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For environmental applications, it is crucial to rationally design and synthesize photocatalysts with positive exciton splitting and interfacial charge transfer. Here, a novel Ag-bridged dual Z-scheme Ag/g-C3N4/CoNi-LDH plasmonic heterojunction was successfully synthesized using a simple method, with the goal of overcoming the common drawbacks of traditional photocatalysts such as weak photoresponsivity, rapid combination of photo-generated carriers, and unstable structure. These materials were characterized by XRD, FT-IR, SEM, TEM UV-Vis/DRS, and XPS to verify the structure and stability of the heterostructure. The pristine LDH, g-C3N4, and Ag/g-C3N4/CoNi-LDH composite were investigated as photocatalysts for water remediation, an environmentally motivated process. Specifically, the photocatalytic degradation of tetracycline was studied as a model reaction. The performance of the supports and composite catalyst were determined by evaluating both the degradation and adsorption phenomenon. The influence of several experimental parameters such as catalyst loading, pH, and tetracycline concentration were evaluated. The current study provides important data for water treatment and similar environmental protection applications.

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A novel Fe-g-C3N4/Bi2MoO6 (FCNB) Z-scheme heterojunction enriched with oxygen vacancy is constructed and employed for the photo-Fenton degradation of tetracycline (TC). The 2% FCNB demonstrates prominent catalytic performance and mineralization efficiency for TC wastewater, showing activity of 8.20 times greater than that of pure photocatalytic technology. Density-functional theory (DFT) calculations and degradation experiments confirm that the formation of Fe-N4 sites induces spin-polarization in the material, and the difference in Fermi energy levels results in the formation of built-in electric field at the contact interface, which facilitates the continuous generation and migration of photogenerated carriers to address the issue of insufficient cycling power of Fe (III)/Fe (II).The reactive radicals persistently target the extremely reactive sites anticipated by the Fukui function, causing the mineralization of TC molecules into "non-toxic" compounds through processes of hydroxylation, demethylation, and deamidation. This work holds significant importance in the domain of eliminating organic pollutants from water.

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Ciprofloxacin antibiotic (CP) is one of the antibiotics with broad-spectrum antimicrobial activity that has the highest rate of antibiotic resistance. This antibiotic undergoes incomplete metabolism within the human body and is excreted into the water, resulting in its hazardous biological and ecotoxicological effects. In this study, a novel photocatalyst, comprised of graphitic carbon nitride (g-CN) and Tetrakis(acetonitrile)copper(I)hexafluorophosphate ([(CH3CN)4Cu]PF6), denoted as CuPF6/g-CN, was employed for the degradation of ciprofloxacin under visible-light irradiation. The Cu complex, functioning as a co-catalyst, assumes a crucial role in facilitating the efficient separation of photogenerated charges and exhibiting high absorption in the visible-light region. More surprisingly, CuPF6/g-CN does surpass by up to 6 times the behavior reached with bare g-CN. The experimental findings indicated that the optimal degradation of ciprofloxacin (CP) occurred after 50 min when using a concentration of 20 mg L-1 CP and a concentration of 0.05 g/L CuPF6/g-CN, under a pH of 8. This research offers valuable insights into the advancement of cost-effective co-catalysts that enhance the photocatalytic capabilities of established photocatalysts. It contributes to improving the overall performance and efficiency of these photocatalytic systems.

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Graphitic carbon nitride (g-C3N4, CN) has emerged as a promising photocatalytic material due to its inherent stability, antibacterial properties, and eco-friendliness. However, its tendency to aggregate and limited dispersion hinder its efficacy in practical antibacterial applications. To address these limitations, this study focuses on developing a composite hydrogel coating, in which sodium alginate (SA) molecules interact electrostatically and through hydrogen bonding to anchor CN, thereby significantly improving its dispersion. The optimal CN loading of 35% results in a hydrogel with a tensile strength of 120 MPa and an antibacterial rate of 99.87% within 6 h. The enhanced mechanical properties are attributed to hydrogen bonding between the -NH2 groups of CN and the -OH groups of SA, while the -OH groups of SA facilitate the attraction of photogenerated holes from CN, promoting carrier transfer and separation, thereby strengthening the antibacterial action. Moreover, the hydrogel coating exhibits excellent antibacterial and corrosion resistance capabilities against Pseudomonas aeruginosa on 316L stainless steel (316L SS), laying the foundation for advanced antimicrobial and anticorrosion hydrogel systems.

