. The experimental results with additional capture agents indicated that the main reactive species of the composite photocatalyst were superoxide radicals (·O2−) and holes (h+). [ABSTRACT FROM AUTHOR]

This work reports the design and manufacturing of a new electrochemical sensing platform for the monitoring of prednisolone (PE) steroid in physiological fluids. To reach this, palladium (Pd) nanoparticles were successfully deposited on carbon nitride (CN) nanosheets using chemical reduction approach. The prepared CN-Pd hybrid material along with an ionic liquid (IL, 1-ethyl-3-methylimidazolium tetrafluoroborate) were employed for modification of a low expense carbon paste electrode (CPE). The CN-Pd-IL modified CPE was electrochemically characterized to ensure the electrochemical performance towards PE reduction. The important parameters affecting the performance of the PE sensor including CN-Pd dosage and pH of buffer were studied and optimized. The CN-Pd-IL modified CPE illustrated a wide linear response in a PE concentration range of 0.6 nM to 60 nM using SWV methodology. The limit of detection (based on S/N=3) was 0.1 nM at optimal conditions. The suggested PE sensor illustrated the satisfactory reproducibility and good matrix-effectless character. In addition, the CN-Pd-IL modified CPE was facilely used for the electrochemical measuring of PE in the serum samples of athletes with high recovery values (97.6%-102.4%). The proposed methodology can be employed for the sensitive, selective and fast detection of PE.

Abstract Lithium-ion batteries (LIBs) are widely used in portable energy storage. The capacity of commercial graphite is difficult to improve due to the stoichiometry limit of LiC6 of graphite, thus new anodes need to be developed to meet the demand of high-energy–density LIB. The growing interest in graphitized carbon nitride (g-C3N4) stems from its structural resemblance to graphite and its capacity to offer abundant adsorption and intercalation sites. However, g-C3N4, as a semiconductor, has a low lithium transfer rate due to its poor conductivity and high diffusion resistance. Improving the electron transport rate of g-C3N4 and reducing the adsorption energy barrier of Li+ in g-C3N4 are the keys to improving the electrochemical performances of g-C3N4. In this study, lignin and melamine were homogeneously mixed using the spray drying method, followed by the preparation of covalently bonded C3N4/LC material through a one-step carbonization process. The uniform dispersion of g-C3N4 in amorphous carbon can improve the conductivity and reduce the diffusion energy barrier of Li+. As a result, the C3N4/LC-x anode has better electrochemical behavior, including higher reversible capacity, better rate performance, and cycle stability.

Graphitic carbon nitride (g-C3N4) is emerging as a promising visible-light photocatalyst while the low crystallinity with sluggish charge separation/migration dynamics significantly restricts its practical applications. Currently, synthesizing highly crystalline g-C3N4 with sufficient surface activities still remains challenging. Herein, different from using alkali molten salts which is commonly reported, we propose an approach for synthesis of highly crystalline g-C3N4 with FeCl3/KCl rock/molten mixed salts. The rock salt can serve as the structure-directing template while molten salt provides the required liquid medium for re-condensation. Intriguingly, the synthesized photocatalyst showed further enhanced crystallinity and improved surface area along with high π→π∗ excitation compared with crystalline C3N4 prepared from conventional molten-salt methods. These catalytically advantageous features lead to its superior photocatalytic and piezocatalytic activities with a high reactivity for overall water splitting that is not commonly reported for C3N4. This work provides an effective strategy for structural optimization of organic semiconductor based materials and may inspire new ideas for the design of advanced photocatalysts.

Abstract The development of environmentally friendly catalysts for organic transformations is of great importance in the field of green chemistry. Aldehyde oxidation reactions play a crucial role in various industrial processes, including the synthesis of pharmaceuticals, agrochemicals, and fine chemicals. This paper presents the synthesis and evaluation of a new metallosalen carbon nitride catalyst named Co(salen)@g-C3N4. The catalyst was prepared by doping salicylaldehyde onto carbon nitride, and subsequently, incorporating cobalt through Schiff base chemistry. The Co(salen)@g-C3N4 catalyst was characterized using various spectroscopic techniques including Scanning Electron Microscopy (SEM), X-ray Diffraction (XRD), Infrared Spectroscopy (IR), and Thermogravimetric Analysis (TGA). Furthermore, after modification with salicylaldehyde, the carbon nitride component of the catalyst exhibited remarkable yields (74–98%) in oxidizing various aldehyde derivatives (20 examples) to benzoic acid. This oxidation reaction was carried out under mild conditions and resulted in short reaction times (120–300 min). Importantly, the catalyst demonstrated recyclability, as it could be reused for five consecutive runs without any loss of activity. The reusable nature of the catalyst, coupled with its excellent yields in oxidation reactions, makes it a promising and sustainable option for future applications.