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Graphite carbon nitride (g-C3N4) is a two-dimensional nano-sheet with electronic properties, which shows unique characteristics with high chemical and thermal stability in its structure. The functionalization of these compounds through covalent bonding is an important step towards significantly improving their properties and capabilities. To achieve this goal, a novel strategy for the covalent functionalization of Fe3O4@g-C3N4 with thiamine hydrochloride (vitamin B1) via cyanuric chloride (TCT), which is a divalent covalent linker, was presented. The efficiency of Fe3O4@gC3N4@Thiamine as a heterogeneous organic catalyst in the synthesis of spirooxindole-pyran derivatives and 2-amino-4H-pyran under solvent-free conditions was evaluated and the yields of high-purity products were presented. In addition, easy recycling and reuse for seven consecutive cycles without significant reduction in catalytic activity are other features of this catalyst. Moreover, the performance of the prepared sorbent in the microextraction technique (herein, magnetic solid phase extraction) was studied. The tebuconazole was selected as the target analyte. The target analyte was extracted and determined by HPLC-UV. Under the optimum condition, the linear range of the method (LDR) was estimated in the range of 0.2-100 µg L-1 (the coefficient of determination of 0.9962 for tebuconazole). The detection limit (LOD) of the method for tebuconazole was calculated to be 0.05 µg L-1. The limit of quantification (LOQ) of the method was also estimated to be 0.16 µg L-1. In order to check the precision of the proposed method, the intra-day and inter-day relative standard deviations (RSD%) were calculated, which were in the range of 1.5- 2.8%. The method was used for the successful extraction and determination of tebuconazole in tomato, cucumber, and carrot samples.

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Graphitic carbon nitride is a semiconducting material of a graphite-like 2D layered structure. It is well known for its photocatalytic properties, which can be exploited for solar-light-driven water splitting and degradation of organic pollutants. Here, we report its capabilities of catalyzing the reduction of the azo bond by hydrazine to two amines under visible light. This photocatalytic reaction provides a novel, appealing way to reduce azo dye wastes as pollutants other than degradation. With this method, the azo dye wastes can be photochemically converted to amines, which can be used as precursors for new azo dyes.

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The MnO2/CN S-scheme heterojunctions were prepared using the hydrothermal method, which significantly promoted periodate (PI) activation for the TC removal. Notably, the MnO2/CN-0.1 achieved a TC removal rate of 79.7 % within 25 min in the PI/Vis system, which was 1.39 and 3.68 times that of MnO2 and g-C3N4, respectively. The improved TC degradation performance could be attributed to the synergetic effect of photothermal effect of MnO2 and the S-scheme heterojunction. On the basis of the infrared thermography images, the photothermal properties of MnO2 could increase temperatures of the reaction system, leading to the promotion of the PI activation. The formation of the MnO2/CN S-scheme not only effectively suppressed charge recombination, but also facilitated the Mn(IV)/Mn(III) redox cycle within the reaction. Under different pH and anion conditions, the MnO2/CN-0.1/PI system exhibited excellent capability in TC removal. Additionally, the toxicity of the degraded solution was evaluated based on the LC-MS test results and the growth experiment of Mung bean seeds. This work put forward an efficient approach on S-scheme photothermal catalysts to achieve efficient utilization of PI on TC degradation, which demonstrates a promising method for photothermal assistance PI activation to remediate the water environment efficiently.