A series of Ag2CrO4/g-C3N4 composites with photocatalytic hydrogen (H2) production were prepared by in-situ chemical deposition method. The phase composition, functional group structure, microscopic morphology, elemental compositions and their species of the composites were characterized using X-ray diffraction, Fourier transform infrared, field emission scanning electron microscope, transmission electron microscope and X-ray photoelectron spectroscopy. The light absorption properties and photogenerated carrier separation of the samples were investigated by UV-visible diffuse reflectance spectra, photoluminescence spectroscopy and photocurrent testing. The H2 production performance of the photocatalysts and the influencing factors were investigated experimentally. The results showed that the introduction of Ag2CrO4 did not change the originally heterocyclic structure of g-C3N4, and nanostructure Ag2CrO4 was dispersed on the surface of g-C3N4. Although Ag2CrO4 had no H2 production effect, the H2 production rate of the composite increased first and then decreased with the increase of Ag2CrO4 content. The H2 production rate of the optimal photocatalyst Ag2CrO4/C3N4-4% was 2.7 times that of pure g-C3N4. The reason was mainly attributed to the appearance of Z-type heterojunction between of Ag2CrO4 and g-C3N4, which broadened the visible light response range of g-C3N4, reduced the charge transfer impedance, and promoted the separation and migration of photogenerated carriers. [ABSTRACT FROM AUTHOR]

A comprehensive vision has been promoted for straightforward oxidative amidation, deploying a majority of amines and aldehydes via a robust and novel nano-catalyst of W/Co@g-C3N4. This approach would yield the primary, secondary, and tertiary amides with excellent efficiency experiencing mild conditions, in which the environmentally benign oxidizing agent of TBHP was predominantly used, holding remarkable attributes such as cost-effectiveness as well as facile approachability. More specifically, simultaneously embedding of W and Co on the surface of g-C3N4 has been an integral part in effectually progressing direct operation of amidation reaction in comparison with pure g-C3N4. The most important point highlighted in this work is the productive contribution of materials choice in designing as well as manufacturing approaches with respect to new required products while giving the most extreme level of accessible quality and efficiency with the most reduced level of costs. Emphatically, a variety of extraordinary merits can be awarded to this as-prepared catalyst, such as notable activity, reasonable recyclability, sustainable nature, and easy work-up. Moreover, a simple process was conducted to synthesize W/Co@g-C3N4 evaluated by employing FT-IR, XRD, SEM, EDX, and TGA. Highlights: Nano-W/Co@g-C3N4 was introduced for the first time as a robust and efficient catalyst. Employing of tungsten and cobalt revealed a considerable shift in the catalytic performance of g-C3N4. Short reaction time as well as high yield with respect to the reported literatures for formation of amide bond through direct oxidative amidation. W/Co@g-C3N4 could be used in five consecutive runs without any significant drop in activity. [ABSTRACT FROM AUTHOR]

[Display omitted] The development of highly reusable, affordable, and durable photocatalysts for the production of hydrogen peroxide (H 2 O 2) remained a challenge. In this study, a homojunction photocatalyst (SPGCN) is constructed between phosphorylated g-C 3 N 4 (PCN) and sulfur self-doped g-C 3 N 4 (SCN) using a simple wet impregnation method. Later, the obtained SPGCN homojunction is transformed into hydrogel beads using carboxymethyl cellulose via an effective cross-linking strategy (SPGCN/CMC). The photocatalytic beads displayed a phenomenal H 2 O 2 production of 3.5 mM under visible light illumination for 60 min. The SPGCN/CMC hydrogel beads showed a maximum reusability of 10 cycles with a decline of 1.5 mM H 2 O 2 production. The improved photocatalytic efficiency is indicated by strengthened utilization of visible light via tuning of the band gap, suppressed recombination of electron-hole pairs, and higher separation efficiency through the effective construction of Z-scheme between the phosphorylated carbon nitride and the sulfur-self-doped carbon nitride present in the SPGCN/CMC beads. The mechanistic studies affirmed the dominant role of superoxide radicals in H 2 O 2 production. The photocatalytic H 2 O 2 production followed a highly selective two-electron reduction reaction. Overall, this study highlights the efficient engineering of carbon nitride-based materials towards artificial photosynthesis. [ABSTRACT FROM AUTHOR]