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Photocatalytic reforming of ethanol provides an effective way to produce hydrogen energy using natural and nontoxic ethanol as raw material. Developing highly efficient catalysts is central to this field. Although traditional semiconductor/metal heterostructures (e.g., Rh/TiO2) can result in relatively high catalyst performance by promoting the separation of photoinduced hot carriers, it will still be highly promising to further improve the catalytic performance via a cost-effective and convenient method. In this study, we developed a highly efficient photocatalyst for ethanol reformation by preparing a ternary composite structure of Rh/TiO2/g-C3N4. Hydrogen is the main product, and the reaction rate could reach up to 27.5 mmol g-1 h-1, which is ∼1.41-fold higher than that of Rh/TiO2. The catalytic performance here is highly dependent on the wavelength of the light illumination. Moreover, the photocatalytic reforming of ethanol and production of hydrogen were also dependent on the Rh loading and g-C3N4:TiO2 ratio in Rh/TiO2/g-C3N4 composites as well as the ethanol content in the reaction system. The mechanism of the enhanced hydrogen production in Rh/TiO2/g-C3N4 is determined as the improvement in the separation of photoinduced hot carriers. This work provides an effective photocatalyst for ethanol reforming, largely expanding its application in the field of renewable energy and interface science.

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Based on sonochemistry, green synthesis methods play an important role in the development of nanomaterials. In this work, a novel chitosan modified MnMoO4/g-C3N4 (MnMoO4/g-C3N4/CHIT) was developed using ultrasonic cell disruptor (500 W, 30 kHz) for ultra-sensitive electrochemical detection of tinidazole (TNZ) in the environment. The morphology and surface properties of the synthesized MnMoO4/g-C3N4/CHIT electrode were characterized using X-ray diffraction (XRD), fourier transform infrared spectroscopy (FT-IR), scanning electron microscope (SEM) and transmission electron microscope (TEM). Cyclic voltammetry (CV) and differential pulse voltammetry (DPV) techniques were utilized to assess the electrochemical performance of TNZ. The results indicate that the electrochemical detection performance of TNZ is highly efficient, with a detection limit (LOD) of 3.78 nM, sensitivity of 1.320 µA·µM-1·cm-2, and a detection range of 0.1-200 µM. Additionally, the prepared electrode exhibits excellent selectivity, desirable anti-interference capability, and decent stability. MnMoO4/g-C3N4/CHIT can be successfully employed to detect TNZ in both the Songhua River and tap water, achieving good recovery rates within the range of 93.0 % to 106.6 %. Consequently, MnMoO4/g-C3N4/CHIT's simple synthesis might provide a new electrode for the sensitive, repeatable, and selective measurement of TNZ in real-time applications. Using the MnMoO4/g-C3N4/CHIT electrode can effectively monitor and detect the concentration of TNZ in environmental water, guiding the sewage treatment process and reducing the pollution level of antibiotics in the water environment.

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Photocatalytic wastewater purification is essential for environmental remediation, but rapid carrier recombination and limited oxidative capacity hinder progress. This study proposes an innovative strategy by integrating homogeneous and heterogeneous electron acceptors into a g-C3N4-based photocatalytic system, significantly enhancing the multipath utilization of photogenerated electrons. A novel Fe3O4@P-C3N4 was developed to activate an advanced peroxymonosulfate-assisted photocatalysis (PAP) system, achieving complete degradation and significant mineralization of tetracycline (TC) in real water environments, outperforming others reported in the last five years. Phytic acid, as a key precursor, modifies the hollow tubular morphology and introduces phosphorus (P) heteroatoms as electronic trapping centers, enhancing the visible light response and carrier separation, thereby promoting the Fe2+/Fe3+ cycle and the formation of reactive species. Density functional theory (DFT) calculations pinpointed TC's vulnerable sites and synergically identified reactive species, revealing almost non-toxic degradation processes. Moreover, the recyclable magnetic Fe3O4@P-C3N4/PAP system demonstrates practical application potential and leaching stability in cyclic and continuous testing. This study offers unique insights into the strategic design of photocatalysts and catalytic environments, potentially advancing practical wastewater remediation.

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The selective cleavage of lignin C-C bonds is a highly sought-after process with the goal of obtaining low-molecular-weight aromatic chemicals from renewable resources. However, it remains a challenging task to achieve under mild conditions. Photocatalysis is a potentially promising approach to address this issue, but the development of efficient photocatalysts is still in progress. In this study, we introduce the heterostructured TiO2@g-C3N4 photocatalyst for the development of a visible light photocatalytic procedure for the selective cleavage of lignin C-C bonds under mild conditions. The photocatalyst displays favourable visible light absorption, efficient charge separation efficiency, and promising reusability. A typical ß-O-4 dimer model, 2-phenoxy-1-phenylethanol, was effectively (96.0% conversion) and selectively (95.0 selectivity) cleaved under visible light at ambient conditions. This photocatalytic procedure was also effective when subjected to solar irradiation or other lignin dimer models with ß-O-4 or ß-1 linkages. This reaction occurred through a Cß-centred radical intermediate and a six-membered transition state with photogenerated holes as the primary active species. The Cα-OH oxidative dehydrogenation of the substrate could also take place but was a relatively minor route. This study provides a new photocatalytic procedure for visible-light-driven lignin valorisation and sheds light on the design of high-performance nanocomposite photocatalysts for C-C bond cleavage. .

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An environmentally friendly, versatile multicomponent reaction for synthesizing isoxazol-5-one and pyrazol-3-one derivatives has been developed, utilizing a freshly prepared g-C3N4·OH nanocomposite as a highly efficient catalyst at room temperature in aqueous environment. This innovative approach yielded all the desired products with exceptionally high yields and concise reaction durations. The catalyst was well characterized by FT-IR, XRD, SEM, EDAX, and TGA/DTA studies. Notably, the catalyst demonstrated outstanding recyclability, maintaining its catalytic efficacy over six consecutive cycles without any loss. The sustainability of this methodology was assessed through various eco-friendly parameters, including E-factor and eco-score, confirming its viability as a green synthetic route in organic chemistry. Additionally, the gram-scale synthesis verifies its potential for industrial applications. The ten synthesized compounds were also analyzed via a PASS online tool to check their several pharmacological activities. The study is complemented by in silico molecular docking, pharmacokinetics, and molecular dynamics simulation studies. These studies discover 5D as a potential candidate for drug development, supported by its favorable drug-like properties, ADMET studies, docking interaction, and stable behavior in the protein binding cavity.

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Currently, one of the primary challenges that human society must overcome is the task of decreasing the amount of energy used and the adverse effects that it has on the environment. The daily increase in liquid waste (comprising organic pollutants) is a direct result of the creation and expansion of new companies, causing significant environmental disruption. Water contamination is attributed to several industries such as textile, chemical, poultry, dairy, and pharmaceutical. In this study, we present the successful degradation of methylene blue dye using g-C3N4 (GCN) mixed with WO3 and V2O5 composites (GCN/WO3/V2O5 ternary composite) as a photocatalyst, prepared by a simple mechanochemistry method. The GCN/WO3/V2O5 ternary composite revealed a notable enhancement in photocatalytic performance, achieving around 97% degradation of aqueous methylene blue (MB). This performance surpasses that of the individual photocatalysts, namely pure GCN, GCN/WO3, and GCN/V2O5 composites. Furthermore, the GCN/WO3/V2O5 ternary composite exhibited exceptional stability even after undergoing five consecutive cycles. The exceptional photocatalytic activity of the GCN/WO3/V2O5 ternary composite can be ascribed to the synergistic effect of metal-free GCN and metal oxides, resulting in the alteration of the band gap and suppression of charge recombination in the ternary photocatalyst. This study offers a better platform for understanding the characteristics of materials and their photocatalytic performance under visible light conditions.

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Designing efficient dual-functional catalysts for photocatalytic oxygen reduction to produce hydrogen peroxide (H2O2) and photodegradation of dye pollutants is challenging. In this work, we designed and fabricated an S-scheme heterojunction (g-C3N4/ZnO composite photocatalyst) via one-pot calcination of a mixture of ZIF-8 and melamine in the KCl/LiCl molten salt medium. The KCN/ZnO composite produced 4.72 mM of H2O2 within 90 min under illumination (with AM 1.5 filter), which is almost 1.3 and 7.8 times than that produced over KCN and ZnO, respectively. Simultaneously, the KCN/ZnO also showed excellent photodegradation performance for the dye pollutants (Rhodamine B, RhB), with a removal rate of 92 % within 2 h. The apparent degradation rate constant of RhB over KCN/ZnO was approximately 5-8 times that of KCN and ZnO. In the photocatalytic process, photo-generated holes and superoxide radicals are the main active species. Oxygen (O2) was mainly reduced to produce H2O2 via a two-electron (2e-) pathway with superoxide radicals as intermediates and the 2e- oxygen reduction reaction selectivity of KCN/ZnO was close to 69.82 %. Photo-generated holes are mainly responsible for the degradation of RhB. Compared with pure KCN and ZnO, the enhanced photocatalytic activity of the KCN/ZnO composite is mainly attributed to the following aspects: 1) larger specific surface area and pore volume is beneficial to expose more active sites; 2) stronger light harvesting ability and red-shifted absorption edge bestow the compound a stronger light utilization efficiency; 3) the construction of S-scheme heterostructure between KCN and ZnO improve the photogenerated electron-hole pairs separation ability and bestow photogenerated carriers a higher redox potential.