This work reports the design and manufacturing of a new electrochemical sensing platform for the monitoring of prednisolone (PE) steroid in physiological fluids. To reach this, palladium (Pd) nanoparticles were successfully deposited on carbon nitride (CN) nanosheets using chemical reduction approach. The prepared CN-Pd hybrid material along with an ionic liquid (IL, 1-ethyl-3-methylimidazolium tetrafluoroborate) were employed for modification of a low expense carbon paste electrode (CPE). The CN-Pd-IL modified CPE was electrochemically characterized to ensure the electrochemical performance towards PE reduction. The important parameters affecting the performance of the PE sensor including CN-Pd dosage and pH of buffer were studied and optimized. The CN-Pd-IL modified CPE illustrated a wide linear response in a PE concentration range of 0.6 nM to 60 nM using SWV methodology. The limit of detection (based on S/N=3) was 0.1 nM at optimal conditions. The suggested PE sensor illustrated the satisfactory reproducibility and good matrix-effectless character. In addition, the CN-Pd-IL modified CPE was facilely used for the electrochemical measuring of PE in the serum samples of athletes with high recovery values (97.6%-102.4%). The proposed methodology can be employed for the sensitive, selective and fast detection of PE. [Display omitted] • Novel electrochemical sensing platform for voltammetric screening of prednisolone was proposed. • The suggested sensor illustrated the matrix-effectless character with admissible reproducibility. • The modified electrode was successfully utilized for prednisolone analysis in serum samples of athletes. [ABSTRACT FROM AUTHOR]

Indole‐3‐acetic acid (IAA) assumes a pivotal role as a phytohormone of utmost importance, intricately orchestrating the nuanced processes associated with the growth and developmental trajectories of botanical organisms. In this study, we have designed and fabricated a label‐free electrochemical impedance immunosensor for the precise detection of IAA. The detection strategy predominantly relied upon polydopamine modified carbon nitride (C3N4) nanosheets (PCN) and polyamidoamine (PAMAM) dendrimer. Through the modification with PCN and PAMAM, the electrode has increased the active area and enhanced the immobilization capacity of antibodies for IAA. The immunosensor's ability to capture IAA was significantly improved by enhancing the immunoreaction between the antibody and antigen. This enhancement led to an increased response in the electrochemical behavior of the Fe(CN)63−/4− redox probe. The impedance immunosensor developed exhibits remarkable sensitivity, exceptional selectivity, and consistent performance in the detection of IAA. This assay method, with the potential to replace antibodies, could offer an alternative approach for detecting various phytohormones. [ABSTRACT FROM AUTHOR]

Photocatalytic hydrogen evolution is an environmentally friendly means of energy generation. Although g‐C3N4 possesses fascinating features, its inherent shortcomings limit its photocatalytic applications. Therefore, modifying the intrinsic properties of g‐C3N4 and introducing cocatalysts are essential to ameliorate the photocatalytic efficiency. To achieve this, metal‐like Ti3C2Tx is integrated with crystalline g‐C3N4 via a combined salt‐assisted and freeze‐drying approach to form crystalline g‐C3N4/Ti3C2Tx (CCN/TCT) hybrids with different Ti3C2Tx loading amounts (0, 0.2, 0.3, 0.4, 0.5, 1, 5, 10 wt.%). Benefiting from the crystallization of CN, as evidenced by the XRD graph, and the marvelous conductivity of Ti3C2Tx supported by EIS plots, CCN/TCT/Pt loaded with 0.5 wt.% Ti3C2Tx displays an elevated H2 (2) should be subscripted evolution rate of 2651.93 µmol g−1 h−1 and a high apparent quantum efficiency of 7.26% (420 nm), outperforming CN/Pt, CCN/Pt, and other CCN/TCT/Pt hybrids. The enhanced performance is attributed to the synergistic effect of the highly crystalline structure of CCN that enables fleet charge transport and the efficient dual cocatalysts, Ti3C2Tx and Pt, that foster charge separation and provide plentiful active sites. This work demonstrates the potential of CCN/TCT as a promising material for hydrogen production, suggesting a significant advancement in the design of CCN heterostructures for effective photocatalytic systems. [ABSTRACT FROM AUTHOR]