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BACKGROUND: There is widespread interest in the design of portable electrochemical sensors for the selective monitoring of biomolecules. Dopamine (DA) is one of the neurotransmitter molecules that play a key role in the monitoring of some neuronal disorders such as Alzheimer's and Parkinson's diseases. Facile synthesis of the highly active surface interface to design a portable electrochemical sensor for the sensitive and selective monitoring of biomolecules (i.e., DA) in its resources such as human fluids is highly required. RESULTS: The designed sensor is based on a three-dimensional phosphorous and sulfur resembling a g-C3N4 hornet's nest (3D-PS-doped CNHN). The morphological structure of 3D-PS-doped CNHN features multi-open gates and numerous vacant voids, presenting a novel design reminiscent of a hornet's nest. The outer surface exhibits a heterogeneous structure with a wave orientation and rough surface texture. Each gate structure takes on a hexagonal shape with a wall size of approximately 100 nm. These structural characteristics, including high surface area and hierarchical design, facilitate the diffusion of electrolytes and enhance the binding and high loading of DA molecules on both inner and outer surfaces. The multifunctional nature of g-C3N4, incorporating phosphorous and sulfur atoms, contributes to a versatile surface that improves DA binding. Additionally, the phosphate and sulfate groups' functionalities enhance sensing properties, thereby outlining selectivity. The resulting portable 3D-PS-doped CNHN sensor demonstrates high sensitivity with a low limit of detection (7.8 nM) and a broad linear range spanning from 10 to 500 nM. SIGNIFICANCE: The portable DA sensor based on the 3D-PS-doped CNHN/SPCE exhibits excellent recovery of DA molecules in human fluids, such as human serum and urine samples, demonstrating high stability and good reproducibility. The designed portable DA sensor could find utility in the detection of DA in clinical samples, showcasing its potential for practical applications in medical settings.

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The adoption of photothermal synergistic catalysis for cyclohexane oxidation can balance the advantages of high conversion of thermal catalysis and high selectivity of photocatalytic technology to achieve better catalytic performance. Here, we prepared functional carbon nitride (BCA-CN) by self-assembly strategy of ionic liquid [Bmim]CA (1-Butyl-3-methylimidazole citrate) with melamine and cyanuric acid utilizing abundant elements and anionic/cationic hydrogen bonding interactions. The introduction of [Bmim]CA embeds C-C (carbon and carbon band) and C-O-C (ether bond) structures into graphitic carbon nitride (g-C3N4) framework, significantly improving light absorption capacity and migration of photo generated charge carriers. Compared to g-C3N4, both BCA-CN increases cyclohexane conversion and KA oil (the mixture of cyclohexanol and cyclohexanone) selectivity by 1.3 times under photothermal catalysis. The surface reactions are facilitated by changing adsorption sites of cyclohexane to increase adsorption energy and obtaining more hydroxyl radicals and superoxide radicals. Furthermore, the enhanced selectivity is attributed to the difficulty in generating cyclohexanone radicals. This work offers the reference scheme for the development of efficient photothermal catalysts in the selective oxidation of cyclohexane.

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Photocatalysis has been proven to be an excellent technology for treating antibiotic wastewater, but the impact of each active species involved in the process on antibiotic degradation is still unclear. Therefore, the S-scheme heterojunction photocatalyst Ti3C2/g-C3N4/TiO2 was successfully synthesized using melamine and Ti3C2 as precursors by a one-step calcination method using mechanical stirring and ultrasound assistance. Its formation mechanism was studied in detail through multiple characterizations and work function calculations. The heterojunction photocatalyst not only enabled it to retain active species with strong oxidation and reduction abilities, but also significantly promoted the separation and transfer of photo-generated carriers, exhibiting an excellent degradation efficiency of 94.19 % for tetracycline (TC) within 120 min. Importantly, the priority attack sites, degradation pathways, degradation intermediates and their ecological toxicity of TC under the action of each single active species (·O2-, h+, ·OH) were first positively explored and evaluated through design experiments, Fukui function theory calculations, HPLC-MS, Escherichia coli toxicity experiments, and ECOSAR program. The results indicated that the preferred attack sites of ·O2- on TC were O20, C7, C11, O21, and N25 atoms with high f+ value. The toxicity of intermediates produced by ·O2- was also lower than those produced by h+ and ·OH.

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CO2 reduction photocatalysts are favorable for obtaining renewable energy. Enriched active sites and effective photogenerated-carriers separation are keys for improving CO2 photo-reduction. A thulium (Tm) single atom tailoring strategy introducing carbon vacancies in porous tubular graphitic carbon nitride (g-C3N4) surpassing the ever-reported g-C3N4 based photocatalysts, with 199.47 µmol g-1 h-1 CO yield, 96.8% CO selectivity, 0.84% apparent quantum efficiency and excellent photocatalytic stability, is implemented in this work. Results revealed that in-plane Tm sites and interlayer-bridged Tm-N charge transfer channels significantly enhanced the aggregation/transfer of photogenerated electrons thus promoting CO2 adsorption/activation and contributing to *COOH intermediates formation. Meanwhile, Tm atoms and carbon vacancies both benefit for rich active sites and enhanced photogenerated-charge separation, thus optimizing reaction pathway and leading to excellent CO2 photo-reduction. This work not only provides guidelines for CO2 photo-reduction catalysts design but also offers mechanistic insights into single-atom based photocatalysts for solar fuel production.

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Graphite carbon nitride (g-C3N4) is a two-dimensional conjugated polymer with a unique energy band structure similar to graphene. Due to its outstanding analytical advantages, such as relatively small band gap (2.7 eV), low-cost synthesis, high thermal stability, excellent photocatalytic ability, and good biocompatibility, g-C3N4 has attracted the interest of researchers and industry, especially in the medical field. This paper summarizes the latest research on g-C3N4-based composites in various biomedical applications, including therapy, diagnostic imaging, biosensors, antibacterial, and wearable devices. In addition, the application prospects and possible challenges of g-C3N4 in nanomedicine are also discussed in detail. This review is expected to inspire emerging biomedical applications based on g-C3N4.

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The occurrence of xenobiotic pollutants in the aquatic environment troubling the present and future generation. Persistent Organic Pollutants (POPs) is one such class of xenobiotic that was dominant in that category. In the present paper, a competent visible light driven heterojunction photocatalyst combining Bismuth niobate and g-C3N4 was developed for the effective removal of Bisphenol A (BPA), a notable POP. Before constructing the heterostructure the calcination temperature for bismuth niobate synthesis was optimised for achieving most proficient photocatalysis. A phase change in the crystal structure of bismuth niobate was apparent. The Bi3NbO7 at 300-500 °C transformed to Bi5Nb3O15 at 600-700 °C and to orthorhombic BiNbO4 at 900 °C as the temperature was enhanced. With the increment in the temperature the light absorbance of the materials enhanced in UV and reduced in visible light. Thus, the bismuth niobate obtained by calcining at 500 °C demonstrated highest BPA removal under sunlight was chosen for heterojunction construction. After the heterojunction construction with g-C3N4 the crystal lattice strain was observed to be reduced for all composites, and a greater mobility of charge carriers was observed within the composite. The presence of either of the materials resulted in a different band structure and thus Type II and Z-scheme pathway was inferred. A commendable photocatalytic activity was observed for B1.5G and BG1.5 under sunlight and LED light respectively. Hight amount of g-C3N4 in the BG1.5 resulted in maximum absorbance in LED light. Superoxide radicals (*O2-) radicals were observed as major radicals for B1.5G composite, whereas both *O2- and holes (h+) were the major radicals in case of BG1.5.