Because of the low reactivity of cyclic nitrides, liquid-phase synthesis of carbon nitride introduces challenges despite its favorable potential for energy-efficient preparation and superior applications. In this study, we demonstrate a strong interaction between citric acid and melamine through experimental observation and theoretical simulation, which effectively activates melamine-condensation activity and produces carbon-rich carbon nitride nanosheets (CCN NSs) during hydrothermal reaction. Under a large specific surface area and increased light absorption, these CCN NSs demonstrate significantly enhanced photocatalytic activity in CO2 reduction, increasing the CO production rate by approximately tenfold compared with hexagonal melamine (h-Me). Moreover, the product selectivity of CCN NSs reaches up to 93.5% to generate CO from CO2. Furthermore, the annealed CCN NSs exhibit a CO conversion rate of up to 95.30 μmol/(g h), which indicates an 18-fold increase compared with traditional carbon nitride. During the CCN NS synthesis, nitrogen-doped carbon quantum dots (NDC QDs) are simultaneously produced and remain suspended in the supernatant after centrifugation. These QDs disperse well in water and exhibit excellent luminescent properties (QY = 67.2%), allowing their application in the design of selective and sensitive sensors to detect pollutants such as pesticide 2,4-dichlorophenol with a detection limit of as low as 0.04 µmol/L. Notably, the simultaneous synthesis of CCN NSs and NDC QDs provides a cost-effective and highly efficient process, yielding products with superior capabilities for catalytic conversion of CO2 and pollutant detection, respectively. [ABSTRACT FROM AUTHOR]

In recent years, the management of antibiotics has garnered significant attention due to their unique ecological effects, such as inducing antibiotic resistance. Traditional water treatment methods struggle to effectively eliminate trace amounts of antibiotics, posing threats to both ecological environment and drinking water safety. Photocatalysis technology, with its advantages of mild reaction conditions, low cost, high degradation efficiency, and thorough removal, holds great potential for the degradation of antibiotics. Carbon nitride (CN) materials, serving as non-metallic photocatalysts responsive to visible light, have been a focal point in photocatalysis research. However, pure CN suffers from issues like insufficient sunlight absorption, small surface area, and rapid recombination of photogenerated electron-hole pairs, resulting in low photocatalytic activity. Modification strategies such as element doping and the formation of heterojunctions with other materials can effectively enhance the photocatalytic performance of CN, improving its light absorption, promoting the separation and transfer of photogenerated charge carriers. Here, we reviewed the significant progress in the design strategies and mechanisms of charge carrier separation/transfer in CN-modified photocatalysts, summarized their application in the photocatalytic degradation of antibiotics, and prospected the directions for developing advanced CN-modified photocatalysts. [ABSTRACT FROM AUTHOR]

Water molecules, which act as both solvent and reactant, play critical roles in photocatalytic reactions for methanol conversion. However, the influence of water on the adsorption of methanol and desorption of liquid products, which are two essential steps that control the performance in photocatalysis, has been well under‐explored. Herein, we reveal the role of water in heterogeneous photocatalytic processes of methanol conversion on the platinized carbon nitride (Pt/C3N4) model photocatalyst. In situ spectroscopy techniques, isotope effects, and computational calculations demonstrate that water shows adverse effects on the adsorption of methanol molecules and desorption processes of methanol oxidation products on the surface of Pt/C3N4, significantly altering the reaction pathways in photocatalytic methanol conversion process. Guided by these discoveries, a photothermal‐assisted photocatalytic system is designed to achieve a high solar‐to‐hydrogen (STH) conversion efficiency of 2.3 %, which is among the highest values reported. This work highlights the important roles of solvents in controlling the adsorption/desorption behaviours of liquid‐phase heterogeneous catalysis. [ABSTRACT FROM AUTHOR]

A novel and efficient approach for the synthesis of α, β‐unsaturated sulfones through heterogeneous photocatalyzed C−S coupling reactions have been developed. The use of molten‐salt method derived carbon nitride (MCN), a transition metal‐free polymeric photocatalyst, combined with enhanced crystallinity and potassium iodide as an additive, effectively modulates photogenerated reactive redox species, markedly increasing the overall reaction selectivity. This method achieves the shortest reaction time (2 h) with high yield (up to 95 %) among the reported heterogeneous catalytic C−S bond formation reactions, matching the efficiency of the homogeneous photocatalysts. Furthermore, the application to challenging alkyne substrates has been demonstrated, underscoring the potential for a broad range of applications in pharmaceutical research and synthetic chemistry. [ABSTRACT FROM AUTHOR]

Dispersible and functionalizable long persistent luminescent (LPL) materials are highly desired for flexible use of LPL in various fields. However, synthesizing metal‐free LPL systems with stable long‐lived intermediates and reactive surface groups, which are key requirements for robust LPL and the ability to be functionalized, has proven to be challenging. Herein, the microwave‐assisted preparation of carbon dots (CDs)‐based LPL materials is demonstrated with abundant surface amino groups via in situ embedding of CDs into carbon nitrides (CNs). The incorporation of CDs leads to the formation of deep traps and promotes exciton transmission between CDs and trap states, contributing to the generation of LPL. By varying the embedded CDs, tunable LPL ranging from blue to yellow can be achieved, with a duration exceeding 10 min. Due to the covalent bonding between CDs and CNs, the materials (named CDs@CNs) exhibit robust LPL under ambient conditions and evenly dispersed in water through ultrasonic treatment. Furthermore, the surface amino groups serve as sites for further modification, allowing for on‐demand performance design and control, such as adjustable hydrophilicity–hydrophobicity for various applications. This work provides new insights into designing superior flexible CDs‐based LPL materials and expanding the domain of metal‐free LPL materials. [ABSTRACT FROM AUTHOR]

The food industry is responsible for generating considerable amounts of waste, such as excess fruits and leftover sugars, which contribute to resource depletion and pose environmental challenges. This research delves into the application of gold-modified graphitic carbon nitride nanosheets (Au/CN) as a potent catalyst for the transformation of these food wastes into H2 via piezoelectric reforming during sonication. Au/CN demonstrated a superior rate of H2 evolution compared to pristine g-C3N4 (i.e., 1533.3 vs. 364.9 µmol/g/h) and it maintained its efficiency through multiple cycles of use. The catalytic activity was found to be optimal at a neutral pH level and with increased sugar concentrations. The enhanced catalytic performance of Au/CN was ascribed to the efficient segregation of charge carriers as well as the reduced charge transfer distance. This study underscores the viability of using Au/CN as a means for converting food wastes into a sustainable source of H2 energy. [ABSTRACT FROM AUTHOR]

Solar‐driven synthesis of hydrogen peroxide (H2O2) through photocatalysis stands out as a promising avenue for sustainable energy generation, marked by environmental friendliness and industrial feasibility. However, the inherent limitations of carbon nitride (CN) in photocatalytic H2O2 production significantly impede their performance. Herein, a novel 0D/2D carbon dots‐modified CN nanosheet heterojunction (CDsMCN) is introduced, synthesized through a hydrothermal‐calcination tandem strategy induced by CDs derived from melamine. This innovative technique enhances the n→π* electronic transition in CDsMCN, accelerating the separation efficiency of electron‐hole pairs, boosting oxygen adsorption, and promoting a highly selective 2e− ORR. Comparative to pristine CN, CDs10MCN exhibited a remarkable tenfold increase in H2O2 production, reaching an impressive 1.48 mmol L−1. Furthermore, CDs10MCN demonstrates exceptional stability, maintaining its catalytic efficiency at the initial level over four consecutive cycles. The notable achievement of a molar selectivity of H2O2 ≈80% at an onset potential of 0.6 V (vs RHE) underscores its exceptional ability to produce the desired product selectively. Advanced in situ characterization together with DFT calculations revealed that the ultrathin CDs10MCN nanosheet heterojunction with enhanced n→π* electronic transition improves its optical properties, reduces bandgap, facilitates fast charge migration, and increases photocatalytic H2O2 performance, thereby serving as a promising candidate for advanced catalytic applications. [ABSTRACT FROM AUTHOR]